const xxx = {
      x: 0,
      y: 0,
      canvasId: 'canvas',
      quality:'1',
      fileType:'png',
      width: 300,
      height: 200,
      destWidth: 600,
      destHeight: 400,}
wx.canvasToTempFilePath({
          ...xxx,
          success(res) {
            console.log(res)
   }
})