Add images preview in edit mode plus add keydown cleanup

README.md

@@ -73,6 +73,8 @@ var easyMDE = new EasyMDE();
 </script>
 ```
 
+If you need to remove installed listeners (when editor not needed anymore), call `easyMDE.cleanup()`
+
 Alternatively you can select a specific TextArea, via Javascript:
 
 ```html
@@ -133,6 +135,7 @@ easyMDE.value('New input for **EasyMDE**');
 - **hideIcons**: An array of icon names to hide. Can be used to hide specific icons shown by default without completely customizing the toolbar.
 - **indentWithTabs**: If set to `false`, indent using spaces instead of tabs. Defaults to `true`.
 - **initialValue**: If set, will customize the initial value of the editor.
+- **previewImagesInEditor**: - EasyMDE will show preview of images, `true` by default, use `false` to disable.
 - **insertTexts**: Customize how certain buttons that insert text behave. Takes an array with two elements. The first element will be the text inserted before the cursor or highlight, and the second element will be inserted after. For example, this is the default link value: `["[", "](http://)"]`.
   - horizontalRule
   - image

src/css/easymde.css

@@ -373,3 +373,16 @@
 .easymde-dropdown:focus .easymde-dropdown-content {
     display: block;
 }
+
+span[data-img-src]::before{
+    content: '';
+    background-image: var(--bg-image);
+    display: block;
+    max-height: 100%;
+    max-width: 100%;
+    background-size: contain;
+    height: 0;
+    padding-top: var(--height);
+    width: var(--width);
+    background-repeat: no-repeat;
+}

src/js/easymde.js

@@ -1969,13 +1969,14 @@ EasyMDE.prototype.render = function (el) {
         if (cm.getOption('fullScreen')) toggleFullScreen(self);
     };
 
-    document.addEventListener('keydown', function (e) {
+    this.documentOnKeyDown = function (e) {
         e = e || window.event;
 
         if (e.keyCode == 27) {
             if (self.codemirror.getOption('fullScreen')) toggleFullScreen(self);
         }
-    }, false);
+    };
+    document.addEventListener('keydown', this.documentOnKeyDown, false);
 
     var mode, backdrop;
     if (options.spellChecker !== false) {
@@ -2048,7 +2049,8 @@ EasyMDE.prototype.render = function (el) {
     if (options.status !== false) {
         this.gui.statusbar = this.createStatusbar();
     }
-    if (options.autosave != undefined && options.autosave.enabled === true) {
+    var autosaveEnabled = options.autosave != undefined && options.autosave.enabled === true;
+    if (autosaveEnabled) {
         this.autosave(); // use to load localstorage content
         this.codemirror.on('change', function () {
             clearTimeout(self._autosave_timeout);
@@ -2057,11 +2059,59 @@ EasyMDE.prototype.render = function (el) {
             }, self.options.autosave.submit_delay || self.options.autosave.delay || 1000);
         });
     }
+    
 
-    this.gui.sideBySide = this.createSideBySide();
+    function handleImages() {
+        if (options.previewImagesInEditor === false) {
+            return;
+        }
+        function calcHeight(naturalWidth, naturalHeight) {
+            var height;
+            var viewportWidth = window.getComputedStyle(document.querySelector('.CodeMirror-sizer')).width.replace('px', '');
+            if (naturalWidth < viewportWidth) {
+                height = naturalHeight + 'px';
+            } else {
+                height = (naturalHeight / naturalWidth * 100) + '%';
+            }
+            return height;
+        }
+        easyMDEContainer.querySelectorAll('.cm-formatting-image').forEach(function(e) {
+            var parentEl =  e.parentElement;
+            if (!parentEl.hasAttribute('data-img-src')) {
+                var srcAttr = parentEl.innerText.match('\\((.*)\\)'); // might require better parsing according to markdown spec
+                if (srcAttr && srcAttr.length >= 2) {
+                    var img = document.createElement('img');
+                    img.onload = function() {
+                        parentEl.setAttribute('data-img-src', srcAttr[1]);
+                        parentEl.setAttribute('data-img-width', img.naturalWidth);
+                        parentEl.setAttribute('data-img-height', img.naturalHeight);
+                        parentEl.setAttribute('style', '--bg-image:url('+srcAttr[1]+');--width:'+img.naturalWidth+'px;--height:'+calcHeight(img.naturalWidth, img.naturalHeight));
+                    };
+                    img.src = srcAttr[1];
+                }
+            } else {
+                // handle resizes case
+                var src = parentEl.getAttribute('data-img-src');
+                var naturalWidth = +parentEl.getAttribute('data-img-width');
+                var naturalHeight = +parentEl.getAttribute('data-img-height');
+                parentEl.setAttribute('style', '--bg-image:url('+src+');--width:'+naturalWidth+'px;--height:'+calcHeight(naturalWidth, naturalHeight));
+            }
+        });
+    }
+    this.codemirror.on('update', function () {
+        handleImages();
+    });
 
-    this._rendered = this.element;
+    
+
+    this.onWindowResize = function() {
+        handleImages();
+    };
 
+    window.addEventListener('resize', this.onWindowResize, true);
+
+    this.gui.sideBySide = this.createSideBySide();
+    this._rendered = this.element;
 
     // Fixes CodeMirror bug (#344)
     var temp_cm = this.codemirror;
@@ -2070,6 +2120,11 @@ EasyMDE.prototype.render = function (el) {
     }.bind(temp_cm), 0);
 };
 
+EasyMDE.prototype.cleanup = function () {
+    window.removeEventListener(this.onWindowResize);
+    document.removeEventListener('keydown', this.documentOnKeyDown);
+};
+
 // Safari, in Private Browsing Mode, looks like it supports localStorage but all calls to setItem throw QuotaExceededError. We're going to detect this and set a variable accordingly.
 function isLocalStorageAvailable() {
     if (typeof localStorage === 'object') {