Download diagram as SVG (#558)

Author: intjftw

webgui/scripts/codecompass/view/diagram.js

@@ -293,4 +293,24 @@ function (declare, attr, dom, query, topic, BorderContainer, ContentPane,
     priority : 30,
     center   : 'diagram'
   });
+
+  var downloadImageButton = new Button({
+    label   : 'Download image',
+    render  : function () { return this; },
+    onClick : function () {
+      var element = document.createElement('a');
+      element.setAttribute('href',
+          'data:image/svg+xml;charset=utf-8,' + encodeURIComponent(diagram._svg));
+      element.setAttribute('download', 'diagram.svg');
+      document.body.appendChild(element);
+      element.click();
+      document.body.removeChild(element);
+    }
+  });
+
+  viewHandler.registerModule(downloadImageButton, {
+    type     : viewHandler.moduleType.ContextButton,
+    priority : 40,
+    center   : 'diagram'
+  });
 });