微信小程序弹球游戏

// index.js
Page({
    data:{
      cx:200,
      cy:50,
      destinaX:3,
      destinaY:2
    },
    //初次渲染触发
    onReady:function(){
      var c=wx.createCanvasContext("canvasTest");
      // var c=wx.createSelectorQuery('canvasTest')
      var that=this;
      var timer=setInterval(canvasSize,20);
      function canvasSize(){
        //画布数据
        const width=300;
        const height=300;
        const speed=2;
        const r=7;
        //下面是相对左上角基点距离 和画布大小
        c.rect(0,0,width,height);
        c.stroke();
        //球会根据实时位置发生变化
        c.beginPath();
        var ox1=that.datacox;
        var oy1=that.datacoy;
          ox1=that.data.destinaX*speed+that.data.cx;
          oy1=that.data.cy-that.data.destinaY*speed;
          if(ox1>=width||ox1<=0){
            var bounceX=-that.data.destinaX;
            that.setData({destinaX:bounceX});
            ox1=that.data.destinaX*speed+that.data.cx;
          }
          if(oy1>=height||oy1<=0){
            var bounceY=-that.data.destinaY;
            that.setData({destinaY:bounceY});
            oy1=that.data.cy-that.data.destinaY*speed;
          }
 
     console.log(that.data.ox1,that.data.oy1);
        that.setData({cx:ox1,cy:oy1});
        c.arc(that.data.cx,that.data.cy,r,0,2*Math.PI);
        c.fill();
        c.stroke();
        c.draw();
      }
    }
  })

<!--index.wxml-->
<view class="canvasStyle">
<canvas canvas-id="canvasTest" style="width: 300px;height: 300px;"></canvas> 
</view>

/**index.wxss**/
.canvasStyle{
  display: flex;
  justify-content: center;
  margin: 10px;
  margin-top: 70px;
  background-color: aqua;
  }