js+canvas简单绘制圆圈的方法

Z时代
2024-01-10
分类：综合

本文实例讲述了js+canvas简单绘制圆圈的方法。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://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
  <title>canvas画圆圈</title>
  <script type="text/javascript" >
  function drawCircle(id){
    var canvas = document.getElementById(id);
    if(canvas ) {
      var context = canvas.getContext("2d");
      context.fillStyle = "gray";
      context.strokeStyle = "black";
      context.fillRect(0, 0, 400, 400);
      context.beginPath();
      context.arc(100, 100, 50, 0, Math.PI*2, true);
      context.closePath();
      context.fillStyle = "green";
      context.fill();
    } else {
      return;
    }
  }
  window.onload = function () {
    drawCircle("canvas");
  }
  </script>
</head>
<body>
<canvas id="canvas" width="400" style="background:red;" height="400"></canvas>
<hr />
</body>
</html>