Javascript canvas 画图实例

用Javascript和canvas实现的涂鸦板，不支持IE浏览器，大家都懂的。 <IGNORE_JS_OP>canvas涂鸦-深海博客


撤销原意是撤销画布上次画的东西，但在撤销还不完善，撤销只实现了恢复上次画笔的状态，不能实现画布撤销，日后完善由于发帖有字数限制，注释都去了，我华丽丽的注释啊。。。

<!doctype html>
<html>
<head>
<meta content="text/html; charset=utf-8" http-equiv="Content-Type" />
<title>javascript canvas画图实例</title>
<meta http-equiv="X-UA-Compatible" content="IE=7" />
<meta name="keywords" content="" />
<meta name="description" content="" />
<style>
*{margin:0;padding:0;}
.fa{width:740px;margin:0 auto;}
.top{margin:20px 0;}
.top input{width:25px;height:25px;border:1px solid #fff;border-radius:4px;background:#ddd;}
.top .i1{background:#000000;}
.top .i2{background:#FF0000;}
.top .i3{background:#80FF00;}
.top .i4{background:#00FFFF;}
.top .i5{background:#808080;}
.top .i6{background:#FF8000;}
.top .i7{background:#408080;}
.top .i8{background:#8000FF;}
.top .i9{background:#CCCC00;}
#canvas{background:#eee;cursor:default;}
.font input{font-size:14px;}
.top .grea{background:#aaa;}
</style>
</head>
<body>
<div class="fa">
<div class="top">
<div id="color">
请选择画笔颜色：
<input class="i1" type="button" value="" />
<input class="i2" type="button" value="" />
<input class="i3" type="button" value="" />
<input class="i4" type="button" value="" />
<input class="i5" type="button" value="" />
<input class="i6" type="button" value="" />
<input class="i7" type="button" value="" />
<input class="i8" type="button" value="" />
<input class="i9" type="button" value="" />
</div>
<div class="font" id="font">
请选择画笔的宽度：
<input type="button" value="细" />
<input type="button" value="中" class="grea"/>
<input type="button" value="粗" />
</div>
<div>
<span id="error">如果有错误，请使用橡皮擦：</span>
<input id="eraser" style="width:60px;font-size:14px;"type="button" value="橡皮擦" />
</div>
<input id="clear" type="button" value="清除画布" style="width:80px;"/>
<input id="revocation" type="button" value="撤销" style="width:80px;"/>
<input id="imgurl" type="button" value="导出图片路径" style="width:80px;"/>
</div>
<canvas id="canvas" width="740" height="420">您的浏览器不支持 canvas 标签</canvas>
<div id="div1"></div>
</div>
<div id="html">

</div>
<script>
/*
//深海博客
//http://www.qdway.com/
//@torry 2012-05-01
//
*/
(function(){
var paint={
init:function()
{
this.load();
this.bind();
},
load:function()
{ 
this.x=[];//记录鼠标移动是的X坐标
this.y=[];//记录鼠标移动是的Y坐标
this.clickDrag=[];
this.lock=false;
this.isEraser=false;
this.storageColor="#000000";
this.eraserRadius=15;
this.color=["#000000","#FF0000","#80FF00","#00FFFF","#808080","#FF8000","#408080","#8000FF","#CCCC00"];
this.fontWeight=[2,5,8];
this.$=function(id){return typeof id=="string"?document.getElementById(id):id;};
this.canvas=this.$("canvas");
this.cxt=this.canvas.getContext('2d');
this.cxt.lineJoin = "round";
this.cxt.lineWidth = 5;
this.iptClear=this.$("clear");
this.revocation=this.$("revocation");
this.imgurl=this.$("imgurl");
this.w=this.canvas.width;
this.h=this.canvas.height;
this.touch =("createTouch" in document);
this.StartEvent = this.touch ? "touchstart" : "mousedown";
this.MoveEvent = this.touch ? "touchmove" : "mousemove";
this.EndEvent = this.touch ? "touchend" : "mouseup";
},
bind:function()
{
var t=this;
this.iptClear.onclick=function()
{
t.clear();
};
this.canvas['on'+t.StartEvent]=function(e)
{ 
var touch=t.touch ? e.touches[0] : e; 
var _x=touch.clientX - touch.target.offsetLeft;
var _y=touch.clientY - touch.target.offsetTop;
if(t.isEraser)
{
t.resetEraser(_x,_y,touch);
}else
{
t.movePoint(_x,_y);
t.drawPoint();
}
t.lock=true;
};
this.canvas['on'+t.MoveEvent]=function(e)
{
var touch=t.touch ? e.touches[0] : e;
if(t.lock)
{
var _x=touch.clientX - touch.target.offsetLeft;
var _y=touch.clientY - touch.target.offsetTop;
if(t.isEraser)
{
t.resetEraser(_x,_y,touch);
}
else
{
t.movePoint(_x,_y,true);
t.drawPoint();
}
}
};
this.canvas['on'+t.EndEvent]=function(e)
{
t.lock=false;
t.x=[];
t.y=[];
t.clickDrag=[];
clearInterval(t.Timer);
t.Timer=null;
};
this.revocation.onclick=function()
{
t.redraw();
};
this.changeColor();
this.imgurl.onclick=function()
{
t.getUrl();
};
this.$("eraser").onclick=function(e)
{
t.isEraser=true;
t.$("error").style.color="red";
t.$("error").innerHTML="您已使用橡皮擦！";
};
},
movePoint:function(x,y,dragging)
{ 
this.x.push(x);
this.y.push(y);
this.clickDrag.push(y);
},
drawPoint:function(x,y,radius)
{
for(var i=0; i < this.x.length; i++)
{ 
this.cxt.beginPath();

if(this.clickDrag[i] && i){
this.cxt.moveTo(this.x[i-1], this.y[i-1]);
}else{
this.cxt.moveTo(this.x[i]-1, this.y[i]);
}
this.cxt.lineTo(this.x[i], this.y[i]);
this.cxt.closePath();
this.cxt.stroke();
}
},
clear:function()
{
this.cxt.clearRect(0, 0, this.w, this.h);
},
redraw:function()
{ 
this.cxt.restore(); 
}, 
preventDefault:function(e){
var touch=this.touch ? e.touches[0] : e;
if(this.touch)touch.preventDefault();
else window.event.returnValue = false;
},
changeColor:function()
{
var t=this,iptNum=this.$("color").getElementsByTagName("input"),fontIptNum=this.$("font").getElementsByTagName("input");
for(var i=0,l=iptNum.length;i<l;i++)
{
iptNum[i].index=i;
iptNum[i].onclick=function()
{
t.cxt.save();
t.cxt.strokeStyle = t.color[this.index];
t.storageColor=t.color[this.index];
t.$("error").style.color="#000";
t.$("error").innerHTML="如果有错误，请使用橡皮擦：";
t.cxt.strokeStyle = t.storageColor;
t.isEraser=false;
}
}
for(var i=0,l=fontIptNum.length;i<l;i++)
{
t.cxt.save();
fontIptNum[i].index=i;
fontIptNum[i].onclick=function()
{
t.changeBackground(this.index);
t.cxt.lineWidth = t.fontWeight[this.index];
t.$("error").style.color="#000";
t.$("error").innerHTML="如果有错误，请使用橡皮擦：";
t.isEraser=false;
t.cxt.strokeStyle = t.storageColor;
}
}
},
changeBackground:function(num)
{
var fontIptNum=this.$("font").getElementsByTagName("input");
for(var j=0,m=fontIptNum.length;j<m;j++)
{
fontIptNum[j].className="";
if(j==num) fontIptNum[j].className="grea";
}
},
getUrl:function()
{
this.$("html").innerHTML=this.canvas.toDataURL();
},
resetEraser:function(_x,_y,touch)
{ 
var t=this;
t.cxt.globalCompositeOperation = "destination-out";
t.cxt.beginPath();
t.cxt.arc(_x, _y, t.eraserRadius, 0, Math.PI * 2);
t.cxt.strokeStyle = "rgba(250,250,250,0)";
t.cxt.fill();
t.cxt.globalCompositeOperation = "source-over"
}
};
paint.init();
})();
</script>
<script>
(function(){
var oDiv = document.createElement("div");
oDiv.style.width = "604px";        
oDiv.style.textAlign = "right";        
oDiv.style.margin = "5px auto 10px";        
oDiv.innerHTML = "<iframe width=\"117\" height=\"24\" frameborder=\"0\" allowtransparency=\"true\" marginwidth=\"0\" marginheight=\"0\" scrolling=\"no\" border=\"0\" src=\"http://widget.weibo.com/relationship/followbutton.php?language=zh_cn&width=136&height=24&uid=1813602245&style=2&btn=red&dpc=1\"></iframe>";        
document.body.appendChild(oDiv);
})();
</script>

</body>
</html>

 

 

 

posted @ 2012-05-28 15:29  脉凌网络  阅读(852)  评论(0)  编辑  收藏  举报