canvas小球乱撞
分类：实例代码
canvas小球乱撞属于前端实例代码，有关更多实例代码大家可以查看。
本章节分享一段代码实例，它利用canvas实现了小球乱撞的效果。
想要对canvas有所了解的朋友可以自行分析一下代码。
代码实例如下：
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="author" content="http://www.pipipi.net/" />
<title>前端教程网</title>
<style>
body{
font-family: 微软雅黑;
}
body,h1{
margin:0;
}
canvas{
display:block;
margin-left:auto;
margin-right: auto;
border:1px solid #DDD;
background:-webkit-linear-gradient(top, #222,#111);
}
</style>
</head>
<body>
<canvas id="canvas" ></canvas>
<button id="stop">stop</button>
<button id="run">run</button>
<button id="addBall">addBall</button>
<script src="jquery-1.6.2.min.js"></script>
<script>
var nimo={
aniamted:null,
content:null,
data:{
radiusRange:[5,20],
speedRange:[-5,5],
scrollHeight:null,
scrollWdith:null
},
balls:[],
ele:{
canvas:null
},
fn:{
creatRandom:function(startInt,endInt){//生产随机数
var iResult;
iResult=startInt+(Math.floor(Math.random()*(endInt-startInt+1)));
return iResult
},
init:function(){
nimo.data.scrollWdith=document.body.scrollWidth;
nimo.data.scrollHeight=document.body.scrollHeight;
nimo.ele.canvas=document.getElementById('canvas');
nimo.content=nimo.ele.canvas.getContext('2d');
nimo.ele.canvas.width=nimo.data.scrollWdith-50;
nimo.ele.canvas.height=nimo.data.scrollHeight-100;
},
addBall:function(){
var aRandomColor=[];
aRandomColor.push(nimo.fn.creatRandom(0,255));
aRandomColor.push(nimo.fn.creatRandom(0,255));
aRandomColor.push(nimo.fn.creatRandom(0,255));
var iRandomRadius=nimo.fn.creatRandom(nimo.data.radiusRange[0],nimo.data.radiusRange[1]);
var oTempBall={
coordsX:nimo.fn.creatRandom(iRandomRadius,nimo.ele.canvas.width-iRandomRadius),
coordsY:nimo.fn.creatRandom(iRandomRadius,nimo.ele.canvas.height-iRandomRadius),
radius:iRandomRadius,
bgColor:'rgba('+aRandomColor[0]+','+aRandomColor[1]+','+aRandomColor[2]+',0.5)'
};
oTempBall.speedX=nimo.fn.creatRandom(nimo.data.speedRange[0],nimo.data.speedRange[1]);
if(oTempBall.speedX===0){
oTempBall.speedX=1
}
if(oTempBall.speedY===0){
oTempBall.speedY=1
}
oTempBall.speedY=nimo.fn.creatRandom(nimo.data.speedRange[0],nimo.data.speedRange[1]);
nimo.balls.push(oTempBall)
},
drawBall:function(bStatic){
var i,iSize;
nimo.content.clearRect(0,0,nimo.ele.canvas.width,nimo.ele.canvas.height)
for(var i=0,iSize=nimo.balls.length;i<iSize;i++){
var oTarger=nimo.balls[i];
nimo.content.beginPath();
nimo.content.arc(oTarger.coordsX,oTarger.coordsY,oTarger.radius,0,10);
nimo.content.fillStyle=oTarger.bgColor;
nimo.content.fill();
if(!bStatic){
if(oTarger.coordsX+oTarger.radius>=nimo.ele.canvas.width){
oTarger.speedX=-(Math.abs(oTarger.speedX))
}
if(oTarger.coordsX-oTarger.radius<=0){
oTarger.speedX=Math.abs(oTarger.speedX)
}
if(oTarger.coordsY-oTarger.radius<=0){
oTarger.speedY=Math.abs(oTarger.speedY)
}
if(oTarger.coordsY+oTarger.radius>=nimo.ele.canvas.height){
oTarger.speedY=-(Math.abs(oTarger.speedY))
}
oTarger.coordsX=oTarger.coordsX+oTarger.speedX;
oTarger.coordsY=oTarger.coordsY+oTarger.speedY;
}
}
},
run:function(){
nimo.fn.drawBall();
nimo.aniamted=setTimeout(function(){
nimo.fn.drawBall();
nimo.aniamted=setTimeout(arguments.callee,10)
},10)
},
stop:function(){
clearTimeout(nimo.aniamted)
}
}
}
window.onload=function(){
nimo.fn.init();
var i;
for(var i=0;i<10;i++){
nimo.fn.addBall();
}
nimo.fn.run();
document.getElementById('stop').onclick=function(){
nimo.fn.stop()
}
document.getElementById('run').onclick=function(){
nimo.fn.stop()
nimo.fn.run()
}
document.getElementById('addBall').onclick=function(){
var i;
for(var i=0;i<10;i++){
nimo.fn.addBall();
}
nimo.fn.drawBall(true);
}
}
</script>
</body>
</html>
canvas小球乱撞，这样的场景在实际项目中还是用的比较多的，关于canvas小球乱撞就介绍到这了。