diff --git a/fonts.js b/fonts.js
index 607e2aab9..f33cab9c3 100755
--- a/fonts.js
+++ b/fonts.js
@@ -21,47 +21,18 @@ var kMaxWaitForFontFace = 1000;
  *      http://cgit.freedesktop.org/poppler/poppler/tree/poppler/GfxFont.cc#n65
  */
 
-var Fonts = (function Fonts() {
+var FontMeasure = (function FontMeasure() {
   var kScalePrecision = 40;
-  var fonts = [];
 
-  if (!isWorker) {
-    var ctx = document.createElement('canvas').getContext('2d');
-    ctx.scale(1 / kScalePrecision, 1);
-  }
-
-  var fontCount = 0;
-  
-  function FontInfo(name, data, properties) {
-    this.name = name;
-    this.data = data;
-    this.properties = properties;
-    this.id = fontCount++;
-    this.loading = true;
-    this.sizes = [];
-  }
+  var ctx = document.createElement('canvas').getContext('2d');
+  ctx.scale(1 / kScalePrecision, 1);
 
   var current;
   var measureCache;
 
   return {
-    registerFont: function fonts_registerFont(fontName, data, properties) {
-      var font = new FontInfo(fontName, data, properties);
-      fonts.push(font);
-      return font.id;
-    },
-    blacklistFont: function fonts_blacklistFont(fontName) {
-      var id = registerFont(fontName, null, {});
-      markLoaded(fontName);
-      return id;
-    },
-    lookupById: function fonts_lookupById(id) {
-      return fonts[id];
-    },
-    setActive: function fonts_setActive(fontName, fontObj, size) {
-      // |current| can be null is fontName is a built-in font
-      // (e.g. "sans-serif")
-      if (fontObj && (current = fonts[fontObj.id])) {
+    setActive: function fonts_setActive(font, size) {
+      if (current = font) {
         var sizes = current.sizes;
         if (!(measureCache = sizes[size]))
           measureCache = sizes[size] = Object.create(null);
@@ -69,7 +40,7 @@ var Fonts = (function Fonts() {
         measureCache = null
       }
 
-      ctx.font = (size * kScalePrecision) + 'px "' + fontName + '"';
+      ctx.font = (size * kScalePrecision) + 'px "' + font.loadedName + '"';
     },
     measureText: function fonts_measureText(text) {
       var width;
@@ -88,9 +59,9 @@ var FontLoader = {
 
   bind: function(fonts, callback) {
     function checkFontsLoaded() {
-      for (var i = 0; i < allIds.length; i++) {
-        var id = allIds[i];
-        if (Fonts.lookupById(id).loading) {
+      for (var i = 0; i < objs.length; i++) {
+        var fontObj = objs[i];
+        if (fontObj.loading) {
           return false;
         }
       }
@@ -102,18 +73,17 @@ var FontLoader = {
       return true;
     }
 
-    var allIds = [];
-    var rules = [], names = [], ids = [];
+    var rules = [], names = [], objs = [];
 
     for (var i = 0; i < fonts.length; i++) {
       var font = fonts[i];
 
       var obj = new Font(font.name, font.file, font.properties);
-      font.fontDict.fontObj = obj;
-      allIds.push(obj.id);
+      obj.loading = true;
+      objs.push(obj);
 
       var str = '';
-      var data = Fonts.lookupById(obj.id).data;
+      var data = obj.data;
       var length = data.length;
       for (var j = 0; j < length; j++)
         str += String.fromCharCode(data[j]);
@@ -122,13 +92,12 @@ var FontLoader = {
       if (rule) {
         rules.push(rule);
         names.push(obj.loadedName);
-        ids.push(obj.id);
       }
     }
 
     this.listeningForFontLoad = false;
     if (!isWorker && rules.length) {
-      FontLoader.prepareFontLoadEvent(rules, names, ids);
+      FontLoader.prepareFontLoadEvent(rules, names, objs);
     }
     
     if (!checkFontsLoaded()) {
@@ -136,14 +105,14 @@ var FontLoader = {
         'pdfjsFontLoad', checkFontsLoaded, false);
     }
 
-    return;
+    return objs;
   },
   // Set things up so that at least one pdfjsFontLoad event is
   // dispatched when all the @font-face |rules| for |names| have been
   // loaded in a subdocument.  It's expected that the load of |rules|
   // has already started in this (outer) document, so that they should
   // be ordered before the load in the subdocument.
-  prepareFontLoadEvent: function(rules, names, ids) {
+  prepareFontLoadEvent: function(rules, names, objs) {
       /** Hack begin */
       // There's no event when a font has finished downloading so the
       // following code is a dirty hack to 'guess' when a font is
@@ -184,8 +153,8 @@ var FontLoader = {
           'message',
           function(e) {
             var fontNames = JSON.parse(e.data);
-            for (var i = 0; i < fontNames.length; ++i) {
-              var font = Fonts.lookupById(fontNames[i].substring(7) | 0);
+            for (var i = 0; i < objs.length; ++i) {
+              var font = objs[i];
               font.loading = false;
             }
             var evt = document.createEvent('Events');
@@ -377,12 +346,12 @@ var Font = (function() {
     this.name = name;
     this.textMatrix = properties.textMatrix || IDENTITY_MATRIX;
     this.encoding = properties.encoding;
+    this.sizes = [];
 
     // If the font is to be ignored, register it like an already loaded font
     // to avoid the cost of waiting for it be be loaded by the platform.
     if (properties.ignore) {
-      this.id = Fonts.blacklistFont(name);
-      this.loadedName = 'pdfFont' + this.id;
+      this.loadedName = 'Arial';
       return;
     }
 
@@ -412,11 +381,15 @@ var Font = (function() {
     }
     this.data = data;
     this.type = properties.type;
-    this.id = Fonts.registerFont(name, data, properties);
-    this.loadedName = 'pdfFont' + this.id;
+    this.loadedName = getUniqueName();
     this.compositeFont = properties.compositeFont;
   };
 
+  var numFonts = 0;
+  function getUniqueName() {
+    return 'pdfFont' + numFonts++;
+  }
+
   function stringToArray(str) {
     var array = [];
     for (var i = 0; i < str.length; ++i)
diff --git a/pdf.js b/pdf.js
index df8e3f3cc..1f02d7d6d 100644
--- a/pdf.js
+++ b/pdf.js
@@ -19,6 +19,7 @@ function warn(msg) {
 }
 
 function error(msg) {
+  log(backtrace());
   throw new Error(msg);
 }
 
@@ -43,6 +44,16 @@ function assertWellFormed(cond, msg) {
     malformed(msg);
 }
 
+function backtrace() {
+  var stackStr;
+  try {
+    throw new Error();
+  } catch(e) {
+    stackStr = e.stack;
+  };
+  return stackStr.split('\n').slice(1).join('\n');
+}
+
 function shadow(obj, prop, value) {
   Object.defineProperty(obj, prop, { value: value, enumerable: true, configurable: true, writable: false });
     return value;
@@ -2959,7 +2970,7 @@ var Page = (function() {
       return shadow(this, 'mediaBox',
                     ((IsArray(obj) && obj.length == 4) ? obj : null));
     },
-    startRendering: function(canvasCtx, continuation) {
+    startRendering: function(canvasCtx, continuation, onerror) {
       var self = this;
       var stats = self.stats;
       stats.compile = stats.fonts = stats.render = 0;
@@ -2970,18 +2981,26 @@ var Page = (function() {
       this.compile(gfx, fonts);
       stats.compile = Date.now();
 
-      FontLoader.bind(
+      var fontObjs = FontLoader.bind(
         fonts,
         function() {
           stats.fonts = Date.now();
           // Always defer call to display() to work around bug in
           // Firefox error reporting from XHR callbacks.
           setTimeout(function () {
-            self.display(gfx);
-            stats.render = Date.now();
-            continuation();
+            var exc = null;
+            try {
+              self.display(gfx);
+              stats.render = Date.now();
+            } catch (e) {
+              exc = e.toString();
+            }
+            continuation(exc);
           });
         });
+
+      for (var i = 0, ii = fonts.length; i < ii; ++i)
+        fonts[i].fontDict.fontObj = fontObjs[i];
     },
 
 
@@ -3544,23 +3563,9 @@ var PartialEvaluator = (function() {
     eval: function(stream, xref, resources, fonts) {
       resources = xref.fetchIfRef(resources) || new Dict();
       var xobjs = xref.fetchIfRef(resources.get('XObject')) || new Dict();
-
       var parser = new Parser(new Lexer(stream), false);
-      var objpool = [];
-
-      function emitArg(arg) {
-        if (typeof arg == 'object' || typeof arg == 'string') {
-          var index = objpool.length;
-          objpool[index] = arg;
-          return 'objpool[' + index + ']';
-        }
-        return arg;
-      }
-
-      var src = '';
-
-      var args = [];
-      var obj;
+      var args = [], argsArray = [], fnArray = [], obj;
+      
       while (!IsEOF(obj = parser.getObj())) {
         if (IsCmd(obj)) {
           var cmd = obj.cmd;
@@ -3582,10 +3587,7 @@ var PartialEvaluator = (function() {
               );
 
               if ('Form' == type.name) {
-                args[0].code = this.eval(xobj,
-                                         xref,
-                                         xobj.dict.get('Resources'),
-                                         fonts);
+                args[0].code = this.eval(xobj, xref, xobj.dict.get('Resources'), fonts);
               }
             }
           } else if (cmd == 'Tf') { // eagerly collect all fonts
@@ -3605,21 +3607,19 @@ var PartialEvaluator = (function() {
             }
           }
 
-          src += 'this.';
-          src += fn;
-          src += '(';
-          src += args.map(emitArg).join(',');
-          src += ');\n';
-
-          args.length = 0;
+          fnArray.push(fn);
+          argsArray.push(args);
+          args = [];
         } else {
           assertWellFormed(args.length <= 33, 'Too many arguments');
           args.push(obj);
         }
       }
 
-      var fn = Function('objpool', src);
-      return function(gfx) { fn.call(gfx, objpool); };
+      return function(gfx) {
+        for(var i = 0, length = argsArray.length; i < length; i++)
+          gfx[fnArray[i]].apply(gfx, argsArray[i]);
+      }
     },
 
     translateFont: function(fontDict, xref, resources) {
@@ -3638,7 +3638,12 @@ var PartialEvaluator = (function() {
         if (!df)
           return null;
         compositeFont = true;
-        descendant = xref.fetch(df[0]);
+
+        if (IsRef(df)) {
+          df = xref.fetch(df);
+        }
+
+        descendant = xref.fetch(IsRef(df) ? df : df[0]);
         subType = descendant.get('Subtype');
         fd = descendant.get('FontDescriptor');
       } else {
@@ -4090,7 +4095,7 @@ var CanvasGraphics = (function() {
         this.ctx.$setFont(fontName, size);
       } else {
         this.ctx.font = size + 'px "' + fontName + '"';
-        Fonts.setActive(fontName, fontObj, size);
+        FontMeasure.setActive(fontObj, size);
       }
     },
     setTextRenderingMode: function(mode) {
@@ -4142,7 +4147,7 @@ var CanvasGraphics = (function() {
           text = font.charsToUnicode(text);
         }
         ctx.fillText(text, 0, 0);
-        current.x += Fonts.measureText(text);
+        current.x += FontMeasure.measureText(text);
       }
 
       this.ctx.restore();
@@ -4853,10 +4858,10 @@ var ColorSpace = (function() {
       case 'Lab':
       case 'DeviceN':
       default:
-        error("unrecognized color space object '" + mode + "'");
+        error("unimplemented color space object '" + mode + "'");
       }
     } else {
-      error('unrecognized color space object');
+      error('unrecognized color space object: "'+ cs +"'");
     }
   };
 
@@ -5130,6 +5135,10 @@ var PDFImage = (function() {
     this.bpc = bitsPerComponent;
 
     var colorSpace = dict.get('ColorSpace', 'CS');
+    if (!colorSpace) {
+      TODO('JPX images (which don"t require color spaces');
+      colorSpace = new Name('DeviceRGB');
+    }
     this.colorSpace = ColorSpace.parse(colorSpace, xref, res);
 
     this.numComps = this.colorSpace.numComps;
diff --git a/test/driver.js b/test/driver.js
index e397f108b..a6b0b1dc2 100644
--- a/test/driver.js
+++ b/test/driver.js
@@ -111,7 +111,10 @@ function nextPage(task, loadError) {
 
             page.startRendering(
               ctx,
-              function() { snapshotCurrentPage(page, task, failure); });
+              function(e) {
+                snapshotCurrentPage(page, task,
+                                    (!failure && e) ? ('render: '+ e) : failure);
+              });
         } catch(e) {
             failure = 'page setup: '+ e.toString();
         }