HTML5之Canvas画正方形
1、设计源码
<!DOCTYPE html>
<head>
<meta charset="utf-8" />
<title>HTML5之Canvas画正方形</title>
<script type="text/javascript">
function drawFour(id)
{
//获取canvas元素
var canvas = document.getElementById("canvas");
if(canvas == null)
return false;
//获取上下文
var context = canvas.getContext('2d');
//设定填充图形的样式
context.fillStyle = "#EEEEFF";
//绘制图形
context.fillRect(0,0,800,800);
context.fillStyle = "yellow";
//设定图形边框的样式
context.strokeStyle = "blue";
//指定线宽
context.lineWidth = 150;
context.fillRect(50,50,500,500);
context.strokeRect(50,50,500,500);
}
</script>
</head>
<body onLoad="drawFour('canvas')">
<canvas id="canvas" width="1200" height="560"/>
</body>
2、设计结果
3、分析说明
（1）获取Canvas元素
var canvas = document.getElementById("canvas");
（2）取到上下文
var context = canvas.getContext('2d');
（3）填充绘制边框
context.fillStyle = "#EEEEFF";//填充的样式
（4）设定绘图样式
strokeStyle：图形边框的样式
（5）指定线宽
context.lineWidth = 150;
（6）指定颜色值
（7）绘制正方形
context.fillRect(50,50,500,500);
context.strokeRect(50,50,500,500);