added save as png

app/index.html

@@ -242,6 +242,7 @@
                     </div>
                 </div>
                 <div class="topbar-btn" id="editor-btn-convert">Convert to commands..</div>
+                <div class="topbar-btn" id="editor-btn-save-png">Save as PNG..</div>
                 <div class="topbar-btn">Help
                     <div class="topbar-menu topbar-menu-help">
                         <div class="topbar-menu-item" id="editor-help-faq">

app/models/canvas.js

@@ -1702,6 +1702,14 @@ function MineartCanvas() {
         this.render()
     }
 
+    this.getDataUrl = function() {
+        if (store.imageWidth > 256 || store.imageHeight > 256) {
+            if (!confirm("Images with width/length more than 256 blocks may cause performance issues.\nContinue?"))
+                return null
+        }
+        return canvasTemp.toDataURL()
+    }
+
     this.render = () => {
         this._renderMainCanvas()
         this._renderOverlayCanvas()

app/screens/editor.js

@@ -498,6 +498,14 @@ const store = {
         this.$helpControls.onclick = () => {
             store.parent.modals.openModal('controls')
         }
+        this.$btnSavePng.onclick = function() {
+            var n = new Image
+                , e = store.parent.mineartCanvas.getDataUrl();
+            if (null !== e) {
+                n.src = e;
+                window.open(e).document.write(n.outerHTML)
+            }
+        }
     }
 }