h5图片压缩上传

偏执的太偏执、 2023-08-17 15:47 239阅读 0赞

1、图片上传过慢，图片进行压缩上传

1021765-20190706163117700-599513873.png

  1. <div class="form-item item-first">
  2.     <input type="file" id="choose" accept="image/*" multiple>
  3.     <ul class="img-list">
  4.       <li class="tmp-img"></li>
  5.     </ul>
  6.     <div id="upload">上传图片</div>
  7. </div>
  9. .item-first{
  10.     display:flex;align-items:flex-end;}
  11. .img-list li{
  12.     position:relative;display:block;margin:0 auto;margin:0 auto;width:90px;height:120px;background-color:#fff;background-position:center center;background-repeat:no-repeat;}
  13. .progress{
  14.     position:absolute;bottom:0;left:0;width:100%;height:20px;background-color:rgba(254,61,73,.5);line-height:20px;}
  15. .progress span{
  16.     display:block;width:0;height:100%;background-color:#fe3d49;color:#fff;text-align:center;font-size:13px;}
  17. .size{
  18.     position:absolute;bottom:-18px;width:100%;height:15px;color:#666;text-align:center;font-size:13px;line-height:15px;}
  19. .tips{
  20.     display:block;margin:10px;color:#999;text-align:center;font-size:13px;}
  21. .pic-list{
  22.     margin:10px;font-size:13px;line-height:18px;}
  23. .pic-list a{
  24.     display:block;margin:10px 0;}
  25. .pic-list a img{
  26.     margin:-4px 0 0 10px;max-width:30px;max-height:30px;vertical-align:middle;}
  27. .tmp-img{
  28.     margin:0 auto;width:90px;height:120px;background-color:#fff;background-image:url(../images/upload_img.png);background-size:67px 64px;}
  30. <script>
  31.   var filechooser = document.getElementById("choose");
  32.   //    用于压缩图片的canvas
  33.   var canvas = document.createElement("canvas");
  34.   var ctx = canvas.getContext('2d');
  35.   //    瓦片canvas
  36.   var tCanvas = document.createElement("canvas");
  37.   var tctx = tCanvas.getContext("2d");
  38.   var maxsize = 100 * 1024;
  39.   $("#upload").on("click", function() {
  40.         filechooser.click();
  41.       })
  42.       .on("touchstart", function() {
  43.         $(this).addClass("touch")
  44.       })
  45.       .on("touchend", function() {
  46.         $(this).removeClass("touch")
  47.       });
  48.   filechooser.onchange = function() {
  49.     if (!this.files.length) return;
  50.     var files = Array.prototype.slice.call(this.files);
  51.     if (files.length > 9) {
  52.       alert("最多同时只可上传9张图片");
  53.       return;
  54.     }
  55.     files.forEach(function(file, i) {
  56.       if (!/\/(?:jpeg|png|gif)/i.test(file.type)) return;
  57.       var reader = new FileReader();
  58.       var li = document.createElement("li");
  59. //          获取图片大小
  60.       var size = file.size / 1024 > 1024 ? (~~(10 * file.size / 1024 / 1024)) / 10 + "MB" : ~~(file.size / 1024) + "KB";
  61.       li.innerHTML = '<div class="progress"><span></span></div>';
  62.       $(".img-list").html($(li));
  63.       $('.img-list li').attr("style","background-image: url(../images/loading_big.gif);background-size: 60px 60px");
  64.       reader.onload = function() {
  65.         var result = this.result;
  66.         var img = new Image();
  67.         img.src = result;
  68.         // $(li).css("background-image", "url(" + result + ")");
  69.         //如果图片大小小于100kb，则直接上传
  70.         if (result.length <= maxsize) {
  71.           img = null;
  72.           upload(result, file.type, $(li));
  73.           return;
  74.         }
  75. //      图片加载完毕之后进行压缩，然后上传
  76.         if (img.complete) {
  77.           callback();
  78.         } else {
  79.           img.onload = callback;
  80.         }
  81.         function callback() {
  82.           var data = compress(img);
  83.           upload(data, file.type, $(li));
  84.           img = null;
  85.         }
  86.       };
  87.       reader.readAsDataURL(file);
  88.     })
  89.   };
  90.   //    使用canvas对大图片进行压缩
  91.   function compress(img) {
  92.     console.log(img);
  93.     var initSize = img.src.length;
  94.     var width = img.width;
  95.     var height = img.height;
  96.     //如果图片大于四百万像素，计算压缩比并将大小压至400万以下
  97.     var ratio;
  98.     if ((ratio = width * height / 4000000) > 1) {
  99.       ratio = Math.sqrt(ratio);
  100.       width /= ratio;
  101.       height /= ratio;
  102.     } else {
  103.       ratio = 1;
  104.     }
  105.     canvas.width = width;
  106.     canvas.height = height;
  107. //        铺底色
  108.     ctx.fillStyle = "#fff";
  109.     ctx.fillRect(0, 0, canvas.width, canvas.height);
  110.     //如果图片像素大于100万则使用瓦片绘制
  111.     var count;
  112.     if ((count = width * height / 1000000) > 1) {
  113.       count = ~~(Math.sqrt(count) + 1); //计算要分成多少块瓦片
  114. //            计算每块瓦片的宽和高
  115.       var nw = ~~(width / count);
  116.       var nh = ~~(height / count);
  117.       tCanvas.width = nw;
  118.       tCanvas.height = nh;
  119.       for (var i = 0; i < count; i++) {
  120.         for (var j = 0; j < count; j++) {
  121.           tctx.drawImage(img, i * nw * ratio, j * nh * ratio, nw * ratio, nh * ratio, 0, 0, nw, nh);
  122.           ctx.drawImage(tCanvas, i * nw, j * nh, nw, nh);
  123.         }
  124.       }
  125.     } else {
  126.       ctx.drawImage(img, 0, 0, width, height);
  127.     }
  128.     //进行最小压缩
  129.     var ndata = canvas.toDataURL('image/jpeg', 0.1);
  130.     console.log('压缩前：' + initSize);
  131.     console.log('压缩后：' + ndata.length);
  132.     console.log('压缩率：' + ~~(100 * (initSize - ndata.length) / initSize) + "%");
  133.     tCanvas.width = tCanvas.height = canvas.width = canvas.height = 0;
  134.     return ndata;
  135.   }
  136.   //    图片上传，将base64的图片转成二进制对象，塞进formdata上传
  137.   function upload(basestr, type, $li) {
  138.     var text = window.atob(basestr.split(",")[1]);
  139.     var buffer = new Uint8Array(text.length);
  140.     var pecent = 0, loop = null;
  141.     for (var i = 0; i < text.length; i++) {
  142.       buffer[i] = text.charCodeAt(i);
  143.     }
  144.     var blob = getBlob([buffer], type);
  145.     var xhr = new XMLHttpRequest();
  146.     var formdata = getFormData();
  147.     formdata.append('file', blob);
  148.     xhr.open('post', '上传图片地址url');
  149.     xhr.onreadystatechange = function() {
  151.       if (xhr.readyState == 4 && xhr.status == 200) {
  152.         var jsonData = JSON.parse(xhr.responseText);
  153.         var imagedata = jsonData.data || {};
  154.         var text = imagedata.url ? '上传成功' : '上传失败';
  155.         console.log(text + '：' + imagedata.url);
  156.         $('.img-list li').attr("style","background-image: url("+imagedata.url+");background-size: 100% 100%");
  157.         $('#upload').attr('data-picId',imagedata.url);
  158.         clearInterval(loop);
  159.         //当收到该消息时上传完毕
  160.         $li.find(".progress span").animate({'width': "100%"}, pecent < 95 ? 200 : 0, function() {
  161.           $(this).html(text);
  162.         });
  163.         if (!imagedata.path) return;
  164.         $(".pic-list").append('<a href="' + imagedata.path + '">' + imagedata.name + '（' + imagedata.size + '）<img src="' + imagedata.path + '" /></a>');
  165.       }
  166.     };
  167.     //数据发送进度，前50%展示该进度
  168.     xhr.upload.addEventListener('progress', function(e) {
  169.       if (loop) return;
  170.       pecent = ~~(100 * e.loaded / e.total) / 2;
  171.       $li.find(".progress span").css('width', pecent + "%");
  172.       if (pecent == 50) {
  173.         mockProgress();
  174.       }
  175.     }, false);
  176.     //数据后50%用模拟进度
  177.     function mockProgress() {
  178.       if (loop) return;
  179.       loop = setInterval(function() {
  180.         pecent++;
  181.         $li.find(".progress span").css('width', pecent + "%");
  182.         if (pecent == 99) {
  183.           clearInterval(loop);
  184.         }
  185.       }, 100)
  186.     }
  187.     xhr.send(formdata);
  188.   }
  189.   /**
  190.    * 获取blob对象的兼容性写法
  191.    * @param buffer
  192.    * @param format
  193.    * @returns {*}
  194.    */
  195.   function getBlob(buffer, format) {
  196.     try {
  197.       return new Blob(buffer, {type: format});
  198.     } catch (e) {
  199.       var bb = new (window.BlobBuilder || window.WebKitBlobBuilder || window.MSBlobBuilder);
  200.       buffer.forEach(function(buf) {
  201.         bb.append(buf);
  202.       });
  203.       return bb.getBlob(format);
  204.     }
  205.   }
  206.   /**
  207.    * 获取formdata
  208.    */
  209.   function getFormData() {
  210.     var isNeedShim = ~navigator.userAgent.indexOf('Android')
  211.         && ~navigator.vendor.indexOf('Google')
  212.         && !~navigator.userAgent.indexOf('Chrome')
  213.         && navigator.userAgent.match(/AppleWebKit\/(\d+)/).pop() <= 534;
  214.     return isNeedShim ? new FormDataShim() : new FormData()
  215.   }
  216.   /**
  217.    * formdata 补丁, 给不支持formdata上传blob的android机打补丁
  218.    * @constructor
  219.    */
  220.   function FormDataShim() {
  221.     console.warn('using formdata shim');
  222.     var o = this,
  223.         parts = [],
  224.         boundary = Array(21).join('-') + (+new Date() * (1e16 * Math.random())).toString(36),
  225.         oldSend = XMLHttpRequest.prototype.send;
  226.     this.append = function(name, value, filename) {
  227.       parts.push('--' + boundary + '\r\nContent-Disposition: form-data; name="' + name + '"');
  228.       if (value instanceof Blob) {
  229.         parts.push('; filename="' + (filename || 'blob') + '"\r\nContent-Type: ' + value.type + '\r\n\r\n');
  230.         parts.push(value);
  231.       }
  232.       else {
  233.         parts.push('\r\n\r\n' + value);
  234.       }
  235.       parts.push('\r\n');
  236.     };
  237.     // Override XHR send()
  238.     XMLHttpRequest.prototype.send = function(val) {
  239.       var fr,
  240.           data,
  241.           oXHR = this;
  242.       if (val === o) {
  243.         // Append the final boundary string
  244.         parts.push('--' + boundary + '--\r\n');
  245.         // Create the blob
  246.         data = getBlob(parts);
  247.         // Set up and read the blob into an array to be sent
  248.         fr = new FileReader();
  249.         fr.onload = function() {
  250.           oldSend.call(oXHR, fr.result);
  251.         };
  252.         fr.onerror = function(err) {
  253.           throw err;
  254.         };
  255.         fr.readAsArrayBuffer(data);
  256.         // Set the multipart content type and boudary
  257.         this.setRequestHeader('Content-Type', 'multipart/form-data; boundary=' + boundary);
  258.         XMLHttpRequest.prototype.send = oldSend;
  259.       }
  260.       else {
  261.         oldSend.call(this, val);
  262.       }
  263.     };
  264.   }
  265. </script>

转载于:https://www.cnblogs.com/congfeicong/p/11143183.html

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