本文实例讲述了javascript+HTML5的Canvas实现Lab单车动画效果。分享给大家供大家参考。具体如下：
这里运用HTML5实现的单车动画，运行一下效果你就明白了，不过不要在IE8下测试，没效果的。请在支持最新HTML3和CSS3的浏览器下测试，祝您好运。
运行效果截图如下：
具体代码如下：
<html>
<head>
<title>Canvas Lab单车动画，HTML5动画</title>
</head>
<script type="text/javascript">
var framecounter = 800;//为了完成作业，无耻了点，在这里设置变量……
var direction = "left";
function drawBikeBody () {
var canvas = document.getElementById('diagonal');
var context = canvas.getContext('2d');
context.lineWidth = 3;
context.beginPath();
context.moveTo(0,0);
context.lineTo(150,0);
context.lineTo(100,100);
context.closePath();
context.moveTo(100,100);
context.lineTo(200,75);//后轮轴承点
context.lineTo(150,0);
//下面那个一个脚踏
context.moveTo(100,100);
context.lineTo(110,120);
context.lineTo(120,120);
context.moveTo(110,120);
context.lineTo(100,120);
//另一个脚踏
context.moveTo(100,100);
context.lineTo(90,80);
context.lineTo(100,80);
context.moveTo(90,80);
context.lineTo(80,80);
//座包
context.moveTo(150,0);
context.lineTo(160,-20);
context.lineTo(175,-20);
context.moveTo(160,-20);
context.lineTo(135,-20);
//扶手
context.moveTo(0,0);
context.lineTo(15,-30);
context.lineTo(10,-35);
context.lineTo(20,-40);
context.lineTo(40,-40);
//前轮轴承
context.moveTo(0,0);
context.lineTo(-35.5,75);//前轮轴承点
//前轮
context.moveTo(75-35.5,75);//去掉这个目测不行啊，貌似context.arc()方法里有lineTo
context.arc(-35.5,75,75,0,Math.PI*2,true);
//后轮
context.moveTo(200+75,75);
context.arc(200,75,75,0,Math.PI*2,true);
}
function drawForcePiece1(){
var canvas = document.getElementById('diagonal');
var context = canvas.getContext('2d');
context.beginPath();
for(var i = framecounter; i < framecounter+360; i += 20) {
context.moveTo(-35.5,75);
x = Math.cos(Math.PI / 180 * i) * 75 + (-35.5);
y = Math.sin(Math.PI / 180 * i) * 75 + 75;
context.lineTo(x,y);
}
}
function drawForcePiece2(){
var canvas = document.getElementById('diagonal');
var context = canvas.getContext('2d');
context.beginPath();
for(var i = framecounter; i < framecounter+360; i += 20) {
context.moveTo(200,75);
x = Math.cos(Math.PI / 180 * i) * 75 + 200;
y = Math.sin(Math.PI / 180 * i) * 75 + 75;
context.lineTo(x,y);
}
}
function drawBike(){
var canvas = document.getElementById('diagonal');
var context = canvas.getContext('2d');
context.clearRect(0, 0, 800, 600);
context.save();
context.translate(framecounter,300);
drawBikeBody();
context.stroke();
context.restore();
context.save();
context.translate(framecounter,300);
drawForcePiece1();
context.stroke();
context.restore();
context.save();
context.translate(framecounter,300);
drawForcePiece2();
context.stroke();
context.restore();
if (direction==="left") {
framecounter--;
}else{
framecounter++;
}
}
function move() {
var interal = setInterval(function () {
drawBike();
}, 10);
}
window.addEventListener("load",move,true);
</script>
<body>
<canvas id="diagonal" width="800" height="600" style="border:1px dashed">Please update your brower to the newest version!</canvas>
<br>
<button id="reset" onclick="framecounter=800;">Reset</button>
<button id="left" onclick="direction='left'">Go Left</button>
<button id="right" onclick="direction='ture'">Go Right</button>
</body>
</html>
希望本文所述对大家的javascript程序设计有所帮助。
