【微信小程序】根据屏幕尺寸去调整图片尺寸宽高比

1.获取图片的原始宽高，并获取到图片原始宽高的宽高比

let src = "图片地址"
wx.getImageInfo({
    src,
    success: function(res){
        let originalWidth = res.width;
        let originalHeight = res.height;
        let originalScale = parseInt(originalHeight/originalWidth);//图片高宽比   
    }
}）

2.获取屏幕的宽高，并获取到屏幕宽高的宽高比

        wx.getSystemInfo({
            success: function (res) {
              let windowWidth = res.windowWidth - 36 ;
              let windowHeight = res.windowHeight;
              let windowscale = parseInt(windowHeight/windowWidth);//屏幕高宽比
            }
        }）

3.计算图片尺寸

if(originalScale < windowscale){//图片高宽比小于屏幕高宽比
    //图片缩放后的宽为屏幕宽
    imageSize.imageWidth = parseInt(windowWidth);
    imageSize.imageHeight = parseInt((windowWidth * originalHeight) / originalWidth);
}else{//图片高宽比大于屏幕高宽比
    //图片缩放后的高为屏幕高
    imageSize.imageHeight = parseInt(windowHeight);
    imageSize.imageWidth = parseInt((windowHeight * originalWidth) / originalHeight);
}

4.整合代码，方便调用 新建一个util.js

function imageUtil(src,callback) {
  let imageSize = {};
  wx.getImageInfo({
    src,
    success: function(res){
      console.log(res,"1111111111111111111111")
      let originalWidth = res.width;
      let originalHeight = res.height;
      let originalScale = parseInt(originalHeight/originalWidth);//图片高宽比
      console.log('originalWidth: ' + originalWidth)
      console.log('originalHeight: ' + originalHeight)
      console.log(app.globalData)

      wx.getSystemInfo({
        success: function (res) {
          let windowWidth = res.windowWidth - 36 ;
          let windowHeight = res.windowHeight;
          let windowscale = parseInt(windowHeight/windowWidth);//屏幕高宽比
          console.log('windowWidth: ' + windowWidth)
          console.log('windowHeight: ' + windowHeight)
          if(originalScale < windowscale){//图片高宽比小于屏幕高宽比
            //图片缩放后的宽为屏幕宽
            imageSize.imageWidth = parseInt(windowWidth);
            imageSize.imageHeight = parseInt((windowWidth * originalHeight) / originalWidth);
          }else{//图片高宽比大于屏幕高宽比
            //图片缩放后的高为屏幕高
            imageSize.imageHeight = parseInt(windowHeight);
            imageSize.imageWidth = parseInt((windowHeight * originalWidth) / originalHeight);
          }
        },
      })
      console.log('缩放后的宽: ' + imageSize.imageWidth)
      console.log('缩放后的高: ' + imageSize.imageHeight)
      return callback(imageSize);
    }
  })

//抛出
module.exports = {
  imageUtil,
}

本文地址：https://blog.csdn.net/qq_37949737/article/details/109247673