HTML5的Canvas自带API可以显示阴影效果,主要还是在画布(canvas)的上下文对象(context)上做文章
- <!DOCTYPE html>
- <head>
- <meta charset="UTF-8">
- <title>HTML5 Combine Shape DEMO</title>
- <script type="text/javascript" src="js/drawShadow.js"></script>
- </head>
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- <body onload="draw('canvas')"></body>
- <h2>canvas:显示阴影效果</h2>
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- <canvas id="canvas" width="400” height="400"/>
- <br><br>
画带阴影效果的图形见如下的js代码:
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- function draw (id){
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- var canvas = document.getElementById(id);
- if(canvas ==null)
- return false;
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- var context = canvas.getContext('2d');
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- context.fillStyle='#FFEEFF';
- context.fillRect(0,0,400,400);
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- context.shadowOffSetX=10;
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- context.shadowOffsetY=10;
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- context.shadowColor="rgba(50,50,100,0.5)";
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- context.shadowBlur=7.5;
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- context.translate(50,50);
- create5star(context);
- context.fill();
- }
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- function create5star(context){
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- var n = 0;
- var dx=100;
- var dy=0;
- var s = 50;
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- context.beginPath();
- context.fillStyle='rgba(255,0,0,0.5)';
- var x = Math.sin(0);
- var y=Math.cos(0);
- var dig = Math.PI/5*4;
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- for(var i =0;i<5;i++){
- var x = Math.sin(i * dig);
- var y = Math.cos(i* dig);
- context.lineTo(dx+x*s,dy+y*s);
- }
- context.closePath();
- }
最终展示效果如图:
本文转自 charles_wang888 51CTO博客,原文链接:http://blog.51cto.com/supercharles888/854126,如需转载请自行联系原作者