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<!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>多个图像围绕中心点旋转</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.setTransform(1,0,0,1,0,0); var angleInRadians = 45 * Math.PI / 180; var x = 50; var y = 100; var width = 40; var height = 40; context.translate(x+.5*width,y+.5*height); context.rotate(angleInRadians); context.fillStyle="red"; context.fillRect(-.5*width,-.5*height,width,height); context.setTransform(1,0,0,1,0,0); var angleInRadians = 75 * Math.PI / 180; var x = 100; var y = 100; var width = 40; var height = 40; context.translate(x+.5*width,y+.5*height); context.rotate(angleInRadians); context.fillStyle="red"; context.fillRect(-.5*width,-.5*height,width,height); context.setTransform(1,0,0,1,0,0); var angleInRadians = 90 * Math.PI / 180; var x = 150; var y = 100; var width = 40; var height = 40; context.translate(x+.5*width,y+.5*height); context.rotate(angleInRadians); context.fillStyle="red"; context.fillRect(-.5*width,-.5*height,width,height); context.setTransform(1,0,0,1,0,0); var angleInRadians = 120 * Math.PI / 180; var x = 200; var y = 100; var width = 40; var height = 40; context.translate(x+.5*width,y+.5*height); context.rotate(angleInRadians); context.fillStyle="red"; context.fillRect(-.5*width,-.5*height,width,height); } } </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>
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原文地址：http://www.cnblogs.com/LoveOrHate/p/4422555.html
