//util.js 
function imageUtil(e) { 
  var imageSize = {}; 
  var originalWidth = e.detail.width;//图片原始宽 
  var originalHeight = e.detail.height;//图片原始高 
  var originalScale = originalHeight/originalWidth;//图片高宽比 
  console.log('originalWidth: ' + originalWidth) 
  console.log('originalHeight: ' + originalHeight) 
  //获取屏幕宽高 
  wx.getSystemInfo({ 
   success: function (res) { 
    var windowWidth = res.windowWidth; 
    var windowHeight = res.windowHeight; 
    var windowscale = 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 = windowWidth; 
      imageSize.imageHeight = (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 = windowHeight; 
      imageSize.imageWidth = (windowHeight * originalWidth) / originalHeight; 
    } 
     
   } 
  }) 
  console.log('缩放后的宽: ' + imageSize.imageWidth) 
  console.log('缩放后的高: ' + imageSize.imageHeight) 
  return imageSize; 
 } 
  
 module.exports = { 
  imageUtil: imageUtil 
 }