Render identicons in notifications

Render an svg, then canvas, then data url.

Fixes #325

// FREEBIE

background.html

@@ -87,9 +87,17 @@
         <div class='scrollable'></div>
       </div>
   </script>
+  <script type='text/x-tmpl-mustache' id='identicon-svg'>
+      <svg xmlns="http://www.w3.org/2000/svg" width="44" height="44">
+         <circle cx="22" cy="22" r="22" fill="{{ color }}" />
+          <text text-anchor="middle" fill="white" font-size="14px" x="22" y="22" baseline-shift="-4px">
+              {{ content }}
+          </text>
+      </svg>
+  </script>
   <script type='text/x-tmpl-mustache' id='avatar'>
-    <span class='avatar {{#avatar.color }} color{{avatar.color}} {{/avatar.color}}'
-          style='background-image: url("{{ avatar.url }}");'>
+    <span class='avatar'
+          style='background-image: url("{{ avatar.url }}"); background-color: {{ avatar.color }}'>
         {{ avatar.content }}
     </span>
   </script>
@@ -286,6 +294,7 @@
   <script type="text/javascript" src="js/views/window_controls_view.js"></script>
   <script type="text/javascript" src="js/views/inbox_view.js"></script>
   <script type="text/javascript" src="js/views/confirmation_dialog_view.js"></script>
+  <script type="text/javascript" src="js/views/identicon_svg_view.js"></script>
 
   <script type="text/javascript" src="js/background.js"></script>
 </head>

js/models/conversations.js

@@ -7,6 +7,24 @@
 
    // TODO: Factor out private and group subclasses of Conversation
 
+   var COLORS = [
+        "#EF5350", // red
+        "#EC407A", // pink
+        "#AB47BC", // purple
+        "#7E57C2", // deep purple
+        "#5C6BC0", // indigo
+        "#2196F3", // blue
+        "#03A9F4", // light blue
+        "#00BCD4", // cyan
+        "#009688", // teal
+        "#4CAF50", // green
+        "#7CB342", // light green
+        "#FF9800", // orange
+        "#FF5722", // deep orange
+        "#FFB300", // amber
+        "#607D8B", // blue grey
+    ];
+
   Whisper.Conversation = Backbone.Model.extend({
     database: Whisper.Database,
     storeName: 'conversations',
@@ -219,6 +237,17 @@
         }
     },
 
+    getNotificationIcon: function() {
+        return new Promise(function(resolve) {
+            var avatar = this.getAvatar();
+            if (avatar.url) {
+                resolve(avatar.url);
+            } else {
+                resolve(new Whisper.IdenticonSVGView(avatar).getDataUrl());
+            }
+        }.bind(this));
+    },
+
     updateAvatarUrl: function(silent) {
         this.revokeAvatarUrl();
         var avatar = this.get('avatar');
@@ -243,11 +272,11 @@
         } else if (this.isPrivate()) {
             var title = this.get('name');
             if (!title) {
-                return { content: '#', color: 'gray' };
+                return { content: '#', color: '#999999' };
             }
             var initials = title.trim()[0];
             return {
-                color: 1 + (Math.abs(this.hashCode()) % 15),
+                color: COLORS[Math.abs(this.hashCode()) % 15],
                 content: initials
             };
         } else {

js/panel_controller.js

@@ -93,14 +93,16 @@
             var sender = ConversationController.create({id: message.get('source')});
             conversation.fetch().then(function() {
                 sender.fetch().then(function() {
-                    var notification = new Notification(sender.getTitle(), {
-                        body: message.getDescription(),
-                        icon: sender.getAvatar().url,
-                        tag: conversation.id
+                    sender.getNotificationIcon().then(function(icon) {
+                        var notification = new Notification(sender.getTitle(), {
+                            body: message.getDescription(),
+                            icon: icon,
+                            tag: conversation.id
+                        });
+                        notification.onclick = function() {
+                            openConversation(conversation);
+                        };
                     });
-                    notification.onclick = function() {
-                        openConversation(conversation);
-                    };
                 });
             });
         } else {

js/views/identicon_svg_view.js

@@ -0,0 +1,39 @@
+/*
+ * vim: ts=4:sw=4:expandtab
+ */
+(function () {
+    'use strict';
+    window.Whisper = window.Whisper || {};
+
+    /*
+    * Render an avatar identicon to an svg for use in a notification.
+    */
+    Whisper.IdenticonSVGView = Whisper.View.extend({
+        templateName: 'identicon-svg',
+        initialize: function(options) {
+            this.render_attributes = options;
+        },
+        getSVGUrl: function() {
+            var html = this.render().$el.html();
+            var svg = new Blob([html], {type: 'image/svg+xml;charset=utf-8'});
+            return URL.createObjectURL(svg);
+        },
+        getDataUrl: function() {
+            var svgurl = this.getSVGUrl();
+            return new Promise(function(resolve) {
+                var img = document.createElement('img');
+                img.onload = function () {
+                    var canvas = loadImage.scale(img, {
+                        canvas: true, maxWidth: 44, maxHeight: 44
+                    });
+                    var ctx = canvas.getContext('2d');
+                    ctx.drawImage(img, 0, 0);
+                    URL.revokeObjectURL(svgurl);
+                    resolve(canvas.toDataURL("image/png"));
+                };
+
+                img.src = svgurl;
+            });
+        }
+    });
+})();