html5 手写的canvas实现
试用支持canvas的浏览器，无JS依赖，运用新的HTML5技术
DrawBoard.renderDrawer('myHandWrite',{
penColor:'#FF0000',
penWidth:'1px'
});
仅一段代码就可渲染出整个绘图板
1. [文件] Drawer.js
/**
* @class Canvas DrawBoard
* @author Jason <brotherqian@163.com>
* @version 1.1
* @singleton
* @fileoverview
* Build Date:2014/04/12
* The application is valid in a browser that supports HTML5 canvas object.
* A default canvas tag will render to the div you have appointed
* You can use this application like this:
* DrawBoard.renderDrawer('myHandWrite',{
* penColor:'#FF0000',
* penWidth:'1px'
* });
* If you need a text background,this will help:
* DrawBoard.formatText('Sign here');
* See {@link DrawBoard.renderDrawer} for more details
*/
var DrawBoard/*DrawBoard对象*/={};
DrawBoard.Id="";
DrawBoard.penColor="#FF0000";
DrawBoard.penWidth=0;
DrawBoard.mouseX/*鼠标位置X*/=0;
DrawBoard.mouseY/*鼠标位置Y*/=0;
DrawBoard.isMouseDown/**/=false;
DrawBoard.isMouseMove/**/=false;
DrawBoard.mousePath/**/=new Array();
DrawBoard.mousePosition/**/={x:0,y:0};
DrawBoard.Events/*事件列表*/={
onMouseMove/*鼠标移动*/:function(e){
var me=DrawBoard;
var ctx=me.Context;
var canvas=me.Canvas;
if(me.isMouseDown){
if(me.isMouseMove){
ctx.moveTo(me.mouseX,me.mouseY);
me.isMouseMove=false;
}
me.mouseX= e.layerX;
me.mouseY= e.layerY+32;
me.mousePosition={"x":me.mouseX,"y":me.mouseY};
me.mousePath.push(me.mousePosition);
ctx.lineTo(me.mouseX, me.mouseY);
ctx.stroke();
}
},
onMouseDown/*鼠标按下*/:function(e){
var me=DrawBoard;
var ctx=me.Context;
var canvas=me.Canvas;
canvas.style.borderColor="#808080";
var rect=canvas.getBoundingClientRect();
me.isMouseDown=true;
me.isMouseMove=true;
//计算鼠标位置 仅适用fireFox
me.mouseX= e.layerX;
me.mouseY= e.layerY+32;
if(me.mousePath.length==0){
me.redo();
}
},
onMouseOut/*鼠标移出*/:function(e){
var me=DrawBoard;
me.isMouseDown=false;
},
onMouseUp/*鼠标放开*/:function(e){
var me=DrawBoard;
var ctx=me.Context;
var canvas=me.Canvas;
canvas.style.borderColor="#C0C0C0";
me.isMouseDown=false;
}
};
/**
* Render a child element to the node that has a id attribute which values @param id
* @param {String} id the name that canvas will render as it's child element
* @param {Object} option the pen color
* @argument {String} penColor rgb(0,0,0) or #000000 color
* @argument {String} penWidth pen width in pixel
* @argument {Int} width canvas board width
* @argument {Int} height canvas board height
*/
DrawBoard.renderDrawer/*渲染绘图对象*/=function(id,option){
var me=DrawBoard;
var p=option;
me.Id=id;
me.penColor=p.penColor||me.penColor;
me.penWidth= p.penWidth;
var objContainer=document.getElementById(id);
//初始化Canvas元素
var objCanvas=document.getElementById('DrawBoard')||document.createElement('canvas');
with(objCanvas){
width= p.width||720;
height= p.height||400;
id='DrawBoard';
style.margin='auto';
style.border="1px solid #C0C0C0";
style.borderRadius="4px";
style.position="absolute";
style.cursor="url(images/site/pencil.gif),auto";
}
objContainer.appendChild(objCanvas);
var ctx=objCanvas.getContext('2d');
//初始化canvas上下文对象
with(ctx){
lineWidth/*线宽*/=me.penWidth;
strokeStyle/*描绘颜色*/=me.penColor;
fillStyle/*填充颜色*/=me.penColor;
lineCap/*线头样式*/="round";
lineJoin/*转角样式*/="round";
miterLimit/*折角锐利度*/=1;
shadowColor='#FC0000';
shadowBlur=1;
}
//为Canvas元素附加事件
objCanvas.addEventListener("mousemove",me.Events.onMouseMove,false);
objCanvas.addEventListener("mouseout",me.Events.onMouseOut,false);
objCanvas.addEventListener("mouseup",me.Events.onMouseUp,false);
objCanvas.addEventListener("mousedown",me.Events.onMouseDown,false);
objCanvas.addEventListener("contextmenu",DrawBoard.redo,false);
//赋值对象http://www.huiyi8.com/hunsha/hanshi/
me.Canvas=me.Canvas||objCanvas;
me.Context=me.Context||ctx;
}韩式婚纱照片
DrawBoard.redo/*清空所有窗体*/=function(){
var me=DrawBoard;
var canvas=me.Canvas;
var ctx=me.Context;
ctx.clearRect(0,0,canvas.width,canvas.height);
canvas.width=canvas.width;
//置空鼠标路径数组
me.mousePath.splice(0,me.mousePath.length);
me.renderDrawer(me.Id,me.penColor,me.penWidth);
};
DrawBoard.formatText/*绘制一个水印*/=function(text){
var me=DrawBoard;
var canvas=me.Canvas;
var ctx=me.Context;
ctx.font/*字体*/="100px 宋体";
ctx.fillText(text,100,200);
ctx.stroke();
};
//取png数据类型
DrawBoard.getImage=function(){
return DrawBoard.Context!=null?DrawBoard.Canvas.toDataURL('image/png'):"";
}
DrawBoard.download=function(){
}
/**
* POST you data to the server
* @param option
* @argument {String} method 'POST' or 'GET' is valid
* @argument {String} url the address to post to
* @argument {String} isDirect if true to use a asynchronous method,or false to not use
* @argument {Function} onSuccess the method to be called upon the success of the request
*/
DrawBoard.post=function(option){
var p=option;
var request=new XMLHttpRequest()||window.ActiveXObject("Microsoft.XMLHttp");
request.onreadystatechange=function(){
if(request.readyState==4){
if(request.status==200){
eval(option.onSuccess);
}else{
}
}else{
}
};
request.open(p.method||'POST', p.url, p.isDirect||true);
request.send(p.params)
}
