Initial import of zefyr package

packages/zefyr/.gitignore

@@ -0,0 +1,15 @@
+.DS_Store
+.atom/
+.idea
+.vscode/
+*.code-workspace
+.packages
+.pub/
+packages
+pubspec.lock
+coverage/
+ios/Flutter/Generated.xcconfig
+.flutter-plugins
+example/ios/.symlinks
+example/ios/Flutter/Generated.xcconfig
+doc/api/

packages/zefyr/AUTHORS

@@ -0,0 +1,8 @@
+# Below is a list of people and organizations that have contributed
+# to the Zefyr project. Names should be added to the list like so:
+#
+#   Name/Organization <email address>
+
+Memspace <team@memspace.app>
+
+Anatoly Pulyaevskiy <anatoly.pulyaevskiy@gmail.com>

packages/zefyr/CHANGELOG.md

@@ -0,0 +1,3 @@
+## [0.1.0] - Add release date
+
+*  Initial release.

packages/zefyr/LICENSE

@@ -0,0 +1,23 @@
+Copyright 2018, the Zefyr project authors. All rights reserved.
+
+Redistribution and use in source and binary forms, with or without
+modification, are permitted provided that the following conditions are met:
+    * Redistributions of source code must retain the above copyright
+      notice, this list of conditions and the following disclaimer.
+    * Redistributions in binary form must reproduce the above copyright
+      notice, this list of conditions and the following disclaimer in the
+      documentation and/or other materials provided with the distribution.
+    * Neither the name of the <organization> nor the
+      names of its contributors may be used to endorse or promote products
+      derived from this software without specific prior written permission.
+
+THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+DISCLAIMED. IN NO EVENT SHALL <COPYRIGHT HOLDER> BE LIABLE FOR ANY
+DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+(INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+(INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

packages/zefyr/README.md

@@ -0,0 +1,59 @@
+# Zefyr [![Build Status](https://travis-ci.org/memspace/zefyr.svg?branch=master)](https://travis-ci.org/memspace/zefyr)
+
+*Soft and gentle rich text editing for Flutter applications.*
+
+Zefyr is currently in **early preview**. If you have a feature
+request or found a bug, please file it at the [issue tracker][].
+
+[issue tracker]: https://github.com/memspace/zefyr/issues
+
+### Documentation
+
+* [Quick Start][quick_start]
+* [Data Format and Document Model][data_and_document]
+* [Style attributes][attributes]
+* [Heuristic rules][heuristics]
+* [FAQ][faq]
+
+[quick_start]: /doc/quick_start.md
+[data_and_document]: /doc/data_and_document.md
+[attributes]: /doc/attributes.md
+[heuristics]: /doc/heuristics.md
+[faq]: /doc/faq.md
+
+## Clean and modern look
+
+Zefyr's rich text editor is built with simplicity and flexibility in
+mind. It provides clean interface for distraction-free editing. Think
+Medium.com-like experience.
+
+[screenshot]
+
+## Markdown-style semantics
+
+Ever needed to have a heading line inside of a quote block, like in
+this Markdown block:
+
+> ### I'm a Markdown heading
+> And I'm a regular paragraph
+
+Zefyr can deliver exactly that:
+
+[screenshot]
+
+> Nested blocks support (e.g. lists inside quote blocks) is planned.
+
+## Collaborative editing built-in
+
+Zefyr's document model uses data format compatible with
+[Operational Transformation][ot] which makes it possible to use for
+collaborative editing use cases. Or whenever there is a need for
+conflict-free resolution of changes.
+
+> Zefyr editor uses Quill.js **Delta** as underlying data format. Read
+> more about Zefyr and Deltas in our [documentation][data_and_document].
+> Make sure to checkout [official documentation][delta] for Delta format
+> as well.
+
+[delta]: https://quilljs.com/docs/delta/
+[ot]: https://en.wikipedia.org/wiki/Operational_transformation

packages/zefyr/analysis_options.yaml

@@ -0,0 +1,20 @@
+analyzer:
+  strong-mode: true
+  language:
+    enableSuperMixins: true
+
+# Lint rules and documentation, see http://dart-lang.github.io/linter/lints
+linter:
+  rules:
+    # - avoid_init_to_null
+    - cancel_subscriptions
+    - close_sinks
+    - directives_ordering
+    - hash_and_equals
+    - iterable_contains_unrelated_type
+    - list_remove_unrelated_type
+    - prefer_final_fields
+    - prefer_is_not_empty
+    - test_types_in_equals
+    - unrelated_type_equality_checks
+    - valid_regexps

packages/zefyr/example/.gitignore

@@ -0,0 +1,9 @@
+.DS_Store
+.dart_tool/
+
+.packages
+.pub/
+
+build/
+
+.flutter-plugins

packages/zefyr/example/.metadata

@@ -0,0 +1,8 @@
+# This file tracks properties of this Flutter project.
+# Used by Flutter tool to assess capabilities and perform upgrades etc.
+#
+# This file should be version controlled and should not be manually edited.
+
+version:
+  revision: 3351423a42b05e3e099a9227b1f52d24c0306d67
+  channel: master

packages/zefyr/example/README.md

@@ -0,0 +1,8 @@
+# example
+
+A new Flutter project.
+
+## Getting Started
+
+For help getting started with Flutter, view our online
+[documentation](https://flutter.io/).

packages/zefyr/example/android/.gitignore

@@ -0,0 +1,10 @@
+*.iml
+*.class
+.gradle
+/local.properties
+/.idea/workspace.xml
+/.idea/libraries
+.DS_Store
+/build
+/captures
+GeneratedPluginRegistrant.java

packages/zefyr/example/android/app/build.gradle

@@ -0,0 +1,61 @@
+def localProperties = new Properties()
+def localPropertiesFile = rootProject.file('local.properties')
+if (localPropertiesFile.exists()) {
+    localPropertiesFile.withReader('UTF-8') { reader ->
+        localProperties.load(reader)
+    }
+}
+
+def flutterRoot = localProperties.getProperty('flutter.sdk')
+if (flutterRoot == null) {
+    throw new GradleException("Flutter SDK not found. Define location with flutter.sdk in the local.properties file.")
+}
+
+def flutterVersionCode = localProperties.getProperty('flutter.versionCode')
+if (flutterVersionCode == null) {
+    throw new GradleException("versionCode not found. Define flutter.versionCode in the local.properties file.")
+}
+
+def flutterVersionName = localProperties.getProperty('flutter.versionName')
+if (flutterVersionName == null) {
+    throw new GradleException("versionName not found. Define flutter.versionName in the local.properties file.")
+}
+
+apply plugin: 'com.android.application'
+apply from: "$flutterRoot/packages/flutter_tools/gradle/flutter.gradle"
+
+android {
+    compileSdkVersion 27
+
+    lintOptions {
+        disable 'InvalidPackage'
+    }
+
+    defaultConfig {
+        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
+        applicationId "com.zefyr.example"
+        minSdkVersion 16
+        targetSdkVersion 27
+        versionCode flutterVersionCode.toInteger()
+        versionName flutterVersionName
+        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
+    }
+
+    buildTypes {
+        release {
+            // TODO: Add your own signing config for the release build.
+            // Signing with the debug keys for now, so `flutter run --release` works.
+            signingConfig signingConfigs.debug
+        }
+    }
+}
+
+flutter {
+    source '../..'
+}
+
+dependencies {
+    testImplementation 'junit:junit:4.12'
+    androidTestImplementation 'com.android.support.test:runner:1.0.2'
+    androidTestImplementation 'com.android.support.test.espresso:espresso-core:3.0.2'
+}

packages/zefyr/example/android/app/src/main/AndroidManifest.xml

@@ -0,0 +1,39 @@
+<manifest xmlns:android="http://schemas.android.com/apk/res/android"
+    package="com.zefyr.example">
+
+    <!-- The INTERNET permission is required for development. Specifically,
+         flutter needs it to communicate with the running application
+         to allow setting breakpoints, to provide hot reload, etc.
+    -->
+    <uses-permission android:name="android.permission.INTERNET"/>
+
+    <!-- io.flutter.app.FlutterApplication is an android.app.Application that
+         calls FlutterMain.startInitialization(this); in its onCreate method.
+         In most cases you can leave this as-is, but you if you want to provide
+         additional functionality it is fine to subclass or reimplement
+         FlutterApplication and put your custom class here. -->
+    <application
+        android:name="io.flutter.app.FlutterApplication"
+        android:label="example"
+        android:icon="@mipmap/ic_launcher">
+        <activity
+            android:name=".MainActivity"
+            android:launchMode="singleTop"
+            android:theme="@style/LaunchTheme"
+            android:configChanges="orientation|keyboardHidden|keyboard|screenSize|locale|layoutDirection|fontScale|screenLayout|density"
+            android:hardwareAccelerated="true"
+            android:windowSoftInputMode="adjustResize">
+            <!-- This keeps the window background of the activity showing
+                 until Flutter renders its first frame. It can be removed if
+                 there is no splash screen (such as the default splash screen
+                 defined in @style/LaunchTheme). -->
+            <meta-data
+                android:name="io.flutter.app.android.SplashScreenUntilFirstFrame"
+                android:value="true" />
+            <intent-filter>
+                <action android:name="android.intent.action.MAIN"/>
+                <category android:name="android.intent.category.LAUNCHER"/>
+            </intent-filter>
+        </activity>
+    </application>
+</manifest>

packages/zefyr/example/android/app/src/main/java/com/zefyr/example/MainActivity.java

@@ -0,0 +1,13 @@
+package com.zefyr.example;
+
+import android.os.Bundle;
+import io.flutter.app.FlutterActivity;
+import io.flutter.plugins.GeneratedPluginRegistrant;
+
+public class MainActivity extends FlutterActivity {
+  @Override
+  protected void onCreate(Bundle savedInstanceState) {
+    super.onCreate(savedInstanceState);
+    GeneratedPluginRegistrant.registerWith(this);
+  }
+}

packages/zefyr/example/android/app/src/main/res/drawable/launch_background.xml

@@ -0,0 +1,12 @@
+<?xml version="1.0" encoding="utf-8"?>
+<!-- Modify this file to customize your launch splash screen -->
+<layer-list xmlns:android="http://schemas.android.com/apk/res/android">
+    <item android:drawable="@android:color/white" />
+
+    <!-- You can insert your own image assets here -->
+    <!-- <item>
+        <bitmap
+            android:gravity="center"
+            android:src="@mipmap/launch_image" />
+    </item> -->
+</layer-list>

packages/zefyr/example/android/app/src/main/res/values/styles.xml

@@ -0,0 +1,8 @@
+<?xml version="1.0" encoding="utf-8"?>
+<resources>
+    <style name="LaunchTheme" parent="@android:style/Theme.Black.NoTitleBar">
+        <!-- Show a splash screen on the activity. Automatically removed when
+             Flutter draws its first frame -->
+        <item name="android:windowBackground">@drawable/launch_background</item>
+    </style>
+</resources>

packages/zefyr/example/android/build.gradle

@@ -0,0 +1,29 @@
+buildscript {
+    repositories {
+        google()
+        jcenter()
+    }
+
+    dependencies {
+        classpath 'com.android.tools.build:gradle:3.1.2'
+    }
+}
+
+allprojects {
+    repositories {
+        google()
+        jcenter()
+    }
+}
+
+rootProject.buildDir = '../build'
+subprojects {
+    project.buildDir = "${rootProject.buildDir}/${project.name}"
+}
+subprojects {
+    project.evaluationDependsOn(':app')
+}
+
+task clean(type: Delete) {
+    delete rootProject.buildDir
+}

packages/zefyr/example/android/gradle.properties

@@ -0,0 +1 @@
+org.gradle.jvmargs=-Xmx1536M

packages/zefyr/example/android/gradle/wrapper/gradle-wrapper.properties

@@ -0,0 +1,6 @@
+#Fri Jun 23 08:50:38 CEST 2017
+distributionBase=GRADLE_USER_HOME
+distributionPath=wrapper/dists
+zipStoreBase=GRADLE_USER_HOME
+zipStorePath=wrapper/dists
+distributionUrl=https\://services.gradle.org/distributions/gradle-4.4-all.zip

packages/zefyr/example/android/gradlew

@@ -0,0 +1,160 @@
+#!/usr/bin/env bash
+
+##############################################################################
+##
+##  Gradle start up script for UN*X
+##
+##############################################################################
+
+# Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+DEFAULT_JVM_OPTS=""
+
+APP_NAME="Gradle"
+APP_BASE_NAME=`basename "$0"`
+
+# Use the maximum available, or set MAX_FD != -1 to use that value.
+MAX_FD="maximum"
+
+warn ( ) {
+    echo "$*"
+}
+
+die ( ) {
+    echo
+    echo "$*"
+    echo
+    exit 1
+}
+
+# OS specific support (must be 'true' or 'false').
+cygwin=false
+msys=false
+darwin=false
+case "`uname`" in
+  CYGWIN* )
+    cygwin=true
+    ;;
+  Darwin* )
+    darwin=true
+    ;;
+  MINGW* )
+    msys=true
+    ;;
+esac
+
+# Attempt to set APP_HOME
+# Resolve links: $0 may be a link
+PRG="$0"
+# Need this for relative symlinks.
+while [ -h "$PRG" ] ; do
+    ls=`ls -ld "$PRG"`
+    link=`expr "$ls" : '.*-> \(.*\)$'`
+    if expr "$link" : '/.*' > /dev/null; then
+        PRG="$link"
+    else
+        PRG=`dirname "$PRG"`"/$link"
+    fi
+done
+SAVED="`pwd`"
+cd "`dirname \"$PRG\"`/" >/dev/null
+APP_HOME="`pwd -P`"
+cd "$SAVED" >/dev/null
+
+CLASSPATH=$APP_HOME/gradle/wrapper/gradle-wrapper.jar
+
+# Determine the Java command to use to start the JVM.
+if [ -n "$JAVA_HOME" ] ; then
+    if [ -x "$JAVA_HOME/jre/sh/java" ] ; then
+        # IBM's JDK on AIX uses strange locations for the executables
+        JAVACMD="$JAVA_HOME/jre/sh/java"
+    else
+        JAVACMD="$JAVA_HOME/bin/java"
+    fi
+    if [ ! -x "$JAVACMD" ] ; then
+        die "ERROR: JAVA_HOME is set to an invalid directory: $JAVA_HOME
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+    fi
+else
+    JAVACMD="java"
+    which java >/dev/null 2>&1 || die "ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+
+Please set the JAVA_HOME variable in your environment to match the
+location of your Java installation."
+fi
+
+# Increase the maximum file descriptors if we can.
+if [ "$cygwin" = "false" -a "$darwin" = "false" ] ; then
+    MAX_FD_LIMIT=`ulimit -H -n`
+    if [ $? -eq 0 ] ; then
+        if [ "$MAX_FD" = "maximum" -o "$MAX_FD" = "max" ] ; then
+            MAX_FD="$MAX_FD_LIMIT"
+        fi
+        ulimit -n $MAX_FD
+        if [ $? -ne 0 ] ; then
+            warn "Could not set maximum file descriptor limit: $MAX_FD"
+        fi
+    else
+        warn "Could not query maximum file descriptor limit: $MAX_FD_LIMIT"
+    fi
+fi
+
+# For Darwin, add options to specify how the application appears in the dock
+if $darwin; then
+    GRADLE_OPTS="$GRADLE_OPTS \"-Xdock:name=$APP_NAME\" \"-Xdock:icon=$APP_HOME/media/gradle.icns\""
+fi
+
+# For Cygwin, switch paths to Windows format before running java
+if $cygwin ; then
+    APP_HOME=`cygpath --path --mixed "$APP_HOME"`
+    CLASSPATH=`cygpath --path --mixed "$CLASSPATH"`
+    JAVACMD=`cygpath --unix "$JAVACMD"`
+
+    # We build the pattern for arguments to be converted via cygpath
+    ROOTDIRSRAW=`find -L / -maxdepth 1 -mindepth 1 -type d 2>/dev/null`
+    SEP=""
+    for dir in $ROOTDIRSRAW ; do
+        ROOTDIRS="$ROOTDIRS$SEP$dir"
+        SEP="|"
+    done
+    OURCYGPATTERN="(^($ROOTDIRS))"
+    # Add a user-defined pattern to the cygpath arguments
+    if [ "$GRADLE_CYGPATTERN" != "" ] ; then
+        OURCYGPATTERN="$OURCYGPATTERN|($GRADLE_CYGPATTERN)"
+    fi
+    # Now convert the arguments - kludge to limit ourselves to /bin/sh
+    i=0
+    for arg in "$@" ; do
+        CHECK=`echo "$arg"|egrep -c "$OURCYGPATTERN" -`
+        CHECK2=`echo "$arg"|egrep -c "^-"`                                 ### Determine if an option
+
+        if [ $CHECK -ne 0 ] && [ $CHECK2 -eq 0 ] ; then                    ### Added a condition
+            eval `echo args$i`=`cygpath --path --ignore --mixed "$arg"`
+        else
+            eval `echo args$i`="\"$arg\""
+        fi
+        i=$((i+1))
+    done
+    case $i in
+        (0) set -- ;;
+        (1) set -- "$args0" ;;
+        (2) set -- "$args0" "$args1" ;;
+        (3) set -- "$args0" "$args1" "$args2" ;;
+        (4) set -- "$args0" "$args1" "$args2" "$args3" ;;
+        (5) set -- "$args0" "$args1" "$args2" "$args3" "$args4" ;;
+        (6) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" ;;
+        (7) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" ;;
+        (8) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" ;;
+        (9) set -- "$args0" "$args1" "$args2" "$args3" "$args4" "$args5" "$args6" "$args7" "$args8" ;;
+    esac
+fi
+
+# Split up the JVM_OPTS And GRADLE_OPTS values into an array, following the shell quoting and substitution rules
+function splitJvmOpts() {
+    JVM_OPTS=("$@")
+}
+eval splitJvmOpts $DEFAULT_JVM_OPTS $JAVA_OPTS $GRADLE_OPTS
+JVM_OPTS[${#JVM_OPTS[*]}]="-Dorg.gradle.appname=$APP_BASE_NAME"
+
+exec "$JAVACMD" "${JVM_OPTS[@]}" -classpath "$CLASSPATH" org.gradle.wrapper.GradleWrapperMain "$@"

packages/zefyr/example/android/gradlew.bat

@@ -0,0 +1,90 @@
+@if "%DEBUG%" == "" @echo off
+@rem ##########################################################################
+@rem
+@rem  Gradle startup script for Windows
+@rem
+@rem ##########################################################################
+
+@rem Set local scope for the variables with windows NT shell
+if "%OS%"=="Windows_NT" setlocal
+
+@rem Add default JVM options here. You can also use JAVA_OPTS and GRADLE_OPTS to pass JVM options to this script.
+set DEFAULT_JVM_OPTS=
+
+set DIRNAME=%~dp0
+if "%DIRNAME%" == "" set DIRNAME=.
+set APP_BASE_NAME=%~n0
+set APP_HOME=%DIRNAME%
+
+@rem Find java.exe
+if defined JAVA_HOME goto findJavaFromJavaHome
+
+set JAVA_EXE=java.exe
+%JAVA_EXE% -version >NUL 2>&1
+if "%ERRORLEVEL%" == "0" goto init
+
+echo.
+echo ERROR: JAVA_HOME is not set and no 'java' command could be found in your PATH.
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:findJavaFromJavaHome
+set JAVA_HOME=%JAVA_HOME:"=%
+set JAVA_EXE=%JAVA_HOME%/bin/java.exe
+
+if exist "%JAVA_EXE%" goto init
+
+echo.
+echo ERROR: JAVA_HOME is set to an invalid directory: %JAVA_HOME%
+echo.
+echo Please set the JAVA_HOME variable in your environment to match the
+echo location of your Java installation.
+
+goto fail
+
+:init
+@rem Get command-line arguments, handling Windowz variants
+
+if not "%OS%" == "Windows_NT" goto win9xME_args
+if "%@eval[2+2]" == "4" goto 4NT_args
+
+:win9xME_args
+@rem Slurp the command line arguments.
+set CMD_LINE_ARGS=
+set _SKIP=2
+
+:win9xME_args_slurp
+if "x%~1" == "x" goto execute
+
+set CMD_LINE_ARGS=%*
+goto execute
+
+:4NT_args
+@rem Get arguments from the 4NT Shell from JP Software
+set CMD_LINE_ARGS=%$
+
+:execute
+@rem Setup the command line
+
+set CLASSPATH=%APP_HOME%\gradle\wrapper\gradle-wrapper.jar
+
+@rem Execute Gradle
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" org.gradle.wrapper.GradleWrapperMain %CMD_LINE_ARGS%
+
+:end
+@rem End local scope for the variables with windows NT shell
+if "%ERRORLEVEL%"=="0" goto mainEnd
+
+:fail
+rem Set variable GRADLE_EXIT_CONSOLE if you need the _script_ return code instead of
+rem the _cmd.exe /c_ return code!
+if  not "" == "%GRADLE_EXIT_CONSOLE%" exit 1
+exit /b 1
+
+:mainEnd
+if "%OS%"=="Windows_NT" endlocal
+
+:omega

packages/zefyr/example/android/settings.gradle

@@ -0,0 +1,15 @@
+include ':app'
+
+def flutterProjectRoot = rootProject.projectDir.parentFile.toPath()
+
+def plugins = new Properties()
+def pluginsFile = new File(flutterProjectRoot.toFile(), '.flutter-plugins')
+if (pluginsFile.exists()) {
+    pluginsFile.withReader('UTF-8') { reader -> plugins.load(reader) }
+}
+
+plugins.each { name, path ->
+    def pluginDirectory = flutterProjectRoot.resolve(path).resolve('android').toFile()
+    include ":$name"
+    project(":$name").projectDir = pluginDirectory
+}

packages/zefyr/example/example.iml

@@ -0,0 +1,18 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$">
+      <sourceFolder url="file://$MODULE_DIR$/lib" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/test" isTestSource="true" />
+      <excludeFolder url="file://$MODULE_DIR$/.dart_tool" />
+      <excludeFolder url="file://$MODULE_DIR$/.idea" />
+      <excludeFolder url="file://$MODULE_DIR$/.pub" />
+      <excludeFolder url="file://$MODULE_DIR$/build" />
+    </content>
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="Dart SDK" level="project" />
+    <orderEntry type="library" name="Flutter Plugins" level="project" />
+    <orderEntry type="library" name="Dart Packages" level="project" />
+  </component>
+</module>

packages/zefyr/example/example_android.iml

@@ -0,0 +1,27 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<module type="JAVA_MODULE" version="4">
+  <component name="FacetManager">
+    <facet type="android" name="Android">
+      <configuration>
+        <option name="ALLOW_USER_CONFIGURATION" value="false" />
+        <option name="GEN_FOLDER_RELATIVE_PATH_APT" value="/android/gen" />
+        <option name="GEN_FOLDER_RELATIVE_PATH_AIDL" value="/android/gen" />
+        <option name="MANIFEST_FILE_RELATIVE_PATH" value="/android/AndroidManifest.xml" />
+        <option name="RES_FOLDER_RELATIVE_PATH" value="/android/res" />
+        <option name="ASSETS_FOLDER_RELATIVE_PATH" value="/android/assets" />
+        <option name="LIBS_FOLDER_RELATIVE_PATH" value="/android/libs" />
+        <option name="PROGUARD_LOGS_FOLDER_RELATIVE_PATH" value="/android/proguard_logs" />
+      </configuration>
+    </facet>
+  </component>
+  <component name="NewModuleRootManager" inherit-compiler-output="true">
+    <exclude-output />
+    <content url="file://$MODULE_DIR$/android">
+      <sourceFolder url="file://$MODULE_DIR$/android/app/src/main/java" isTestSource="false" />
+      <sourceFolder url="file://$MODULE_DIR$/android/gen" isTestSource="false" generated="true" />
+    </content>
+    <orderEntry type="jdk" jdkName="Android API 25 Platform" jdkType="Android SDK" />
+    <orderEntry type="sourceFolder" forTests="false" />
+    <orderEntry type="library" name="Flutter for Android" level="project" />
+  </component>
+</module>

packages/zefyr/example/ios/.gitignore

@@ -0,0 +1,45 @@
+.idea/
+.vagrant/
+.sconsign.dblite
+.svn/
+
+.DS_Store
+*.swp
+profile
+
+DerivedData/
+build/
+GeneratedPluginRegistrant.h
+GeneratedPluginRegistrant.m
+
+.generated/
+
+*.pbxuser
+*.mode1v3
+*.mode2v3
+*.perspectivev3
+
+!default.pbxuser
+!default.mode1v3
+!default.mode2v3
+!default.perspectivev3
+
+xcuserdata
+
+*.moved-aside
+
+*.pyc
+*sync/
+Icon?
+.tags*
+
+/Flutter/app.flx
+/Flutter/app.zip
+/Flutter/flutter_assets/
+/Flutter/App.framework
+/Flutter/Flutter.framework
+/Flutter/Generated.xcconfig
+/ServiceDefinitions.json
+
+Pods/
+.symlinks/

packages/zefyr/example/ios/Flutter/AppFrameworkInfo.plist

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+  <key>CFBundleDevelopmentRegion</key>
+  <string>en</string>
+  <key>CFBundleExecutable</key>
+  <string>App</string>
+  <key>CFBundleIdentifier</key>
+  <string>io.flutter.flutter.app</string>
+  <key>CFBundleInfoDictionaryVersion</key>
+  <string>6.0</string>
+  <key>CFBundleName</key>
+  <string>App</string>
+  <key>CFBundlePackageType</key>
+  <string>FMWK</string>
+  <key>CFBundleShortVersionString</key>
+  <string>1.0</string>
+  <key>CFBundleSignature</key>
+  <string>????</string>
+  <key>CFBundleVersion</key>
+  <string>1.0</string>
+  <key>MinimumOSVersion</key>
+  <string>8.0</string>
+</dict>
+</plist>

packages/zefyr/example/ios/Flutter/Debug.xcconfig

@@ -0,0 +1,2 @@
+#include "Pods/Target Support Files/Pods-Runner/Pods-Runner.debug.xcconfig"
+#include "Generated.xcconfig"

packages/zefyr/example/ios/Flutter/Release.xcconfig

@@ -0,0 +1,2 @@
+#include "Pods/Target Support Files/Pods-Runner/Pods-Runner.release.xcconfig"
+#include "Generated.xcconfig"

packages/zefyr/example/ios/Podfile

@@ -0,0 +1,63 @@
+# Uncomment this line to define a global platform for your project
+# platform :ios, '9.0'
+
+# CocoaPods analytics sends network stats synchronously affecting flutter build latency.
+ENV['COCOAPODS_DISABLE_STATS'] = 'true'
+
+def parse_KV_file(file, separator='=')
+  file_abs_path = File.expand_path(file)
+  if !File.exists? file_abs_path
+    return [];
+  end
+  pods_ary = []
+  skip_line_start_symbols = ["#", "/"]
+  File.foreach(file_abs_path) { |line|
+      next if skip_line_start_symbols.any? { |symbol| line =~ /^\s*#{symbol}/ }
+      plugin = line.split(pattern=separator)
+      if plugin.length == 2
+        podname = plugin[0].strip()
+        path = plugin[1].strip()
+        podpath = File.expand_path("#{path}", file_abs_path)
+        pods_ary.push({:name => podname, :path => podpath});
+      else
+        puts "Invalid plugin specification: #{line}"
+      end
+  }
+  return pods_ary
+end
+
+target 'Runner' do
+  # Prepare symlinks folder. We use symlinks to avoid having Podfile.lock
+  # referring to absolute paths on developers' machines.
+  system('rm -rf .symlinks')
+  system('mkdir -p .symlinks/plugins')
+
+  # Flutter Pods
+  generated_xcode_build_settings = parse_KV_file('./Flutter/Generated.xcconfig')
+  if generated_xcode_build_settings.empty?
+    puts "Generated.xcconfig must exist. If you're running pod install manually, make sure flutter packages get is executed first."
+  end
+  generated_xcode_build_settings.map { |p|
+    if p[:name] == 'FLUTTER_FRAMEWORK_DIR'
+      symlink = File.join('.symlinks', 'flutter')
+      File.symlink(File.dirname(p[:path]), symlink)
+      pod 'Flutter', :path => File.join(symlink, File.basename(p[:path]))
+    end
+  }
+
+  # Plugin Pods
+  plugin_pods = parse_KV_file('../.flutter-plugins')
+  plugin_pods.map { |p|
+    symlink = File.join('.symlinks', 'plugins', p[:name])
+    File.symlink(p[:path], symlink)
+    pod p[:name], :path => File.join(symlink, 'ios')
+  }
+end
+
+post_install do |installer|
+  installer.pods_project.targets.each do |target|
+    target.build_configurations.each do |config|
+      config.build_settings['ENABLE_BITCODE'] = 'NO'
+    end
+  end
+end

packages/zefyr/example/ios/Podfile.lock

@@ -0,0 +1,22 @@
+PODS:
+  - Flutter (1.0.0)
+  - url_launcher (0.0.1):
+    - Flutter
+
+DEPENDENCIES:
+  - Flutter (from `.symlinks/flutter/ios`)
+  - url_launcher (from `.symlinks/plugins/url_launcher/ios`)
+
+EXTERNAL SOURCES:
+  Flutter:
+    :path: ".symlinks/flutter/ios"
+  url_launcher:
+    :path: ".symlinks/plugins/url_launcher/ios"
+
+SPEC CHECKSUMS:
+  Flutter: 9d0fac939486c9aba2809b7982dfdbb47a7b0296
+  url_launcher: 92b89c1029a0373879933c21642958c874539095
+
+PODFILE CHECKSUM: 1e5af4103afd21ca5ead147d7b81d06f494f51a2
+
+COCOAPODS: 1.5.2

packages/zefyr/example/ios/Runner.xcodeproj/project.pbxproj

@@ -0,0 +1,495 @@
+// !$*UTF8*$!
+{
+	archiveVersion = 1;
+	classes = {
+	};
+	objectVersion = 46;
+	objects = {
+
+/* Begin PBXBuildFile section */
+		1498D2341E8E89220040F4C2 /* GeneratedPluginRegistrant.m in Sources */ = {isa = PBXBuildFile; fileRef = 1498D2331E8E89220040F4C2 /* GeneratedPluginRegistrant.m */; };
+		2D5378261FAA1A9400D5DBA9 /* flutter_assets in Resources */ = {isa = PBXBuildFile; fileRef = 2D5378251FAA1A9400D5DBA9 /* flutter_assets */; };
+		3B3967161E833CAA004F5970 /* AppFrameworkInfo.plist in Resources */ = {isa = PBXBuildFile; fileRef = 3B3967151E833CAA004F5970 /* AppFrameworkInfo.plist */; };
+		3B80C3941E831B6300D905FE /* App.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 3B80C3931E831B6300D905FE /* App.framework */; };
+		3B80C3951E831B6300D905FE /* App.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 3B80C3931E831B6300D905FE /* App.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
+		9705A1C61CF904A100538489 /* Flutter.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = 9740EEBA1CF902C7004384FC /* Flutter.framework */; };
+		9705A1C71CF904A300538489 /* Flutter.framework in Embed Frameworks */ = {isa = PBXBuildFile; fileRef = 9740EEBA1CF902C7004384FC /* Flutter.framework */; settings = {ATTRIBUTES = (CodeSignOnCopy, RemoveHeadersOnCopy, ); }; };
+		9740EEB41CF90195004384FC /* Debug.xcconfig in Resources */ = {isa = PBXBuildFile; fileRef = 9740EEB21CF90195004384FC /* Debug.xcconfig */; };
+		9740EEB51CF90195004384FC /* Generated.xcconfig in Resources */ = {isa = PBXBuildFile; fileRef = 9740EEB31CF90195004384FC /* Generated.xcconfig */; };
+		978B8F6F1D3862AE00F588F7 /* AppDelegate.m in Sources */ = {isa = PBXBuildFile; fileRef = 7AFFD8EE1D35381100E5BB4D /* AppDelegate.m */; };
+		97C146F31CF9000F007C117D /* main.m in Sources */ = {isa = PBXBuildFile; fileRef = 97C146F21CF9000F007C117D /* main.m */; };
+		97C146FC1CF9000F007C117D /* Main.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 97C146FA1CF9000F007C117D /* Main.storyboard */; };
+		97C146FE1CF9000F007C117D /* Assets.xcassets in Resources */ = {isa = PBXBuildFile; fileRef = 97C146FD1CF9000F007C117D /* Assets.xcassets */; };
+		97C147011CF9000F007C117D /* LaunchScreen.storyboard in Resources */ = {isa = PBXBuildFile; fileRef = 97C146FF1CF9000F007C117D /* LaunchScreen.storyboard */; };
+		A287E1B0D09CE333E91C72F8 /* libPods-Runner.a in Frameworks */ = {isa = PBXBuildFile; fileRef = A1CCE149440E9C6B5CCC0FA7 /* libPods-Runner.a */; };
+/* End PBXBuildFile section */
+
+/* Begin PBXCopyFilesBuildPhase section */
+		9705A1C41CF9048500538489 /* Embed Frameworks */ = {
+			isa = PBXCopyFilesBuildPhase;
+			buildActionMask = 2147483647;
+			dstPath = "";
+			dstSubfolderSpec = 10;
+			files = (
+				3B80C3951E831B6300D905FE /* App.framework in Embed Frameworks */,
+				9705A1C71CF904A300538489 /* Flutter.framework in Embed Frameworks */,
+			);
+			name = "Embed Frameworks";
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+/* End PBXCopyFilesBuildPhase section */
+
+/* Begin PBXFileReference section */
+		1498D2321E8E86230040F4C2 /* GeneratedPluginRegistrant.h */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.h; path = GeneratedPluginRegistrant.h; sourceTree = "<group>"; };
+		1498D2331E8E89220040F4C2 /* GeneratedPluginRegistrant.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = GeneratedPluginRegistrant.m; sourceTree = "<group>"; };
+		2D5378251FAA1A9400D5DBA9 /* flutter_assets */ = {isa = PBXFileReference; lastKnownFileType = folder; name = flutter_assets; path = Flutter/flutter_assets; sourceTree = SOURCE_ROOT; };
+		3B3967151E833CAA004F5970 /* AppFrameworkInfo.plist */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.plist.xml; name = AppFrameworkInfo.plist; path = Flutter/AppFrameworkInfo.plist; sourceTree = "<group>"; };
+		3B80C3931E831B6300D905FE /* App.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = App.framework; path = Flutter/App.framework; sourceTree = "<group>"; };
+		7AFA3C8E1D35360C0083082E /* Release.xcconfig */ = {isa = PBXFileReference; lastKnownFileType = text.xcconfig; name = Release.xcconfig; path = Flutter/Release.xcconfig; sourceTree = "<group>"; };
+		7AFFD8ED1D35381100E5BB4D /* AppDelegate.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = AppDelegate.h; sourceTree = "<group>"; };
+		7AFFD8EE1D35381100E5BB4D /* AppDelegate.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = AppDelegate.m; sourceTree = "<group>"; };
+		9740EEB21CF90195004384FC /* Debug.xcconfig */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.xcconfig; name = Debug.xcconfig; path = Flutter/Debug.xcconfig; sourceTree = "<group>"; };
+		9740EEB31CF90195004384FC /* Generated.xcconfig */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = text.xcconfig; name = Generated.xcconfig; path = Flutter/Generated.xcconfig; sourceTree = "<group>"; };
+		9740EEBA1CF902C7004384FC /* Flutter.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = Flutter.framework; path = Flutter/Flutter.framework; sourceTree = "<group>"; };
+		97C146EE1CF9000F007C117D /* Runner.app */ = {isa = PBXFileReference; explicitFileType = wrapper.application; includeInIndex = 0; path = Runner.app; sourceTree = BUILT_PRODUCTS_DIR; };
+		97C146F21CF9000F007C117D /* main.m */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.c.objc; path = main.m; sourceTree = "<group>"; };
+		97C146FB1CF9000F007C117D /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/Main.storyboard; sourceTree = "<group>"; };
+		97C146FD1CF9000F007C117D /* Assets.xcassets */ = {isa = PBXFileReference; lastKnownFileType = folder.assetcatalog; path = Assets.xcassets; sourceTree = "<group>"; };
+		97C147001CF9000F007C117D /* Base */ = {isa = PBXFileReference; lastKnownFileType = file.storyboard; name = Base; path = Base.lproj/LaunchScreen.storyboard; sourceTree = "<group>"; };
+		97C147021CF9000F007C117D /* Info.plist */ = {isa = PBXFileReference; lastKnownFileType = text.plist.xml; path = Info.plist; sourceTree = "<group>"; };
+		A1CCE149440E9C6B5CCC0FA7 /* libPods-Runner.a */ = {isa = PBXFileReference; explicitFileType = archive.ar; includeInIndex = 0; path = "libPods-Runner.a"; sourceTree = BUILT_PRODUCTS_DIR; };
+/* End PBXFileReference section */
+
+/* Begin PBXFrameworksBuildPhase section */
+		97C146EB1CF9000F007C117D /* Frameworks */ = {
+			isa = PBXFrameworksBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				9705A1C61CF904A100538489 /* Flutter.framework in Frameworks */,
+				3B80C3941E831B6300D905FE /* App.framework in Frameworks */,
+				A287E1B0D09CE333E91C72F8 /* libPods-Runner.a in Frameworks */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+/* End PBXFrameworksBuildPhase section */
+
+/* Begin PBXGroup section */
+		8488E8CB1FA32CE8522EADB7 /* Frameworks */ = {
+			isa = PBXGroup;
+			children = (
+				A1CCE149440E9C6B5CCC0FA7 /* libPods-Runner.a */,
+			);
+			name = Frameworks;
+			sourceTree = "<group>";
+		};
+		9740EEB11CF90186004384FC /* Flutter */ = {
+			isa = PBXGroup;
+			children = (
+				2D5378251FAA1A9400D5DBA9 /* flutter_assets */,
+				3B80C3931E831B6300D905FE /* App.framework */,
+				3B3967151E833CAA004F5970 /* AppFrameworkInfo.plist */,
+				9740EEBA1CF902C7004384FC /* Flutter.framework */,
+				9740EEB21CF90195004384FC /* Debug.xcconfig */,
+				7AFA3C8E1D35360C0083082E /* Release.xcconfig */,
+				9740EEB31CF90195004384FC /* Generated.xcconfig */,
+			);
+			name = Flutter;
+			sourceTree = "<group>";
+		};
+		97C146E51CF9000F007C117D = {
+			isa = PBXGroup;
+			children = (
+				9740EEB11CF90186004384FC /* Flutter */,
+				97C146F01CF9000F007C117D /* Runner */,
+				97C146EF1CF9000F007C117D /* Products */,
+				E477B343036FAA13A2565E3A /* Pods */,
+				8488E8CB1FA32CE8522EADB7 /* Frameworks */,
+			);
+			sourceTree = "<group>";
+		};
+		97C146EF1CF9000F007C117D /* Products */ = {
+			isa = PBXGroup;
+			children = (
+				97C146EE1CF9000F007C117D /* Runner.app */,
+			);
+			name = Products;
+			sourceTree = "<group>";
+		};
+		97C146F01CF9000F007C117D /* Runner */ = {
+			isa = PBXGroup;
+			children = (
+				7AFFD8ED1D35381100E5BB4D /* AppDelegate.h */,
+				7AFFD8EE1D35381100E5BB4D /* AppDelegate.m */,
+				97C146FA1CF9000F007C117D /* Main.storyboard */,
+				97C146FD1CF9000F007C117D /* Assets.xcassets */,
+				97C146FF1CF9000F007C117D /* LaunchScreen.storyboard */,
+				97C147021CF9000F007C117D /* Info.plist */,
+				97C146F11CF9000F007C117D /* Supporting Files */,
+				1498D2321E8E86230040F4C2 /* GeneratedPluginRegistrant.h */,
+				1498D2331E8E89220040F4C2 /* GeneratedPluginRegistrant.m */,
+			);
+			path = Runner;
+			sourceTree = "<group>";
+		};
+		97C146F11CF9000F007C117D /* Supporting Files */ = {
+			isa = PBXGroup;
+			children = (
+				97C146F21CF9000F007C117D /* main.m */,
+			);
+			name = "Supporting Files";
+			sourceTree = "<group>";
+		};
+		E477B343036FAA13A2565E3A /* Pods */ = {
+			isa = PBXGroup;
+			children = (
+			);
+			name = Pods;
+			sourceTree = "<group>";
+		};
+/* End PBXGroup section */
+
+/* Begin PBXNativeTarget section */
+		97C146ED1CF9000F007C117D /* Runner */ = {
+			isa = PBXNativeTarget;
+			buildConfigurationList = 97C147051CF9000F007C117D /* Build configuration list for PBXNativeTarget "Runner" */;
+			buildPhases = (
+				497F746AAAAAA284327A4563 /* [CP] Check Pods Manifest.lock */,
+				9740EEB61CF901F6004384FC /* Run Script */,
+				97C146EA1CF9000F007C117D /* Sources */,
+				97C146EB1CF9000F007C117D /* Frameworks */,
+				97C146EC1CF9000F007C117D /* Resources */,
+				9705A1C41CF9048500538489 /* Embed Frameworks */,
+				3B06AD1E1E4923F5004D2608 /* Thin Binary */,
+				130991D2A439F8766FDFE1D7 /* [CP] Embed Pods Frameworks */,
+			);
+			buildRules = (
+			);
+			dependencies = (
+			);
+			name = Runner;
+			productName = Runner;
+			productReference = 97C146EE1CF9000F007C117D /* Runner.app */;
+			productType = "com.apple.product-type.application";
+		};
+/* End PBXNativeTarget section */
+
+/* Begin PBXProject section */
+		97C146E61CF9000F007C117D /* Project object */ = {
+			isa = PBXProject;
+			attributes = {
+				LastUpgradeCheck = 0910;
+				ORGANIZATIONNAME = "The Chromium Authors";
+				TargetAttributes = {
+					97C146ED1CF9000F007C117D = {
+						CreatedOnToolsVersion = 7.3.1;
+					};
+				};
+			};
+			buildConfigurationList = 97C146E91CF9000F007C117D /* Build configuration list for PBXProject "Runner" */;
+			compatibilityVersion = "Xcode 3.2";
+			developmentRegion = English;
+			hasScannedForEncodings = 0;
+			knownRegions = (
+				en,
+				Base,
+			);
+			mainGroup = 97C146E51CF9000F007C117D;
+			productRefGroup = 97C146EF1CF9000F007C117D /* Products */;
+			projectDirPath = "";
+			projectRoot = "";
+			targets = (
+				97C146ED1CF9000F007C117D /* Runner */,
+			);
+		};
+/* End PBXProject section */
+
+/* Begin PBXResourcesBuildPhase section */
+		97C146EC1CF9000F007C117D /* Resources */ = {
+			isa = PBXResourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				97C147011CF9000F007C117D /* LaunchScreen.storyboard in Resources */,
+				9740EEB51CF90195004384FC /* Generated.xcconfig in Resources */,
+				3B3967161E833CAA004F5970 /* AppFrameworkInfo.plist in Resources */,
+				9740EEB41CF90195004384FC /* Debug.xcconfig in Resources */,
+				97C146FE1CF9000F007C117D /* Assets.xcassets in Resources */,
+				2D5378261FAA1A9400D5DBA9 /* flutter_assets in Resources */,
+				97C146FC1CF9000F007C117D /* Main.storyboard in Resources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+/* End PBXResourcesBuildPhase section */
+
+/* Begin PBXShellScriptBuildPhase section */
+		130991D2A439F8766FDFE1D7 /* [CP] Embed Pods Frameworks */ = {
+			isa = PBXShellScriptBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			inputPaths = (
+				"${SRCROOT}/Pods/Target Support Files/Pods-Runner/Pods-Runner-frameworks.sh",
+				"${PODS_ROOT}/../.symlinks/flutter/ios/Flutter.framework",
+			);
+			name = "[CP] Embed Pods Frameworks";
+			outputPaths = (
+				"${TARGET_BUILD_DIR}/${FRAMEWORKS_FOLDER_PATH}/Flutter.framework",
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "\"${SRCROOT}/Pods/Target Support Files/Pods-Runner/Pods-Runner-frameworks.sh\"\n";
+			showEnvVarsInLog = 0;
+		};
+		3B06AD1E1E4923F5004D2608 /* Thin Binary */ = {
+			isa = PBXShellScriptBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			inputPaths = (
+			);
+			name = "Thin Binary";
+			outputPaths = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "/bin/sh \"$FLUTTER_ROOT/packages/flutter_tools/bin/xcode_backend.sh\" thin";
+		};
+		497F746AAAAAA284327A4563 /* [CP] Check Pods Manifest.lock */ = {
+			isa = PBXShellScriptBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			inputPaths = (
+				"${PODS_PODFILE_DIR_PATH}/Podfile.lock",
+				"${PODS_ROOT}/Manifest.lock",
+			);
+			name = "[CP] Check Pods Manifest.lock";
+			outputPaths = (
+				"$(DERIVED_FILE_DIR)/Pods-Runner-checkManifestLockResult.txt",
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "diff \"${PODS_PODFILE_DIR_PATH}/Podfile.lock\" \"${PODS_ROOT}/Manifest.lock\" > /dev/null\nif [ $? != 0 ] ; then\n    # print error to STDERR\n    echo \"error: The sandbox is not in sync with the Podfile.lock. Run 'pod install' or update your CocoaPods installation.\" >&2\n    exit 1\nfi\n# This output is used by Xcode 'outputs' to avoid re-running this script phase.\necho \"SUCCESS\" > \"${SCRIPT_OUTPUT_FILE_0}\"\n";
+			showEnvVarsInLog = 0;
+		};
+		9740EEB61CF901F6004384FC /* Run Script */ = {
+			isa = PBXShellScriptBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			inputPaths = (
+			);
+			name = "Run Script";
+			outputPaths = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "/bin/sh \"$FLUTTER_ROOT/packages/flutter_tools/bin/xcode_backend.sh\" build";
+		};
+/* End PBXShellScriptBuildPhase section */
+
+/* Begin PBXSourcesBuildPhase section */
+		97C146EA1CF9000F007C117D /* Sources */ = {
+			isa = PBXSourcesBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+				978B8F6F1D3862AE00F588F7 /* AppDelegate.m in Sources */,
+				97C146F31CF9000F007C117D /* main.m in Sources */,
+				1498D2341E8E89220040F4C2 /* GeneratedPluginRegistrant.m in Sources */,
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+		};
+/* End PBXSourcesBuildPhase section */
+
+/* Begin PBXVariantGroup section */
+		97C146FA1CF9000F007C117D /* Main.storyboard */ = {
+			isa = PBXVariantGroup;
+			children = (
+				97C146FB1CF9000F007C117D /* Base */,
+			);
+			name = Main.storyboard;
+			sourceTree = "<group>";
+		};
+		97C146FF1CF9000F007C117D /* LaunchScreen.storyboard */ = {
+			isa = PBXVariantGroup;
+			children = (
+				97C147001CF9000F007C117D /* Base */,
+			);
+			name = LaunchScreen.storyboard;
+			sourceTree = "<group>";
+		};
+/* End PBXVariantGroup section */
+
+/* Begin XCBuildConfiguration section */
+		97C147031CF9000F007C117D /* Debug */ = {
+			isa = XCBuildConfiguration;
+			baseConfigurationReference = 9740EEB21CF90195004384FC /* Debug.xcconfig */;
+			buildSettings = {
+				ALWAYS_SEARCH_USER_PATHS = NO;
+				CLANG_ANALYZER_NONNULL = YES;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
+				CLANG_CXX_LIBRARY = "libc++";
+				CLANG_ENABLE_MODULES = YES;
+				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
+				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
+				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
+				CLANG_WARN_EMPTY_BODY = YES;
+				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
+				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
+				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
+				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
+				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
+				COPY_PHASE_STRIP = NO;
+				DEBUG_INFORMATION_FORMAT = dwarf;
+				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				ENABLE_TESTABILITY = YES;
+				GCC_C_LANGUAGE_STANDARD = gnu99;
+				GCC_DYNAMIC_NO_PIC = NO;
+				GCC_NO_COMMON_BLOCKS = YES;
+				GCC_OPTIMIZATION_LEVEL = 0;
+				GCC_PREPROCESSOR_DEFINITIONS = (
+					"DEBUG=1",
+					"$(inherited)",
+				);
+				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
+				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
+				GCC_WARN_UNDECLARED_SELECTOR = YES;
+				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
+				GCC_WARN_UNUSED_FUNCTION = YES;
+				GCC_WARN_UNUSED_VARIABLE = YES;
+				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
+				MTL_ENABLE_DEBUG_INFO = YES;
+				ONLY_ACTIVE_ARCH = YES;
+				SDKROOT = iphoneos;
+				TARGETED_DEVICE_FAMILY = "1,2";
+			};
+			name = Debug;
+		};
+		97C147041CF9000F007C117D /* Release */ = {
+			isa = XCBuildConfiguration;
+			baseConfigurationReference = 7AFA3C8E1D35360C0083082E /* Release.xcconfig */;
+			buildSettings = {
+				ALWAYS_SEARCH_USER_PATHS = NO;
+				CLANG_ANALYZER_NONNULL = YES;
+				CLANG_CXX_LANGUAGE_STANDARD = "gnu++0x";
+				CLANG_CXX_LIBRARY = "libc++";
+				CLANG_ENABLE_MODULES = YES;
+				CLANG_ENABLE_OBJC_ARC = YES;
+				CLANG_WARN_BLOCK_CAPTURE_AUTORELEASING = YES;
+				CLANG_WARN_BOOL_CONVERSION = YES;
+				CLANG_WARN_COMMA = YES;
+				CLANG_WARN_CONSTANT_CONVERSION = YES;
+				CLANG_WARN_DIRECT_OBJC_ISA_USAGE = YES_ERROR;
+				CLANG_WARN_EMPTY_BODY = YES;
+				CLANG_WARN_ENUM_CONVERSION = YES;
+				CLANG_WARN_INFINITE_RECURSION = YES;
+				CLANG_WARN_INT_CONVERSION = YES;
+				CLANG_WARN_NON_LITERAL_NULL_CONVERSION = YES;
+				CLANG_WARN_OBJC_LITERAL_CONVERSION = YES;
+				CLANG_WARN_OBJC_ROOT_CLASS = YES_ERROR;
+				CLANG_WARN_RANGE_LOOP_ANALYSIS = YES;
+				CLANG_WARN_STRICT_PROTOTYPES = YES;
+				CLANG_WARN_SUSPICIOUS_MOVE = YES;
+				CLANG_WARN_UNREACHABLE_CODE = YES;
+				CLANG_WARN__DUPLICATE_METHOD_MATCH = YES;
+				"CODE_SIGN_IDENTITY[sdk=iphoneos*]" = "iPhone Developer";
+				COPY_PHASE_STRIP = NO;
+				DEBUG_INFORMATION_FORMAT = "dwarf-with-dsym";
+				ENABLE_NS_ASSERTIONS = NO;
+				ENABLE_STRICT_OBJC_MSGSEND = YES;
+				GCC_C_LANGUAGE_STANDARD = gnu99;
+				GCC_NO_COMMON_BLOCKS = YES;
+				GCC_WARN_64_TO_32_BIT_CONVERSION = YES;
+				GCC_WARN_ABOUT_RETURN_TYPE = YES_ERROR;
+				GCC_WARN_UNDECLARED_SELECTOR = YES;
+				GCC_WARN_UNINITIALIZED_AUTOS = YES_AGGRESSIVE;
+				GCC_WARN_UNUSED_FUNCTION = YES;
+				GCC_WARN_UNUSED_VARIABLE = YES;
+				IPHONEOS_DEPLOYMENT_TARGET = 8.0;
+				MTL_ENABLE_DEBUG_INFO = NO;
+				SDKROOT = iphoneos;
+				TARGETED_DEVICE_FAMILY = "1,2";
+				VALIDATE_PRODUCT = YES;
+			};
+			name = Release;
+		};
+		97C147061CF9000F007C117D /* Debug */ = {
+			isa = XCBuildConfiguration;
+			baseConfigurationReference = 9740EEB21CF90195004384FC /* Debug.xcconfig */;
+			buildSettings = {
+				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				CURRENT_PROJECT_VERSION = "$(FLUTTER_BUILD_NUMBER)";
+				ENABLE_BITCODE = NO;
+				FRAMEWORK_SEARCH_PATHS = (
+					"$(inherited)",
+					"$(PROJECT_DIR)/Flutter",
+				);
+				INFOPLIST_FILE = Runner/Info.plist;
+				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
+				LIBRARY_SEARCH_PATHS = (
+					"$(inherited)",
+					"$(PROJECT_DIR)/Flutter",
+				);
+				PRODUCT_BUNDLE_IDENTIFIER = com.zefyr.example;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				VERSIONING_SYSTEM = "apple-generic";
+			};
+			name = Debug;
+		};
+		97C147071CF9000F007C117D /* Release */ = {
+			isa = XCBuildConfiguration;
+			baseConfigurationReference = 7AFA3C8E1D35360C0083082E /* Release.xcconfig */;
+			buildSettings = {
+				ASSETCATALOG_COMPILER_APPICON_NAME = AppIcon;
+				CURRENT_PROJECT_VERSION = "$(FLUTTER_BUILD_NUMBER)";
+				ENABLE_BITCODE = NO;
+				FRAMEWORK_SEARCH_PATHS = (
+					"$(inherited)",
+					"$(PROJECT_DIR)/Flutter",
+				);
+				INFOPLIST_FILE = Runner/Info.plist;
+				LD_RUNPATH_SEARCH_PATHS = "$(inherited) @executable_path/Frameworks";
+				LIBRARY_SEARCH_PATHS = (
+					"$(inherited)",
+					"$(PROJECT_DIR)/Flutter",
+				);
+				PRODUCT_BUNDLE_IDENTIFIER = com.zefyr.example;
+				PRODUCT_NAME = "$(TARGET_NAME)";
+				VERSIONING_SYSTEM = "apple-generic";
+			};
+			name = Release;
+		};
+/* End XCBuildConfiguration section */
+
+/* Begin XCConfigurationList section */
+		97C146E91CF9000F007C117D /* Build configuration list for PBXProject "Runner" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				97C147031CF9000F007C117D /* Debug */,
+				97C147041CF9000F007C117D /* Release */,
+			);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
+		97C147051CF9000F007C117D /* Build configuration list for PBXNativeTarget "Runner" */ = {
+			isa = XCConfigurationList;
+			buildConfigurations = (
+				97C147061CF9000F007C117D /* Debug */,
+				97C147071CF9000F007C117D /* Release */,
+			);
+			defaultConfigurationIsVisible = 0;
+			defaultConfigurationName = Release;
+		};
+/* End XCConfigurationList section */
+	};
+	rootObject = 97C146E61CF9000F007C117D /* Project object */;
+}

packages/zefyr/example/ios/Runner.xcodeproj/project.xcworkspace/contents.xcworkspacedata

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Workspace
+   version = "1.0">
+   <FileRef
+      location = "group:Runner.xcodeproj">
+   </FileRef>
+</Workspace>

packages/zefyr/example/ios/Runner.xcodeproj/xcshareddata/xcschemes/Runner.xcscheme

@@ -0,0 +1,93 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Scheme
+   LastUpgradeVersion = "0910"
+   version = "1.3">
+   <BuildAction
+      parallelizeBuildables = "YES"
+      buildImplicitDependencies = "YES">
+      <BuildActionEntries>
+         <BuildActionEntry
+            buildForTesting = "YES"
+            buildForRunning = "YES"
+            buildForProfiling = "YES"
+            buildForArchiving = "YES"
+            buildForAnalyzing = "YES">
+            <BuildableReference
+               BuildableIdentifier = "primary"
+               BlueprintIdentifier = "97C146ED1CF9000F007C117D"
+               BuildableName = "Runner.app"
+               BlueprintName = "Runner"
+               ReferencedContainer = "container:Runner.xcodeproj">
+            </BuildableReference>
+         </BuildActionEntry>
+      </BuildActionEntries>
+   </BuildAction>
+   <TestAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
+      shouldUseLaunchSchemeArgsEnv = "YES">
+      <Testables>
+      </Testables>
+      <MacroExpansion>
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "97C146ED1CF9000F007C117D"
+            BuildableName = "Runner.app"
+            BlueprintName = "Runner"
+            ReferencedContainer = "container:Runner.xcodeproj">
+         </BuildableReference>
+      </MacroExpansion>
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </TestAction>
+   <LaunchAction
+      buildConfiguration = "Debug"
+      selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
+      selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
+      language = ""
+      launchStyle = "0"
+      useCustomWorkingDirectory = "NO"
+      ignoresPersistentStateOnLaunch = "NO"
+      debugDocumentVersioning = "YES"
+      debugServiceExtension = "internal"
+      allowLocationSimulation = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "97C146ED1CF9000F007C117D"
+            BuildableName = "Runner.app"
+            BlueprintName = "Runner"
+            ReferencedContainer = "container:Runner.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+      <AdditionalOptions>
+      </AdditionalOptions>
+   </LaunchAction>
+   <ProfileAction
+      buildConfiguration = "Release"
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      savedToolIdentifier = ""
+      useCustomWorkingDirectory = "NO"
+      debugDocumentVersioning = "YES">
+      <BuildableProductRunnable
+         runnableDebuggingMode = "0">
+         <BuildableReference
+            BuildableIdentifier = "primary"
+            BlueprintIdentifier = "97C146ED1CF9000F007C117D"
+            BuildableName = "Runner.app"
+            BlueprintName = "Runner"
+            ReferencedContainer = "container:Runner.xcodeproj">
+         </BuildableReference>
+      </BuildableProductRunnable>
+   </ProfileAction>
+   <AnalyzeAction
+      buildConfiguration = "Debug">
+   </AnalyzeAction>
+   <ArchiveAction
+      buildConfiguration = "Release"
+      revealArchiveInOrganizer = "YES">
+   </ArchiveAction>
+</Scheme>

packages/zefyr/example/ios/Runner.xcworkspace/contents.xcworkspacedata

@@ -0,0 +1,10 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<Workspace
+   version = "1.0">
+   <FileRef
+      location = "group:Runner.xcodeproj">
+   </FileRef>
+   <FileRef
+      location = "group:Pods/Pods.xcodeproj">
+   </FileRef>
+</Workspace>

packages/zefyr/example/ios/Runner/AppDelegate.h

@@ -0,0 +1,6 @@
+#import <Flutter/Flutter.h>
+#import <UIKit/UIKit.h>
+
+@interface AppDelegate : FlutterAppDelegate
+
+@end

packages/zefyr/example/ios/Runner/AppDelegate.m

@@ -0,0 +1,13 @@
+#include "AppDelegate.h"
+#include "GeneratedPluginRegistrant.h"
+
+@implementation AppDelegate
+
+- (BOOL)application:(UIApplication *)application
+    didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
+  [GeneratedPluginRegistrant registerWithRegistry:self];
+  // Override point for customization after application launch.
+  return [super application:application didFinishLaunchingWithOptions:launchOptions];
+}
+
+@end

packages/zefyr/example/ios/Runner/Assets.xcassets/AppIcon.appiconset/Contents.json

@@ -0,0 +1,122 @@
+{
+  "images" : [
+    {
+      "size" : "20x20",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-20x20@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "20x20",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-20x20@3x.png",
+      "scale" : "3x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-29x29@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-29x29@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-29x29@3x.png",
+      "scale" : "3x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-40x40@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-40x40@3x.png",
+      "scale" : "3x"
+    },
+    {
+      "size" : "60x60",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-60x60@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "60x60",
+      "idiom" : "iphone",
+      "filename" : "Icon-App-60x60@3x.png",
+      "scale" : "3x"
+    },
+    {
+      "size" : "20x20",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-20x20@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "20x20",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-20x20@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-29x29@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "29x29",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-29x29@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-40x40@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "40x40",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-40x40@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "76x76",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-76x76@1x.png",
+      "scale" : "1x"
+    },
+    {
+      "size" : "76x76",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-76x76@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "83.5x83.5",
+      "idiom" : "ipad",
+      "filename" : "Icon-App-83.5x83.5@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "size" : "1024x1024",
+      "idiom" : "ios-marketing",
+      "filename" : "Icon-App-1024x1024@1x.png",
+      "scale" : "1x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

packages/zefyr/example/ios/Runner/Assets.xcassets/LaunchImage.imageset/Contents.json

@@ -0,0 +1,23 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "filename" : "LaunchImage.png",
+      "scale" : "1x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "LaunchImage@2x.png",
+      "scale" : "2x"
+    },
+    {
+      "idiom" : "universal",
+      "filename" : "LaunchImage@3x.png",
+      "scale" : "3x"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  }
+}

packages/zefyr/example/ios/Runner/Assets.xcassets/LaunchImage.imageset/README.md

@@ -0,0 +1,5 @@
+# Launch Screen Assets
+
+You can customize the launch screen with your own desired assets by replacing the image files in this directory.
+
+You can also do it by opening your Flutter project's Xcode project with `open ios/Runner.xcworkspace`, selecting `Runner/Assets.xcassets` in the Project Navigator and dropping in the desired images.

packages/zefyr/example/ios/Runner/Base.lproj/LaunchScreen.storyboard

@@ -0,0 +1,37 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="12121" systemVersion="16G29" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" launchScreen="YES" colorMatched="YES" initialViewController="01J-lp-oVM">
+    <dependencies>
+        <deployment identifier="iOS"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="12089"/>
+    </dependencies>
+    <scenes>
+        <!--View Controller-->
+        <scene sceneID="EHf-IW-A2E">
+            <objects>
+                <viewController id="01J-lp-oVM" sceneMemberID="viewController">
+                    <layoutGuides>
+                        <viewControllerLayoutGuide type="top" id="Ydg-fD-yQy"/>
+                        <viewControllerLayoutGuide type="bottom" id="xbc-2k-c8Z"/>
+                    </layoutGuides>
+                    <view key="view" contentMode="scaleToFill" id="Ze5-6b-2t3">
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <subviews>
+                            <imageView opaque="NO" clipsSubviews="YES" multipleTouchEnabled="YES" contentMode="center" image="LaunchImage" translatesAutoresizingMaskIntoConstraints="NO" id="YRO-k0-Ey4">
+                            </imageView>
+                        </subviews>
+                        <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
+                        <constraints>
+                            <constraint firstItem="YRO-k0-Ey4" firstAttribute="centerX" secondItem="Ze5-6b-2t3" secondAttribute="centerX" id="1a2-6s-vTC"/>
+                            <constraint firstItem="YRO-k0-Ey4" firstAttribute="centerY" secondItem="Ze5-6b-2t3" secondAttribute="centerY" id="4X2-HB-R7a"/>
+                        </constraints>
+                    </view>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="iYj-Kq-Ea1" userLabel="First Responder" sceneMemberID="firstResponder"/>
+            </objects>
+            <point key="canvasLocation" x="53" y="375"/>
+        </scene>
+    </scenes>
+    <resources>
+        <image name="LaunchImage" width="168" height="185"/>
+    </resources>
+</document>

packages/zefyr/example/ios/Runner/Base.lproj/Main.storyboard

@@ -0,0 +1,26 @@
+<?xml version="1.0" encoding="UTF-8" standalone="no"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.Storyboard.XIB" version="3.0" toolsVersion="10117" systemVersion="15F34" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" useTraitCollections="YES" initialViewController="BYZ-38-t0r">
+    <dependencies>
+        <deployment identifier="iOS"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="10085"/>
+    </dependencies>
+    <scenes>
+        <!--Flutter View Controller-->
+        <scene sceneID="tne-QT-ifu">
+            <objects>
+                <viewController id="BYZ-38-t0r" customClass="FlutterViewController" sceneMemberID="viewController">
+                    <layoutGuides>
+                        <viewControllerLayoutGuide type="top" id="y3c-jy-aDJ"/>
+                        <viewControllerLayoutGuide type="bottom" id="wfy-db-euE"/>
+                    </layoutGuides>
+                    <view key="view" contentMode="scaleToFill" id="8bC-Xf-vdC">
+                        <rect key="frame" x="0.0" y="0.0" width="600" height="600"/>
+                        <autoresizingMask key="autoresizingMask" widthSizable="YES" heightSizable="YES"/>
+                        <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite"/>
+                    </view>
+                </viewController>
+                <placeholder placeholderIdentifier="IBFirstResponder" id="dkx-z0-nzr" sceneMemberID="firstResponder"/>
+            </objects>
+        </scene>
+    </scenes>
+</document>

packages/zefyr/example/ios/Runner/Info.plist

@@ -0,0 +1,45 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
+<plist version="1.0">
+<dict>
+	<key>CFBundleDevelopmentRegion</key>
+	<string>en</string>
+	<key>CFBundleExecutable</key>
+	<string>$(EXECUTABLE_NAME)</string>
+	<key>CFBundleIdentifier</key>
+	<string>$(PRODUCT_BUNDLE_IDENTIFIER)</string>
+	<key>CFBundleInfoDictionaryVersion</key>
+	<string>6.0</string>
+	<key>CFBundleName</key>
+	<string>example</string>
+	<key>CFBundlePackageType</key>
+	<string>APPL</string>
+	<key>CFBundleShortVersionString</key>
+	<string>$(FLUTTER_BUILD_NAME)</string>
+	<key>CFBundleSignature</key>
+	<string>????</string>
+	<key>CFBundleVersion</key>
+	<string>$(FLUTTER_BUILD_NUMBER)</string>
+	<key>LSRequiresIPhoneOS</key>
+	<true/>
+	<key>UILaunchStoryboardName</key>
+	<string>LaunchScreen</string>
+	<key>UIMainStoryboardFile</key>
+	<string>Main</string>
+	<key>UISupportedInterfaceOrientations</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+	</array>
+	<key>UISupportedInterfaceOrientations~ipad</key>
+	<array>
+		<string>UIInterfaceOrientationPortrait</string>
+		<string>UIInterfaceOrientationPortraitUpsideDown</string>
+		<string>UIInterfaceOrientationLandscapeLeft</string>
+		<string>UIInterfaceOrientationLandscapeRight</string>
+	</array>
+	<key>UIViewControllerBasedStatusBarAppearance</key>
+	<false/>
+</dict>
+</plist>

packages/zefyr/example/ios/Runner/main.m

@@ -0,0 +1,9 @@
+#import <Flutter/Flutter.h>
+#import <UIKit/UIKit.h>
+#import "AppDelegate.h"
+
+int main(int argc, char* argv[]) {
+  @autoreleasepool {
+    return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));
+  }
+}

packages/zefyr/example/lib/main.dart

@@ -0,0 +1,102 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:convert';
+
+import 'package:flutter/material.dart';
+import 'package:quill_delta/quill_delta.dart';
+import 'package:zefyr/zefyr.dart';
+
+void main() {
+  runApp(new ZefyrApp());
+}
+
+class ZefyrLogo extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return Row(
+      mainAxisAlignment: MainAxisAlignment.center,
+      children: <Widget>[
+        Text('Ze'),
+        FlutterLogo(size: 24.0),
+        Text('yr'),
+      ],
+    );
+  }
+}
+
+class ZefyrApp extends StatelessWidget {
+  @override
+  Widget build(BuildContext context) {
+    return new MaterialApp(
+      title: 'Zefyr Editor',
+      theme: new ThemeData(primarySwatch: Colors.cyan),
+      home: new MyHomePage(),
+    );
+  }
+}
+
+class MyHomePage extends StatefulWidget {
+  @override
+  _MyHomePageState createState() => new _MyHomePageState();
+}
+
+final doc =
+    r'[{"insert":"Zefyr"},{"insert":"\n","attributes":{"heading":1}},{"insert":"​","attributes":{"embed":{"type":"hr"}}},{"insert":"\n"},{"insert":"Soft and gentle rich text editing for Flutter applications.","attributes":{"i":true}},{"insert":"\nZefyr is an "},{"insert":"early preview","attributes":{"b":true}},{"insert":" open source library.\nDocumentation"},{"insert":"\n","attributes":{"heading":3}},{"insert":"Quick Start"},{"insert":"\n","attributes":{"block":"ul"}},{"insert":"Data format and Document Model"},{"insert":"\n","attributes":{"block":"ul"}},{"insert":"Style attributes"},{"insert":"\n","attributes":{"block":"ul"}},{"insert":"Heuristic rules"},{"insert":"\n","attributes":{"block":"ul"}},{"insert":"Clean and modern look"},{"insert":"\n","attributes":{"heading":2}},{"insert":"Zefyr’s rich text editor is built with simplicity and flexibility in mind. It provides clean interface for distraction-free editing. Think Medium.com-like experience.\nimport ‘package:flutter/material.dart’;"},{"insert":"\n","attributes":{"block":"code"}},{"insert":"import ‘package:zefyr/zefyr.dart’;"},{"insert":"\n\n","attributes":{"block":"code"}},{"insert":"void main() {"},{"insert":"\n","attributes":{"block":"code"}},{"insert":" print(“Hello world!”);"},{"insert":"\n","attributes":{"block":"code"}},{"insert":"}"},{"insert":"\n","attributes":{"block":"code"}},{"insert":"\n\n\n"}]';
+
+Delta getDelta() {
+  return Delta.fromJson(json.decode(doc));
+}
+
+class _MyHomePageState extends State<MyHomePage> {
+  final ZefyrController _controller =
+      ZefyrController(NotusDocument.fromDelta(getDelta()));
+  final FocusNode _focusNode = new FocusNode();
+  bool _editing = false;
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = new ZefyrThemeData(
+      toolbarTheme: ZefyrToolbarTheme.fallback(context).copyWith(
+            color: Colors.grey.shade800,
+            toggleColor: Colors.grey.shade900,
+            iconColor: Colors.white,
+            disabledIconColor: Colors.grey.shade500,
+          ),
+    );
+
+    final done = _editing
+        ? [new FlatButton(onPressed: _stopEditing, child: Text('DONE'))]
+        : [new FlatButton(onPressed: _startEditing, child: Text('EDIT'))];
+    return Scaffold(
+      resizeToAvoidBottomPadding: true,
+      appBar: AppBar(
+        elevation: 1.0,
+        backgroundColor: Colors.grey.shade200,
+        brightness: Brightness.light,
+        title: ZefyrLogo(),
+        actions: done,
+      ),
+      body: ZefyrTheme(
+        data: theme,
+        child: ZefyrEditor(
+          controller: _controller,
+          focusNode: _focusNode,
+          enabled: _editing,
+        ),
+      ),
+    );
+  }
+
+  void _startEditing() {
+    setState(() {
+      _editing = true;
+    });
+  }
+
+  void _stopEditing() {
+    setState(() {
+      _editing = false;
+    });
+  }
+}

packages/zefyr/example/pubspec.yaml

@@ -0,0 +1,67 @@
+name: example
+description: A new Flutter project.
+
+# The following defines the version and build number for your application.
+# A version number is three numbers separated by dots, like 1.2.43
+# followed by an optional build number separated by a +.
+# Both the version and the builder number may be overridden in flutter
+# build by specifying --build-name and --build-number, respectively.
+# Read more about versioning at semver.org.
+version: 1.0.0+1
+
+dependencies:
+  flutter:
+    sdk: flutter
+
+  # The following adds the Cupertino Icons font to your application.
+  # Use with the CupertinoIcons class for iOS style icons.
+  cupertino_icons: ^0.1.2
+  zefyr:
+    path: ../
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter
+
+
+# For information on the generic Dart part of this file, see the
+# following page: https://www.dartlang.org/tools/pub/pubspec
+
+# The following section is specific to Flutter.
+flutter:
+
+  # The following line ensures that the Material Icons font is
+  # included with your application, so that you can use the icons in
+  # the material Icons class.
+  uses-material-design: true
+
+  # To add assets to your application, add an assets section, like this:
+  # assets:
+  #  - images/a_dot_burr.jpeg
+  #  - images/a_dot_ham.jpeg
+
+  # An image asset can refer to one or more resolution-specific "variants", see
+  # https://flutter.io/assets-and-images/#resolution-aware.
+
+  # For details regarding adding assets from package dependencies, see
+  # https://flutter.io/assets-and-images/#from-packages
+
+  # To add custom fonts to your application, add a fonts section here,
+  # in this "flutter" section. Each entry in this list should have a
+  # "family" key with the font family name, and a "fonts" key with a
+  # list giving the asset and other descriptors for the font. For
+  # example:
+  # fonts:
+  #   - family: Schyler
+  #     fonts:
+  #       - asset: fonts/Schyler-Regular.ttf
+  #       - asset: fonts/Schyler-Italic.ttf
+  #         style: italic
+  #   - family: Trajan Pro
+  #     fonts:
+  #       - asset: fonts/TrajanPro.ttf
+  #       - asset: fonts/TrajanPro_Bold.ttf
+  #         weight: 700
+  #
+  # For details regarding fonts from package dependencies,
+  # see https://flutter.io/custom-fonts/#from-packages

packages/zefyr/lib/src/fast_diff.dart

@@ -0,0 +1,40 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:math' as math;
+
+/// Performs a fast diff operation on two input strings based on provided
+/// [cursorPosition].
+DiffResult fastDiff(String oldText, String newText, int cursorPosition) {
+  var delta = newText.length - oldText.length;
+  var limit = math.max(0, cursorPosition - delta);
+  var end = oldText.length;
+  while (end > limit && oldText[end - 1] == newText[end + delta - 1]) {
+    end -= 1;
+  }
+  var start = 0;
+  var startLimit = cursorPosition - math.max(0, delta);
+  while (start < startLimit && oldText[start] == newText[start]) {
+    start += 1;
+  }
+  final String deleted = (start < end) ? oldText.substring(start, end) : '';
+  final inserted = newText.substring(start, end + delta);
+  return new DiffResult(start, deleted, inserted);
+}
+
+/// A diff between two strings of text.
+class DiffResult {
+  /// Start index in old text at which changes begin.
+  final int start;
+
+  /// Deleted text in old text.
+  final String deleted;
+
+  /// Inserted text.
+  final String inserted;
+
+  DiffResult(this.start, this.deleted, this.inserted);
+
+  @override
+  String toString() => 'DiffResult[$start, "$deleted", "$inserted"]';
+}

packages/zefyr/lib/src/widgets/buttons.dart

@@ -0,0 +1,512 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter/material.dart';
+import 'package:flutter/services.dart';
+import 'package:url_launcher/url_launcher.dart';
+import 'package:notus/notus.dart';
+
+import 'editor.dart';
+import 'theme.dart';
+import 'toolbar.dart';
+
+/// A button used in [ZefyrToolbar].
+///
+/// Create an instance of this widget with [ZefyrButton.icon] or
+/// [ZefyrButton.text] constructors.
+///
+/// Toolbar buttons are normally created by a [ZefyrToolbarDelegate].
+class ZefyrButton extends StatelessWidget {
+  /// Creates a toolbar button with an icon.
+  ZefyrButton.icon({
+    @required this.action,
+    @required IconData icon,
+    double iconSize,
+    this.onPressed,
+  })  : assert(action != null),
+        assert(icon != null),
+        _icon = icon,
+        _iconSize = iconSize,
+        _text = null,
+        _textStyle = null,
+        super();
+
+  /// Creates a toolbar button containing text.
+  ///
+  /// Note that [ZefyrButton] has fixed width and does not expand to accommodate
+  /// long texts.
+  ZefyrButton.text({
+    @required this.action,
+    @required String text,
+    TextStyle style,
+    this.onPressed,
+  })  : assert(action != null),
+        assert(text != null),
+        _icon = null,
+        _iconSize = null,
+        _text = text,
+        _textStyle = style,
+        super();
+
+  /// Toolbar action associated with this button.
+  final ZefyrToolbarAction action;
+  final IconData _icon;
+  final double _iconSize;
+  final String _text;
+  final TextStyle _textStyle;
+
+  /// Callback to trigger when this button is tapped.
+  final VoidCallback onPressed;
+
+  bool get isAttributeAction {
+    return kZefyrToolbarAttributeActions.keys.contains(action);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final editor = ZefyrEditor.of(context);
+    final toolbar = ZefyrToolbar.of(context);
+    final toolbarTheme = ZefyrTheme.of(context).toolbarTheme;
+    final pressedHandler = _getPressedHandler(editor, toolbar);
+    final iconColor = (pressedHandler == null)
+        ? toolbarTheme.disabledIconColor
+        : toolbarTheme.iconColor;
+    if (_icon != null) {
+      return RawZefyrButton.icon(
+        action: action,
+        icon: _icon,
+        size: _iconSize,
+        iconColor: iconColor,
+        color: _getColor(editor, toolbarTheme),
+        onPressed: _getPressedHandler(editor, toolbar),
+      );
+    } else {
+      assert(_text != null);
+      var style = _textStyle ?? new TextStyle();
+      style = style.copyWith(color: iconColor);
+      return RawZefyrButton(
+        action: action,
+        child: new Text(_text, style: style),
+        color: _getColor(editor, toolbarTheme),
+        onPressed: _getPressedHandler(editor, toolbar),
+      );
+    }
+  }
+
+  Color _getColor(ZefyrEditorScope editor, ZefyrToolbarTheme theme) {
+    if (isAttributeAction) {
+      final attribute = kZefyrToolbarAttributeActions[action];
+      final isToggled = (attribute is NotusAttribute)
+          ? editor.selectionStyle.containsSame(attribute)
+          : editor.selectionStyle.contains(attribute);
+      return isToggled ? theme.toggleColor : null;
+    }
+    return null;
+  }
+
+  VoidCallback _getPressedHandler(
+      ZefyrEditorScope editor, ZefyrToolbarState toolbar) {
+    if (onPressed != null) {
+      return onPressed;
+    } else if (isAttributeAction) {
+      final attribute = kZefyrToolbarAttributeActions[action];
+      if (attribute is NotusAttribute) {
+        return () => _toggleAttribute(attribute, editor);
+      }
+    } else if (action == ZefyrToolbarAction.close) {
+      return () => toolbar.closeOverlay();
+    } else if (action == ZefyrToolbarAction.hideKeyboard) {
+      return () => editor.hideKeyboard();
+    }
+
+    return null;
+  }
+
+  void _toggleAttribute(NotusAttribute attribute, ZefyrEditorScope editor) {
+    final isToggled = editor.selectionStyle.containsSame(attribute);
+    if (isToggled) {
+      editor.formatSelection(attribute.unset);
+    } else {
+      editor.formatSelection(attribute);
+    }
+  }
+}
+
+/// Raw button widget used by [ZefyrToolbar].
+///
+/// See also:
+///
+///   * [ZefyrButton], which wraps this widget and implements most of the
+///     action-specific logic.
+class RawZefyrButton extends StatelessWidget {
+  const RawZefyrButton({
+    Key key,
+    @required this.action,
+    @required this.child,
+    @required this.color,
+    @required this.onPressed,
+  }) : super(key: key);
+
+  /// Creates a [RawZefyrButton] containing an icon.
+  RawZefyrButton.icon({
+    @required this.action,
+    @required IconData icon,
+    double size,
+    Color iconColor,
+    @required this.color,
+    @required this.onPressed,
+  })  : child = new Icon(icon, size: size, color: iconColor),
+        super();
+
+  /// Toolbar action associated with this button.
+  final ZefyrToolbarAction action;
+
+  /// Child widget to show inside this button. Usually an icon.
+  final Widget child;
+
+  /// Background color of this button.
+  final Color color;
+
+  /// Callback to trigger when this button is pressed.
+  final VoidCallback onPressed;
+
+  /// Returns `true` if this button is currently toggled on.
+  bool get isToggled => color != null;
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    final width = theme.buttonTheme.constraints.minHeight + 4.0;
+    final constraints = theme.buttonTheme.constraints.copyWith(
+        minWidth: width, maxHeight: theme.buttonTheme.constraints.minHeight);
+    final radius = BorderRadius.all(Radius.circular(3.0));
+    return Padding(
+      padding: const EdgeInsets.symmetric(horizontal: 1.0, vertical: 6.0),
+      child: RawMaterialButton(
+        shape: RoundedRectangleBorder(borderRadius: radius),
+        elevation: 0.0,
+        fillColor: color,
+        constraints: constraints,
+        onPressed: onPressed,
+        child: child,
+      ),
+    );
+  }
+}
+
+/// Controls heading styles.
+///
+/// When pressed, this button displays overlay toolbar with three
+/// buttons for each heading level.
+class HeadingButton extends StatefulWidget {
+  const HeadingButton({Key key}) : super(key: key);
+
+  @override
+  _HeadingButtonState createState() => _HeadingButtonState();
+}
+
+class _HeadingButtonState extends State<HeadingButton> {
+  @override
+  Widget build(BuildContext context) {
+    final toolbar = ZefyrToolbar.of(context);
+    return toolbar.buildButton(
+      context,
+      ZefyrToolbarAction.heading,
+      onPressed: showOverlay,
+    );
+  }
+
+  void showOverlay() {
+    final toolbar = ZefyrToolbar.of(context);
+    toolbar.showOverlay(buildOverlay);
+  }
+
+  Widget buildOverlay(BuildContext context) {
+    final toolbar = ZefyrToolbar.of(context);
+    final buttons = Row(
+      children: <Widget>[
+        SizedBox(width: 8.0),
+        toolbar.buildButton(context, ZefyrToolbarAction.headingLevel1),
+        toolbar.buildButton(context, ZefyrToolbarAction.headingLevel2),
+        toolbar.buildButton(context, ZefyrToolbarAction.headingLevel3),
+      ],
+    );
+    return ZefyrToolbarScaffold(body: buttons);
+  }
+}
+
+class LinkButton extends StatefulWidget {
+  const LinkButton({Key key}) : super(key: key);
+
+  @override
+  _LinkButtonState createState() => _LinkButtonState();
+}
+
+class _LinkButtonState extends State<LinkButton> {
+  final TextEditingController _inputController = new TextEditingController();
+  Key _inputKey;
+  bool _formatError = false;
+  bool get isEditing => _inputKey != null;
+
+  @override
+  Widget build(BuildContext context) {
+    final editor = ZefyrEditor.of(context);
+    final toolbar = ZefyrToolbar.of(context);
+    final enabled =
+        hasLink(editor.selectionStyle) || !editor.selection.isCollapsed;
+
+    return toolbar.buildButton(
+      context,
+      ZefyrToolbarAction.link,
+      onPressed: enabled ? showOverlay : null,
+    );
+  }
+
+  bool hasLink(NotusStyle style) => style.contains(NotusAttribute.link);
+
+  String getLink([String defaultValue]) {
+    final editor = ZefyrEditor.of(context);
+    final attrs = editor.selectionStyle;
+    if (hasLink(attrs)) {
+      return attrs.value(NotusAttribute.link);
+    }
+    return defaultValue;
+  }
+
+  void showOverlay() {
+    final toolbar = ZefyrToolbar.of(context);
+    toolbar.showOverlay(buildOverlay).whenComplete(cancelEdit);
+  }
+
+  void closeOverlay() {
+    final toolbar = ZefyrToolbar.of(context);
+    toolbar.closeOverlay();
+  }
+
+  void edit() {
+    final toolbar = ZefyrToolbar.of(context);
+    setState(() {
+      _inputKey = new UniqueKey();
+      _inputController.text = getLink('https://');
+      _inputController.addListener(_handleInputChange);
+      toolbar.markNeedsRebuild();
+    });
+  }
+
+  void doneEdit() {
+    final editor = ZefyrEditor.of(context);
+    final toolbar = ZefyrToolbar.of(context);
+    setState(() {
+      var error = false;
+      if (_inputController.text.isNotEmpty) {
+        try {
+          var uri = Uri.parse(_inputController.text);
+          if ((uri.isScheme('https') || uri.isScheme('http')) &&
+              uri.host.isNotEmpty) {
+            editor.formatSelection(
+                NotusAttribute.link.fromString(_inputController.text));
+          } else {
+            error = true;
+          }
+        } on FormatException {
+          error = true;
+        }
+      }
+      if (error) {
+        _formatError = error;
+        toolbar.markNeedsRebuild();
+      } else {
+        _inputKey = null;
+        _inputController.text = '';
+        _inputController.removeListener(_handleInputChange);
+        toolbar.markNeedsRebuild();
+        editor.focus(context);
+      }
+    });
+  }
+
+  void cancelEdit() {
+    if (mounted) {
+      final editor = ZefyrEditor.of(context);
+      setState(() {
+        _inputKey = null;
+        _inputController.text = '';
+        _inputController.removeListener(_handleInputChange);
+        editor.focus(context);
+      });
+    }
+  }
+
+  void unlink() {
+    final editor = ZefyrEditor.of(context);
+    editor.formatSelection(NotusAttribute.link.unset);
+    closeOverlay();
+  }
+
+  void copyToClipboard() {
+    var link = getLink();
+    assert(link != null);
+    Clipboard.setData(new ClipboardData(text: link));
+  }
+
+  void openInBrowser() async {
+    final editor = ZefyrEditor.of(context);
+    var link = getLink();
+    assert(link != null);
+    if (await canLaunch(link)) {
+      editor.hideKeyboard();
+      await launch(link, forceWebView: true);
+    }
+  }
+
+  void _handleInputChange() {
+    final toolbar = ZefyrToolbar.of(context);
+    setState(() {
+      _formatError = false;
+      toolbar.markNeedsRebuild();
+    });
+  }
+
+  Widget buildOverlay(BuildContext context) {
+    final editor = ZefyrEditor.of(context);
+    final toolbar = ZefyrToolbar.of(context);
+    final style = editor.selectionStyle;
+
+    String value = 'Tap to edit link';
+    if (style.contains(NotusAttribute.link)) {
+      value = style.value(NotusAttribute.link);
+    }
+    final clipboardEnabled = value != 'Tap to edit link';
+    final body = !isEditing
+        ? _LinkView(value: value, onTap: edit)
+        : _LinkInput(
+            key: _inputKey,
+            controller: _inputController,
+            focusNode: editor.toolbarFocusNode,
+            formatError: _formatError,
+          );
+    final items = <Widget>[Expanded(child: body)];
+    if (!isEditing) {
+      final unlinkHandler = hasLink(style) ? unlink : null;
+      final copyHandler = clipboardEnabled ? copyToClipboard : null;
+      final openHandler = hasLink(style) ? openInBrowser : null;
+      final buttons = <Widget>[
+        toolbar.buildButton(context, ZefyrToolbarAction.unlink,
+            onPressed: unlinkHandler),
+        toolbar.buildButton(context, ZefyrToolbarAction.clipboardCopy,
+            onPressed: copyHandler),
+        toolbar.buildButton(
+          context,
+          ZefyrToolbarAction.openInBrowser,
+          onPressed: openHandler,
+        ),
+      ];
+      items.addAll(buttons);
+    }
+    final trailingPressed = isEditing ? doneEdit : closeOverlay;
+    final trailingAction =
+        isEditing ? ZefyrToolbarAction.confirm : ZefyrToolbarAction.close;
+
+    return ZefyrToolbarScaffold(
+      body: Row(children: items),
+      trailing: toolbar.buildButton(
+        context,
+        trailingAction,
+        onPressed: trailingPressed,
+      ),
+    );
+  }
+}
+
+class _LinkInput extends StatefulWidget {
+  final FocusNode focusNode;
+  final TextEditingController controller;
+  final bool formatError;
+
+  const _LinkInput({
+    Key key,
+    @required this.focusNode,
+    @required this.controller,
+    this.formatError: false,
+  }) : super(key: key);
+  @override
+  _LinkInputState createState() {
+    return new _LinkInputState();
+  }
+}
+
+class _LinkInputState extends State<_LinkInput> {
+  bool _didAutoFocus = false;
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    if (!_didAutoFocus) {
+      FocusScope.of(context).requestFocus(widget.focusNode);
+      _didAutoFocus = true;
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    FocusScope.of(context).reparentIfNeeded(widget.focusNode);
+
+    final theme = Theme.of(context);
+    final toolbarTheme = ZefyrTheme.of(context).toolbarTheme;
+    final color =
+        widget.formatError ? Colors.redAccent : toolbarTheme.iconColor;
+    final style = theme.textTheme.subhead.copyWith(color: color);
+    return TextField(
+      style: style,
+      keyboardType: TextInputType.url,
+      focusNode: widget.focusNode,
+      controller: widget.controller,
+      autofocus: true,
+      decoration: new InputDecoration(
+          hintText: 'https://',
+          filled: true,
+          fillColor: toolbarTheme.color,
+          border: InputBorder.none,
+          contentPadding: const EdgeInsets.all(10.0)),
+    );
+  }
+}
+
+class _LinkView extends StatelessWidget {
+  const _LinkView({Key key, @required this.value, this.onTap})
+      : super(key: key);
+  final String value;
+  final VoidCallback onTap;
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = Theme.of(context);
+    final toolbarTheme = ZefyrTheme.of(context).toolbarTheme;
+    Widget widget = new ClipRect(
+      child: ListView(
+        scrollDirection: Axis.horizontal,
+        children: <Widget>[
+          Container(
+            alignment: AlignmentDirectional.centerStart,
+            constraints: BoxConstraints(minHeight: ZefyrToolbar.kToolbarHeight),
+            padding: const EdgeInsets.all(10.0),
+            child: Text(
+              value,
+              maxLines: 1,
+              overflow: TextOverflow.ellipsis,
+              style: theme.textTheme.subhead
+                  .copyWith(color: toolbarTheme.disabledIconColor),
+            ),
+          )
+        ],
+      ),
+    );
+    if (onTap != null) {
+      widget = GestureDetector(
+        child: widget,
+        onTap: onTap,
+      );
+    }
+    return widget;
+  }
+}

packages/zefyr/lib/src/widgets/caret.dart

@@ -0,0 +1,26 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:ui';
+
+import 'package:flutter/material.dart';
+
+class CaretPainter {
+  static const double _kCaretHeightOffset = 2.0; // pixels
+  static const double _kCaretWidth = 1.0; // pixels
+
+  Rect _prototype;
+
+  Rect get prototype => _prototype;
+
+  void layout(double lineHeight) {
+    _prototype = new Rect.fromLTWH(
+        0.0, 0.0, _kCaretWidth, lineHeight - _kCaretHeightOffset);
+  }
+
+  void paint(Canvas canvas, Offset offset) {
+    final Paint paint = new Paint()..color = Colors.black;
+    final Rect caretRect = _prototype.shift(offset);
+    canvas.drawRect(caretRect, paint);
+  }
+}

packages/zefyr/lib/src/widgets/code.dart

@@ -0,0 +1,47 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter/material.dart';
+import 'package:notus/notus.dart';
+
+import 'common.dart';
+import 'theme.dart';
+
+/// Represents a code snippet in Zefyr editor.
+class ZefyrCode extends StatelessWidget {
+  const ZefyrCode({Key key, @required this.node}) : super(key: key);
+
+  /// Document node represented by this widget.
+  final BlockNode node;
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = ZefyrTheme.of(context);
+
+    List<Widget> items = [];
+    for (var line in node.children) {
+      items.add(_buildLine(line, theme.blockTheme.code.textStyle));
+    }
+
+    return new Padding(
+      padding: theme.blockTheme.code.padding,
+      child: new Container(
+        // TODO: make decorations configurable
+        decoration: BoxDecoration(
+          color: Colors.blueGrey.shade50,
+          borderRadius: BorderRadius.circular(3.0),
+        ),
+        padding: const EdgeInsets.all(16.0),
+        child: new Column(
+          crossAxisAlignment: CrossAxisAlignment.stretch,
+          children: items,
+        ),
+      ),
+    );
+  }
+
+  Widget _buildLine(Node node, TextStyle style) {
+    LineNode line = node;
+    return new RawZefyrLine(node: line, style: style);
+  }
+}

packages/zefyr/lib/src/widgets/common.dart

@@ -0,0 +1,155 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter/rendering.dart';
+import 'package:flutter/widgets.dart';
+import 'package:notus/notus.dart';
+
+import 'editable_paragraph.dart';
+import 'editable_text.dart';
+import 'horizontal_rule.dart';
+import 'theme.dart';
+
+/// Raw widget representing a single line of Notus document in Zefyr editor.
+///
+/// See [ZefyrParagraph] and [ZefyrHeading] which wrap this widget and
+/// integrate it with current [ZefyrTheme].
+class RawZefyrLine extends StatefulWidget {
+  const RawZefyrLine({
+    Key key,
+    @required this.node,
+    this.style,
+    this.padding,
+  }) : super(key: key);
+
+  /// Line in the document represented by this widget.
+  final LineNode node;
+
+  /// Style to apply to this line. Required for lines with text contents,
+  /// ignored for lines containing embeds.
+  final TextStyle style;
+
+  /// Padding to add around this paragraph.
+  final EdgeInsets padding;
+
+  @override
+  _RawZefyrLineState createState() => new _RawZefyrLineState();
+}
+
+class _RawZefyrLineState extends State<RawZefyrLine> {
+  final LayerLink _link = new LayerLink();
+
+  @override
+  Widget build(BuildContext context) {
+    ensureVisible(context);
+    final theme = ZefyrTheme.of(context);
+    final editable = ZefyrEditableText.of(context);
+
+    Widget content;
+    if (widget.node.hasEmbed) {
+      content = buildEmbed(context);
+    } else {
+      assert(widget.style != null);
+      content = new EditableParagraph(
+        node: widget.node,
+        text: buildText(context),
+        layerLink: _link,
+        renderContext: editable.renderContext,
+        showCursor: editable.showCursor,
+        selection: editable.selection,
+        selectionColor: theme.selectionColor,
+      );
+    }
+
+    final result = new CompositedTransformTarget(link: _link, child: content);
+    if (widget.padding != null) {
+      return new Padding(padding: widget.padding, child: result);
+    }
+    return result;
+  }
+
+  void ensureVisible(BuildContext context) {
+    final editable = ZefyrEditableText.of(context);
+    if (editable.selection.isCollapsed &&
+        widget.node.containsOffset(editable.selection.extentOffset)) {
+      WidgetsBinding.instance.addPostFrameCallback((_) {
+        bringIntoView(context);
+      });
+    }
+  }
+
+  void bringIntoView(BuildContext context) {
+    ScrollableState scrollable = Scrollable.of(context);
+    final object = context.findRenderObject();
+    assert(object.attached);
+    final RenderAbstractViewport viewport = RenderAbstractViewport.of(object);
+    assert(viewport != null);
+
+    final double offset = scrollable.position.pixels;
+    double target = viewport.getOffsetToReveal(object, 0.0).offset;
+    if (target - offset < 0.0) {
+      scrollable.position.jumpTo(target);
+      return;
+    }
+    target = viewport.getOffsetToReveal(object, 1.0).offset;
+    if (target - offset > 0.0) {
+      scrollable.position.jumpTo(target);
+    }
+  }
+
+  TextSpan buildText(BuildContext context) {
+    final theme = ZefyrTheme.of(context);
+    final List<TextSpan> children = widget.node.children
+        .map((node) => _segmentToTextSpan(node, theme))
+        .toList(growable: false);
+    return new TextSpan(style: widget.style, children: children);
+  }
+
+  TextSpan _segmentToTextSpan(Node node, ZefyrThemeData theme) {
+    final TextNode segment = node;
+    final attrs = segment.style;
+
+    return new TextSpan(
+      text: segment.value,
+      style: _getTextStyle(attrs, theme),
+    );
+  }
+
+  TextStyle _getTextStyle(NotusStyle style, ZefyrThemeData theme) {
+    TextStyle result = new TextStyle();
+    if (style.containsSame(NotusAttribute.bold)) {
+      result = result.merge(theme.boldStyle);
+    }
+    if (style.containsSame(NotusAttribute.italic)) {
+      result = result.merge(theme.italicStyle);
+    }
+    if (style.contains(NotusAttribute.link)) {
+      result = result.merge(theme.linkStyle);
+    }
+    return result;
+  }
+
+  Widget buildEmbed(BuildContext context) {
+    final theme = ZefyrTheme.of(context);
+    final editable = ZefyrEditableText.of(context);
+
+    EmbedNode node = widget.node.children.single;
+    EmbedAttribute embed = node.style.get(NotusAttribute.embed);
+
+    if (embed.type == EmbedType.horizontalRule) {
+      return new HorizontalRule(
+        node: widget.node,
+        layerLink: _link,
+        renderContext: editable.renderContext,
+        showCursor: editable.showCursor,
+        selection: editable.selection,
+        selectionColor: theme.selectionColor,
+      );
+    } else if (embed.type == EmbedType.image) {
+      // TODO: implement image embeds.
+      return null;
+    } else {
+      throw new UnimplementedError('Unimplemented embed type ${embed.type}');
+    }
+  }
+}

packages/zefyr/lib/src/widgets/controller.dart

@@ -0,0 +1,164 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:math' as math;
+
+import 'package:flutter/widgets.dart';
+import 'package:notus/notus.dart';
+import 'package:quill_delta/quill_delta.dart';
+import 'package:zefyr/util.dart';
+
+const TextSelection _kZeroSelection = const TextSelection.collapsed(
+  offset: 0,
+  affinity: TextAffinity.upstream,
+);
+
+/// Owner of focus.
+enum FocusOwner {
+  /// Current owner is the editor.
+  editor,
+
+  /// Current owner is the toolbar.
+  toolbar,
+
+  /// No focus owner.
+  none,
+}
+
+/// Controls instance of [ZefyrEditor].
+class ZefyrController extends ChangeNotifier {
+  ZefyrController(NotusDocument document)
+      : assert(document != null),
+        _document = document;
+
+  /// Zefyr document managed by this controller.
+  NotusDocument get document => _document;
+  NotusDocument _document;
+
+  /// Currently selected text within the [document].
+  TextSelection get selection => _selection;
+  TextSelection _selection = _kZeroSelection;
+
+  ChangeSource _lastChangeSource;
+
+  /// Source of the last text or selection change.
+  ChangeSource get lastChangeSource => _lastChangeSource;
+
+  /// Updates selection with specified [value].
+  ///
+  /// [value] and [source] cannot be `null`.
+  void updateSelection(TextSelection value,
+      {ChangeSource source: ChangeSource.remote}) {
+    _updateSelectionSilent(value, source: source);
+    notifyListeners();
+  }
+
+  // Updates selection without triggering notifications to listeners.
+  void _updateSelectionSilent(TextSelection value,
+      {ChangeSource source: ChangeSource.remote}) {
+    assert(value != null && source != null);
+    _selection = value;
+    _lastChangeSource = source;
+    _ensureSelectionBeforeLastBreak();
+  }
+
+  @override
+  void dispose() {
+    _document.close();
+    super.dispose();
+  }
+
+  /// Composes [change] into document managed by this controller.
+  ///
+  /// This method does not apply any adjustments or heuristic rules to
+  /// provided [change] and it is caller's responsibility to ensure this change
+  /// can be composed without errors.
+  ///
+  /// If composing this change fails then this method throws [ComposeError].
+  void compose(Delta change,
+      {TextSelection selection, ChangeSource source: ChangeSource.remote}) {
+    if (change.isNotEmpty) {
+      _document.compose(change, source);
+    }
+    if (selection != null) {
+      _updateSelectionSilent(selection, source: source);
+    } else {
+      // Transform selection against the composed change and give priority to
+      // current position (force: false).
+      final base =
+          change.transformPosition(_selection.baseOffset, force: false);
+      final extent =
+          change.transformPosition(_selection.extentOffset, force: false);
+      selection = _selection.copyWith(baseOffset: base, extentOffset: extent);
+      if (_selection != selection) {
+        _updateSelectionSilent(selection, source: source);
+      }
+    }
+    _lastChangeSource = source;
+    notifyListeners();
+  }
+
+  void replaceText(int index, int length, String text,
+      {TextSelection selection}) {
+    Delta delta;
+    if (length > 0 || text.isNotEmpty) {
+      delta = document.replace(index, length, text);
+    }
+    if (selection != null) {
+      if (delta == null) {
+        _updateSelectionSilent(selection, source: ChangeSource.local);
+      } else {
+        // need to transform selection position in case actual delta
+        // is different from user's version (in deletes and inserts).
+        Delta user = new Delta()
+          ..retain(index)
+          ..insert(text)
+          ..delete(length);
+        int positionDelta = getPositionDelta(user, delta);
+        _updateSelectionSilent(
+          selection.copyWith(
+            baseOffset: selection.baseOffset + positionDelta,
+            extentOffset: selection.extentOffset + positionDelta,
+          ),
+          source: ChangeSource.local,
+        );
+      }
+    }
+    _lastChangeSource = ChangeSource.local;
+    notifyListeners();
+  }
+
+  void formatText(int index, int length, NotusAttribute attribute) {
+    document.format(index, length, attribute);
+    _lastChangeSource = ChangeSource.local;
+    notifyListeners();
+  }
+
+  /// Formats current selection with [attribute].
+  void formatSelection(NotusAttribute attribute) {
+    int index = _selection.start;
+    int length = _selection.end - index;
+    formatText(index, length, attribute);
+  }
+
+  NotusStyle getSelectionStyle() {
+    int start = _selection.start;
+    int length = _selection.end - start;
+    return _document.collectStyle(start, length);
+  }
+
+  TextEditingValue get plainTextEditingValue {
+    return new TextEditingValue(
+      text: document.toPlainText(),
+      selection: selection,
+      composing: new TextRange.collapsed(0),
+    );
+  }
+
+  void _ensureSelectionBeforeLastBreak() {
+    final end = _document.length - 1;
+    final base = math.min(_selection.baseOffset, end);
+    final extent = math.min(_selection.extentOffset, end);
+    _selection = _selection.copyWith(baseOffset: base, extentOffset: extent);
+  }
+}

packages/zefyr/lib/src/widgets/editable_box.dart

@@ -0,0 +1,18 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:ui' as ui;
+
+import 'package:flutter/rendering.dart';
+import 'package:notus/notus.dart';
+
+abstract class RenderEditableBox implements RenderBox {
+  ContainerNode get node;
+  double get preferredLineHeight;
+  LayerLink get layerLink;
+  TextPosition getPositionForOffset(Offset offset);
+  List<ui.TextBox> getEndpointsForSelection(TextSelection selection,
+      {bool isLocal: false});
+  TextSelection getLocalSelection(TextSelection selection);
+  TextRange getWordBoundary(TextPosition position);
+}

packages/zefyr/lib/src/widgets/editable_image.dart

@@ -0,0 +1,271 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:math' as math;
+import 'dart:ui' as ui;
+
+import 'package:flutter/rendering.dart';
+import 'package:flutter/widgets.dart';
+import 'package:notus/notus.dart';
+
+import 'editable_box.dart';
+import 'render_context.dart';
+
+class EditableImage extends LeafRenderObjectWidget {
+  EditableImage({
+    @required this.node,
+    @required this.layerLink,
+    @required this.renderContext,
+    @required this.showCursor,
+    @required this.selection,
+    @required this.selectionColor,
+  }) : assert(renderContext != null);
+
+  final ContainerNode node;
+  final LayerLink layerLink;
+  final ZefyrRenderContext renderContext;
+  final ValueNotifier<bool> showCursor;
+  final TextSelection selection;
+  final Color selectionColor;
+
+  @override
+  RenderEditableImage createRenderObject(BuildContext context) {
+    return new RenderEditableImage(
+      node: node,
+      layerLink: layerLink,
+      renderContext: renderContext,
+      showCursor: showCursor,
+      selection: selection,
+      selectionColor: selectionColor,
+    );
+  }
+
+  @override
+  void updateRenderObject(
+      BuildContext context, RenderEditableImage renderObject) {
+    renderObject
+      ..node = node
+      ..layerLink = layerLink
+      ..renderContext = renderContext
+      ..showCursor = showCursor
+      ..selection = selection
+      ..selectionColor = selectionColor;
+  }
+}
+
+class RenderEditableImage extends RenderImage implements RenderEditableBox {
+  RenderEditableImage({
+    ui.Image image,
+    @required ContainerNode node,
+    @required LayerLink layerLink,
+    @required ZefyrRenderContext renderContext,
+    @required ValueNotifier<bool> showCursor,
+    @required TextSelection selection,
+    @required Color selectionColor,
+  })  : _node = node,
+        _layerLink = layerLink,
+        _renderContext = renderContext,
+        _showCursor = showCursor,
+        _selection = selection,
+        _selectionColor = selectionColor,
+        super(
+          image: image,
+        );
+  //
+  // Public members
+  //
+
+  ContainerNode get node => _node;
+  ContainerNode _node;
+  void set node(ContainerNode value) {
+    _node = value;
+  }
+
+  LayerLink get layerLink => _layerLink;
+  LayerLink _layerLink;
+  void set layerLink(LayerLink value) {
+    if (_layerLink == value) return;
+    _layerLink = value;
+  }
+
+  ZefyrRenderContext _renderContext;
+  void set renderContext(ZefyrRenderContext value) {
+    if (_renderContext == value) return;
+    if (attached) _renderContext.removeBox(this);
+    _renderContext = value;
+    if (attached) _renderContext.addBox(this);
+  }
+
+  ValueNotifier<bool> _showCursor;
+  set showCursor(ValueNotifier<bool> value) {
+    assert(value != null);
+    if (_showCursor == value) return;
+    if (attached) _showCursor.removeListener(markNeedsPaint);
+    _showCursor = value;
+    if (attached) _showCursor.addListener(markNeedsPaint);
+    markNeedsPaint();
+  }
+
+  TextSelection _selection;
+  set selection(TextSelection value) {
+    if (_selection == value) return;
+    // TODO: check if selection affects this block (also check previous value)
+    _selection = value;
+    markNeedsPaint();
+  }
+
+  Color _selectionColor;
+  set selectionColor(Color value) {
+    if (_selectionColor == value) return;
+    _selectionColor = value;
+    markNeedsPaint();
+  }
+
+  double get preferredLineHeight => size.height;
+
+  /// Returns part of document [selection] local to this paragraph. May return
+  /// `null`.
+  ///
+  /// [selection] must not be collapsed.
+  TextSelection getLocalSelection(TextSelection selection) {
+    if (!_intersectsWithSelection(selection)) return null;
+
+    int nodeBase = node.documentOffset;
+    int nodeExtent = nodeBase + node.length;
+    int base = math.max(0, selection.baseOffset - nodeBase);
+    int extent = math.min(selection.extentOffset, nodeExtent) - nodeBase;
+    return _selection.copyWith(baseOffset: base, extentOffset: extent);
+  }
+
+  List<ui.TextBox> getEndpointsForSelection(TextSelection selection,
+      {bool isLocal: false}) {
+    TextSelection local = isLocal ? selection : getLocalSelection(selection);
+    if (local.isCollapsed) {
+      return [
+        new ui.TextBox.fromLTRBD(0.0, 0.0, 0.0, size.height, TextDirection.ltr),
+      ];
+    }
+
+    return [
+      new ui.TextBox.fromLTRBD(0.0, 0.0, 0.0, size.height, TextDirection.ltr),
+      new ui.TextBox.fromLTRBD(
+          size.width, 0.0, size.width, size.height, TextDirection.ltr),
+    ];
+  }
+
+  //
+  // Overridden members
+  //
+
+  @override
+  void attach(PipelineOwner owner) {
+    super.attach(owner);
+    _showCursor.addListener(markNeedsPaint);
+    _renderContext.addBox(this);
+  }
+
+  @override
+  void detach() {
+    _showCursor.removeListener(markNeedsPaint);
+    _renderContext.removeBox(this);
+    super.detach();
+  }
+
+  @override
+  bool hitTestSelf(Offset position) => true;
+
+  @override
+  bool hitTest(HitTestResult result, {Offset position}) {
+    if (size.contains(position)) {
+      result.add(new BoxHitTestEntry(this, position));
+      return true;
+    }
+    return false;
+  }
+
+  @override
+  void performLayout() {
+    super.performLayout();
+//    _prototypePainter.layout(
+//        minWidth: constraints.minWidth, maxWidth: constraints.maxWidth);
+//    _caretPainter.layout(_prototypePainter.height);
+    // Indicate to render context that this object can be used by other
+    // layers (selection overlay, for instance).
+    _renderContext.markDirty(this, false);
+  }
+
+  @override
+  void paint(PaintingContext context, Offset offset) {
+//    if (_isSelectionVisible) _paintSelection(context, offset);
+    super.paint(context, offset);
+//    if (_isCaretVisible) _paintCaret(context, offset);
+  }
+
+  @override
+  void markNeedsLayout() {
+    // Temporarily remove this object from the render context.
+    _renderContext.markDirty(this, true);
+    super.markNeedsLayout();
+  }
+
+  @override
+  ui.TextPosition getPositionForOffset(ui.Offset offset) {
+    return new ui.TextPosition(offset: node.documentOffset);
+  }
+
+  //
+  // Private members
+  //
+
+//  final CaretPainter _caretPainter = new CaretPainter();
+//  List<ui.TextBox> _selectionRects;
+
+  /// Returns `true` if current selection is collapsed, located within
+  /// this paragraph and is visible according to tick timer.
+//  bool get _isCaretVisible {
+//    if (!_selection.isCollapsed) return false;
+//    if (!_showCursor.value) return false;
+//
+//    final int start = node.documentOffset;
+//    final int end = start + node.length;
+//    final int caretOffset = _selection.extentOffset;
+//    return caretOffset >= start && caretOffset < end;
+//  }
+
+  /// Returns `true` if selection is not collapsed and intersects with this
+  /// paragraph.
+//  bool get _isSelectionVisible {
+//    if (_selection.isCollapsed) return false;
+//    return _intersectsWithSelection(_selection);
+//  }
+
+  /// Returns `true` if this paragraph intersects with document [selection].
+  bool _intersectsWithSelection(TextSelection selection) {
+    final int base = node.documentOffset;
+    final int extent = base + node.length;
+    return base <= selection.extentOffset && selection.baseOffset <= extent;
+  }
+
+  @override
+  TextRange getWordBoundary(ui.TextPosition position) {
+    return new TextRange(start: position.offset, end: position.offset + 1);
+  }
+
+//
+//  void _paintCaret(PaintingContext context, Offset offset) {
+//    final TextPosition caret = new TextPosition(
+//      offset: _selection.extentOffset - node.documentOffset,
+//    );
+//    Offset caretOffset = getOffsetForCaret(caret, _caretPainter.prototype);
+//    _caretPainter.paint(context.canvas, caretOffset + offset);
+//  }
+//
+//  void _paintSelection(PaintingContext context, Offset offset) {
+//    assert(_isSelectionVisible);
+//    // TODO: this could be improved by painting additional box for line-break characters.
+//    _selectionRects ??= getBoxesForSelection(getLocalSelection(_selection));
+//    final Paint paint = new Paint()..color = _selectionColor;
+//    for (ui.TextBox box in _selectionRects)
+//      context.canvas.drawRect(box.toRect().shift(offset), paint);
+//  }
+}

packages/zefyr/lib/src/widgets/editable_paragraph.dart

@@ -0,0 +1,333 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:math' as math;
+import 'dart:ui' as ui;
+
+import 'package:flutter/rendering.dart';
+import 'package:flutter/widgets.dart';
+import 'package:notus/notus.dart';
+
+import 'caret.dart';
+import 'editable_box.dart';
+import 'render_context.dart';
+
+class EditableParagraph extends LeafRenderObjectWidget {
+  EditableParagraph({
+    @required this.node,
+    @required this.text,
+    @required this.layerLink,
+    @required this.renderContext,
+    @required this.showCursor,
+    @required this.selection,
+    @required this.selectionColor,
+  }) : assert(renderContext != null);
+
+  final ContainerNode node;
+  final TextSpan text;
+  final LayerLink layerLink;
+  final ZefyrRenderContext renderContext;
+  final ValueNotifier<bool> showCursor;
+  final TextSelection selection;
+  final Color selectionColor;
+
+  @override
+  RenderObject createRenderObject(BuildContext context) {
+    return new RenderEditableParagraph(
+      text,
+      node: node,
+      layerLink: layerLink,
+      renderContext: renderContext,
+      showCursor: showCursor,
+      selection: selection,
+      selectionColor: selectionColor,
+      textDirection: Directionality.of(context),
+    );
+  }
+
+  @override
+  void updateRenderObject(
+      BuildContext context, RenderEditableParagraph renderObject) {
+    renderObject
+      ..text = text
+      ..node = node
+      ..layerLink = layerLink
+      ..renderContext = renderContext
+      ..showCursor = showCursor
+      ..selection = selection
+      ..selectionColor = selectionColor;
+  }
+}
+
+class RenderEditableParagraph extends RenderParagraph
+    implements RenderEditableBox {
+  RenderEditableParagraph(
+    TextSpan text, {
+    @required ContainerNode node,
+    @required LayerLink layerLink,
+    @required ZefyrRenderContext renderContext,
+    @required ValueNotifier<bool> showCursor,
+    @required TextSelection selection,
+    @required Color selectionColor,
+    TextAlign textAlign: TextAlign.start,
+    @required TextDirection textDirection,
+    bool softWrap: true,
+    TextOverflow overflow: TextOverflow.clip,
+    double textScaleFactor: 1.0,
+    int maxLines,
+  })  : _node = node,
+        _layerLink = layerLink,
+        _renderContext = renderContext,
+        _showCursor = showCursor,
+        _selection = selection,
+        _selectionColor = selectionColor,
+        _prototypePainter = new TextPainter(
+          text: new TextSpan(text: '.', style: text.style),
+          textAlign: textAlign,
+          textDirection: textDirection,
+          textScaleFactor: textScaleFactor,
+        ),
+        super(
+          text,
+          textAlign: textAlign,
+          textDirection: textDirection,
+          softWrap: softWrap,
+          overflow: overflow,
+          textScaleFactor: textScaleFactor,
+          maxLines: maxLines,
+        );
+
+  //
+  // Public members
+  //
+
+  ContainerNode get node => _node;
+  ContainerNode _node;
+  void set node(ContainerNode value) {
+    _node = value;
+  }
+
+  LayerLink get layerLink => _layerLink;
+  LayerLink _layerLink;
+  void set layerLink(LayerLink value) {
+    if (_layerLink == value) return;
+    _layerLink = value;
+  }
+
+  ZefyrRenderContext _renderContext;
+  void set renderContext(ZefyrRenderContext value) {
+    if (_renderContext == value) return;
+    if (attached) _renderContext.removeBox(this);
+    _renderContext = value;
+    if (attached) _renderContext.addBox(this);
+  }
+
+  ValueNotifier<bool> _showCursor;
+  set showCursor(ValueNotifier<bool> value) {
+    assert(value != null);
+    if (_showCursor == value) return;
+    if (attached) _showCursor.removeListener(markNeedsPaint);
+    _showCursor = value;
+    if (attached) _showCursor.addListener(markNeedsPaint);
+    markNeedsPaint();
+  }
+
+  TextSelection _selection;
+  set selection(TextSelection value) {
+    if (_selection == value) return;
+    // TODO: check if selection affects this block (also check previous value)
+    _selection = value;
+    _selectionRects = null;
+    markNeedsPaint();
+  }
+
+  Color _selectionColor;
+  set selectionColor(Color value) {
+    if (_selectionColor == value) return;
+    _selectionColor = value;
+    markNeedsPaint();
+  }
+
+  double get preferredLineHeight => _prototypePainter.height;
+
+  /// Returns part of document [selection] local to this paragraph. May return
+  /// `null`.
+  ///
+  /// [selection] must not be collapsed.
+  TextSelection getLocalSelection(TextSelection selection) {
+    if (!_intersectsWithSelection(selection)) return null;
+
+    int nodeBase = node.documentOffset;
+    int nodeExtent = nodeBase + node.length;
+    int base = math.max(0, selection.baseOffset - nodeBase);
+    int extent = math.min(selection.extentOffset, nodeExtent) - nodeBase;
+    return _selection.copyWith(baseOffset: base, extentOffset: extent);
+  }
+
+  // This method works around some issues in getBoxesForSelection and handleы
+  // edge-case with our TextSpan objects not having last line-break character.
+  // Wait for https://github.com/flutter/flutter/issues/16418 to be resolved.
+  List<ui.TextBox> getEndpointsForSelection(TextSelection selection,
+      {bool isLocal: false}) {
+    TextSelection local = isLocal ? selection : getLocalSelection(selection);
+    if (local.isCollapsed) {
+      final offset = getOffsetForCaret(local.extent, _caretPainter.prototype);
+      return [
+        new ui.TextBox.fromLTRBD(
+          offset.dx,
+          offset.dy,
+          offset.dx,
+          offset.dy + _caretPainter.prototype.height,
+          TextDirection.ltr,
+        )
+      ];
+    }
+
+    int isBaseShifted = 0;
+    bool isExtentShifted = false;
+    if (local.baseOffset == node.length - 1 && local.baseOffset > 0) {
+      // Since we exclude last line-break from rendered TextSpan we have to
+      // handle end-of-line selection explicitly.
+      local = local.copyWith(baseOffset: local.baseOffset - 1);
+      isBaseShifted = -1;
+    } else if (local.baseOffset == 0 && local.isCollapsed) {
+      // This takes care of beginning of line position.
+      local = local.copyWith(baseOffset: local.baseOffset + 1);
+      isBaseShifted = 1;
+    }
+    if (text.codeUnitAt(local.extentOffset - 1) == 0xA) {
+      // This takes care of the rest end-of-line scenarios, where there are
+      // actually line-breaks in the TextSpan (e.g. in code blocks).
+      local = local.copyWith(extentOffset: local.extentOffset + 1);
+      isExtentShifted = true;
+    }
+    final result = getBoxesForSelection(local).toList();
+    if (isBaseShifted != 0) {
+      final box = result.first;
+      final dx = isBaseShifted == -1 ? box.right : box.left;
+      result.removeAt(0);
+      result.insert(0,
+          new ui.TextBox.fromLTRBD(dx, box.top, dx, box.bottom, box.direction));
+    }
+    if (isExtentShifted) {
+      final box = result.last;
+      result.removeLast;
+      result.add(new ui.TextBox.fromLTRBD(
+          box.left, box.top, box.left, box.bottom, box.direction));
+    }
+    return result;
+  }
+
+  //
+  // Overridden members
+  //
+
+  @override
+  void set text(TextSpan value) {
+    _prototypePainter.text = new TextSpan(text: '.', style: value.style);
+    _selectionRects = null;
+    super.text = value;
+  }
+
+  @override
+  void attach(PipelineOwner owner) {
+    super.attach(owner);
+    _showCursor.addListener(markNeedsPaint);
+    _renderContext.addBox(this);
+  }
+
+  @override
+  void detach() {
+    _showCursor.removeListener(markNeedsPaint);
+    _renderContext.removeBox(this);
+    super.detach();
+  }
+
+  @override
+  bool hitTestSelf(Offset position) => true;
+
+  @override
+  bool hitTest(HitTestResult result, {Offset position}) {
+    if (size.contains(position)) {
+      result.add(new BoxHitTestEntry(this, position));
+      return true;
+    }
+    return false;
+  }
+
+  @override
+  void performLayout() {
+    super.performLayout();
+    _prototypePainter.layout(
+        minWidth: constraints.minWidth, maxWidth: constraints.maxWidth);
+    _caretPainter.layout(_prototypePainter.height);
+    // Indicate to render context that this object can be used by other
+    // layers (selection overlay, for instance).
+    _renderContext.markDirty(this, false);
+  }
+
+  @override
+  void paint(PaintingContext context, Offset offset) {
+    if (_isSelectionVisible) _paintSelection(context, offset);
+    super.paint(context, offset);
+    if (_isCaretVisible) _paintCaret(context, offset);
+  }
+
+  @override
+  void markNeedsLayout() {
+    // Temporarily remove this object from the render context.
+    _renderContext.markDirty(this, true);
+    super.markNeedsLayout();
+  }
+
+  //
+  // Private members
+  //
+
+  final TextPainter _prototypePainter;
+  final CaretPainter _caretPainter = new CaretPainter();
+  List<ui.TextBox> _selectionRects;
+
+  /// Returns `true` if current selection is collapsed, located within
+  /// this paragraph and is visible according to tick timer.
+  bool get _isCaretVisible {
+    if (!_selection.isCollapsed) return false;
+    if (!_showCursor.value) return false;
+
+    final int start = node.documentOffset;
+    final int end = start + node.length;
+    final int caretOffset = _selection.extentOffset;
+    return caretOffset >= start && caretOffset < end;
+  }
+
+  /// Returns `true` if selection is not collapsed and intersects with this
+  /// paragraph.
+  bool get _isSelectionVisible {
+    if (_selection.isCollapsed) return false;
+    return _intersectsWithSelection(_selection);
+  }
+
+  /// Returns `true` if this paragraph intersects with document [selection].
+  bool _intersectsWithSelection(TextSelection selection) {
+    final int base = node.documentOffset;
+    final int extent = base + node.length;
+    return base <= selection.extentOffset && selection.baseOffset <= extent;
+  }
+
+  void _paintCaret(PaintingContext context, Offset offset) {
+    final TextPosition caret = new TextPosition(
+      offset: _selection.extentOffset - node.documentOffset,
+    );
+    Offset caretOffset = getOffsetForCaret(caret, _caretPainter.prototype);
+    _caretPainter.paint(context.canvas, caretOffset + offset);
+  }
+
+  void _paintSelection(PaintingContext context, Offset offset) {
+    assert(_isSelectionVisible);
+    // TODO: this could be improved by painting additional box for line-break characters.
+    _selectionRects ??= getBoxesForSelection(getLocalSelection(_selection));
+    final Paint paint = new Paint()..color = _selectionColor;
+    for (ui.TextBox box in _selectionRects)
+      context.canvas.drawRect(box.toRect().shift(offset), paint);
+  }
+}

packages/zefyr/lib/src/widgets/editable_text.dart

@@ -0,0 +1,322 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:async';
+
+import 'package:collection/collection.dart';
+import 'package:flutter/cupertino.dart';
+import 'package:flutter/widgets.dart';
+import 'package:notus/notus.dart';
+
+import 'code.dart';
+import 'common.dart';
+import 'controller.dart';
+import 'editable_box.dart';
+import 'editor.dart';
+import 'input.dart';
+import 'list.dart';
+import 'paragraph.dart';
+import 'quote.dart';
+import 'render_context.dart';
+import 'selection.dart';
+
+/// Core widget responsible for editing Zefyr documents.
+///
+/// Depends on presence of [ZefyrTheme] somewhere up the widget tree.
+///
+/// Consider using [ZefyrEditor] which wraps this widget and adds a toolbar to
+/// edit style attributes.
+class ZefyrEditableText extends StatefulWidget {
+  const ZefyrEditableText({
+    Key key,
+    @required this.controller,
+    @required this.focusNode,
+    this.autofocus: true,
+    this.enabled: true,
+  }) : super(key: key);
+
+  final ZefyrController controller;
+  final FocusNode focusNode;
+  final bool autofocus;
+  final bool enabled;
+
+  static ZefyrEditableTextScope of(BuildContext context) {
+    final ZefyrEditableTextScope result =
+        context.inheritFromWidgetOfExactType(ZefyrEditableTextScope);
+    return result;
+  }
+
+  @override
+  _ZefyrEditableTextState createState() => new _ZefyrEditableTextState();
+}
+
+/// Provides access to shared state of [ZefyrEditableText].
+class ZefyrEditableTextScope extends InheritedWidget {
+  static const _kEquality = const SetEquality<RenderEditableBox>();
+
+  ZefyrEditableTextScope({
+    Key key,
+    @required Widget child,
+    @required this.selection,
+    @required this.showCursor,
+    @required this.renderContext,
+  })  : _activeParagraphs = new Set.from(renderContext.active),
+        super(key: key, child: child);
+
+  final TextSelection selection;
+  final ValueNotifier<bool> showCursor;
+  final ZefyrRenderContext renderContext;
+  final Set<RenderEditableBox> _activeParagraphs;
+
+  @override
+  bool updateShouldNotify(ZefyrEditableTextScope oldWidget) {
+    return selection != oldWidget.selection ||
+        showCursor != oldWidget.showCursor ||
+        !_kEquality.equals(_activeParagraphs, oldWidget._activeParagraphs);
+  }
+}
+
+class _ZefyrEditableTextState extends State<ZefyrEditableText>
+    with AutomaticKeepAliveClientMixin {
+  //
+  // New public members
+  //
+
+  /// Focus node of this widget.
+  FocusNode get focusNode => widget.focusNode;
+
+  /// Document controlled by this widget.
+  NotusDocument get document => widget.controller.document;
+
+  /// Current text selection.
+  TextSelection get selection => widget.controller.selection;
+  ZefyrRenderContext get renderContext => _renderContext;
+  ValueNotifier<bool> get showCursor => _cursorTimer.value;
+
+  /// Express interest in interacting with the keyboard.
+  ///
+  /// If this control is already attached to the keyboard, this function will
+  /// request that the keyboard become visible. Otherwise, this function will
+  /// ask the focus system that it become focused. If successful in acquiring
+  /// focus, the control will then attach to the keyboard and request that the
+  /// keyboard become visible.
+  void requestKeyboard() {
+    if (focusNode.hasFocus)
+      _input.openConnection(widget.controller.plainTextEditingValue);
+    else
+      FocusScope.of(context).requestFocus(focusNode);
+  }
+
+  //
+  // Overridden members of State
+  //
+
+  @override
+  Widget build(BuildContext context) {
+    FocusScope.of(context).reparentIfNeeded(focusNode);
+    super.build(context); // See AutomaticKeepAliveState.
+    ZefyrEditor.of(context);
+
+    final scrollable = SingleChildScrollView(
+      padding: EdgeInsets.only(top: 16.0),
+      physics: AlwaysScrollableScrollPhysics(),
+      controller: _scrollController,
+      child: ListBody(children: _buildChildren(context)),
+    );
+
+    final overlay = Overlay.of(context, debugRequiredFor: widget);
+    final layers = <Widget>[scrollable];
+    if (widget.enabled) {
+      layers.add(ZefyrSelectionOverlay(
+        controller: widget.controller,
+        controls: cupertinoTextSelectionControls,
+        overlay: overlay,
+      ));
+    }
+
+    return new ZefyrEditableTextScope(
+      selection: selection,
+      showCursor: showCursor,
+      renderContext: renderContext,
+      child: Stack(fit: StackFit.expand, children: layers),
+    );
+  }
+
+  @override
+  void initState() {
+    super.initState();
+    _input = new InputConnectionController(_handleRemoteValueChange);
+    _updateSubscriptions();
+  }
+
+  @override
+  void didUpdateWidget(ZefyrEditableText oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    _updateSubscriptions(oldWidget);
+    if (!_didAutoFocus && widget.autofocus && widget.enabled) {
+      FocusScope.of(context).autofocus(focusNode);
+      _didAutoFocus = true;
+    }
+    if (!widget.enabled && focusNode.hasFocus) {
+      _didAutoFocus = false;
+      focusNode.unfocus();
+    }
+  }
+
+  @override
+  void dispose() {
+    _cancelSubscriptions();
+    super.dispose();
+  }
+
+  //
+  // Overridden members of AutomaticKeepAliveClientMixin
+  //
+
+  @override
+  bool get wantKeepAlive => focusNode.hasFocus;
+
+  //
+  // Private members
+  //
+
+  final ScrollController _scrollController = new ScrollController();
+  final ZefyrRenderContext _renderContext = new ZefyrRenderContext();
+  final _CursorTimer _cursorTimer = new _CursorTimer();
+  InputConnectionController _input;
+  bool _didAutoFocus = false;
+
+  List<Widget> _buildChildren(BuildContext context) {
+    final result = <Widget>[];
+    for (var node in document.root.children) {
+      result.add(_defaultChildBuilder(context, node));
+    }
+    return result;
+  }
+
+  Widget _defaultChildBuilder(BuildContext context, Node node) {
+    if (node is LineNode) {
+      if (node.hasEmbed) {
+        return new RawZefyrLine(node: node);
+      } else if (node.style.contains(NotusAttribute.heading)) {
+        return new ZefyrHeading(node: node);
+      }
+      return new ZefyrParagraph(node: node);
+    }
+
+    final BlockNode block = node;
+    final blockStyle = block.style.get(NotusAttribute.block);
+    if (blockStyle == NotusAttribute.block.code) {
+      return new ZefyrCode(node: node);
+    } else if (blockStyle == NotusAttribute.block.bulletList) {
+      return new ZefyrList(node: node);
+    } else if (blockStyle == NotusAttribute.block.numberList) {
+      return new ZefyrList(node: node);
+    } else if (blockStyle == NotusAttribute.block.quote) {
+      return new ZefyrQuote(node: node);
+    }
+
+    throw new UnimplementedError('Block format $blockStyle.');
+  }
+
+  void _updateSubscriptions([ZefyrEditableText oldWidget]) {
+    if (oldWidget == null) {
+      _renderContext.addListener(_handleRenderContextChange);
+      widget.controller.addListener(_handleLocalValueChange);
+      focusNode.addListener(_handleFocusChange);
+      return;
+    }
+
+    if (widget.controller != oldWidget.controller) {
+      oldWidget.controller.removeListener(_handleLocalValueChange);
+      widget.controller.addListener(_handleLocalValueChange);
+      _input.updateRemoteValue(widget.controller.plainTextEditingValue);
+    }
+    if (widget.focusNode != oldWidget.focusNode) {
+      oldWidget.focusNode.removeListener(_handleFocusChange);
+      widget.focusNode.addListener(_handleFocusChange);
+      updateKeepAlive();
+    }
+  }
+
+  void _cancelSubscriptions() {
+    _renderContext.removeListener(_handleRenderContextChange);
+    _renderContext.dispose();
+    widget.controller.removeListener(_handleLocalValueChange);
+    focusNode.removeListener(_handleFocusChange);
+    _input.closeConnection();
+    _cursorTimer.stop();
+  }
+
+  // Triggered for both text and selection changes.
+  void _handleLocalValueChange() {
+    if (widget.enabled &&
+        widget.controller.lastChangeSource == ChangeSource.local) {
+      // Only request keyboard for user actions.
+      requestKeyboard();
+    }
+    _input.updateRemoteValue(widget.controller.plainTextEditingValue);
+    _cursorTimer.startOrStop(focusNode, selection);
+    setState(() {
+      // nothing to update internally.
+    });
+  }
+
+  void _handleFocusChange() {
+    _input.openOrCloseConnection(
+        focusNode, widget.controller.plainTextEditingValue);
+    _cursorTimer.startOrStop(focusNode, selection);
+    updateKeepAlive();
+  }
+
+  void _handleRemoteValueChange(
+      int start, String deleted, String inserted, TextSelection selection) {
+    widget.controller
+        .replaceText(start, deleted.length, inserted, selection: selection);
+  }
+
+  void _handleRenderContextChange() {
+    setState(() {
+      // nothing to update internally.
+    });
+  }
+}
+
+/// Helper class that keeps state relevant to the cursor.
+class _CursorTimer {
+  static const _kCursorBlinkHalfPeriod = const Duration(milliseconds: 500);
+
+  Timer _timer;
+  final ValueNotifier<bool> _showCursor = new ValueNotifier<bool>(false);
+
+  ValueNotifier<bool> get value => _showCursor;
+
+  void _cursorTick(Timer timer) {
+    _showCursor.value = !_showCursor.value;
+  }
+
+  /// Starts cursor timer.
+  void start() {
+    _showCursor.value = true;
+    _timer = new Timer.periodic(_kCursorBlinkHalfPeriod, _cursorTick);
+  }
+
+  /// Stops cursor timer.
+  void stop() {
+    _timer?.cancel();
+    _timer = null;
+    _showCursor.value = false;
+  }
+
+  /// Starts or stops cursor timer based on current state of [focusNode]
+  /// and [selection].
+  void startOrStop(FocusNode focusNode, TextSelection selection) {
+    final hasFocus = focusNode.hasFocus;
+    final selectionCollapsed = selection.isCollapsed;
+    if (_timer == null && hasFocus && selectionCollapsed) {
+      start();
+    } else if (_timer != null && (!hasFocus || !selectionCollapsed)) {
+      stop();
+    }
+  }
+}

packages/zefyr/lib/src/widgets/editor.dart

@@ -0,0 +1,206 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter/widgets.dart';
+import 'package:notus/notus.dart';
+
+import 'controller.dart';
+import 'editable_text.dart';
+import 'theme.dart';
+import 'toolbar.dart';
+
+/// Widget for editing Zefyr documents.
+class ZefyrEditor extends StatefulWidget {
+  const ZefyrEditor({
+    Key key,
+    @required this.controller,
+    @required this.focusNode,
+    this.autofocus: true,
+    this.enabled: true,
+    this.padding: const EdgeInsets.symmetric(horizontal: 16.0),
+    this.toolbarDelegate,
+  }) : super(key: key);
+
+  final ZefyrController controller;
+  final FocusNode focusNode;
+  final bool autofocus;
+  final bool enabled;
+  final ZefyrToolbarDelegate toolbarDelegate;
+
+  /// Padding around editable area.
+  final EdgeInsets padding;
+
+  static ZefyrEditorScope of(BuildContext context) {
+    ZefyrEditorScope scope =
+        context.inheritFromWidgetOfExactType(ZefyrEditorScope);
+    return scope;
+  }
+
+  @override
+  _ZefyrEditorState createState() => new _ZefyrEditorState();
+}
+
+/// Inherited widget which provides access to shared state of a Zefyr editor.
+class ZefyrEditorScope extends InheritedWidget {
+  /// Current selection style
+  final NotusStyle selectionStyle;
+  final TextSelection selection;
+  final FocusOwner focusOwner;
+  final FocusNode toolbarFocusNode;
+  final ZefyrController _controller;
+  final FocusNode _focusNode;
+
+  ZefyrEditorScope({
+    Key key,
+    @required Widget child,
+    @required this.selectionStyle,
+    @required this.selection,
+    @required this.focusOwner,
+    @required this.toolbarFocusNode,
+    @required ZefyrController controller,
+    @required FocusNode focusNode,
+  })  : _controller = controller,
+        _focusNode = focusNode,
+        super(key: key, child: child);
+
+  void updateSelection(TextSelection value,
+      {ChangeSource source: ChangeSource.remote}) {
+    _controller.updateSelection(value, source: source);
+  }
+
+  void formatSelection(NotusAttribute value) {
+    _controller.formatSelection(value);
+  }
+
+  void focus(BuildContext context) {
+    FocusScope.of(context).requestFocus(_focusNode);
+  }
+
+  void hideKeyboard() {
+    _focusNode.unfocus();
+  }
+
+  @override
+  bool updateShouldNotify(ZefyrEditorScope oldWidget) {
+    return (selectionStyle != oldWidget.selectionStyle ||
+        selection != oldWidget.selection ||
+        focusOwner != oldWidget.focusOwner);
+  }
+}
+
+class _ZefyrEditorState extends State<ZefyrEditor> {
+  final FocusNode _toolbarFocusNode = new FocusNode();
+
+  NotusStyle _selectionStyle;
+  TextSelection _selection;
+  FocusOwner _focusOwner;
+
+  FocusOwner getFocusOwner() {
+    if (widget.focusNode.hasFocus) {
+      return FocusOwner.editor;
+    } else if (_toolbarFocusNode.hasFocus) {
+      return FocusOwner.toolbar;
+    } else {
+      return FocusOwner.none;
+    }
+  }
+
+  @override
+  void initState() {
+    super.initState();
+    _selectionStyle = widget.controller.getSelectionStyle();
+    _selection = widget.controller.selection;
+    _focusOwner = getFocusOwner();
+    widget.controller.addListener(_handleControllerChange);
+    _toolbarFocusNode.addListener(_handleFocusChange);
+    widget.focusNode.addListener(_handleFocusChange);
+  }
+
+  @override
+  void didUpdateWidget(ZefyrEditor oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (widget.focusNode != oldWidget.focusNode) {
+      oldWidget.focusNode.removeListener(_handleFocusChange);
+      widget.focusNode.addListener(_handleFocusChange);
+    }
+    if (widget.controller != oldWidget.controller) {
+      oldWidget.controller.removeListener(_handleControllerChange);
+      widget.controller.addListener(_handleControllerChange);
+      _selectionStyle = widget.controller.getSelectionStyle();
+      _selection = widget.controller.selection;
+    }
+  }
+
+  @override
+  void dispose() {
+    widget.controller.removeListener(_handleControllerChange);
+    widget.focusNode.removeListener(_handleFocusChange);
+    _toolbarFocusNode.removeListener(_handleFocusChange);
+    _toolbarFocusNode.dispose();
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    Widget editable = new ZefyrEditableText(
+      controller: widget.controller,
+      focusNode: widget.focusNode,
+      autofocus: widget.autofocus,
+      enabled: widget.enabled,
+    );
+    if (widget.padding != null) {
+      editable = new Padding(padding: widget.padding, child: editable);
+    }
+    final children = <Widget>[];
+    children.add(Expanded(child: editable));
+    final toolbar = ZefyrToolbar(
+      focusNode: _toolbarFocusNode,
+      controller: widget.controller,
+      delegate: widget.toolbarDelegate,
+    );
+    children.add(toolbar);
+
+    final parentTheme = ZefyrTheme.of(context, nullOk: true);
+    final fallbackTheme = ZefyrThemeData.fallback(context);
+    final actualTheme = (parentTheme != null)
+        ? fallbackTheme.merge(parentTheme)
+        : fallbackTheme;
+
+    return ZefyrTheme(
+      data: actualTheme,
+      child: ZefyrEditorScope(
+        selection: _selection,
+        selectionStyle: _selectionStyle,
+        focusOwner: _focusOwner,
+        toolbarFocusNode: _toolbarFocusNode,
+        controller: widget.controller,
+        focusNode: widget.focusNode,
+        child: Column(children: children),
+      ),
+    );
+  }
+
+  void _handleControllerChange() {
+    final attrs = widget.controller.getSelectionStyle();
+    final selection = widget.controller.selection;
+    if (_selectionStyle != attrs || _selection != selection) {
+      setState(() {
+        _selectionStyle = attrs;
+        _selection = widget.controller.selection;
+      });
+    }
+  }
+
+  void _handleFocusChange() {
+    setState(() {
+      _focusOwner = getFocusOwner();
+      if (_focusOwner == FocusOwner.none && !_selection.isCollapsed) {
+        // Collapse selection if there is nothing focused.
+        widget.controller.updateSelection(_selection.copyWith(
+          baseOffset: _selection.extentOffset,
+          extentOffset: _selection.extentOffset,
+        ));
+      }
+    });
+  }
+}

packages/zefyr/lib/src/widgets/horizontal_rule.dart

@@ -0,0 +1,277 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:math' as math;
+import 'dart:ui' as ui;
+
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flutter/widgets.dart';
+import 'package:notus/notus.dart';
+
+import 'caret.dart';
+import 'editable_box.dart';
+import 'render_context.dart';
+
+class HorizontalRule extends LeafRenderObjectWidget {
+  HorizontalRule({
+    @required this.node,
+    @required this.layerLink,
+    @required this.renderContext,
+    @required this.showCursor,
+    @required this.selection,
+    @required this.selectionColor,
+  }) : assert(renderContext != null);
+
+  final ContainerNode node;
+  final LayerLink layerLink;
+  final ZefyrRenderContext renderContext;
+  final ValueNotifier<bool> showCursor;
+  final TextSelection selection;
+  final Color selectionColor;
+
+  @override
+  RenderHorizontalRule createRenderObject(BuildContext context) {
+    return new RenderHorizontalRule(
+      node: node,
+      layerLink: layerLink,
+      renderContext: renderContext,
+      showCursor: showCursor,
+      selection: selection,
+      selectionColor: selectionColor,
+    );
+  }
+
+  @override
+  void updateRenderObject(
+      BuildContext context, RenderHorizontalRule renderObject) {
+    renderObject
+      ..node = node
+      ..layerLink = layerLink
+      ..renderContext = renderContext
+      ..showCursor = showCursor
+      ..selection = selection
+      ..selectionColor = selectionColor;
+  }
+}
+
+class RenderHorizontalRule extends RenderBox implements RenderEditableBox {
+  static const kPaddingBottom = 16.0;
+  static const kWidth = 3.0;
+
+  RenderHorizontalRule({
+    @required ContainerNode node,
+    @required LayerLink layerLink,
+    @required ZefyrRenderContext renderContext,
+    @required ValueNotifier<bool> showCursor,
+    @required TextSelection selection,
+    @required Color selectionColor,
+  })  : _node = node,
+        _layerLink = layerLink,
+        _renderContext = renderContext,
+        _showCursor = showCursor,
+        _selection = selection,
+        _selectionColor = selectionColor,
+        super();
+
+  //
+  // Public members
+  //
+
+  ContainerNode get node => _node;
+  ContainerNode _node;
+  void set node(ContainerNode value) {
+    _node = value;
+  }
+
+  LayerLink get layerLink => _layerLink;
+  LayerLink _layerLink;
+  void set layerLink(LayerLink value) {
+    if (_layerLink == value) return;
+    _layerLink = value;
+  }
+
+  ZefyrRenderContext _renderContext;
+  void set renderContext(ZefyrRenderContext value) {
+    if (_renderContext == value) return;
+    if (attached) _renderContext.removeBox(this);
+    _renderContext = value;
+    if (attached) _renderContext.addBox(this);
+  }
+
+  ValueNotifier<bool> _showCursor;
+  set showCursor(ValueNotifier<bool> value) {
+    assert(value != null);
+    if (_showCursor == value) return;
+    if (attached) _showCursor.removeListener(markNeedsPaint);
+    _showCursor = value;
+    if (attached) _showCursor.addListener(markNeedsPaint);
+    markNeedsPaint();
+  }
+
+  TextSelection _selection;
+  set selection(TextSelection value) {
+    if (_selection == value) return;
+    // TODO: check if selection affects this block (also check previous value)
+    _selection = value;
+    markNeedsPaint();
+  }
+
+  Color _selectionColor;
+  set selectionColor(Color value) {
+    if (_selectionColor == value) return;
+    _selectionColor = value;
+    markNeedsPaint();
+  }
+
+  double get preferredLineHeight => size.height;
+
+  /// Returns part of document [selection] local to this paragraph. May return
+  /// `null`.
+  ///
+  /// [selection] must not be collapsed.
+  TextSelection getLocalSelection(TextSelection selection) {
+    if (!_intersectsWithSelection(selection)) return null;
+
+    int nodeBase = node.documentOffset;
+    int nodeExtent = nodeBase + node.length;
+    int base = math.max(0, selection.baseOffset - nodeBase);
+    int extent = math.min(selection.extentOffset, nodeExtent) - nodeBase;
+    return _selection.copyWith(baseOffset: base, extentOffset: extent);
+  }
+
+  List<ui.TextBox> getEndpointsForSelection(TextSelection selection,
+      {bool isLocal: false}) {
+    TextSelection local = isLocal ? selection : getLocalSelection(selection);
+    if (local.isCollapsed) {
+      return [
+        new ui.TextBox.fromLTRBD(0.0, 0.0, 0.0, size.height, TextDirection.ltr),
+      ];
+    }
+
+    return [
+      new ui.TextBox.fromLTRBD(0.0, 0.0, 0.0, size.height, TextDirection.ltr),
+      new ui.TextBox.fromLTRBD(
+          size.width, 0.0, size.width, size.height, TextDirection.ltr),
+    ];
+  }
+
+  //
+  // Overridden members
+  //
+
+  @override
+  void attach(PipelineOwner owner) {
+    super.attach(owner);
+    _showCursor.addListener(markNeedsPaint);
+    _renderContext.addBox(this);
+  }
+
+  @override
+  void detach() {
+    _showCursor.removeListener(markNeedsPaint);
+    _renderContext.removeBox(this);
+    super.detach();
+  }
+
+  @override
+  bool hitTestSelf(Offset position) => true;
+
+  @override
+  bool hitTest(HitTestResult result, {Offset position}) {
+    if (size.contains(position)) {
+      result.add(new BoxHitTestEntry(this, position));
+      return true;
+    }
+    return false;
+  }
+
+  @override
+  void performLayout() {
+    assert(constraints.hasBoundedWidth);
+    final height = kWidth + kPaddingBottom;
+    size = new Size(constraints.maxWidth, height);
+    _caretPainter.layout(height);
+    // Indicate to render context that this object can be used by other
+    // layers (selection overlay, for instance).
+    _renderContext.markDirty(this, false);
+  }
+
+  @override
+  void paint(PaintingContext context, Offset offset) {
+//    if (_isSelectionVisible) _paintSelection(context, offset);
+    final rect = new Rect.fromLTWH(0.0, 0.0, size.width, kWidth);
+    final paint = new ui.Paint()..color = Colors.grey.shade200;
+    context.canvas.drawRect(rect.shift(offset), paint);
+    if (_isCaretVisible) _paintCaret(context, offset);
+  }
+
+  @override
+  void markNeedsLayout() {
+    // Temporarily remove this object from the render context.
+    _renderContext.markDirty(this, true);
+    super.markNeedsLayout();
+  }
+
+  @override
+  ui.TextPosition getPositionForOffset(ui.Offset offset) {
+    return new ui.TextPosition(offset: node.documentOffset);
+  }
+
+  @override
+  TextRange getWordBoundary(ui.TextPosition position) {
+    return new TextRange(start: position.offset, end: position.offset + 1);
+  }
+
+  //
+  // Private members
+  //
+
+  final CaretPainter _caretPainter = new CaretPainter();
+//  List<ui.TextBox> _selectionRects;
+
+  /// Returns `true` if current selection is collapsed, located within
+  /// this paragraph and is visible according to tick timer.
+  bool get _isCaretVisible {
+    if (!_selection.isCollapsed) return false;
+    if (!_showCursor.value) return false;
+
+    final int start = node.documentOffset;
+    final int end = start + node.length;
+    final int caretOffset = _selection.extentOffset;
+    return caretOffset >= start && caretOffset < end;
+  }
+
+  /// Returns `true` if selection is not collapsed and intersects with this
+  /// paragraph.
+//  bool get _isSelectionVisible {
+//    if (_selection.isCollapsed) return false;
+//    return _intersectsWithSelection(_selection);
+//  }
+
+  /// Returns `true` if this paragraph intersects with document [selection].
+  bool _intersectsWithSelection(TextSelection selection) {
+    final int base = node.documentOffset;
+    final int extent = base + node.length;
+    return base <= selection.extentOffset && selection.baseOffset <= extent;
+  }
+
+  void _paintCaret(PaintingContext context, Offset offset) {
+    final pos = _selection.extentOffset - node.documentOffset;
+    Offset caretOffset = Offset.zero;
+    if (pos == 1) {
+      caretOffset = caretOffset + new Offset(size.width - 1.0, 0.0);
+    }
+    _caretPainter.paint(context.canvas, caretOffset + offset);
+  }
+
+//
+//  void _paintSelection(PaintingContext context, Offset offset) {
+//    assert(_isSelectionVisible);
+//    // TODO: this could be improved by painting additional box for line-break characters.
+//    _selectionRects ??= getBoxesForSelection(getLocalSelection(_selection));
+//    final Paint paint = new Paint()..color = _selectionColor;
+//    for (ui.TextBox box in _selectionRects)
+//      context.canvas.drawRect(box.toRect().shift(offset), paint);
+//  }
+}

packages/zefyr/lib/src/widgets/input.dart

@@ -0,0 +1,123 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter/services.dart';
+import 'package:flutter/widgets.dart';
+import 'package:zefyr/util.dart';
+
+typedef RemoteValueChanged = Function(
+    int start, String deleted, String inserted, TextSelection selection);
+
+class InputConnectionController implements TextInputClient {
+  InputConnectionController(this.onValueChanged)
+      : assert(onValueChanged != null);
+
+  //
+  // New public members
+  //
+
+  final RemoteValueChanged onValueChanged;
+
+  /// Returns `true` if there is open input connection.
+  bool get hasConnection =>
+      _textInputConnection != null && _textInputConnection.attached;
+
+  /// Opens or closes input connection based on the current state of
+  /// [focusNode] and [value].
+  void openOrCloseConnection(FocusNode focusNode, TextEditingValue value) {
+    if (focusNode.hasFocus && focusNode.consumeKeyboardToken()) {
+      openConnection(value);
+    } else if (!focusNode.hasFocus) {
+      closeConnection();
+    }
+  }
+
+  void openConnection(TextEditingValue value) {
+    if (!hasConnection) {
+      _lastKnownRemoteTextEditingValue = value;
+      _textInputConnection = TextInput.attach(
+        this,
+        new TextInputConfiguration(
+          inputType: TextInputType.multiline,
+          obscureText: false,
+          autocorrect: true,
+          inputAction: TextInputAction.newline,
+        ),
+      )..setEditingState(value);
+      _sentRemoteValues.add(value);
+    }
+    _textInputConnection.show();
+  }
+
+  /// Closes input connection if it's currently open. Otherwise does nothing.
+  void closeConnection() {
+    if (hasConnection) {
+      _textInputConnection.close();
+      _textInputConnection = null;
+      _lastKnownRemoteTextEditingValue = null;
+      _sentRemoteValues.clear();
+    }
+  }
+
+  /// Updates remote value based on current state of [document] and
+  /// [selection].
+  ///
+  /// This method may not actually send an update to native side if it thinks
+  /// remote value is up to date or identical.
+  void updateRemoteValue(TextEditingValue value) {
+    if (!hasConnection) return;
+
+    if (value == _lastKnownRemoteTextEditingValue) return;
+    bool shouldRemember = value.text != _lastKnownRemoteTextEditingValue.text;
+    _lastKnownRemoteTextEditingValue = value;
+    _textInputConnection.setEditingState(value);
+    // Only keep track if text changed (selection changes are not relevant)
+    if (shouldRemember) {
+      _sentRemoteValues.add(value);
+    }
+  }
+
+  //
+  // Overridden members
+  //
+
+  @override
+  void performAction(TextInputAction action) {
+    // no-op
+  }
+
+  @override
+  void updateEditingValue(TextEditingValue value) {
+    if (_sentRemoteValues.contains(value)) {
+      /// There is a race condition in Flutter text input plugin where sending
+      /// updates to native side too often results in broken behavior.
+      /// TextInputConnection.setEditingValue is an async call to native side.
+      /// For each such call native side _always_ sends update which triggers
+      /// this method (updateEditingValue) with the same value we've sent it.
+      /// If multiple calls to setEditingValue happen too fast and we only
+      /// track the last sent value then there is no way for us to filter out
+      /// automatic callbacks from native side.
+      /// Therefore we have to keep track of all values we send to the native
+      /// side and when we see this same value appear here we skip it.
+      /// This is fragile but it's probably the only available option.
+      _sentRemoteValues.remove(value);
+      return;
+    }
+
+    final effectiveLastKnownValue = _lastKnownRemoteTextEditingValue;
+    _lastKnownRemoteTextEditingValue = value;
+    final oldText = effectiveLastKnownValue.text;
+    final text = value.text;
+    final cursorPosition = value.selection.extentOffset;
+    final diff = fastDiff(oldText, text, cursorPosition);
+    onValueChanged(diff.start, diff.deleted, diff.inserted, value.selection);
+  }
+
+  //
+  // Private members
+  //
+
+  final List<TextEditingValue> _sentRemoteValues = [];
+  TextInputConnection _textInputConnection;
+  TextEditingValue _lastKnownRemoteTextEditingValue;
+}

packages/zefyr/lib/src/widgets/list.dart

@@ -0,0 +1,86 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter/material.dart';
+import 'package:notus/notus.dart';
+
+import 'common.dart';
+import 'paragraph.dart';
+import 'theme.dart';
+
+/// Represents number lists and bullet lists in a Zefyr editor.
+class ZefyrList extends StatelessWidget {
+  const ZefyrList({Key key, @required this.node}) : super(key: key);
+
+  final BlockNode node;
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = ZefyrTheme.of(context);
+    List<Widget> items = [];
+    int index = 1;
+    for (var line in node.children) {
+      items.add(_buildItem(line, index));
+      index++;
+    }
+
+    final isNumberList =
+        node.style.get(NotusAttribute.block) == NotusAttribute.block.numberList;
+    EdgeInsets padding = isNumberList
+        ? theme.blockTheme.numberList.padding
+        : theme.blockTheme.bulletList.padding;
+    padding = padding.copyWith(left: theme.indentSize);
+
+    return new Padding(
+      padding: padding,
+      child: new Column(children: items),
+    );
+  }
+
+  Widget _buildItem(Node node, int index) {
+    LineNode line = node;
+    return new ZefyrListItem(index: index, node: line);
+  }
+}
+
+/// An item in a [ZefyrList].
+class ZefyrListItem extends StatelessWidget {
+  ZefyrListItem({Key key, this.index, this.node}) : super(key: key);
+
+  final int index;
+  final LineNode node;
+
+  @override
+  Widget build(BuildContext context) {
+    final BlockNode block = node.parent;
+    final style = block.style.get(NotusAttribute.block);
+    final theme = ZefyrTheme.of(context);
+    final bulletText =
+        (style == NotusAttribute.block.bulletList) ? '•' : '$index.';
+
+    TextStyle textStyle;
+    Widget content;
+    EdgeInsets padding;
+
+    if (node.style.contains(NotusAttribute.heading)) {
+      final headingTheme = ZefyrHeading.themeOf(node, context);
+      textStyle = headingTheme.textStyle;
+      padding = headingTheme.padding;
+      content = new ZefyrHeading(node: node);
+    } else {
+      textStyle = theme.paragraphTheme.textStyle;
+      content = new RawZefyrLine(node: node, style: textStyle);
+    }
+
+    Widget bullet =
+        SizedBox(width: 24.0, child: Text(bulletText, style: textStyle));
+    if (padding != null) {
+      bullet = Padding(padding: padding, child: bullet);
+    }
+
+    return Row(
+      crossAxisAlignment: CrossAxisAlignment.start,
+      children: <Widget>[bullet, Expanded(child: content)],
+    );
+  }
+}

packages/zefyr/lib/src/widgets/paragraph.dart

@@ -0,0 +1,68 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter/material.dart';
+import 'package:notus/notus.dart';
+
+import 'common.dart';
+import 'theme.dart';
+
+/// Represents regular paragraph line in a Zefyr editor.
+class ZefyrParagraph extends StatelessWidget {
+  ZefyrParagraph({Key key, @required this.node, this.blockStyle})
+      : super(key: key);
+
+  final LineNode node;
+  final TextStyle blockStyle;
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = ZefyrTheme.of(context);
+    TextStyle style = theme.paragraphTheme.textStyle;
+    if (blockStyle != null) {
+      style = style.merge(blockStyle);
+    }
+    return new RawZefyrLine(
+      node: node,
+      style: style,
+      padding: theme.paragraphTheme.padding,
+    );
+  }
+}
+
+/// Represents heading-styled line in [ZefyrEditor].
+class ZefyrHeading extends StatelessWidget {
+  ZefyrHeading({Key key, @required this.node, this.blockStyle})
+      : assert(node.style.contains(NotusAttribute.heading)),
+        super(key: key);
+
+  final LineNode node;
+  final TextStyle blockStyle;
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = themeOf(node, context);
+    TextStyle style = theme.textStyle;
+    if (blockStyle != null) {
+      style = style.merge(blockStyle);
+    }
+    return new RawZefyrLine(
+      node: node,
+      style: style,
+      padding: theme.padding,
+    );
+  }
+
+  static StyleTheme themeOf(LineNode node, BuildContext context) {
+    final theme = ZefyrTheme.of(context);
+    final style = node.style.get(NotusAttribute.heading);
+    if (style == NotusAttribute.heading.level1) {
+      return theme.headingTheme.level1;
+    } else if (style == NotusAttribute.heading.level2) {
+      return theme.headingTheme.level2;
+    } else if (style == NotusAttribute.heading.level3) {
+      return theme.headingTheme.level3;
+    }
+    throw new UnimplementedError('Unsupported heading style $style');
+  }
+}

packages/zefyr/lib/src/widgets/quote.dart

@@ -0,0 +1,55 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter/material.dart';
+import 'package:notus/notus.dart';
+
+import 'paragraph.dart';
+import 'theme.dart';
+
+/// Represents a quote block in a Zefyr editor.
+class ZefyrQuote extends StatelessWidget {
+  const ZefyrQuote({Key key, @required this.node}) : super(key: key);
+
+  final BlockNode node;
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = ZefyrTheme.of(context);
+    final style = theme.blockTheme.quote.textStyle;
+    List<Widget> items = [];
+    for (var line in node.children) {
+      items.add(_buildLine(line, style, theme.indentSize));
+    }
+
+    return Padding(
+      padding: theme.blockTheme.quote.padding,
+      child: Column(
+        crossAxisAlignment: CrossAxisAlignment.stretch,
+        children: items,
+      ),
+    );
+  }
+
+  Widget _buildLine(Node node, TextStyle blockStyle, double indentSize) {
+    LineNode line = node;
+
+    Widget content;
+    if (line.style.contains(NotusAttribute.heading)) {
+      content = new ZefyrHeading(node: node, blockStyle: blockStyle);
+    } else {
+      content = new ZefyrParagraph(node: node, blockStyle: blockStyle);
+    }
+
+    final row = Row(children: <Widget>[Expanded(child: content)]);
+    return Container(
+      decoration: BoxDecoration(
+        border: Border(
+          left: BorderSide(width: 4.0, color: Colors.grey.shade300),
+        ),
+      ),
+      padding: EdgeInsets.only(left: indentSize),
+      child: row,
+    );
+  }
+}

packages/zefyr/lib/src/widgets/render_context.dart

@@ -0,0 +1,116 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter/foundation.dart';
+import 'package:flutter/widgets.dart';
+
+import 'editable_box.dart';
+
+/// Registry of all [RenderEditableBox]es inside a [ZefyrEditableText].
+///
+/// Provides access to all currently active [RenderEditableBox]
+/// instances of a [ZefyrEditableText].
+///
+/// Use [boxForTextOffset] or [boxForGlobalPoint] to retrieve a
+/// specific box.
+///
+/// The [addBox], [removeBox] and [markDirty] are intended to be
+/// only used by [RenderEditableBox] objects to register with a rendering
+/// context.
+///
+/// ### Life cycle details
+///
+/// When a box object is attached to rendering pipeline it registers
+/// itself with a render scope by calling [addBox]. At this point the context
+/// treats this object as "dirty" and query methods like [boxForTextOffset]
+/// still exclude this object from returned results.
+///
+/// When this box considers itself initialized it calls [markDirty] with
+/// `isDirty` set to `false` which activates it. At this point query methods
+/// include this object in results.
+///
+/// When a box is rebuilt it may deactivate itself by calling [markDirty]
+/// again.
+///
+/// When a box is detached from rendering pipeline it unregisters
+/// itself by calling [removeBox].
+class ZefyrRenderContext extends ChangeNotifier {
+  final Set<RenderEditableBox> _dirtyBoxes = new Set();
+  final Set<RenderEditableBox> _activeBoxes = new Set();
+
+  Set<RenderEditableBox> get dirty => _dirtyBoxes;
+  Set<RenderEditableBox> get active => _activeBoxes;
+
+  bool _disposed = false;
+
+  /// Adds [box] to this context. The box is considered "dirty" at
+  /// this point and is not included in query results of `boxFor*`
+  /// methods.
+  void addBox(RenderEditableBox box) {
+    assert(!_disposed);
+    _dirtyBoxes.add(box);
+  }
+
+  /// Removes [box] from this render context.
+  void removeBox(RenderEditableBox box) {
+    assert(!_disposed);
+    _dirtyBoxes.remove(box);
+    _activeBoxes.remove(box);
+    notifyListeners();
+  }
+
+  void markDirty(RenderEditableBox box, bool isDirty) {
+    assert(!_disposed);
+
+    var collection = isDirty ? _dirtyBoxes : _activeBoxes;
+    if (collection.contains(box)) return;
+
+    if (isDirty) {
+      _activeBoxes.remove(box);
+      _dirtyBoxes.add(box);
+    } else {
+      _dirtyBoxes.remove(box);
+      _activeBoxes.add(box);
+    }
+    notifyListeners();
+  }
+
+  /// Returns box containing character at specified document [offset].
+  RenderEditableBox boxForTextOffset(int offset) {
+    assert(!_disposed);
+    return _activeBoxes.firstWhere(
+      (p) => p.node.containsOffset(offset),
+      orElse: _null,
+    );
+  }
+
+  /// Returns box located at specified global [point] on the screen or
+  /// `null`.
+  RenderEditableBox boxForGlobalPoint(Offset point) {
+    assert(!_disposed);
+    return _activeBoxes.firstWhere((p) {
+      final localPoint = p.globalToLocal(point);
+      return p.size.contains(localPoint);
+    }, orElse: _null);
+  }
+
+  static Null _null() => null;
+
+  @override
+  void dispose() {
+    _disposed = true;
+    _activeBoxes.clear();
+    _dirtyBoxes.clear();
+    super.dispose();
+  }
+
+  @override
+  void notifyListeners() {
+    /// Ensures listeners are not notified during rendering phase where they
+    /// cannot react by updating their state or rebuilding.
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      if (_disposed) return;
+      super.notifyListeners();
+    });
+  }
+}

packages/zefyr/lib/src/widgets/selection.dart

@@ -0,0 +1,453 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:ui' as ui;
+
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+import 'package:notus/notus.dart';
+import 'package:zefyr/util.dart';
+
+import 'controller.dart';
+import 'editable_box.dart';
+import 'editable_text.dart';
+import 'editor.dart';
+
+RenderEditableBox _getRenderParagraph(HitTestResult result) {
+  for (var entry in result.path) {
+    if (entry.target is RenderEditableBox) {
+      return entry.target;
+    }
+  }
+  return null;
+}
+
+/// Selection overlay controls selection handles and other gestures.
+class ZefyrSelectionOverlay extends StatefulWidget {
+  const ZefyrSelectionOverlay({
+    Key key,
+    @required this.controller,
+    @required this.controls,
+    @required this.overlay,
+  }) : super(key: key);
+
+  final ZefyrController controller;
+  final TextSelectionControls controls;
+  final OverlayState overlay;
+
+  @override
+  _ZefyrSelectionOverlayState createState() =>
+      new _ZefyrSelectionOverlayState();
+}
+
+class _ZefyrSelectionOverlayState extends State<ZefyrSelectionOverlay>
+    implements TextSelectionDelegate {
+  @override
+  TextEditingValue get textEditingValue =>
+      widget.controller.plainTextEditingValue;
+
+  set textEditingValue(TextEditingValue value) {
+    final cursorPosition = value.selection.extentOffset;
+    final oldText = widget.controller.document.toPlainText();
+    final newText = value.text;
+    final diff = fastDiff(oldText, newText, cursorPosition);
+    widget.controller.replaceText(
+        diff.start, diff.deleted.length, diff.inserted,
+        selection: value.selection);
+  }
+
+  @override
+  void bringIntoView(ui.TextPosition position) {
+    // TODO: implement bringIntoView
+  }
+
+  bool get isToolbarVisible => _toolbar != null;
+  bool get isToolbarHidden => _toolbar == null;
+
+  @override
+  void hideToolbar() {
+    _toolbar?.remove();
+    _toolbar = null;
+    _toolbarController.stop();
+  }
+
+  void showToolbar() {
+    final editable = ZefyrEditableText.of(context);
+    assert(editable != null);
+    final toolbarOpacity = _toolbarController.view;
+    _toolbar = new OverlayEntry(
+      builder: (context) => new FadeTransition(
+            opacity: toolbarOpacity,
+            child: new _SelectionToolbar(
+              editable: editable,
+              controls: widget.controls,
+              delegate: this,
+              visible: true,
+            ),
+          ),
+    );
+    widget.overlay.insert(_toolbar);
+    _toolbarController.forward(from: 0.0);
+  }
+
+  //
+  // Overridden members of State
+  //
+
+  @override
+  void initState() {
+    super.initState();
+    _toolbarController = new AnimationController(
+        duration: _kFadeDuration, vsync: widget.overlay);
+  }
+
+  static const Duration _kFadeDuration = const Duration(milliseconds: 150);
+
+  @override
+  void didUpdateWidget(ZefyrSelectionOverlay oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (oldWidget.overlay != widget.overlay) {
+      hideToolbar();
+      _toolbarController.dispose();
+      _toolbarController = new AnimationController(
+          duration: _kFadeDuration, vsync: widget.overlay);
+    }
+  }
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    WidgetsBinding.instance.addPostFrameCallback((_) {
+      _updateToolbar();
+    });
+  }
+
+  @override
+  void dispose() {
+    hideToolbar();
+    _toolbarController.dispose();
+    _toolbarController = null;
+    super.dispose();
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final overlay = new GestureDetector(
+      behavior: HitTestBehavior.translucent,
+      onTapDown: _handleTapDown,
+      onTap: _handleTap,
+      onTapCancel: _handleTapCancel,
+      onLongPress: _handleLongPress,
+      child: new Stack(
+        fit: StackFit.expand,
+        children: <Widget>[
+          new SelectionHandleDriver(
+            position: _SelectionHandlePosition.base,
+            controls: widget.controls,
+          ),
+          new SelectionHandleDriver(
+            position: _SelectionHandlePosition.extent,
+            controls: widget.controls,
+          ),
+        ],
+      ),
+    );
+    return new Container(child: overlay);
+  }
+
+  //
+  // Private members
+  //
+
+  /// Global position of last TapDown event.
+  Offset _lastTapDownPosition;
+
+  /// Global position of last TapDown which is potentially a long press.
+  Offset _longPressPosition;
+
+  OverlayEntry _toolbar;
+  AnimationController _toolbarController;
+
+  TextSelection _selection;
+
+  bool _didCaretTap = false;
+
+  void _updateToolbar() {
+    final editor = ZefyrEditor.of(context);
+    final selection = editor.selection;
+    final focusOwner = editor.focusOwner;
+    setState(() {
+      if (focusOwner != FocusOwner.editor) {
+        hideToolbar();
+      } else {
+        if (_selection != selection) {
+          if (selection.isCollapsed && isToolbarVisible) hideToolbar();
+          _toolbar?.markNeedsBuild();
+          if (!selection.isCollapsed && isToolbarHidden) showToolbar();
+        } else {
+          if (!selection.isCollapsed && isToolbarHidden) {
+            showToolbar();
+          } else if (isToolbarVisible) {
+            _toolbar?.markNeedsBuild();
+          }
+        }
+      }
+      _selection = selection;
+    });
+  }
+
+  void _handleTapDown(TapDownDetails details) {
+    _lastTapDownPosition = details.globalPosition;
+  }
+
+  void _handleTapCancel() {
+    // longPress arrives after tapCancel, so remember the tap position.
+    _longPressPosition = _lastTapDownPosition;
+    _lastTapDownPosition = null;
+  }
+
+  void _handleTap() {
+    assert(_lastTapDownPosition != null);
+    final globalPoint = _lastTapDownPosition;
+    _lastTapDownPosition = null;
+    HitTestResult result = new HitTestResult();
+    WidgetsBinding.instance.hitTest(result, globalPoint);
+
+    final paragraph = _getRenderParagraph(result);
+    if (paragraph == null) return;
+
+    final localPoint = paragraph.globalToLocal(globalPoint);
+    final position = paragraph.getPositionForOffset(localPoint);
+    final selection = new TextSelection.collapsed(
+        offset: paragraph.node.documentOffset + position.offset);
+    if (_didCaretTap && _selection == selection) {
+      _didCaretTap = false;
+      hideToolbar();
+      showToolbar();
+    } else {
+      _didCaretTap = true;
+    }
+    widget.controller.updateSelection(selection, source: ChangeSource.local);
+  }
+
+  void _handleLongPress() {
+    final Offset globalPoint = _longPressPosition;
+    _longPressPosition = null;
+    HitTestResult result = new HitTestResult();
+    WidgetsBinding.instance.hitTest(result, globalPoint);
+    final paragraph = _getRenderParagraph(result);
+    if (paragraph == null) {
+      return;
+    }
+    final localPoint = paragraph.globalToLocal(globalPoint);
+    final position = paragraph.getPositionForOffset(localPoint);
+    final word = paragraph.getWordBoundary(position);
+    final selection = new TextSelection(
+      baseOffset: paragraph.node.documentOffset + word.start,
+      extentOffset: paragraph.node.documentOffset + word.end,
+    );
+    widget.controller.updateSelection(selection, source: ChangeSource.local);
+  }
+}
+
+enum _SelectionHandlePosition { base, extent }
+
+class SelectionHandleDriver extends StatefulWidget {
+  const SelectionHandleDriver({
+    Key key,
+    @required this.position,
+    @required this.controls,
+  }) : super(key: key);
+
+  final _SelectionHandlePosition position;
+  final TextSelectionControls controls;
+
+  @override
+  _SelectionHandleDriverState createState() =>
+      new _SelectionHandleDriverState();
+}
+
+class _SelectionHandleDriverState extends State<SelectionHandleDriver> {
+  /// Current document selection.
+  TextSelection get selection => _selection;
+  TextSelection _selection;
+
+  /// Returns `true` if this handle is located at the baseOffset of selection.
+  bool get isBaseHandle => widget.position == _SelectionHandlePosition.base;
+
+  /// Character offset of this handle in the document.
+  ///
+  /// For base handle this equals to [TextSelection.baseOffset] and for
+  /// extent handle - [TextSelection.extentOffset].
+  int get documentOffset =>
+      isBaseHandle ? selection.baseOffset : selection.extentOffset;
+
+  /// Position in pixels of this selection handle within its paragraph [block].
+  Offset getPosition(RenderEditableBox block) {
+    if (block == null) return null;
+
+    final localSelection = block.getLocalSelection(selection);
+    assert(localSelection != null);
+
+    final boxes = block.getEndpointsForSelection(selection);
+    if (boxes.isEmpty) {
+      print('Got empty boxes for selection ${selection}');
+      return null;
+    }
+    final box = isBaseHandle ? boxes.first : boxes.last;
+    final dx = isBaseHandle ? box.start : box.end;
+    return new Offset(dx, box.bottom);
+  }
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    final editable = ZefyrEditableText.of(context);
+    _selection = editable.selection;
+  }
+
+  //
+  // Overridden members
+  //
+
+  @override
+  Widget build(BuildContext context) {
+    final editor = ZefyrEditor.of(context);
+    final editable = ZefyrEditableText.of(context);
+    if (selection == null ||
+        selection.isCollapsed ||
+        widget.controls == null ||
+        editor.focusOwner != FocusOwner.editor) {
+      return new Container();
+    }
+    final block = editable.renderContext.boxForTextOffset(documentOffset);
+    final position = getPosition(block);
+    Widget handle;
+    if (position == null) {
+      handle = new Container();
+    } else {
+      final handleType = isBaseHandle
+          ? TextSelectionHandleType.left
+          : TextSelectionHandleType.right;
+      handle = new Positioned(
+        left: position.dx,
+        top: position.dy,
+        child: widget.controls.buildHandle(
+          context,
+          handleType,
+          block.preferredLineHeight,
+        ),
+      );
+      handle = new CompositedTransformFollower(
+        link: block.layerLink,
+        showWhenUnlinked: false,
+        child: new Stack(children: <Widget>[handle]),
+      );
+    }
+    // Always return this gesture detector even if handle is an empty container
+    // This way we prevent drag gesture from being canceled in case current
+    // position is somewhere outside of any visible paragraph block.
+    return new GestureDetector(
+      onPanStart: _handleDragStart,
+      onPanUpdate: _handleDragUpdate,
+      child: handle,
+    );
+  }
+
+  //
+  // Private members
+  //
+
+  Offset _dragPosition;
+
+  void _handleDragStart(DragStartDetails details) {
+    _dragPosition = details.globalPosition;
+  }
+
+  void _handleDragUpdate(DragUpdateDetails details) {
+    _dragPosition += details.delta;
+    final globalPoint = _dragPosition;
+    final editor = ZefyrEditor.of(context);
+    final editable = ZefyrEditableText.of(context);
+    final paragraph =
+        editable.renderContext.boxForGlobalPoint(globalPoint);
+    if (paragraph == null) {
+      return;
+    }
+
+    final localPoint = paragraph.globalToLocal(globalPoint);
+    final position = paragraph.getPositionForOffset(localPoint);
+    final documentOffset = paragraph.node.documentOffset + position.offset;
+    final newSelection = selection.copyWith(
+      baseOffset: isBaseHandle ? documentOffset : selection.baseOffset,
+      extentOffset: isBaseHandle ? selection.extentOffset : documentOffset,
+    );
+    if (newSelection.baseOffset >= newSelection.extentOffset) {
+      // Don't allow reversed or collapsed selection.
+      return;
+    }
+
+    if (newSelection != _selection) {
+      editor.updateSelection(newSelection, source: ChangeSource.local);
+    }
+  }
+}
+
+class _SelectionToolbar extends StatefulWidget {
+  const _SelectionToolbar({
+    Key key,
+    @required this.editable,
+    @required this.controls,
+    @required this.delegate,
+    @required this.visible,
+  }) : super(key: key);
+
+  final ZefyrEditableTextScope editable;
+  final TextSelectionControls controls;
+  final TextSelectionDelegate delegate;
+  final bool visible;
+
+  @override
+  _SelectionToolbarState createState() => new _SelectionToolbarState();
+}
+
+class _SelectionToolbarState extends State<_SelectionToolbar> {
+  ZefyrEditableTextScope get editable => widget.editable;
+
+  @override
+  Widget build(BuildContext context) {
+    return _buildToolbar(context);
+  }
+
+  Widget _buildToolbar(BuildContext context) {
+    final base = editable.selection.baseOffset;
+    final block = editable.renderContext.boxForTextOffset(base);
+    if (block == null) {
+      return Container();
+    }
+
+    final boxes = block.getEndpointsForSelection(editable.selection);
+
+    // Find the horizontal midpoint, just above the selected text.
+    final Offset midpoint = new Offset(
+      (boxes.length == 1)
+          ? (boxes[0].start + boxes[0].end) / 2.0
+          : (boxes[0].start + boxes[1].start) / 2.0,
+      boxes[0].bottom - block.preferredLineHeight,
+    );
+
+    final Rect editingRegion = new Rect.fromPoints(
+      block.localToGlobal(Offset.zero),
+      block.localToGlobal(block.size.bottomRight(Offset.zero)),
+    );
+
+    final toolbar = widget.controls
+        .buildToolbar(context, editingRegion, midpoint, widget.delegate);
+    return new CompositedTransformFollower(
+      link: block.layerLink,
+      showWhenUnlinked: false,
+      offset: -editingRegion.topLeft,
+      child: toolbar,
+    );
+  }
+}

packages/zefyr/lib/src/widgets/theme.dart

@@ -0,0 +1,306 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:io';
+
+import 'package:flutter/material.dart';
+import 'package:flutter/widgets.dart';
+import 'package:meta/meta.dart';
+
+/// Applies a Zefyr editor theme to descendant widgets.
+///
+/// Describes colors and typographic styles for an editor.
+///
+/// Descendant widgets obtain the current theme's [ZefyrThemeData] object using
+/// [ZefyrTheme.of].
+///
+/// See also:
+///
+///   * [ZefyrThemeData], which describes actual configuration of a theme.
+class ZefyrTheme extends InheritedWidget {
+  final ZefyrThemeData data;
+
+  /// Applies the given theme [data] to [child].
+  ///
+  /// The [data] and [child] arguments must not be null.
+  ZefyrTheme({
+    Key key,
+    @required this.data,
+    @required Widget child,
+  })  : assert(data != null),
+        assert(child != null),
+        super(key: key, child: child);
+
+  @override
+  bool updateShouldNotify(ZefyrTheme oldWidget) {
+    return data != oldWidget.data;
+  }
+
+  /// The data from the closest [ZefyrTheme] instance that encloses the given
+  /// context.
+  ///
+  /// Returns `null` if there is no [ZefyrTheme] in the given build context
+  /// and [nullOk] is set to `true`. If [nullOk] is set to `false` (default)
+  /// then this method asserts.
+  static ZefyrThemeData of(BuildContext context, {bool nullOk: false}) {
+    final ZefyrTheme widget = context.inheritFromWidgetOfExactType(ZefyrTheme);
+    if (widget == null && nullOk) return null;
+    assert(widget != null,
+        '$ZefyrTheme.of() called with a context that does not contain a ZefyrEditor.');
+    return widget.data;
+  }
+}
+
+/// Holds colors and typography styles for [ZefyrEditor].
+class ZefyrThemeData {
+  final TextStyle boldStyle;
+  final TextStyle italicStyle;
+  final TextStyle linkStyle;
+  final StyleTheme paragraphTheme;
+  final HeadingTheme headingTheme;
+  final BlockTheme blockTheme;
+  final Color selectionColor;
+
+  /// Size of indentation for blocks.
+  final double indentSize;
+  final ZefyrToolbarTheme toolbarTheme;
+
+  factory ZefyrThemeData.fallback(BuildContext context) {
+    final defaultStyle = DefaultTextStyle.of(context);
+    final paragraphStyle = defaultStyle.style.copyWith(
+      fontSize: 16.0,
+      height: 1.25,
+      fontWeight: FontWeight.normal,
+      color: Colors.grey.shade800,
+    );
+    final padding = const EdgeInsets.only(bottom: 8.0);
+    final boldStyle = new TextStyle(fontWeight: FontWeight.bold);
+    final italicStyle = new TextStyle(fontStyle: FontStyle.italic);
+    final linkStyle =
+        TextStyle(color: Colors.blue, decoration: TextDecoration.underline);
+
+    return new ZefyrThemeData(
+      boldStyle: boldStyle,
+      italicStyle: italicStyle,
+      linkStyle: linkStyle,
+      paragraphTheme:
+          new StyleTheme(textStyle: paragraphStyle, padding: padding),
+      headingTheme: new HeadingTheme.fallback(),
+      blockTheme: new BlockTheme.fallback(),
+      selectionColor: Colors.lightBlueAccent.shade100,
+      indentSize: 16.0,
+      toolbarTheme: new ZefyrToolbarTheme.fallback(context),
+    );
+  }
+
+  const ZefyrThemeData({
+    this.boldStyle,
+    this.italicStyle,
+    this.linkStyle,
+    this.paragraphTheme,
+    this.headingTheme,
+    this.blockTheme,
+    this.selectionColor,
+    this.indentSize,
+    this.toolbarTheme,
+  });
+
+  ZefyrThemeData copyWith({
+    TextStyle textStyle,
+    TextStyle boldStyle,
+    TextStyle italicStyle,
+    TextStyle linkStyle,
+    StyleTheme paragraphTheme,
+    HeadingTheme headingTheme,
+    BlockTheme blockTheme,
+    Color selectionColor,
+    double indentSize,
+    ZefyrToolbarTheme toolbarTheme,
+  }) {
+    return new ZefyrThemeData(
+      boldStyle: boldStyle ?? this.boldStyle,
+      italicStyle: italicStyle ?? this.italicStyle,
+      linkStyle: linkStyle ?? this.linkStyle,
+      paragraphTheme: paragraphTheme ?? this.paragraphTheme,
+      headingTheme: headingTheme ?? this.headingTheme,
+      blockTheme: blockTheme ?? this.blockTheme,
+      selectionColor: selectionColor ?? this.selectionColor,
+      indentSize: indentSize ?? this.indentSize,
+      toolbarTheme: toolbarTheme ?? this.toolbarTheme,
+    );
+  }
+
+  ZefyrThemeData merge(ZefyrThemeData other) {
+    return copyWith(
+      boldStyle: other.boldStyle,
+      italicStyle: other.italicStyle,
+      linkStyle: other.linkStyle,
+      paragraphTheme: other.paragraphTheme,
+      headingTheme: other.headingTheme,
+      blockTheme: other.blockTheme,
+      selectionColor: other.selectionColor,
+      indentSize: other.indentSize,
+      toolbarTheme: other.toolbarTheme,
+    );
+  }
+}
+
+/// Theme for heading-styled lines of text.
+class HeadingTheme {
+  /// Style theme for level 1 headings.
+  final StyleTheme level1;
+
+  /// Style theme for level 2 headings.
+  final StyleTheme level2;
+
+  /// Style theme for level 3 headings.
+  final StyleTheme level3;
+
+  HeadingTheme({
+    @required this.level1,
+    @required this.level2,
+    @required this.level3,
+  });
+
+  /// Creates fallback theme for headings.
+  factory HeadingTheme.fallback() {
+    return HeadingTheme(
+      level1: StyleTheme(
+        textStyle: TextStyle(
+          fontSize: 30.0,
+          color: Colors.grey.shade800,
+          height: 1.25,
+          fontWeight: FontWeight.w600,
+        ),
+        padding: EdgeInsets.only(bottom: 16.0),
+      ),
+      level2: StyleTheme(
+        textStyle: TextStyle(
+          fontSize: 24.0,
+          color: Colors.grey.shade800,
+          height: 1.25,
+          fontWeight: FontWeight.w600,
+        ),
+        padding: EdgeInsets.only(bottom: 8.0, top: 16.0),
+      ),
+      level3: StyleTheme(
+        textStyle: TextStyle(
+          fontSize: 20.0,
+          color: Colors.grey.shade800,
+          height: 1.25,
+          fontWeight: FontWeight.w600,
+        ),
+        padding: EdgeInsets.only(bottom: 8.0, top: 16.0),
+      ),
+    );
+  }
+}
+
+/// Theme for a block of lines in a document.
+class BlockTheme {
+  /// Style theme for bullet lists.
+  final StyleTheme bulletList;
+
+  /// Style theme for number lists.
+  final StyleTheme numberList;
+
+  /// Style theme for code snippets.
+  final StyleTheme code;
+
+  /// Style theme for quotes.
+  final StyleTheme quote;
+
+  BlockTheme({
+    @required this.bulletList,
+    @required this.numberList,
+    @required this.quote,
+    @required this.code,
+  });
+
+  /// Creates fallback theme for blocks.
+  factory BlockTheme.fallback() {
+    final padding = const EdgeInsets.only(bottom: 8.0);
+    return new BlockTheme(
+      bulletList: new StyleTheme(padding: padding),
+      numberList: new StyleTheme(padding: padding),
+      quote: new StyleTheme(
+        textStyle: new TextStyle(color: Colors.grey.shade700),
+        padding: padding,
+      ),
+      code: new StyleTheme(
+        textStyle: new TextStyle(
+          color: Colors.blueGrey.shade800,
+          fontFamily: Platform.isIOS ? 'Menlo' : 'Roboto Mono',
+          fontSize: 14.0,
+          height: 1.25,
+        ),
+        padding: padding,
+      ),
+    );
+  }
+}
+
+/// Theme for a specific attribute style.
+///
+/// Used in [HeadingTheme] and [BlockTheme], as well as in
+/// [ZefyrThemeData.paragraphTheme].
+class StyleTheme {
+  /// Text style of this theme.
+  final TextStyle textStyle;
+
+  /// Padding to apply around lines of text.
+  final EdgeInsets padding;
+
+  /// Creates a new [StyleTheme].
+  StyleTheme({
+    this.textStyle,
+    this.padding,
+  });
+}
+
+/// Defines styles and colors for [ZefyrToolbar].
+class ZefyrToolbarTheme {
+  /// The background color of toolbar.
+  final Color color;
+
+  /// Color of buttons in toggled state.
+  final Color toggleColor;
+
+  /// Color of button icons.
+  final Color iconColor;
+
+  /// Color of button icons in disabled state.
+  final Color disabledIconColor;
+
+  /// Creates fallback theme for editor toolbars.
+  factory ZefyrToolbarTheme.fallback(BuildContext context) {
+    final theme = Theme.of(context);
+    return ZefyrToolbarTheme._(
+      color: theme.primaryColorLight,
+      toggleColor: theme.primaryColor,
+      iconColor: theme.primaryIconTheme.color,
+      disabledIconColor: theme.primaryColor,
+    );
+  }
+
+  ZefyrToolbarTheme._({
+    @required this.color,
+    @required this.toggleColor,
+    @required this.iconColor,
+    @required this.disabledIconColor,
+  });
+
+  ZefyrToolbarTheme copyWith({
+    Color color,
+    Color toggleColor,
+    Color iconColor,
+    Color disabledIconColor,
+  }) {
+    return ZefyrToolbarTheme._(
+      color: color ?? this.color,
+      toggleColor: toggleColor ?? this.toggleColor,
+      iconColor: iconColor ?? this.iconColor,
+      disabledIconColor: disabledIconColor ?? this.disabledIconColor,
+    );
+  }
+}

packages/zefyr/lib/src/widgets/toolbar.dart

@@ -0,0 +1,392 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:async';
+import 'dart:ui' as ui;
+
+import 'package:flutter/material.dart';
+import 'package:notus/notus.dart';
+
+import 'buttons.dart';
+import 'controller.dart';
+import 'editor.dart';
+import 'theme.dart';
+
+/// List of all button actions supported by [ZefyrToolbar] buttons.
+enum ZefyrToolbarAction {
+  bold,
+  italic,
+  link,
+  unlink,
+  clipboardCopy,
+  openInBrowser,
+  heading,
+  headingLevel1,
+  headingLevel2,
+  headingLevel3,
+  bulletList,
+  numberList,
+  code,
+  quote,
+  hideKeyboard,
+  close,
+  confirm,
+}
+
+final kZefyrToolbarAttributeActions = <ZefyrToolbarAction, NotusAttributeKey>{
+  ZefyrToolbarAction.bold: NotusAttribute.bold,
+  ZefyrToolbarAction.italic: NotusAttribute.italic,
+  ZefyrToolbarAction.link: NotusAttribute.link,
+  ZefyrToolbarAction.heading: NotusAttribute.heading,
+  ZefyrToolbarAction.headingLevel1: NotusAttribute.heading.level1,
+  ZefyrToolbarAction.headingLevel2: NotusAttribute.heading.level2,
+  ZefyrToolbarAction.headingLevel3: NotusAttribute.heading.level3,
+  ZefyrToolbarAction.bulletList: NotusAttribute.block.bulletList,
+  ZefyrToolbarAction.numberList: NotusAttribute.block.numberList,
+  ZefyrToolbarAction.code: NotusAttribute.block.code,
+  ZefyrToolbarAction.quote: NotusAttribute.block.quote
+};
+
+/// Allows customizing appearance of [ZefyrToolbar].
+abstract class ZefyrToolbarDelegate {
+  /// Builds toolbar button for specified [action].
+  ///
+  /// Returned widget is usually an instance of [ZefyrButton].
+  Widget buildButton(BuildContext context, ZefyrToolbarAction action,
+      {VoidCallback onPressed});
+}
+
+/// Scaffold for [ZefyrToolbar].
+class ZefyrToolbarScaffold extends StatelessWidget {
+  const ZefyrToolbarScaffold({
+    Key key,
+    @required this.body,
+    this.trailing,
+    this.autoImplyTrailing: true,
+  }) : super(key: key);
+
+  final Widget body;
+  final Widget trailing;
+  final bool autoImplyTrailing;
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = ZefyrTheme.of(context).toolbarTheme;
+    final toolbar = ZefyrToolbar.of(context);
+    final constraints =
+        BoxConstraints.tightFor(height: ZefyrToolbar.kToolbarHeight);
+    final children = <Widget>[
+      Expanded(child: body),
+    ];
+
+    if (trailing != null) {
+      children.add(trailing);
+    } else if (autoImplyTrailing) {
+      children.add(toolbar.buildButton(context, ZefyrToolbarAction.close));
+    }
+    return new Container(
+      constraints: constraints,
+      child: Material(color: theme.color, child: Row(children: children)),
+    );
+  }
+}
+
+/// Toolbar for [ZefyrEditor].
+class ZefyrToolbar extends StatefulWidget implements PreferredSizeWidget {
+  static const kToolbarHeight = 50.0;
+
+  const ZefyrToolbar({
+    Key key,
+    @required this.focusNode,
+    @required this.controller,
+    this.autoHide: true,
+    this.delegate,
+  }) : super(key: key);
+
+  final FocusNode focusNode;
+  final ZefyrController controller;
+  final ZefyrToolbarDelegate delegate;
+
+  /// Whether to automatically hide this toolbar when editor loses focus.
+  final bool autoHide;
+
+  static ZefyrToolbarState of(BuildContext context) {
+    final _ZefyrToolbarScope scope =
+        context.inheritFromWidgetOfExactType(_ZefyrToolbarScope);
+    return scope?.toolbar;
+  }
+
+  @override
+  ZefyrToolbarState createState() => ZefyrToolbarState();
+
+  @override
+  ui.Size get preferredSize => new Size.fromHeight(ZefyrToolbar.kToolbarHeight);
+}
+
+class _ZefyrToolbarScope extends InheritedWidget {
+  _ZefyrToolbarScope({Key key, @required Widget child, @required this.toolbar})
+      : super(key: key, child: child);
+
+  final ZefyrToolbarState toolbar;
+
+  @override
+  bool updateShouldNotify(_ZefyrToolbarScope oldWidget) {
+    return toolbar != oldWidget.toolbar;
+  }
+}
+
+class ZefyrToolbarState extends State<ZefyrToolbar>
+    with SingleTickerProviderStateMixin {
+  final Key _toolbarKey = UniqueKey();
+  final Key _overlayKey = UniqueKey();
+
+  ZefyrToolbarDelegate _delegate;
+  AnimationController _overlayAnimation;
+  WidgetBuilder _overlayBuilder;
+  Completer<void> _overlayCompleter;
+
+  TextSelection _selection;
+
+  void markNeedsRebuild() {
+    setState(() {});
+  }
+
+  Widget buildButton(BuildContext context, ZefyrToolbarAction action,
+      {VoidCallback onPressed}) {
+    return _delegate.buildButton(context, action, onPressed: onPressed);
+  }
+
+  Future<void> showOverlay(WidgetBuilder builder) async {
+    assert(_overlayBuilder == null);
+    final completer = new Completer<void>();
+    setState(() {
+      _overlayBuilder = builder;
+      _overlayCompleter = completer;
+      _overlayAnimation.forward();
+    });
+    return completer.future;
+  }
+
+  void closeOverlay() {
+    if (!hasOverlay) return;
+    _overlayAnimation.reverse().whenComplete(() {
+      setState(() {
+        _overlayBuilder = null;
+        _overlayCompleter?.complete();
+        _overlayCompleter = null;
+      });
+    });
+  }
+
+  bool get hasOverlay => _overlayBuilder != null;
+
+  @override
+  void initState() {
+    super.initState();
+    _delegate = widget.delegate ?? new _DefaultZefyrToolbarDelegate();
+    _overlayAnimation = new AnimationController(
+        vsync: this, duration: Duration(milliseconds: 100));
+  }
+
+  @override
+  void didUpdateWidget(ZefyrToolbar oldWidget) {
+    super.didUpdateWidget(oldWidget);
+    if (widget.delegate != oldWidget.delegate) {
+      _delegate = widget.delegate ?? new _DefaultZefyrToolbarDelegate();
+    }
+  }
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    final editor = ZefyrEditor.of(context);
+    if (_selection != editor.selection) {
+      _selection = editor.selection;
+      closeOverlay();
+    }
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final editor = ZefyrEditor.of(context);
+
+    if (editor.focusOwner == FocusOwner.none) {
+      return new Container();
+    }
+
+    final layers = <Widget>[];
+
+    // Must set unique key for the toolbar to prevent it from reconstructing
+    // new state each time we toggle overlay.
+    final toolbar = ZefyrToolbarScaffold(
+      key: _toolbarKey,
+      body: ZefyrButtonList(buttons: _buildButtons(context)),
+      trailing: buildButton(context, ZefyrToolbarAction.hideKeyboard),
+    );
+
+    layers.add(toolbar);
+
+    if (hasOverlay) {
+      Widget widget = new Builder(builder: _overlayBuilder);
+      assert(widget != null);
+      final overlay = FadeTransition(
+        key: _overlayKey,
+        opacity: _overlayAnimation,
+        child: widget,
+      );
+      layers.add(overlay);
+    }
+
+    final constraints =
+        BoxConstraints.tightFor(height: ZefyrToolbar.kToolbarHeight);
+    return new _ZefyrToolbarScope(
+      toolbar: this,
+      child: Container(
+        constraints: constraints,
+        child: Stack(children: layers),
+      ),
+    );
+  }
+
+  List<Widget> _buildButtons(BuildContext context) {
+    final buttons = <Widget>[
+      buildButton(context, ZefyrToolbarAction.bold),
+      buildButton(context, ZefyrToolbarAction.italic),
+      LinkButton(),
+      HeadingButton(),
+      buildButton(context, ZefyrToolbarAction.bulletList),
+      buildButton(context, ZefyrToolbarAction.numberList),
+      buildButton(context, ZefyrToolbarAction.quote),
+      buildButton(context, ZefyrToolbarAction.code),
+    ];
+    return buttons;
+  }
+}
+
+/// Scrollable list of toolbar buttons.
+class ZefyrButtonList extends StatefulWidget {
+  const ZefyrButtonList({Key key, @required this.buttons}) : super(key: key);
+  final List<Widget> buttons;
+
+  @override
+  _ZefyrButtonListState createState() => _ZefyrButtonListState();
+}
+
+class _ZefyrButtonListState extends State<ZefyrButtonList> {
+  final ScrollController _controller = new ScrollController();
+  bool _showLeftArrow = false;
+  bool _showRightArrow = false;
+
+  @override
+  void initState() {
+    super.initState();
+    _controller.addListener(_handleScroll);
+    // Workaround to allow scroll controller attach to our ListView so that
+    // we can detect if overflow arrows need to be shown on init.
+    // TODO: find a better way to detect overflow
+    Timer.run(_handleScroll);
+  }
+
+  @override
+  Widget build(BuildContext context) {
+    final theme = ZefyrTheme.of(context).toolbarTheme;
+    final color = theme.iconColor;
+    final list = ListView(
+      scrollDirection: Axis.horizontal,
+      controller: _controller,
+      children: widget.buttons,
+      physics: ClampingScrollPhysics(),
+    );
+
+    final leftArrow = _showLeftArrow
+        ? Icon(Icons.arrow_left, size: 18.0, color: color)
+        : null;
+    final rightArrow = _showRightArrow
+        ? Icon(Icons.arrow_right, size: 18.0, color: color)
+        : null;
+    return Row(
+      children: <Widget>[
+        SizedBox(
+          width: 12.0,
+          height: ZefyrToolbar.kToolbarHeight,
+          child: Container(child: leftArrow, color: theme.color),
+        ),
+        Expanded(child: ClipRect(child: list)),
+        SizedBox(
+          width: 12.0,
+          height: ZefyrToolbar.kToolbarHeight,
+          child: Container(child: rightArrow, color: theme.color),
+        ),
+      ],
+    );
+  }
+
+  void _handleScroll() {
+    setState(() {
+      _showLeftArrow =
+          _controller.position.minScrollExtent != _controller.position.pixels;
+      _showRightArrow =
+          _controller.position.maxScrollExtent != _controller.position.pixels;
+    });
+  }
+}
+
+class _DefaultZefyrToolbarDelegate implements ZefyrToolbarDelegate {
+  static const kDefaultButtonIcons = {
+    ZefyrToolbarAction.bold: Icons.format_bold,
+    ZefyrToolbarAction.italic: Icons.format_italic,
+    ZefyrToolbarAction.link: Icons.link,
+    ZefyrToolbarAction.unlink: Icons.link_off,
+    ZefyrToolbarAction.clipboardCopy: Icons.content_copy,
+    ZefyrToolbarAction.openInBrowser: Icons.open_in_new,
+    ZefyrToolbarAction.heading: Icons.format_size,
+    ZefyrToolbarAction.bulletList: Icons.format_list_bulleted,
+    ZefyrToolbarAction.numberList: Icons.format_list_numbered,
+    ZefyrToolbarAction.code: Icons.code,
+    ZefyrToolbarAction.quote: Icons.format_quote,
+    ZefyrToolbarAction.hideKeyboard: Icons.keyboard_hide,
+    ZefyrToolbarAction.close: Icons.close,
+    ZefyrToolbarAction.confirm: Icons.check,
+  };
+
+  static const kSpecialIconSizes = {
+    ZefyrToolbarAction.unlink: 20.0,
+    ZefyrToolbarAction.clipboardCopy: 20.0,
+    ZefyrToolbarAction.openInBrowser: 20.0,
+    ZefyrToolbarAction.close: 20.0,
+    ZefyrToolbarAction.confirm: 20.0,
+  };
+
+  static const kDefaultButtonTexts = {
+    ZefyrToolbarAction.headingLevel1: 'H1',
+    ZefyrToolbarAction.headingLevel2: 'H2',
+    ZefyrToolbarAction.headingLevel3: 'H3',
+  };
+
+  @override
+  Widget buildButton(BuildContext context, ZefyrToolbarAction action,
+      {VoidCallback onPressed}) {
+    final theme = Theme.of(context);
+    if (kDefaultButtonIcons.containsKey(action)) {
+      final icon = kDefaultButtonIcons[action];
+      final size = kSpecialIconSizes[action];
+      return ZefyrButton.icon(
+        action: action,
+        icon: icon,
+        iconSize: size,
+        onPressed: onPressed,
+      );
+    } else {
+      final text = kDefaultButtonTexts[action];
+      assert(text != null);
+      final style = theme.textTheme.caption
+          .copyWith(fontWeight: FontWeight.bold, fontSize: 14.0);
+      return ZefyrButton.text(
+        action: action,
+        text: text,
+        style: style,
+        onPressed: onPressed,
+      );
+    }
+  }
+}

packages/zefyr/lib/util.dart

@@ -0,0 +1,35 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// Utility functions for Zefyr.
+library zefyr.util;
+
+import 'dart:math' as math;
+
+import 'package:quill_delta/quill_delta.dart';
+
+export 'src/fast_diff.dart';
+
+int getPositionDelta(Delta user, Delta actual) {
+  final userIter = new DeltaIterator(user);
+  final actualIter = new DeltaIterator(actual);
+  int diff = 0;
+  while (userIter.hasNext || actualIter.hasNext) {
+    num length = math.min(userIter.peekLength(), actualIter.peekLength());
+    final userOp = userIter.next(length);
+    final actualOp = actualIter.next(length);
+    assert(userOp.length == actualOp.length);
+    if (userOp.key == actualOp.key) continue;
+    if (userOp.isInsert && actualOp.isRetain) {
+      diff -= userOp.length;
+    } else if (userOp.isDelete && actualOp.isRetain) {
+      diff += userOp.length;
+    } else if (userOp.isRetain && actualOp.isInsert) {
+      diff += actualOp.length;
+    } else {
+      // TODO: this likely needs to cover more edge cases.
+    }
+  }
+  return diff;
+}

packages/zefyr/lib/widgets.dart

@@ -0,0 +1,18 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+library zefyr.widgets;
+
+export 'src/widgets/buttons.dart' hide HeadingButton, LinkButton;
+export 'src/widgets/code.dart';
+export 'src/widgets/common.dart';
+export 'src/widgets/controller.dart';
+export 'src/widgets/editable_text.dart';
+export 'src/widgets/editor.dart';
+export 'src/widgets/list.dart';
+export 'src/widgets/paragraph.dart';
+export 'src/widgets/quote.dart';
+//export 'src/widgets/render_context.dart';
+export 'src/widgets/selection.dart' hide SelectionHandleDriver;
+export 'src/widgets/theme.dart';
+export 'src/widgets/toolbar.dart';

packages/zefyr/lib/zefyr.dart

@@ -0,0 +1,18 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+/// Zefyr widgets and document model.
+///
+/// To use, `import 'package:zefyr/zefyr.dart';`.
+///
+/// See also:
+///
+///   * [Quick start]()
+///   * [NotusDocument], model for Zefyr documents.
+///   * [ZefyrEditor], widget for editing Zefyr documents.
+library zefyr;
+
+export 'package:notus/notus.dart';
+
+export 'widgets.dart';

packages/zefyr/pubspec.yaml

@@ -0,0 +1,19 @@
+name: zefyr
+description: Flutter widgets for editing rich text.
+version: 0.1.0
+author: anatoly.pulyaevskiy@gmail.com
+homepage: https://github.com/pulyaevskiy/zefyr
+
+dependencies:
+  flutter:
+    sdk: flutter
+  collection: ^1.14.6
+  notus:
+    path: ../notus
+  url_launcher: ^3.0.0
+  quill_delta: ^1.0.0-dev.1.0
+
+dev_dependencies:
+  flutter_test:
+    sdk: flutter
+  test: ^0.12.41

packages/zefyr/test/fast_diff_test.dart

@@ -0,0 +1,37 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter_test/flutter_test.dart';
+import 'package:zefyr/src/fast_diff.dart';
+
+void main() {
+  group('fastDiff', () {
+    test('insert', () {
+      var oldText = 'fastDiff';
+      var newText = 'fasterDiff';
+      var result = fastDiff(oldText, newText, 6);
+      expect(result.start, 4);
+      expect(result.deleted, "");
+      expect(result.inserted, "er");
+      expect("$result", 'DiffResult[4, "", "er"]');
+    });
+
+    test('delete', () {
+      var oldText = 'fastDiff';
+      var newText = 'fasDiff';
+      var result = fastDiff(oldText, newText, 3);
+      expect(result.start, 3);
+      expect(result.deleted, "t");
+      expect(result.inserted, "");
+    });
+
+    test('replace', () {
+      var oldText = 'fastDiff';
+      var newText = 'fas_Diff';
+      var result = fastDiff(oldText, newText, 4);
+      expect(result.start, 3);
+      expect(result.deleted, "t");
+      expect(result.inserted, "_");
+    });
+  });
+}

packages/zefyr/test/painting/caret_painter_test.dart

@@ -0,0 +1,22 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:ui';
+
+import 'package:flutter_test/flutter_test.dart';
+import 'package:zefyr/src/widgets/caret.dart';
+
+void main() {
+  group('$CaretPainter', () {
+    test('prototype is null before layout', () {
+      var painter = new CaretPainter();
+      expect(painter.prototype, isNull);
+    });
+
+    test('prototype is set after layout', () {
+      var painter = new CaretPainter();
+      painter.layout(16.0);
+      expect(painter.prototype, new Rect.fromLTWH(0.0, 0.0, 1.0, 14.0));
+    });
+  });
+}

packages/zefyr/test/rendering/render_editable_paragraph_test.dart

@@ -0,0 +1,49 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'dart:ui';
+
+import 'package:flutter/material.dart';
+import 'package:flutter/rendering.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:zefyr/src/widgets/editable_paragraph.dart';
+import 'package:zefyr/src/widgets/render_context.dart';
+import 'package:zefyr/zefyr.dart';
+
+void main() {
+  group('$RenderEditableParagraph', () {
+    final doc = new NotusDocument();
+    doc.insert(0, 'This House Is A Circus');
+    final text = new TextSpan(text: 'This House Is A Circus');
+    final link = new LayerLink();
+    final showCursor = new ValueNotifier<bool>(true);
+    final selection = new TextSelection.collapsed(offset: 0);
+    final selectionColor = Colors.blue;
+    ZefyrRenderContext viewport;
+
+    RenderEditableParagraph p;
+    setUp(() {
+      WidgetsFlutterBinding.ensureInitialized();
+      viewport = new ZefyrRenderContext();
+      p = new RenderEditableParagraph(
+        text,
+        node: doc.root.children.first,
+        layerLink: link,
+        renderContext: viewport,
+        showCursor: showCursor,
+        selection: selection,
+        selectionColor: selectionColor,
+        textDirection: TextDirection.ltr,
+      );
+    });
+
+    test('it registers with viewport', () {
+      var owner = new PipelineOwner();
+      expect(viewport.active, isNot(contains(p)));
+      p.attach(owner);
+      expect(viewport.dirty, contains(p));
+      p.layout(new BoxConstraints());
+      expect(viewport.active, contains(p));
+    });
+  });
+}

packages/zefyr/test/testing.dart

@@ -0,0 +1,93 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:quill_delta/quill_delta.dart';
+import 'package:zefyr/src/widgets/selection.dart';
+import 'package:zefyr/zefyr.dart';
+
+var delta = new Delta()..insert('This House Is A Circus\n');
+
+class EditorSandBox {
+  final WidgetTester tester;
+  final FocusNode focusNode;
+  final NotusDocument document;
+  final ZefyrController controller;
+  final Widget widget;
+
+  factory EditorSandBox({
+    @required WidgetTester tester,
+    FocusNode focusNode,
+    NotusDocument document,
+    ZefyrThemeData theme,
+  }) {
+    focusNode ??= FocusNode();
+    document ??= NotusDocument.fromDelta(delta);
+    var controller = ZefyrController(document);
+
+    Widget widget = ZefyrEditor(controller: controller, focusNode: focusNode);
+    if (theme != null) {
+      widget = ZefyrTheme(data: theme, child: widget);
+    }
+    widget = MaterialApp(home: widget);
+
+    return EditorSandBox._(tester, focusNode, document, controller, widget);
+  }
+
+  EditorSandBox._(
+      this.tester, this.focusNode, this.document, this.controller, this.widget);
+
+  TextSelection get selection => controller.selection;
+
+  Future<void> unfocus() {
+    focusNode.unfocus();
+    return tester.pumpAndSettle();
+  }
+
+  Future<void> updateSelection({int base, int extent}) {
+    controller.updateSelection(
+      new TextSelection(baseOffset: base, extentOffset: extent),
+    );
+    return tester.pumpAndSettle();
+  }
+
+  Future<void> tapEditor() async {
+    await tester.pumpWidget(widget);
+    await tester.tap(find.byType(ZefyrParagraph).first);
+    await tester.pumpAndSettle();
+    expect(focusNode.hasFocus, isTrue);
+  }
+
+  Future<void> tapHideKeyboardButton() async {
+    await tapButtonWithIcon(Icons.keyboard_hide);
+  }
+
+  Future<void> tapButtonWithIcon(IconData icon) async {
+    await tester.tap(find.widgetWithIcon(ZefyrButton, icon));
+    await tester.pumpAndSettle();
+  }
+
+  Future<void> tapButtonWithText(String text) async {
+    await tester.tap(find.widgetWithText(ZefyrButton, text));
+    await tester.pumpAndSettle();
+  }
+
+  RawZefyrButton findButtonWithIcon(IconData icon) {
+    RawZefyrButton button =
+        tester.widget(find.widgetWithIcon(RawZefyrButton, icon));
+    return button;
+  }
+
+  RawZefyrButton findButtonWithText(String text) {
+    RawZefyrButton button =
+        tester.widget(find.widgetWithText(RawZefyrButton, text));
+    return button;
+  }
+
+  Finder findSelectionHandle() {
+    return find.descendant(
+        of: find.byType(SelectionHandleDriver),
+        matching: find.byType(Positioned));
+  }
+}

packages/zefyr/test/util_test.dart

@@ -0,0 +1,43 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter_test/flutter_test.dart';
+import 'package:quill_delta/quill_delta.dart';
+import 'package:zefyr/util.dart';
+
+void main() {
+  group('getPositionDelta', () {
+    test('actual has more characters inserted than user', () {
+      final user = new Delta()
+        ..retain(7)
+        ..insert('a');
+      final actual = new Delta()
+        ..retain(7)
+        ..insert('\na');
+      final result = getPositionDelta(user, actual);
+      expect(result, 1);
+    });
+
+    test('actual has less characters inserted than user', () {
+      final user = new Delta()
+        ..retain(7)
+        ..insert('abc');
+      final actual = new Delta()
+        ..retain(7)
+        ..insert('ab');
+      final result = getPositionDelta(user, actual);
+      expect(result, -1);
+    });
+
+    test('actual has less characters deleted than user', () {
+      final user = new Delta()
+        ..retain(7)
+        ..delete(3);
+      final actual = new Delta()
+        ..retain(7)
+        ..delete(2);
+      final result = getPositionDelta(user, actual);
+      expect(result, 1);
+    });
+  });
+}

packages/zefyr/test/widgets/buttons_test.dart

@@ -0,0 +1,135 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:zefyr/src/widgets/buttons.dart';
+import 'package:zefyr/zefyr.dart';
+
+import '../testing.dart';
+
+void main() {
+  group('$ZefyrButton', () {
+    testWidgets('toggle style', (tester) async {
+      final editor = new EditorSandBox(tester: tester);
+      await editor.tapEditor();
+      await editor.updateSelection(base: 5, extent: 10);
+      await editor.tapButtonWithIcon(Icons.format_bold);
+
+      LineNode line = editor.document.root.children.first;
+      expect(line.childCount, 3);
+      TextNode bold = line.children.elementAt(1);
+      expect(bold.style.toJson(), NotusAttribute.bold.toJson());
+      expect(bold.value, 'House');
+
+      await editor.tapButtonWithIcon(Icons.format_bold);
+      line = editor.document.root.children.first;
+      expect(line.childCount, 1);
+    });
+
+    testWidgets('toggle state for different styles of the same attribute',
+        (tester) async {
+      final editor = new EditorSandBox(tester: tester);
+      await editor.tapEditor();
+
+      await editor.tapButtonWithIcon(Icons.format_list_bulleted);
+      expect(editor.document.root.children.first, isInstanceOf<BlockNode>());
+
+      var ul = editor.findButtonWithIcon(Icons.format_list_bulleted);
+      var ol = editor.findButtonWithIcon(Icons.format_list_numbered);
+      expect(ul.isToggled, isTrue);
+      expect(ol.isToggled, isFalse);
+    });
+  });
+
+  group('$HeadingButton', () {
+    testWidgets('toggle menu', (tester) async {
+      final editor = new EditorSandBox(tester: tester);
+      await editor.tapEditor();
+      await editor.tapButtonWithIcon(Icons.format_size);
+
+      expect(find.text('H1'), findsOneWidget);
+      var h1 = editor.findButtonWithText('H1');
+      expect(h1.action, ZefyrToolbarAction.headingLevel1);
+      var h2 = editor.findButtonWithText('H2');
+      expect(h2.action, ZefyrToolbarAction.headingLevel2);
+      var h3 = editor.findButtonWithText('H3');
+      expect(h3.action, ZefyrToolbarAction.headingLevel3);
+    });
+
+    testWidgets('toggle styles', (tester) async {
+      final editor = new EditorSandBox(tester: tester);
+      await editor.tapEditor();
+      await editor.tapButtonWithIcon(Icons.format_size);
+      await editor.tapButtonWithText('H3');
+      LineNode line = editor.document.root.children.first;
+      expect(line.style.containsSame(NotusAttribute.heading.level3), isTrue);
+      await editor.tapButtonWithText('H2');
+      expect(line.style.containsSame(NotusAttribute.heading.level2), isTrue);
+    });
+  });
+
+  group('$LinkButton', () {
+    testWidgets('disabled when selection is collapsed', (tester) async {
+      final editor = new EditorSandBox(tester: tester);
+      await editor.tapEditor();
+      await editor.tapButtonWithIcon(Icons.link);
+      expect(find.byIcon(Icons.link_off), findsNothing);
+    });
+
+    testWidgets('enabled and toggles menu with non-empty selection',
+        (tester) async {
+      final editor = new EditorSandBox(tester: tester);
+      await editor.tapEditor();
+      await editor.updateSelection(base: 5, extent: 10);
+      await editor.tapButtonWithIcon(Icons.link);
+      expect(find.byIcon(Icons.link_off), findsOneWidget);
+    });
+
+    testWidgets('auto cancels edit on selection update', (tester) async {
+      final editor = new EditorSandBox(tester: tester);
+      await editor.tapEditor();
+      await editor.updateSelection(base: 5, extent: 10);
+      await editor.tapButtonWithIcon(Icons.link);
+      await tester
+          .tap(find.widgetWithText(GestureDetector, 'Tap to edit link'));
+      await tester.pumpAndSettle();
+      await editor.updateSelection(base: 10, extent: 10);
+      expect(find.byIcon(Icons.link_off), findsNothing);
+    });
+
+    testWidgets('editing link', (tester) async {
+      final editor = new EditorSandBox(tester: tester);
+      await editor.tapEditor();
+      await editor.updateSelection(base: 5, extent: 10);
+
+      await editor.tapButtonWithIcon(Icons.link);
+      await tester
+          .tap(find.widgetWithText(GestureDetector, 'Tap to edit link'));
+      await tester.pumpAndSettle();
+      // TODO: figure out why below finder finds 2 instances of TextField
+      expect(find.widgetWithText(TextField, 'https://'), findsWidgets);
+      await tester.enterText(find.widgetWithText(TextField, 'https://').first,
+          'https://github.com');
+      await tester.pumpAndSettle();
+      expect(
+          find.widgetWithText(TextField, 'https://github.com'), findsOneWidget);
+      await editor.tapButtonWithIcon(Icons.check);
+      expect(find.widgetWithText(ZefyrToolbarScaffold, 'https://github.com'),
+          findsOneWidget);
+      LineNode line = editor.document.root.children.first;
+      expect(line.childCount, 3);
+      TextNode link = line.children.elementAt(1);
+      expect(link.value, 'House');
+      expect(link.style.toJson(),
+          NotusAttribute.link.fromString('https://github.com').toJson());
+
+      // unlink
+      await editor.updateSelection(base: 7, extent: 7);
+      await editor.tapButtonWithIcon(Icons.link);
+      await editor.tapButtonWithIcon(Icons.link_off);
+      line = editor.document.root.children.first;
+      expect(line.childCount, 1);
+    });
+  });
+}

packages/zefyr/test/widgets/code_test.dart

@@ -0,0 +1,21 @@
+// Copyright (c) 2018, the Zefyr project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+import 'package:flutter/material.dart';
+import 'package:flutter_test/flutter_test.dart';
+import 'package:zefyr/zefyr.dart';
+
+import '../testing.dart';
+
+void main() {
+  group('$ZefyrCode', () {
+    testWidgets('format as code', (tester) async {
+      final editor = new EditorSandBox(tester: tester);
+      await editor.tapEditor();
+      await editor.tapButtonWithIcon(Icons.code);
+
+      BlockNode block = editor.document.root.children.first;
+      expect(block.style.get(NotusAttribute.block), NotusAttribute.block.code);
+    });
+  });
+}