一、在页面中加入Canvas _Web前端

1、在页面中加入Canvas
在页面中加入Canvas

画一条直线
1.放置<cavas>
2.写脚本，代码如下

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
		<title>New Web Project</title>
		<script>
			function drawDiagonal() {
				//取得Canvas元素及其绘图上下文
				var canvas=document.getElementById('diagonal');
				var context=canvas.getContext('2d');

				//用绝对坐标来创建一条路径
				context.beginPath();
				context.moveTo(70,140);
				context.lineTo(140,70);

				//将这条线绘制到canvas上
				context.stroke();

			}

			window.addEventListener("load",drawDiagonal,true);
		</script>
	</head>
	<body>
		<h1>New Web Project Page</h1>
		<canvas id="diagonal" style="border:1px solid;" width="200" height="200">
		</canvas>
	</body>
</html>

用变换的方式在Canvas上绘制对角线

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
"http://www.w3.org/TR/html4/loose.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
	<head>
		<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
		<title>New Web Project</title>
		<script>
			function drawDiagonal() {
				//取得Canvas元素及其绘图上下文
				var canvas=document.getElementById('diagonal');
				var context=canvas.getContext('2d');

				//保存当前绘图状态
				context.save();

				//向右下方移动绘图上下文
				context.translate(70,140);

				//以原点为起点，绘制与前面相同的线段

				context.beginPath();
				context.moveTo(0,0);
				context.lineTo(70,-70);

				//将这条线绘制到canvas上
				context.stroke();

				//恢复原有的绘图状态
				context.restore();

			}

			window.addEventListener("load",drawDiagonal,true);
		</script>
	</head>
	<body>
		<h1>New Web Project Page</h1>
		<canvas id="diagonal" style="border:1px solid;" width="200" height="200">
		</canvas>
	</body>
</html>

2011-5-13 23:08 danny