用canvas画心电图的示例编码

日期：2021-01-19 类型：科技新闻我要分享

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本文详细介绍了用canvas画心电图的示例编码，共享给大伙儿，实际以下：

实际效果图：

思路：

1.仿真模拟点（假如你有真正的数据信息，那便是把数据信息坐骑成canvas对应的座标点）

仿真模拟点时留意的点便是高起一部分必须对称性和以便漂亮要任意出現上左右下

2.画线

画线必须留意有1个匀速挪动的全过程。

例如 A点到B点，并不是简易的A画到B，而是A点到A1,A2....最终到B（这1块依照占比挪动较为难）

3.画线的1些实际效果，例如再加黑影（这里便可以随意充分发挥了）实际编码

<!DOCTYPE html>
 <html lang="en">
 <head>
     <meta charset="UTF⑻">
     <title>心电图</title>
     <meta name="viewport" content="width=device-width, initial-scale=1, user-scalable=no">
     <style>
         html,body{
             width: 100%;
             height: 100%;
             margin: 0;
         }
         canvas{
             background: #000;
             width: 100%;
            height: 100%;
         }
     </style>
 </head>
 <body>
 <div id="canvas">
     <canvas id="can"></canvas>
 </div>
 <script>
     var can = document.getElementById('can'),
         pan,
         index = 0,
         flag = true,
         wid = document.body.clientWidth,
         hei = document.body.clientHeight,
         x = 0,
         y = hei/2,
         drawX = 0, 
         drawY = hei/2,
         drawXY = [],
         cDrawX = 0,
         i = 0,
         reX = 0,
         reY = 0;
     start();
     function start(){
         can.height = hei;
         can.width  = wid;
         pan = can.getContext("2d");
         pan.strokeStyle = "white";
         pan.lineJoin = "round";
         pan.lineWidth = 6;
         pan.shadowColor = "#228DFF";
         pan.shadowOffsetX = 0;
         pan.shadowOffsetY = 0;
         pan.shadowBlur = 20;
         pan.beginPath();
         pan.moveTo(x,y);
         drawXYS();
         index = setInterval(move,1);
     };

     function drawXYS(){
         if(drawX > wid){
         }else{
             if(drawY == hei/2){
                 if(flag){
                     flag = false;
                 }else{
                     var _y = Math.ceil(Math.random()*10);
                     _y = _y/2;
                     if(Number.isInteger(_y)){
                         drawY += Math.random()*180+30;
                     }else{
                         drawY -= Math.random()*180+30;
                     }
                     flag = true;
                 }
                 cDrawX = Math.random()*40+15;
             }else{
                 drawY = hei/2;
             }
             drawX += cDrawX;
             drawXY.push({
                 x : drawX,
                 y : drawY
             });
             drawXYS();
         }
     }

     function move(){
         var x = drawXY[i].x,
             y = drawXY[i].y;
         if(reX >= x - 1){
             reX = x;
             reY = y;
             i++;
             cc();
             return;
         }
         if(y > hei/2){
             if(reY >= y){
                 reX = x;
                 reY = y;
                 i++;
                 cc();
                 return;
             }
         }else if(y < hei/2){
             if(reY <= y){
                 reX = x;
                 reY = y;
                 i++;
                 cc();
                 return;
             }
         }else{
             reX = x;
             reY = y;
             i++;
             cc();
             return;
         }

         reX += 1;
         if(y == hei/2){
             reY = hei/2;
         }else{
             var c = Math.abs((drawXY[i].x-drawXY[i⑴].x)/(drawXY[i].y-drawXY[i⑴].y));
             var _yt = (reX-drawXY[i⑴].x)/c;

             if(drawXY[i].y < drawXY[i⑴].y){
                 reY = drawXY[i⑴].y - _yt;
             }else{
                 reY = drawXY[i⑴].y + _yt;
             }
         }
         cc();
     }

    function cc(){
        if(i == drawXY.length){
             pan.closePath();
             clearInterval(index);
             index = 0;
             x = 0;
             y = hei/2;
             flag = true;
             i = 0;
         }else{
             pan.lineTo(reX, reY);
             pan.stroke();
         }
    }
 
</script>
</body>
</html>

以上便是本文的所有內容，期待对大伙儿的学习培训有一定的协助，也期待大伙儿多多适用脚本制作之家。

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