campus_react_local/App/utils/ScreenUtils.js

import {
    Dimensions,
    PixelRatio,
} from 'react-native';


export const deviceWidth = Dimensions.get('window').width;      //设备的宽度
export const deviceHeight = Dimensions.get('window').height;    //设备的高度
let fontScale = PixelRatio.getFontScale();                      //返回字体大小缩放比例

let pixelRatio = PixelRatio.get();      //当前设备的像素密度
const defaultPixel = 2;                           //iphone6的像素密度
//px转换成dp
const w2 = 750 / defaultPixel;
const h2 = 1334 / defaultPixel;
const scale = Math.min(deviceHeight / h2, deviceWidth / w2);   //获取缩放比例
/**
 * 设置text为sp
 * @param size sp
 * return number dp
 */
export function setSpText(size: number) {
    size = Math.round((size * scale ) * pixelRatio / fontScale);
    return size / defaultPixel;
}

export function scaleSize(size: number) {

    size = Math.round(size * scale );
    return size / defaultPixel;
}

export function widthRatio(ratio){
    if(ratio>1)return ''
    return Math.round(ratio*deviceWidth)
}
export function heightRatio(ratio){
    if(ratio>1)return ''
    return Math.round(ratio*deviceHeight)
}
export function widthPxToDp(value){
    const deviceWidthDp = Dimensions.get('window').width;
    const uiWidthPx = 750;//ps图比例
    return value *  deviceWidthDp / uiWidthPx;
}
export function heightPxToDp(value){
    const den = PixelRatio.get();
    const deviceHeightDp = Dimensions.get('window').height;
    const uiHeightPx = 1344;//ps图比例
    // console.log('height:',deviceHeightDp,'translate:',value *  deviceHeightDp / uiHeightPx)
    return value *  deviceHeightDp / uiHeightPx;
}