wx.canvasToTempFilePath({ x: x,y: y,width: width,height: height,destWidth: width,destHeight: height ,canvas: canvas,
    success: (res) => {      console.log(res)    },
    fail(res){console.log(res)},
    complete(res){console.log(res)}
  })

<canvas type="2d" id="canvas1"></canvas>
<canvas type="2d" id="canvas2"></canvas>

第一个canvas，wx.canvasToTempFilePath渲染有返回，

第二个canvas,success,fail,complete，都没任何返回。