use SVG to render identicon so the browser can auto-resize the image

Temporary fix for websites with small width, where the identicon
overlaps with the textarea field.

isso/css/isso.scss

@@ -52,8 +52,9 @@ a {
   > div.avatar {
     @include span-columns(1 of 11);
 
-    > canvas {
+    > svg {
       @include isso-shadow;
+      max-height: 48px;
     }
   }
 
@@ -151,8 +152,9 @@ a {
   > .avatar {
     @include span-columns(1 of 11);
 
-    > canvas {
+    > svg {
       @include isso-shadow;
+      max-height: 48px;
     }
   }
 

isso/js/app/isso.js

@@ -12,13 +12,13 @@ define(["app/text/html", "app/dom", "app/utils", "app/api", "app/markup", "app/i
         var el = $.htmlify(Mark.up(templates["postbox"]));
 
         // add a default identicon to not waste CPU cycles
-        $(".avatar > canvas", el).replace(lib.identicons.blank(48, 48));
+        $(".avatar > svg", el).replace(lib.identicons.blank(4, 48));
 
         // on text area focus, generate identicon from IP address
         $(".textarea-wrapper > textarea", el).on("focus", function() {
-            if ($(".avatar canvas", el).classList.contains("blank")) {
-                $(".avatar canvas", el).replace(
-                    lib.identicons.generate(lib.pbkdf2(api.remote_addr, api.salt, 1000, 6), 48, 48));
+            if ($(".avatar svg", el).classList.contains("blank")) {
+                $(".avatar svg", el).replace(
+                    lib.identicons.generate(lib.pbkdf2(api.remote_addr, api.salt, 1000, 6), 4, 48));
             }
         });
 
@@ -31,7 +31,7 @@ define(["app/text/html", "app/dom", "app/utils", "app/api", "app/markup", "app/i
             active = setTimeout(function() {
                 lib.pbkdf2($(".input-wrapper > [type=email]", el).value || api.remote_addr, api.salt, 1000, 6)
                 .then(function(rv) {
-                    $(".avatar canvas", el).replace(lib.identicons.generate(rv, 48, 48));
+                    $(".avatar svg", el).replace(lib.identicons.generate(rv, 4, 48));
                 });
             }, 200);
         }, false);
@@ -96,7 +96,7 @@ define(["app/text/html", "app/dom", "app/utils", "app/api", "app/markup", "app/i
             setTimeout(refresh, 60*1000);
         };  refresh();
 
-        $("div.avatar > canvas", el).replace(lib.identicons.generate(comment.hash, 48, 48));
+        $("div.avatar > svg", el).replace(lib.identicons.generate(comment.hash, 4, 48));
 
         var entrypoint;
         if (comment.parent === null) {

isso/js/app/lib/identicons.js

@@ -12,7 +12,6 @@ define(["q"], function(Q) {
     var GRID = 5;
 
     // Padding on the edge of the canvas in px
-    var PADDING = 4;
 
     var pad = function(n, width) {
         return n.length >= width ? n : new Array(width - n.length + 1).join("0") + n;
@@ -21,43 +20,39 @@ define(["q"], function(Q) {
     /**
      * Fill in a square on the canvas.
      */
-    var fillBlock = function(x, y, color, ctx) {
-        ctx.beginPath();
-        ctx.rect(
-            PADDING+x*SQUARE,
-            PADDING+y*SQUARE,
-            SQUARE,
-            SQUARE
-        );
-        ctx.fillStyle = color;
-        ctx.fill();
+    var fill = function(svg, x, y, padding, size, color) {
+        var rect = document.createElementNS("http://www.w3.org/2000/svg", "rect");
+
+        rect.setAttribute("x", padding + x * size);
+        rect.setAttribute("y", padding + y * size);
+        rect.setAttribute("width", size);
+        rect.setAttribute("height", size);
+        rect.setAttribute("style", "fill: " + color);
+
+        svg.appendChild(rect);
     };
 
     /**
      * Pick random squares to fill in.
      */
-    var generateIdenticon = function(key, height, width) {
-
-        var canvas = document.createElement("canvas"),
-            ctx = canvas.getContext("2d");
-        canvas.width = width;
-        canvas.height = height;
+    var generateIdenticon = function(key, padding, size) {
 
-        // FILL CANVAS BG
-        ctx.beginPath();
-        ctx.rect(0, 0, height, width);
-        ctx.fillStyle = '#F0F0F0';
-        ctx.fill();
+        var svg =  document.createElementNS("http://www.w3.org/2000/svg", "svg");
+        svg.setAttribute("version", "1.1");
+        svg.setAttribute("viewBox", "0 0 " + size + " " + size);
+        svg.setAttribute("preserveAspectRatio", "xMinYMin meet");
+        svg.setAttribute("shape-rendering", "crispEdges");
+        fill(svg, 0, 0, 0, size + 2*padding, "#F0F0F0");
 
         if (typeof key === null) {
-            return canvas;
+            return svg;
         }
 
         Q.when(key, function(key) {
             var hash = pad((parseInt(key, 16) % Math.pow(2, 18)).toString(2), 18),
                 index = 0, color = null;
 
-            canvas.setAttribute("data-hash", key);
+            svg.setAttribute("data-hash", key);
 
             // via http://colrd.com/palette/19308/
             switch (hash.substring(hash.length - 3, hash.length)) {
@@ -92,11 +87,11 @@ define(["q"], function(Q) {
                 for (var y=0; y<GRID; y++) {
 
                     if (hash.charAt(index) === "1") {
-                        fillBlock(x, y, color, ctx);
+                        fill(svg, x, y, padding, 8, color);
 
                         // FILL RIGHT SIDE SYMMETRICALLY
                         if (x < Math.floor(GRID/2)) {
-                            fillBlock((GRID-1) - x, y, color, ctx);
+                            fill(svg, (GRID-1) - x, y, padding, 8, color);
                         }
                     }
                     index++;
@@ -104,7 +99,7 @@ define(["q"], function(Q) {
             }
         });
 
-        return canvas;
+        return svg;
     };
 
     var generateBlank = function(height, width) {
@@ -116,7 +111,7 @@ define(["q"], function(Q) {
         ].join(""), 2).toString(16);
 
         var el = generateIdenticon(blank, height, width);
-        el.className = "blank";
+        el.classList.add("blank");
 
         return el;
     };

isso/js/app/text/comment.html

@@ -1,6 +1,6 @@
 <div class="isso-comment" id="isso-{{ id | blank }}">
     <div class="avatar">
-        <canvas data-hash="{{ hash }}" height="48px" width="48px"></canvas>
+        <svg data-hash="{{ hash }}"></svg>
     </div>
     <div class="text-wrapper">
         <div class="isso-comment-header" role="meta">

isso/js/app/text/postbox.html

@@ -1,6 +1,6 @@
 <div class="postbox">
     <div class="avatar">
-        <canvas class="placeholder" height="48px" width="48px"></canvas>
+        <svg class="blank" data-hash="{{ hash }}"></svg>
     </div>
     <div class="form-wrapper">
         <div class="textarea-wrapper">