html5 canvas旋转

时间：2022-11-21 22:44:43
<!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

相关文章