HTML5风车特效

2014-04-07 06:22:26 -0400

代码说明

HTML5 写的风车动画特效，请使用火狐浏览，IE9及以上浏览器可以看到效果，IE9以下无效果，甚至出错。转自源码爱好者

HTML代码

<style type="text/css">
#box{ 
	border:2px solid #f60; width:800px; height:600px; margin:0 auto;
}
</style>
<script type="text/javascript">
	var canvas,context;//画布、上下文
	var X,Y;//风车的圆心X坐标、Y坐标
	var canvasWidth,canvasHeight;//画布的宽高
	var speed = 1;//风车的转速、默认为1
	var R = 10;//风车的半径
	/***
		author:qingfeilee
		date:2012-03-21
		description:初始化页面函数
	*/
	function init(){
		initCanvas();
		initParams();
		draw();
		setInterval(draw,20);
	}
	/***
		author:qingfeilee
		date:2012-03-21
		description:初始化画布宽高、风车圆心坐标
	*/
	function initParams(){
		canvasWidth = canvas.width;
		canvasHeight = canvas.height;
		X = canvasWidth/2;
		Y = canvasHeight/4;
	}
	/***
		author:qingfeilee
		date:2012-03-21
		description:设置风的大小
	*/
	function setSpeed(speed){
		this.speed = speed;
	}
	/***
		author:qingfeilee
		date:2012-03-21
		description:设置风的大小
	*/
	function setR(R){
		this.R = R;
	}
	/***
		author:qingfeilee
		date:2012-03-21
		description:初始化画布
	*/
	function initCanvas(){
		try{
		canvas = document.getElementById("windmill");
		context = canvas.getContext("2d");
		}catch(e){
			document.getElementById("tip_info").innerHTML = "您的浏览器不支持！";
		}
	}
	/***
		author:qingfeilee
		date:2012-03-21
		description:绘制半圆
	*/
	function drawArc(tangle, style){
		 context.beginPath();
		 var trunkGradient = context.createLinearGradient(X, Y, X, Y+4*R);
         trunkGradient.addColorStop(0, style);
         trunkGradient.addColorStop(1, '#FFF00F');
         context.fillStyle = trunkGradient;
		 
		context.arc(X - (2*R*Math.cos(tangle)), Y - 2*R*Math.sin(tangle), 2*R, tangle, Math.PI+tangle, true);
		context.closePath();
		context.fill();
		context.save();
	}
	/***
		author:qingfeilee
		date:2012-03-21
		description:绘制手把柄
	*/
	function drawHandle(){
		 var trunkGradient = context.createLinearGradient(X, Y, X+10, Y);
         trunkGradient.addColorStop(0, '#663300');
         trunkGradient.addColorStop(0.4, '#996600');
         trunkGradient.addColorStop(1, '#552200');
         context.fillStyle = trunkGradient;
         context.fillRect(X, Y, 0.2*R, 8*R);
	}
		/***
		author:qingfeilee
		date:2012-03-21
		description:绘制文字
	*/
	function drawText(){
		 context.font = "30px 宋体 bold";
         context.textAlign = 'center';
		 context.fillText('那年我们一起看过的大风车', X, canvasWidth - 300, 300);
	}
	/***
		author:qingfeilee
		date:2012-03-21
		description:绘制函数
	*/
	var tangle = 0;
	function draw(){
		tangle = tangle + (speed*1/32)*Math.PI;
		context.clearRect(0,0,canvasWidth,canvasHeight);
		drawHandle();
		drawText();
		drawArc(tangle,"#552200");
		drawArc(tangle+1/2*Math.PI, "#990000");
		drawArc(tangle+Math.PI, "#0033FF");
		drawArc(tangle+3/2*Math.PI, "#225500");
		document.getElementById("tip_info").innerHTML = "转动角度："+parseInt(tangle)+"    当前的风速："+speed;
	}
	
	window.addEventListener("load",init,true);
</script>
</head>
<body>
	<div id="box">
		<canvas id = "windmill" style = "background-color:#001111" width = "800px" height = "600px"></canvas>
		<div id = "tip_info"></div>
        <div>
        	<button onClick="setSpeed(0)">停止</button>
        	<button onClick="setSpeed(0.1)">微风</button>
        	<button onClick="setSpeed(0.5)">小风</button>
            <button onClick="setSpeed(1)">中风</button>
            <button  onClick="setSpeed(2)">大风</button>
            <button  onClick="setSpeed(4)">狂风</button>
            |
            <button onClick="setR(5)">小号</button>
        	<button onClick="setR(20)">中号</button>
        	<button onClick="setR(30)">大号</button>
            <button onClick="setR(35)">超大号</button>
        </div>
    </div>

代码演示

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