react-native-view-shot/README.md

react-native-view-shot

Snapshot a React Native view and save it to an image.

For React Native version between 0.30.x and 0.39.x, you should use react-native-view-shot@1.5.1.

Usage

import RNViewShot from "react-native-view-shot";

RNViewShot.takeSnapshot(viewRef, {
  format: "jpeg",
  quality: 0.8
})
.then(
  uri => console.log("Image saved to", uri),
  error => console.error("Oops, snapshot failed", error)
);

Example

Checkout react-native-view-shot-example

Full API

RNViewShot.takeSnapshot(view, options)

Returns a Promise of the image URI.

• view is a reference to a React Native component.
• options may include:
  • width / height (number): the width and height of the image to capture.
  • format (string): either png or jpg/jpeg or webm (Android). Defaults to png.
  • quality (number): the quality. 0.0 - 1.0 (default). (only available on lossy formats like jpeg)
  • result (string), the method you want to use to save the snapshot, one of:
  • "file" (default): save to a temporary file (that will only exist for as long as the app is running).
  • "base64": encode as base64 and returns the raw string. Use only with small images as this may result of lags (the string is sent over the bridge). N.B. This is not a data uri, use data-uri instead.
  • "data-uri": same as base64 but also includes the Data URI scheme header.
  • filename (string): the name of the generated file if any (Android only). Defaults to ReactNative_snapshot_image_${timestamp}.
  • snapshotContentContainer (bool): if true and when view is a ScrollView, the “content container” height will be evaluated instead of the container height. (Android only)

Caveats

Snapshots are not guaranteed to be pixel perfect. It also depends on the platform. Here is some difference we have noticed and how to workaround.

• Support of special components like Video / GL views remains untested.
• It’s preferable to use a background color on the view you rasterize to avoid transparent pixels and potential weirdness that some border appear around texts.

specific to Android implementation

• you need to make sure collapsable is set to false if you want to snapshot a View. Otherwise that view won’t reflect any UI View. (found by @gaguirre)
• if you want to share out the screenshoted file, you will have to copy it somewhere first so it’s accessible to an Intent, see comment: https://github.com/gre/react-native-view-shot/issues/11#issuecomment-251080804 .
• if you implement a third party library and want to get back a File, you must first resolve the Uri. the file result returns an Uri so it’s consistent with iOS and you can give it to Image.getSize for instance.

Getting started

npm install --save react-native-view-shot

Mostly automatic installation

react-native link react-native-view-shot

Manual installation

iOS

1. In XCode, in the project navigator, right click Libraries ➜ Add Files to [your project's name]
2. Go to node_modules ➜ react-native-view-shot and add RNViewShot.xcodeproj
3. In XCode, in the project navigator, select your project. Add libRNViewShot.a to your project’s Build Phases ➜ Link Binary With Libraries
4. Run your project (Cmd+R)<

Android

1. Open up android/app/src/main/java/[...]/MainActivity.java
   • Add import fr.greweb.reactnativeviewshot.RNViewShotPackage; to the imports at the top of the file
   • Add new RNViewShotPackage() to the list returned by the getPackages() method
2. Append the following lines to android/settings.gradle: include ':react-native-view-shot' project(':react-native-view-shot').projectDir = new File(rootProject.projectDir, '../node_modules/react-native-view-shot/android')
3. Insert the following lines inside the dependencies block in android/app/build.gradle: compile project(':react-native-view-shot')

Windows

1. In Visual Studio, in the solution explorer, right click on your solution then select Add ➜ ExisitingProject
2. Go to node_modules ➜ react-native-view-shot and add RNViewShot.csproj (UWP) or optionally RNViewShot.Net46.csproj (WPF)
3. In Visual Studio, in the solution explorer, right click on your Application project then select Add ➜ Reference
4. Under the projects tab select RNViewShot (UWP) or RNViewShot.Net46 (WPF)

Thanks

• To initial iOS work done by @jsierles in https://github.com/jsierles/react-native-view-snapshot
• To React Native implementation of takeSnapshot in iOS by @nicklockwood