本小节主要记录下前端页面相关功能的实现。绘图功能主要是利用HTML5 的canvas控件来实现，利用JS来控制鼠标操作，实现绘图。同时利用下拉列表控件来选择不同的工具、不同的画笔颜色、不同的画笔宽度功能。同时利用JS来读取cookie从而验证用户是否登录。同时将生成的图片数据传递给后台进行图片生成，并在后台保存，供用户分享。所有的功能都只是雏形，也存在很大的不足，因此也有很大的提升空间。直接放源码：
<!DOCTYPE HTML>
<html>
<title>
</title>
<head>
<!--css样式设置-->
<style type="text/css">
.class1{
font-family: Georgia;
font-size:15px;
color:red;
}
#canvasDiv{
position:absolute;
}
#myCanvas{
cursor:url(pen.cur),default;
border-style: solid;
border-color: green green green green;
position:absolute;
}
#toolsDiv{
width:50px;
height:60px;
position:absolute;
top:20px;
left:1050px;
}
#lineWidthDiv{
width:100px;
height:60px;
position:absolute;
top:20px;
left:1215px;
}
#lineW{
width:80px;
height:20px;
position:absolute;
top:38px;
}
#colorDiv{
width:50px;
height:60px;
position:absolute;
top:20px;
left:1130px;
}
#buttonDiv{
width:100px;
height:100px;
position:absolute;
top:55px;
left:1310px;
}
#imageDiv{
width:250px;
height:200px;
border-style: solid;
border-color: green green green green;
position:absolute;
top:120px;
left:1050px;
}
#buttonDiv2{
width:150px;
height:100px;
position:absolute;
top:55px;
left:1390px;
}
#tipsDiv{
width:600px;
height:400px;
border-style: solid;
border-color: green green green green;
position:absolute;
top:400px;
left:1050px;
}
#copyrightDiv{
background-color:gray;
width:1680px;
height:30px;
position:absolute;
top:900px;
left:0px;
}
#copyright{
position:absolute;
left:650px;
}
</style>
<script type="text/javascript" src="jquery-1.6.4.min.js"></script>
</head>
<body >
<!--添加HTML5 canvas控件-->
<div id="canvasDiv" onselectstart="return false"">
<canvas id="myCanvas" width=1000; height=800; onmousedown="MouseDown(event)" onmousemove="MouseMove(event)" onmouseup="MouseUp(event)">
你的浏览器不太兼容^_^，可以换用IE7以上版本或谷歌浏览器5以上版本。
</canvas>
</div>
<div id="lineWidthDiv" class="class1">
<br>线宽：</br>
<select onchange="IsLinewSelected(this.value);" id="lineW">
<option value="1">1</option>
<option value="2" >2</option>
<option value="3" >3</option>
<option value="4" >4</option>
<option value="5" >5</option>
<option value="6" >10</option>
<option value="7" >15</option>
<option value="8" >20</option>
<option value="9" >25</option>
<option value="10" >30</option>
<option value="11" >35</option>
<option value="12" >40</option>
</select>
</div>
<div id="colorDiv" class="class1">
<br>颜色：</br>
<select onchange="IsColorSelected(this.value);" id="color">
<option value="1">black</option>
<option value="2" >green</option>
<option value="3" >blue</option>
<option value="4" >gray</option>
<option value="5" >lime</option>
<option value="6" >maroon</option>
<option value="7" >navy</option>
<option value="8" >olive</option>
<option value="9" >purple</option>
<option value="10" >red</option>
<option value="11" >silver</option>
<option value="12" >yellow</option>
</select>
</div>
<div id="toolsDiv" class="class1">
<br>工具：</br>
<select onchange="IsToolsSelected(this.value);" id="tools">
<option value="1">画笔</option>
<option value="2" >橡皮擦</option>
<option value="3" >清屏</option>
</select>
</div>
<div id="buttonDiv">
<button type="button" onclick="GeneratePic()">生成图片</button>
</div>
<div id="imageDiv" class="class1">
<img id="imageOne" src="" height=200 width=250 alt="等待生成图片ing">
</div>
<div id="buttonDiv2">
<button type="button" onclick="GetCookie()">分享</button>
</div>
<div id="tipsDiv" class="class1">
</br>
<label id="visitor">
欢迎来到“画语”世界,亲爱的访客!
</label>
<p>1.您可以在左边的画板上画上任意您想画的东西，然后点击生成图片、分享按钮，将您的“画语”分享给大家。</p>
<p>2.您可以进行登录，将您的图片保存在网站上。如果没有账号，请进行注册。<a href="register.html">【点我注册】</a>(未开通)</p>
</br></br>
<p>(未开通)</p>
<form action="account.php" method="post">
Name: <input type="text" name="name" />
Password: <input type="text" name="pwd" />
<input type="submit" value="登录" />
</form>
</div>
<div id="copyrightDiv">
<span id="copyright">CopyRight @2013 XiaoChong Version 1.0</span>
</div>
<!--JS脚本 实现检查cookie验证用户登录、绘图功能-->
<script type="text/javascript" charset="utf-8">
var tempName="";
var nameEQ = "dwname" + "=";
var ca = document.cookie.split(';');
var flag = false;
for(var i=0;i < ca.length;i++){
var c = ca[i];
if(c.indexOf(nameEQ)==0)
{
tempName=decodeURIComponent(c.substring(nameEQ.length,c.length));
if(tempName==" ")
{
alert("未成功登陆^_^##");
break;
}
else
{
flag = true;
document.getElementById("visitor").innerHTML="欢迎来到“画语”世界,亲爱的"+tempName+"!";
break;
}
}
if(flag == false) ;
//alert("未成功登陆^_^##");
}
function GetCookie()
{
var nameEQ = "filecookie" + "=";
var ca = document.cookie.split(';');
var flag = false;
for(var i=0;i < ca.length;i++){
var cc = ca[i];
/* while (cc.charAt(0)=='')
cc=cc.substring(1,c.length);*/
if(cc.indexOf(nameEQ)==0)
{
var tempUrl=decodeURIComponent(cc.substring(nameEQ.length,cc.length));
if(tempUrl=="")
{
alert(tempUrl);
break;
}
else
{
flag = true;
window.location.href="share.html";
break;
}
}
if(flag == false)
alert("图片未生成^_^##");
}
}
<!--实现绘图功能函数-->
var c=document.getElementById("myCanvas");
var cxt=c.getContext("2d");
cxt.strokeStyle="black";
cxt.lineWidth=1;
var xStart,yStart;
var cursorStyle="url(pen.cur),default";
var checkDrawing=false;
var drawType="画笔";
var dataUrl="";
var offset=10;
var eraserWidth=5;
function MouseDown(e)
{
xStart=e.clientX-offset;
yStart=e.clientY-offset;
checkDrawing=true;
}
function MouseMove(e)
{
if(checkDrawing)
{
if(drawType=="画笔")
{
cxt.beginPath();
cxt.moveTo(xStart,yStart);
cxt.lineTo(e.clientX-offset,e.clientY-offset);
cxt.stroke();
cxt.closePath();
xStart=e.clientX-offset;
yStart=e.clientY-offset;
}
if(drawType=="橡皮擦")
{
xStart=e.clientX-offset;
yStart=e.clientY-offset;
Eraser(e);
}
}
}
function Eraser(e)
{
checkDrawing=true;
cxt.clearRect(xStart-eraserWidth,yStart-eraserWidth,e.clientX-xStart+eraserWidth,e.clientY-yStart+eraserWidth);
xStart=e.clientX-offset;
yStart=e.clientY-offset;
}
function MouseUp(e)
{
checkDrawing=false;
}
function IsLinewSelected(value)
{
if(drawType=="画笔")
{
var lineW = document.getElementById("lineW");
cxt.lineWidth=lineW.options[lineW.selectedIndex].innerText;
}
if(drawType=="橡皮擦")
{
var lineW = document.getElementById("lineW");
}
}
function IsColorSelected(value)
{
var color = document.getElementById("color");
cxt.strokeStyle=color.options[color.selectedIndex].innerText;
}
function IsToolsSelected(value)
{
var color = document.getElementById("tools");
drawType=tools.options[tools.selectedIndex].innerText;
if(drawType=="画笔")
cursorStyle="url(pen.cur),default";
if(drawType=="橡皮擦")
cursorStyle="url(eraser.cur),default";
c.style.cursor=cursorStyle;
if(drawType=="清屏")
{
cxt.clearRect(0,0,1000,800);
}
}
function GeneratePic()
{
dataUrl = c.toDataURL('image/png');
$.post('./test.php',{ 'data' : dataUrl });
document.getElementById("imageOne").src = dataUrl;
//alert(document.getElementById("imageOne").src);
}
</script>
</body>
</html>
