html5 canvas旋转 

<!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>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8" />
<title>html5 canvas旋转</title>
<script src="js/modernizr.js"></script>
</head>

<body>
<script type="text/javascript">
window.addEventListener('load',eventWindowLoaded,false);
function eventWindowLoaded(){
	canvasApp();
}
function canvasSupport(){
	return Modernizr.canvas;
}
function canvasApp(){
	if(!canvasSupport()){
		return;
	}else{
		var theCanvas = document.getElementById('canvas')
		var context = theCanvas.getContext("2d")

	}
	drawScreen();
    function drawScreen(){
		context.fillStyle="black";
		context.fillRect(100,100,50,50);
		
		
		context.setTransform(1,0,0,1,0,0);
		var angleInRadians = 45 * Math.PI / 180;
		context.rotate(angleInRadians);
		context.fillStyle="red";
		context.fillRect(150,100,50,50);
		
    }
	
}


</script>
<canvas id="canvas" width="500" height="500">
你的浏览器无法使用canvas
小白童鞋；你的支持是我最大的快乐！！
</canvas>
</body>
</html>

 context.setTransform(a,b,c,d,e,f);

a 水平旋转绘图
b 水平倾斜绘图
c 垂直倾斜绘图
d 垂直缩放绘图
e 水平移动绘图
f 垂直移动绘图

 

var angleInRadians = 45 * Math.PI / 180;
context.rotate(angleInRadians);
设置函数，调用函数
posted @ 2015-04-12 16:13  一点点白  阅读(379)  评论(0)    收藏  举报