Question

是否可以挂钩已经绘制的Canvas动画？我正在尝试创建3个单独的轨道，必须由“开始”和“停止”按钮控制，但是当按下第一个画布的“开始”按钮时，它会使最后一个画布运行。

这是我到目前为止所做的。

class Animation{
  constructor(){
    this.options = {
      left : 0,
      animate : false
    }
    let tracks = $('.line');
    let self = this;
    tracks.each(function(){
      self.startbtn = $(this).find('button.start');
      self.stopbtn = $(this).find('button.stop');
      self.canvas = $(this).find('canvas').get(0);
      self.canvas.width = 1000;
      self.canvas.height = 30;
      self.ctx = self.canvas.getContext('2d');
      self.draw(self.canvas,self.ctx);
      self.startbtn.bind('click',() => {
        self.options.animate = true;
        self.draw(self.canvas,self.ctx);
      })
    });
  }
  draw(c,ctx){
    ctx.clearRect(0,0,c.height,c.width);
    ctx.fillRect(this.options.left,0,1,30);
    if(this.options.animate){
        requestAnimationFrame(() => {
          console.log('done');
          this.options.left += 1;
          console.log(this.options.left)
          this.draw(c,ctx);
      });
    }
  }
}

new Animation();

Answer 1

您的代码存在范围问题，您必须确保每个轨道与其构造函数分开运行。

这是我确保信息完全独立于给定的track / parent元素的地方。

this.options = *set*;//left and animate separate for own process 
this.node = *set*;//nodes for each track
this.ctx = *set*;//draw command context set at the parent
this.draw = *set*;//draw function moved to track

以下是对您的代码的完整修改：

class Animation{
  constructor(){
    var tracks = $('.line');
    var self = this;
    tracks.each(function () {
      this.options = {//options seperate to parent track node
        left: 0,
        animate: false
      };
      this.node = {//store child nodes for access
        startbtn: $(this).find('button.start'),
        stopbtn: $(this).find('button.stop'),
        canvas: $(this).find('canvas').get(0)
      };
      this.node.canvas.width = 1000;
      this.node.canvas.height = 30;
      this.ctx = this.node.canvas.getContext('2d');
      this.node.startbtn.bind('click',() => {// () => parentNode instantiation
        this.options.animate = true;
        this.draw(this.node.canvas, this.ctx);
      });
      this.draw = self.draw;
    });
  }
  draw(c,ctx){
    parent = c.parentNode;
    ctx.clearRect(0,0,c.height,c.width);
    ctx.fillRect(parent.options.left,0,1,30);
    if(parent.options.animate){
        requestAnimationFrame(() => {
          console.log('done');
          parent.options.left += 1;
          console.log(parent.options.left)
          parent.draw(c,ctx);
      });
    }
  }
}

new Animation();

需要完成范围和对象处理。

http://codepen.io/anon/pen/JKzBLK

控制多个画布动画

1 个答案: