微信小程序小组件 基于Canvas实现直播点赞气泡效果

drawImage:function(data){[/align]
  var that = this
  var p10= data[0][0]; /* 三阶贝塞尔曲线起点坐标值*/
  var p11= data[0][1]; /* 三阶贝塞尔曲线第一个控制点坐标值*/
  var p12= data[0][2]; /* 三阶贝塞尔曲线第二个控制点坐标值*/
  var p13= data[0][3]; /* 三阶贝塞尔曲线终点坐标值*/
  var p20= data[1][0];
  var p21= data[1][1];
  var p22= data[1][2];
  var p23= data[1][3];
  var p30= data[2][0];
  var p31= data[2][1];
  var p32= data[2][2];
  var p33= data[2][3];
  var t = factor.t;
  /*计算多项式系数 （下同）*/ 
  var cx1 = 3*(p11.x-p10.x);
  var bx1 = 3*(p12.x-p11.x)-cx1;
  var ax1 = p13.x-p10.x-cx1-bx1;
  var cy1 = 3*(p11.y-p10.y);
  var by1 = 3*(p12.y-p11.y)-cy1;
  var ay1 = p13.y-p10.y-cy1-by1;
  var xt1 = ax1*(t*t*t)+bx1*(t*t)+cx1*t+p10.x;
  var yt1 = ay1*(t*t*t)+by1*(t*t)+cy1*t+p10.y;
  var cx2 = 3*(p21.x-p20.x);
  var bx2 = 3*(p22.x-p21.x)-cx2;
  var ax2 = p23.x-p20.x-cx2-bx2;
  var cy2 = 3*(p21.y-p20.y);
  var by2 = 3*(p22.y-p21.y)-cy2;
  var ay2 = p23.y-p20.y-cy2-by2;
  var xt2 = ax2*(t*t*t)+bx2*(t*t)+cx2*t+p20.x;
  var yt2 = ay2*(t*t*t)+by2*(t*t)+cy2*t+p20.y;
  var cx3 = 3*(p31.x-p30.x);
  var bx3 = 3*(p32.x-p31.x)-cx3;
  var ax3 = p33.x-p30.x-cx3-bx3;
  var cy3 = 3*(p31.y-p30.y);
  var by3 = 3*(p32.y-p31.y)-cy3;
  var ay3 = p33.y-p30.y-cy3-by3;
  /*计算xt yt的值 */
  var xt3 = ax3*(t*t*t)+bx3*(t*t)+cx3*t+p30.x;
  var yt3 = ay3*(t*t*t)+by3*(t*t)+cy3*t+p30.y;
  factor.t +=factor.speed;
  ctx.drawImage("../../images/heart1.png",xt1,yt1,30,30);
  ctx.drawImage("../../images/heart2.png",xt2,yt2,30,30);
  ctx.drawImage("../../images/heart3.png",xt3,yt3,30,30);
  ctx.draw();
  if(factor.t>1){
   factor.t=0;
   cancelAnimationFrame(timer);
   that.startTimer();
  }else{
   timer =requestAnimationFrame(function(){
    that.drawImage([[{x:30,y:400},{x:70,y:300},{x:-50,y:150},{x:30,y:0}],[{x:30,y:400},{x:30,y:300},{x:80,y:150},{x:30,y:0}],[{x:30,y:400},{x:0,y:90},{x:80,y:100},{x:30,y:0}]])
   })
  }}

cx = 3 * ( x1 - x0 )
bx = 3 * ( x2 - x1 ) - cx
ax = x3 - x0 - cx - bx
cy = 3 * ( y1 - y0 )  
by = 3 * ( y2 - y1 ) - cy
ay = y3 - y0 - cy - by
x(t) = ax * t ^ 3 + bx * t ^ 2 + cx * t + x0
y(t) = ay * t ^ 3 + by * t ^ 2 + cy * t + y0