三角函数画波浪

<!DOCTYPE html>
<html>
<head>
    <style type="text/css">
        #MyCanvas {
            background-color: cornflowerblue;
        }
    </style>
    <script type="text/javascript">
          //带有绘制过程的动画
        /* var i = 1;
          var x = 1;
          var y = 200;
          function moveSin(){
              var my_canvas = document.getElementById( "MyCanvas" );
              var content = my_canvas.getContext( "2d" );
              content.beginPath();
              content.moveTo( x, y );
              i += 0.1;
              x = i * 10;
              y = Math.sin( i ) * 20 + 200;
              content.lineTo( x, y );
              content.stroke();
              content.closePath();
              console.log(x);
              if(x>=1000){
                  console.log("end");
                  window.clearInterval(myTime);
              }
          }
          var myTime = setInterval( moveSin, 10 );*/
        var a=0.1;//控制线体的柔韧度，越大柔韧度越差
        var b=10;//波浪大小，越大，波浪越大
        var c=10;//波浪高度，越大，波浪越高
        function draw(){
            var my_canvas = document.getElementById( "MyCanvas" );
            var content = my_canvas.getContext( "2d" );
            content.beginPath();
            content.moveTo( 1, my_canvas.height/2 );
            for( var i = 1; i < 100; i += a ){ // x 应该等于canvas的 width/10
                var x = i * b;
                var y = Math.sin( i ) * c + my_canvas.height/2;
                content.lineTo( x, y );
                console.log(x);
            }
            content.stroke();
            content.closePath();

}
</script>
</head>
<body onload="draw()">
<canvas id = "MyCanvas" width="1000" height="400"></canvas>
</body>
</html>

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