canvas中图形事件绑定

rain11777 2011-08-05 03:40:40

<!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=gb2312" />
<script type="text/javascript">
var list=[];
var currentC;
var _e={};
var cricle = function(x,y,r){
this.x=x;
this.y=y;
this.r=r;
this.isCurrent=false;
this.drawC=function(ctx,x,y){
ctx.save();
ctx.beginPath();
ctx.moveTo(this.x,this.y-this.r);
ctx.arc(this.x,this.y,this.r,2*Math.PI,0,true);
if ((x && y && ctx.isPointInPath(x, y) && !currentC )||this.isCurrent) {

ctx.fillStyle = '#ff0000';
currentC=this;
this.isCurrent=true;
}else{
ctx.fillStyle = '#999999';
}
ctx.fill();
}

}
function draw(){
var canvas = document.getElementById('tutorial');
if (canvas.getContext){
var ctx = canvas.getContext('2d');
for(var i=0;i<10;i++){
var c=new cricle(20*i,20*i,5*i);
c.drawC(ctx);
list.push(c);
}
}
}

function reDraw(e){
e=e||event;
var canvas = document.getElementById('tutorial');
var x = e.clientX - canvas.offsetLeft;
var y = e.clientY - canvas.offsetTop;
canvas.width = canvas.width;
if (canvas.getContext){
var ctx = canvas.getContext('2d');
for(var i=0;i<list.length;i++){
var c=list[i];
c.drawC(ctx,x,y);

}
}

}

function show(e){
e=e||event;
var canvas = document.getElementById('tutorial');
var ctx = canvas.getContext('2d');
var x = e.clientX - canvas.offsetLeft;
var y = e.clientY - canvas.offsetTop;
if(currentC){
currentC.x=parseInt(x+(x-currentC.x)/5);
currentC.y=parseInt(y+(y-currentC.y)/5);
}
_e=e;
}
window.onload=function(){

var canvas = document.getElementById('tutorial');
draw();

canvas.onmousedown=function(e){
e=e||event;
var x = e.clientX - canvas.offsetLeft;
var y = e.clientY - canvas.offsetTop;
if(currentC)
currentC.isCurrent=false;
currentC=null;
reDraw(e);
_e=e;
var showTimer=setInterval(function(e){
reDraw(e);
},10,_e);
canvas.onmousemove=show;
document.onmouseup=function(){
if(currentC)
currentC.isCurrent=false;
currentC=null;
canvas.onmousemove=null;
clearInterval(showTimer);
}
}
}
</script>
<style type="text/css">
canvas { border: 1px solid black; }
</style>
</head>
<body style="background:#eeeeee;">
<div style="background:#0f0;width:100px;height:100px;position:absolute;left:100px;top:100px;z-index:1;" onclick="alert(1);"></div>
<canvas id="tutorial" width="1000" height="550" style="z-index:100;display:block;position:absolute;"></canvas>

</body>
<script>
</script>
</html>

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向立天 2011-08-17

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您好
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