支持移动手机的canvas刮刮卡插件

.scratch_container {
  position: relative;
  margin: 0 auto;
  max-width: 1024px;
}
 
.scratch_viewport {
  position: relative;
  width: 250px;
  height: 250px;
  margin: 0 auto;
  z-index: 0;
}
 
.scratch_picture-under {
  position: absolute;
  top: 0;
  left: 0;
  display: block;
  z-index: -1;
}
 
.scratch_container canvas {
  position: relative;
  width: 100%;
  height: auto;
  z-index: 1;
}

var scratch = new Scratch({
    canvasId: 'js-scratch-canvas',
    imageBackground: 'loose.jpg',
    pictureOver: 'foreground.jpg',
    cursor: {
        png: 'piece.png',
        cur: 'piece.cur',
        x: '20',
        y: '17'
    },
    radius: 20,
    nPoints: 100,
    percent: 50,
    callback: function () {
      alert('I am Callback.');
    },
    pointSize: { x: 3, y: 3}
});