本文介紹了用canvas畫心電圖的示例代碼，分享給大家，具體如下：
效果圖：
思路：
?1.模擬點（如果你有真實的數據，那就是把數據幻化成canvas對應的坐標點）
? 模擬點時注意的點就是高起部分需要對稱以及為了好看要隨機出現上上下下
2.畫線
? 畫線需要注意有一個勻速移動的過程。
? 比如 A點到B點，不是簡單的A畫到B，而是A點到A1,A2....最后到B（這一塊按照比例移動比較難）
3.畫線的一些效果，比如加上陰影（這里就可以自由發揮了）具體代碼
<!DOCTYPE html> <html lang="en"> <head> <meta charset="UTF-8"> <title>心電圖</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[i-1].x)/(drawXY[i].y-drawXY[i-1].y)); var _yt = (reX-drawXY[i-1].x)/c; if(drawXY[i].y < drawXY[i-1].y){ reY = drawXY[i-1].y - _yt; }else{ reY = drawXY[i-1].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>以上就是本文的全部內容，希望對大家的學習有所幫助，也希望大家多多支持VeVb武林網。
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