js+canvas绘制矩形的方法

网络编程 2021-07-04 21:04www.168986.cn编程入门
这篇文章主要介绍了js+canvas绘制矩形的方法,涉及JavaScript调用html5的canvas组件绘制图形的相关技巧,需要的朋友可以参考下

本文实例讲述了js+canvas绘制矩形的方法。分享给大家供大家参考,具体如下

运行效果截图如下

具体代码如下

<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN"
"http://.w3./TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://.w3./1999/xhtml">
<head>
  <title>canvas绘制矩形</title>
  <script type="text/javascript" >
  function draw(id) {
    var canvas = document.getElementById("canvas");
    if (canvas) {
      var context = canvas.getContext("2d");
      context.fillStyle = "#DDDDDD";
      context.fillRect(0, 0, 400, 400);
      context.strokeStyle = "black";
      context.fillStyle = "gray";
      context.lineWidth = 5;
      context.fillRect(0,0,200,300);
      context.strokeRect(0,0,200,200);
    } else {
     return;
    }
  }
  function drawBorder(id) {
    var canvas = document.getElementById("canvas2");
    if (canvas) {
      var context = canvas.getContext("2d");
      context.fillStyle = "red";
      context.strokeStyle = "black";
      context.lineWidth = 5;
      context.fillRect(0,0, 300, 200);      
      context.strokeRect(0,0,300,200);
    } else {
    return;
    }
  }
  window.onload = function () {
    draw("canvas");
    drawBorder("canvas2");
  }
  </script>
</head>
<body>
<canvas id="canvas" width="400" style="background:red;" height="400"></canvas>
<hr />
<canvas id="canvas2" width="400"  height="400"></canvas>
</body>
</html>

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