editor.md前端压缩图片后上传服务器

替换lib里的image-dialog.js

/*!
 * Image (upload) dialog plugin for Editor.md
 *
 * @file        image-dialog.js
 * @author      pandao
 * @version     1.3.4
 * @updateTime  2015-06-09
 * {@link       https://github.com/pandao/editor.md}
 * @license     MIT
 */

(function () {

    var factory = function (exports) {

        var pluginName = "image-dialog";

        exports.fn.imageDialog = function () {

            var _this = this;
            var cm = this.cm;
            var lang = this.lang;
            var editor = this.editor;
            var settings = this.settings;
            var cursor = cm.getCursor();
            var selection = cm.getSelection();
            var imageLang = lang.dialog.image;
            var classPrefix = this.classPrefix;
            var iframeName = classPrefix + "image-iframe";
            var dialogName = classPrefix + pluginName, dialog;

            cm.focus();

            var loading = function (show) {
                var _loading = dialog.find("." + classPrefix + "dialog-mask");
                _loading[(show) ? "show" : "hide"]();
            };

            if (editor.find("." + dialogName).length < 1) {
                var guid = (new Date).getTime();
                var action = settings.imageUploadURL + (settings.imageUploadURL.indexOf("?") >= 0 ? "&" : "?") + "guid=" + guid;

                if (settings.crossDomainUpload) {
                    action += "&callback=" + settings.uploadCallbackURL + "&dialog_id=editormd-image-dialog-" + guid;
                }
                action = '';
                var dialogContent = ((settings.imageUpload) ? "
" : "
") +
                    ((settings.imageUpload) ? "" : "") +
                    "" + imageLang.url + "" +
                    "" + (function () {
                        return (settings.imageUpload) ? "
" +
                            "" +
                            "" +
                            "
" : "";
                    })() +
                    "
" +
                    "" + imageLang.alt + "" +
                    "" +
                    "
" +
                    "" + imageLang.link + "" +
                    "" +
                    "
" +
                    ((settings.imageUpload) ? "" : "
");

                //var imageFooterHTML = "" + imageLang.managerButton + "";

                dialog = this.createDialog({
                    title: imageLang.title,
                    width: (settings.imageUpload) ? 465 : 380,
                    height: 254,
                    name: dialogName,
                    content: dialogContent,
                    mask: settings.dialogShowMask,
                    drag: settings.dialogDraggable,
                    lockScreen: settings.dialogLockScreen,
                    maskStyle: {
                        opacity: settings.dialogMaskOpacity,
                        backgroundColor: settings.dialogMaskBgColor
                    },
                    buttons: {
                        enter: [lang.buttons.enter, function () {
                            var url = this.find("[data-url]").val();
                            var alt = this.find("[data-alt]").val();
                            var link = this.find("[data-link]").val();

                            if (url === "") {
                                alert(imageLang.imageURLEmpty);
                                return false;
                            }

                            var altAttr = (alt !== "") ? " \"" + alt + "\"" : "";

                            if (link === "" || link === "http://") {
                                cm.replaceSelection("![" + alt + "](" + url + altAttr + ")");
                            } else {
                                cm.replaceSelection("[![" + alt + "](" + url + altAttr + ")](" + link + altAttr + ")");
                            }

                            if (alt === "") {
                                cm.setCursor(cursor.line, cursor.ch + 2);
                            }

                            this.hide().lockScreen(false).hideMask();

                            //删除对话框
                            this.remove();

                            return false;
                        }],

                        cancel: [lang.buttons.cancel, function () {
                            this.hide().lockScreen(false).hideMask();

                            //删除对话框
                            this.remove();

                            return false;
                        }]
                    }
                });

                dialog.attr("id", classPrefix + "image-dialog-" + guid);

                if (!settings.imageUpload) {
                    return;
                }

                var fileInput = dialog.find("[name=\"" + classPrefix + "image-file\"]");

                fileInput.bind("change", function () {
                    var fileName = fileInput.val();
                    var isImage = new RegExp("(\\.(" + settings.imageFormats.join("|") + "))$", "i"); // /(\.(webp|jpg|jpeg|gif|bmp|png))$/

                    if (fileName === "") {
                        alert(imageLang.uploadFileEmpty);

                        return false;
                    }

                    if (!isImage.test(fileName)) {
                        alert(imageLang.formatNotAllowed + settings.imageFormats.join(", "));

                        return false;
                    }

                    loading(true);

                    var submitHandler = function () {
                        var fileObj = dialog.find("[enctype=\"multipart/form-data\"]")[0];
                        compressFile(fileObj[1].files[0],function (files) {
                            var dic = new FormData();
                            dic.append('file', files);
                            $.ajax({
                                type: 'post',
                                // url: "http://localhost:8080/attachment/image/upload", // 你的服务器端的图片上传接口。如果你设置了 imageUploadURL，那么可以使用下面的方式
                                url: settings.imageUploadURL + (settings.imageUploadURL.indexOf("?") >= 0 ? "&" : "?") + "guid=" + guid,
                                data: dic,
                                cache: false,
                                processData: false,
                                contentType: false,
                                success: function (data, textStatus, jqXHR) {
                                    if (data.success === 1) { // 上传成功
                                        dialog.find("[data-url]").val("http://" + window.location.host + data.url); // 设置图片地址
                                    } else {
                                        alert(data.message); // 上传失败，弹出警告信息
                                    }
                                },
                                error: function (XMLHttpRequest, textStatus, errorThrown) {
                                    // console.log(XMLHttpRequest);
                                    // console.log(textStatus);
                                    // console.log(errorThrown);
                                }
                            });
                        });
                        loading(false); // 关闭加载效果
                        return false;
                    };

                    dialog.find("[type=\"submit\"]").bind("click", submitHandler).trigger("click");
                });
            }

            dialog = editor.find("." + dialogName);
            dialog.find("[type=\"text\"]").val("");
            dialog.find("[type=\"file\"]").val("");
            dialog.find("[data-link]").val("http://");

            this.dialogShowMask(dialog);
            this.dialogLockScreen();
            dialog.show();

        };

    };

    // CommonJS/Node.js
    if (typeof require === "function" && typeof exports === "object" && typeof module === "object") {
        module.exports = factory;
    } else if (typeof define === "function")  // AMD/CMD/Sea.js
    {
        if (define.amd) { // for Require.js

            define(["editormd"], function (editormd) {
                factory(editormd);
            });

        } else { // for Sea.js
            define(function (require) {
                var editormd = require("./../../editormd");
                factory(editormd);
            });
        }
    } else {
        factory(window.editormd);
    }

})();

然后压缩方法 :

/**
 * 压缩图片
 * @param file input获取到的文件
 * @param callback 回调函数，压缩完要做的事，例如ajax请求等。
 */
function compressFile(file, callback) {
    var fileObj = file;
    var reader = new FileReader()
    reader.readAsDataURL(fileObj) //转base64
    reader.onload = function (e) {
        var image = new Image() //新建一个img标签（还没嵌入DOM节点)
        image.src = e.target.result
        image.onload = function () {
            var canvas = document.createElement('canvas'), // 新建canvas
                context = canvas.getContext('2d'),
                imageWidth = image.width / 2,    //压缩后图片的大小
                imageHeight = image.height / 2,
                data = ''
            canvas.width = imageWidth
            canvas.height = imageHeight
            context.drawImage(image, 0, 0, imageWidth, imageHeight)
            data = canvas.toDataURL('image/jpeg') // 输出压缩后的base64
            var arr = data.split(','), mime = arr[0].match(/:(.*?);/)[1], // 转成blob
                bstr = atob(arr[1]), n = bstr.length, u8arr = new Uint8Array(n);
            while (n--) {
                u8arr[n] = bstr.charCodeAt(n);
            }
            var files = new window.File([new Blob([u8arr], {type: mime})], 'test.jpeg', {type: 'image/jpeg'}) // 转成file
            callback(files) // 回调
        }
    }
}