html5 canvas 涂鸦画板

浏览数：29 / 时间：2015年06月09日

html5 canvas 的涂鸦画板，可以加载图片进行涂鸦，也可以下载
服务器使用的php
上传的图片不能超过1M，只能是jpg或者png 格式的
演示地址的服务器网速不怎么样，读取文件可能很慢，到达100%的时候点击读取文件，如果没显示就多点几次
?1. [代码]主页面

<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<title>涂鸦画板</title>
<script type="text/javascript" src="jquery-1.8.3.js"></script>
<script type="text/javascript" src="jquery.form.js"></script>
<link href="index.css" rel="stylesheet" type="text/css">

</head>
<body>
<div id="chooseColor"></div>
<div id="chooseSize"></div>
<div id="paint">
<canvas id="pad" width="800" height="600" />
</div>
<input type="button" id="download" value="下载" />

<input type="file" name="mypic" id="chooseFile" />
<input type="button" value="读取文件" id="load" />

<div class="progress">
<span class="bar"></span><span class="percent">0%</span >
</div>

<img id="tulip" src="" alt="加载显示区" />
</body>
<script type="text/javascript" src="index.js"></script>
</html>
2. [代码]页面的简单排版
body,input {
font-size: 9pt;
}

#paint,#chooseSize {
clear: both;
}

.option {
float: left;
width: 20px;
height: 20px;
border: 2px solid #cccccc;
margin-right: 4px;
margin-bottom: 4px;
}

.active {
border: 2px solid black;
}

.lw {
text-align: center;
vertical-align: middle;
}

img.output {
border: 1px solid green;
}

#pad {
border: 2px solid gray;
cursor: arrow;
}

#chooseFile {
float: left;
width: 140px;
}

#tulip {
display: none;
}

#download {
margin-left: 550px;
}

#load {
float: left;
width: 80px;
}
3. [代码]画图，上传，下载处理

$(document).ready(function() {
paint();
downloadPic();
loadImg();
uploadImg();
});

/**
* 绘画
*/
function paint() {
chooseColor();
chooseSize();
canvas();
}

/**
* 颜色选择器
*/
function chooseColor() {
var colors = "red;orange;yellow;green;blue;indigo;purple;black;white".split(‘;‘);
var sb = [];
$.each(colors,function(i,v){
sb.push("<div class=‘option‘ style=‘background-color:" + v + "‘></div>");
});
$("#chooseColor").html(sb.join("\n"));
}

/**
* 大小选择器
*/
function chooseSize(){
sb = [];
for (var i = 1; i <= 9; i++) sb.push("<div class=‘option lw‘>" + "<div style=‘margin-top:#px;margin-left:#px;width:%px;height:%px‘></div></div>".replace(/%/g, i).replace(/#/g, 10 - i / 2));
$("#chooseSize").html(sb.join(‘\n‘));
}

/**
* 画图
*/
function canvas(){
var $clrs = $("#chooseColor .option");
var $lws = $("#chooseSize .option");
$clrs.click(function(){
$clrs.removeClass("active");
$(this).addClass("active");
p_color = this.style.backgroundColor;
$lws.children("div").css("background-color",p_color);
}).first().click();

//点选线条粗细选项时切换焦点并取得宽度存入p_width
$lws.click(function(){
$lws.removeClass("active");
$(this).addClass("active");
p_width = $(this).children("div").css("width").replace("px","");

}).eq(3).click();

// 取得canvas context
var $canvas = $("#pad");
var ctx = $canvas[0].getContext("2d");
ctx.lineCap = "round";
ctx.fillStyle = "white"; //整个canvas涂上白色的背景，避免PNG的透明底色效果
ctx.fillRect(0,0,$canvas.width(),$canvas.height());
var drawMode = false;

// canvas点选，移动，放开按键时进行绘图动作
$canvas.mousedown(function(e){
ctx.beginPath();
ctx.strokeStyle = p_color;
ctx.lineWidth = p_width;
ctx.moveTo(e.pageX - $canvas.position().left, e.pageY - $canvas.position().top);
drawMode = true;
}).mousemove(function(e){
if(drawMode){
ctx.lineTo(e.pageX - $canvas.position().left, e.pageY - $canvas.position().top);
ctx.stroke();
}
}).mouseup(function(e){
drawMode = false;
});
}

/**
* 下载当前所绘制的图像
*/
function downloadPic(){
// 使用toDataURL()将图转换成png文件
var saveFile = function(data, filename) {
var save_link = document.createElementNS(‘http://www.w3.org/1999/xhtml‘, ‘a‘);
save_link.href = data;
save_link.download = filename;
var event = document.createEvent(‘MouseEvents‘);
event.initMouseEvent(‘click‘, true, false, window, 0, 0, 0, 0, 0, false, false, false, false, 0, null);
save_link.dispatchEvent(event);婚纱摄影
};http://www.huiyi8.com/hunsha/?
$("#download").click(function() {
var myCanvas = document.getElementById("pad");
var image = myCanvas.toDataURL("image/png").replace("image/png", "image/octet-stream");
// window.location.href=image;
var filename = ‘paint_‘ + (new Date()).getTime() + ‘.png‘;
saveFile(image, filename);
});
}

//获取当前文件名
function ch_(url){
url=url.split("\\");//这里要将 \ 转义一下
var filename = url[url.length-1];
return filename;
}

//加载隐藏模块中的图片
function loadImg(){
$(‘#load‘).click(function(){
// 加载到canvas
var c= document.getElementById("pad");
var ctx = c.getContext("2d");
var img=document.getElementById("tulip");
ctx.drawImage(img,0,0);
});
}

/**
* 上传图片
*/
function uploadImg(){
var bar = $(‘.bar‘);
var percent = $(‘.percent‘);
var showimg = $(‘#showimg‘);
var progress = $(".progress");
$("#chooseFile").wrap("<form id=‘myupload‘ action=‘upload.php‘ method=‘post‘ enctype=‘multipart/form-data‘></form>");
$("#chooseFile").change(function(){
$("#myupload").ajaxSubmit({
dataType: ‘json‘,
uploadProgress: function(event, position, total, percentComplete) {
var percentVal = percentComplete + ‘%‘;
bar.width(percentVal);
percent.html(percentVal);
},
success: function(data){
// alert(‘上传成功‘);
var file = $(‘#chooseFile‘).val();
var filename = ch_(file);
var src = ‘paint/‘ + filename;
$(‘#tulip‘).attr(‘src‘,src);
},
error: function(xhr){
alert(‘上传失败‘);
}
});
});
}
4. [代码]服务器上传处理
<?php
$picname = $_FILES [‘mypic‘] [‘name‘];
$picsize = $_FILES [‘mypic‘] [‘size‘];
if ($picname != ‘‘) {
if ($picsize > 1024000) {
echo ‘图片的大小不能超过1M‘;
exit ();
}
$type = strstr ( $picname, ‘.‘ );
if ($type != ‘.jpg‘ && $type != ‘.png‘) {
echo ‘图片格式不对‘;
exit ();
}
$pics = $picname;
// 上传路径
$pic_path = ‘paint/‘ . $pics;
move_uploaded_file ( $_FILES [‘mypic‘] [‘tmp_name‘], $pic_path );
}
$size = round ( $picsize / 1024, 2 );
$arr = array (
‘name‘ => $picname,
‘pic‘ => $pics,
‘size‘ => $size
);
echo json_encode ( $arr );
?>
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