html5 canvas 在线图片转换器
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html5 canvas 在线图片转换器
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前天寫完文件上傳的時候，老板給了個任務(wù)，問我能不能把圖片壓縮后再上傳，并且保證前面的功能能正常使用。雖然最后放棄了這個想法，但我在查資料的過程中看到了canvas的toDataURL這個功能。于是就想能不能做一個在線的圖片轉(zhuǎn)換器。在經(jīng)過一天的辛苦耕耘后（我是不會告訴你們我在事件綁定上浪費了半天時間( ′艸｀)ﾑﾌﾟﾌﾟ），總算弄出個大概了。雖然還有一些東西不太明白，但總體沒什么問題了。
主要的幾個功能就是:
1.toDataURL(用來壓縮轉(zhuǎn)碼)
2.通過后臺的臨時儲存來達(dá)到跨域獲取圖片(雖然html5提供了跨域獲取圖片的方式，但這要你情我愿才行啊(′?ω?｀) ）
3.js下載圖片
有關(guān)html5圖片跨域可以參考這篇文章：https://developer.mozilla.org/en-US/docs/Web/HTML/CORS_enabled_image
感謝下面的文章提供的學(xué)習(xí)方向：
http://www.baidufe.com/item/65c055482d26ec59e27e.html
http://blog.csdn.net/chaojie2009/article/details/22047871
演示地址：我是demo
源碼地址：點我下載
首先
HTML:
CSS:
style.css
/*************reset****************/ html{color:#333;-webkit-text-size-adjust:none;height:100%;max-height:100%;overflow: hidden;font-family: 'Microsoft Yahei';} body{height: 100%;max-height:100%;overflow: hidden;} body,div,dl,dt,dd,ul,ol,li,h1,h2,h3,h4,h5,h6,pre,code,form,fieldset,legend,input,button,textarea,p,blockquote,th,td{margin:0;padding:0;} table{border-collapse:collapse;border-spacing:0;} fieldset,img{border:0;} address,caption,cite,code,dfn,em,var,optgroup{font-style:inherit;font-weight:inherit;} del,ins{text-decoration:none;} li{list-style:none;} h1,h2,h3,h4,h5,h6{font-size:100%;}q:before,q:after{content:'';} abbr,acronym{border:0;font-variant:normal;} sup{vertical-align:baseline;} sub{vertical-align:baseline;}legend{color:#000;} input,button,textarea,select,optgroup,option{font-family:inherit;font-size:inherit;font-style:inherit;font-weight:inherit;}input,button,textarea,select{*font-size:100%;} body{font-size:12px;} a{color: #333333;text-decoration: none;} a:hover{text-decoration:underline; color:#c00;}/*font*/ *{font-size: 1.05em;color: #222;font-family: "Microsoft Yahei"; }format.css
body{background: -webkit-linear-gradient(#66ccff,#74b1d1);background: -o-linear-gradient(#66ccff,#74b1d1);background: -moz-linear-gradient(#66ccff,#74b1d1);background: -ms-linear-gradient(#66ccff,#74b1d1);background: linear-gradient(#66ccff,#74b1d1);position: relative; } #header{height: 2.8em;background: -webkit-linear-gradient(rgba(34,34,34,0.9),rgba(0,0,0,0.7));background: -o-linear-gradient(rgba(34,34,34,0.9),rgba(0,0,0,0.7));background: -moz-linear-gradient(rgba(34,34,34,0.9),rgba(0,0,0,0.7));background: -ms-linear-gradient(rgba(34,34,34,0.9),rgba(0,0,0,0.7));background: linear-gradient(rgba(34,34,34,0.9),rgba(0,0,0,0.7));font-size:2.4em;font-weight: bolder;text-align: center;line-height: 2.8em;color: #fff;text-shadow:0 0 0 #eee,0 0 0 #eee,1px 1px 1px #ede,-1px -1px 1px #eee;box-shadow: 0px 2px 6px rgba(16,16,16,0.7); }#content{position: absolute;top: 10em;left: 0em;bottom: 8em;right: 0em;padding: 0em 2em; }#con_box{height: 100%;background: #fff;box-shadow:0px 0px 10px rgba(0,0,0,0.9);border: none;border-radius: 10px;padding:0em 8%;position: relative;text-align: center; }.img_box{width: 100%;max-width: 36%;max-height: 63.4%;height: 100%;display: inline-block;margin-top: 2em;position: relative; }.img_box img{max-width: 100%;max-height: 100%;width: 100%;height: 100%;vertical-align: middle; }#canvas{display: none; }.to{display: inline-block;width: 20%;max-width: 20%;font-size: 3em;font-weight: bolder; }.select_box{text-align: left;width: 92%;margin:0 auto;margin-top: 2em; }#way_choose{float: left;margin-right: 2em; }.file_choose,.url_input{margin: 0 auto;font-weight: bold;font-size:1.4em;text-align: left;display: none; }.file_choose{display: block; }.file_choose>label{margin-left: 2em;padding:0 1.2em;font-size: 1.1em;font-weight: bolder;background: #222;color:#fff; }.file_choose>label:hover{cursor: pointer;box-shadow: 0 0 5px red; }.file_choose>input{display: none; }.url_input>label{margin-right: 1em; }.url_input>input{outline: none;border: 2px solid #dedede;border-radius: 2em;padding-left: 1.5em;width:20em; }.tips{text-align: left;font-size: 1.2em;font-weight: bold;width: 92%;margin:0 auto;margin-top: 1em;display: none; }.t1{display: block; }#footer{position: fixed;bottom: 0em;height: 2.8em;background: #000;line-height: 2.8em;width: 100%;left: 0em;font-size: 1.6em;font-weight: bolder; }#footer>span{float: left;margin-left:1.5em; }.type_list{display: inline;margin-right: 2em; }.type_list>li{display: inline;margin-left: 1em;background: #ffb515;height: 2em;padding:0 0.6em;font-size: 1.05em;color: #fff;text-shadow:-1px 1px 2px rgba(0,0,0,0.7);border-radius:5px;box-shadow:0 0 5px rgba(255,255,255,0.6); }.type_list>li:hover{cursor: pointer;box-shadow: 0 0 5px rgba(255,0,0,0.7); }#quality{margin-left: 1em; }#turnTo,#download{margin-left: 2em;padding: 0 1em;border-radius: 10px;border: 1px solid #d9d9d9;background: -webkit-linear-gradient(#ffffff,#dfdfdf);background: -o-linear-gradient(#ffffff,#dfdfdf);background: -moz-linear-gradient(#ffffff,#dfdfdf);background: linear-gradient(#ffffff,#dfdfdf);box-shadow: 0px 0px 5px rgba(255,255,255,0.7);font-weight: bolder; }#turnTo:hover,#download:hover{background: -webkit-linear-gradient(#66ccff,#74b1d1);background: -o-linear-gradient(#66ccff,#74b1d1);background: -moz-linear-gradient(#66ccff,#74b1d1);background: -ms-linear-gradient(#66ccff,#74b1d1);background: linear-gradient(#66ccff,#74b1d1);cursor: pointer;border: #6cf 1px solid; }.bgAdd{background: red !important; }JS:
//author:孤月 //date:2015/07/17 //變量定義 var sWay = document.getElementById("way_choose"), //獲取得到圖片鏈接的方式sGetUrl = "", //當(dāng)獲取方式為鏈接時,存放獲取的鏈接地址sFile = "", //當(dāng)獲取方式為本地時,存放獲取的文件信息sType = "", //獲取要轉(zhuǎn)換的格式nQuali = document.getElementById("quality"); //獲取圖片轉(zhuǎn)換的質(zhì)量(壓縮比)var urlInput = document.getElementById("urlGet"),file = document.getElementById("file"),sourceImg = document.getElementById("source_img"),previewImg= document.getElementById("preview_img"),canvas = document.getElementById("canvas"),typeList = document.querySelector(".type_list"),turnTo = document.getElementById("turnTo"),download = document.getElementById("download");var mimeTypeGet, //獲取img格式canDownload=false, //是否可以開始下載cross, //是否是外鏈go=true; //是否文件或鏈接或轉(zhuǎn)換格式改變//獲取要轉(zhuǎn)換的目標(biāo)圖片類型 function getType () {var type;//偵聽click事件typeList.addEventListener("click",function(e){e = e || event;if(e.target.tagName.toLowerCase()!="li")return;var val = e.target.innerHTML;var ch = typeList.children;for(var x=0;x<ch.length;x++)ch[x].setAttribute("class","");e.target.setAttribute("class","bgAdd");//當(dāng)目標(biāo)類型改變時，允許轉(zhuǎn)換if(sType!=val.toLowerCase)go = true;sType = val.toLowerCase();if(sType=="jpg"){document.getElementById("quality").style.display="inline-block";document.querySelector(".t2").style.display="none";document.querySelector(".t1").style.display="block";}else{document.getElementById("quality").style.display="none";document.querySelector(".t1").style.display="none";document.querySelector(".t2").style.display="block";}},false); }//獲取圖片取得方式 function wayChange(){//偵聽change事件sWay.addEventListener("change",function(){var fc = document.querySelector(".file_choose"),ui = document.querySelector(".url_input");(sWay.value=="本地文件選擇")?FileShow():UrlShow();function FileShow(){fc.style.display = "block";ui.style.display = "none";cross = false;};function UrlShow(){fc.style.display = "none";ui.style.display = "block";cross = true;}turnTo.style.display = "none";download.style.display="none";file.value = "";urlGet.value = "";},false); }//當(dāng)文件域變化 function fileChange(){file.addEventListener("change",function(){//讀取文件var files = file.files[0];var reader = new FileReader();reader.onload = function(e){go = true;e = e || event;sourceImg.src = e.target.result;turnTo.style.display = "inline-block";download.style.display="inline-block";transformImg();};reader.readAsDataURL(files);},false); }//當(dāng)?shù)刂份斎胪戤?function urlInputEnd(){var match;urlInput.addEventListener("blur",function(){//匹配鏈接if(!urlInput.value)return;match = /.jpg|.png|.gif|.bmp/;sGetUrl = urlGet.value;var temp = sGetUrl.substring(sGetUrl.lastIndexOf("."));if(match.test(temp)){sourceImg.src = sGetUrl;sourceImg.onload = function(){go = true;turnTo.style.display = "inline-block";download.style.display="inline-block";transformImg();};}},false) }//壓縮比變化時 function qualityChange(){nQuali.onchange = function(e){//限制取值var val = e.target.value.toFixed(0);if(!val || val>100 || val<10)nQuali.value = 50;}; }//img下載 function downlo(){download.onclick = function(){if(canDownload){ // 加工image data，替換mime typevar imgData = previewImg.src.replace(mimeTypeGet,'image/octet-stream');//downloadvar down = document.getElementById("downIMG");down.href = imgData;down.download = "IGotIt-"+(new Date()).getTime()+"."+(sType?sType:"jpg");var mouseEv = document.createEvent("MouseEvents");mouseEv.initMouseEvent("click",false,false,window,0,0,0,0,0,false,false,false,false,0,null);down.dispatchEvent(mouseEv);} else {alert("請先進(jìn)行轉(zhuǎn)換!");}}; }//轉(zhuǎn)換 function transformImg(){turnTo.onclick = function(e){e = e || event;e.stopPropagation();e.preventDefault();var type = sType || "jpg" ,mimeType,newImage = new Image(),cv = canvas,ct = cv.getContext('2d');if(type=="jpg")mimeType = "image/jpeg";elsemimeType = "image/"+type;mimeTypeGet = mimeType;if(cross && go){//獲取外鏈地址并將其傳入服務(wù)器var xhr = new XMLHttpRequest();var nForm = new FormData();nForm.append("url",sourceImg.src);nForm.append("type",sourceImg.src.substring(sourceImg.src.lastIndexOf('.')));xhr.open('POST','php/send.php');xhr.send(nForm);xhr.addEventListener("load",function(e){go = false;var newSrc = e.target.responseText;newImage.src = newSrc;newImage.onload = function(){previewImg.src=trans().src;nForm.append("del",true);xhr.open("POST",'php/del.php');xhr.send(nForm);};},false);} else if(go){newImage.src = sourceImg.src;previewImg.src=trans().src;}function trans(){cv.width = newImage.width;cv.height= newImage.height;ct.drawImage(newImage,0,0);if(mimeType=="image/jpeg")var newData = cv.toDataURL(mimeType,nQuali.value/100);elsevar newData = cv.toDataURL(mimeType); var nImage = new Image();nImage.src = newData;canDownload = true;downlo();return nImage;}}; }function init(){getType();wayChange();fileChange();urlInputEnd();qualityChange(); }init();PHP:
send.php
<?php session_start(); if(!$_POST) return false; $dataUrl = trim(mb_convert_encoding($_POST['url'],'gbk','utf-8')); $type = $_POST['type'];$path = "../"; $random = time().rand(1,10000); $dir = "source/".$random."/"; $name = rand(10000,20000).$type;if(!is_dir($path.$dir)) {mkdir($path.$dir);chmod($path.$dir,0777); }$newImageData = @file_get_contents($dataUrl);$createImg = fopen($path.$dir.$name,'w+'); fwrite($createImg,$newImageData); fclose($createImg);$_SESSION['dir'] = $path.$dir; $_SESSION['file']= $name;echo $dir.$name; ?>del.php
<?php session_start(); if(!$_POST) return false;$del = $_POST['del'];if($del) {@unlink($_SESSION['dir'].$_SESSION['file']);rmdir($_SESSION['dir']); }session_destroy(); ?>有什么問題和意見歡迎回復(fù)，吐槽樓主的人注定單身一輩子(ｏ￣?￣ｏ)?
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