From d76f5f681531937276a4a379a56a2efafb123166 Mon Sep 17 00:00:00 2001
From: Brendan Dahl <brendan.dahl@gmail.com>
Date: Tue, 13 Dec 2011 08:48:27 -0800
Subject: [PATCH 01/18] Playing with initial decode map impl.

---
 src/evaluator.js |  2 +-
 src/image.js     | 21 ++++++++++++++++-----
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/src/evaluator.js b/src/evaluator.js
index edef57f91..5c20c8660 100644
--- a/src/evaluator.js
+++ b/src/evaluator.js
@@ -227,7 +227,7 @@ var PartialEvaluator = (function PartialEvaluatorClosure() {
               data: new Uint8Array(w * h * 4)
             };
             var pixels = imgData.data;
-            imageObj.fillRgbaBuffer(pixels, imageObj.decode);
+            imageObj.fillRgbaBuffer(pixels);
             handler.send('obj', [objId, 'Image', imgData]);
           }, handler, xref, resources, image, inline);
       }
diff --git a/src/image.js b/src/image.js
index 987542c58..8adae5030 100644
--- a/src/image.js
+++ b/src/image.js
@@ -104,10 +104,13 @@ var PDFImage = (function PDFImageClosure() {
   };
 
   PDFImage.prototype = {
-    getComponents: function getComponents(buffer, decodeMap) {
+    getComponents: function getComponents(buffer) {
       var bpc = this.bpc;
-      if (bpc == 8)
-        return buffer;
+      var decodeMap = this.decode;
+      //if (decodeMap)
+      //  debugger;
+      //if (bpc == 8)
+      //  return buffer;
 
       var width = this.width;
       var height = this.height;
@@ -160,6 +163,14 @@ var PDFImage = (function PDFImageClosure() {
 
           var remainingBits = bits - bpc;
           output[i] = buf >> remainingBits;
+          if (decodeMap) {
+            var x = output[i];
+            var dmin = decodeMap[0];
+            var dmax = decodeMap[1];
+            var max = Math.pow(2, bpc) - 1;
+            var val = max * (dmin + x * ((dmax - dmin)/(max)));
+            output[i] = val;
+          }
           buf = buf & ((1 << remainingBits) - 1);
           bits = remainingBits;
         }
@@ -210,7 +221,7 @@ var PDFImage = (function PDFImageClosure() {
         }
       }
     },
-    fillRgbaBuffer: function fillRgbaBuffer(buffer, decodeMap) {
+    fillRgbaBuffer: function fillRgbaBuffer(buffer) {
       var numComps = this.numComps;
       var width = this.width;
       var height = this.height;
@@ -221,7 +232,7 @@ var PDFImage = (function PDFImageClosure() {
       var imgArray = this.getImageBytes(height * rowBytes);
 
       var comps = this.colorSpace.getRgbBuffer(
-        this.getComponents(imgArray, decodeMap), bpc);
+        this.getComponents(imgArray), bpc);
       var compsPos = 0;
       var opacity = this.getOpacity();
       var opacityPos = 0;

From 55bbcbc6649504779c1469ecd8a4620466b5f5c0 Mon Sep 17 00:00:00 2001
From: Brendan Dahl <brendan.dahl@gmail.com>
Date: Tue, 13 Dec 2011 13:53:22 -0800
Subject: [PATCH 02/18] Working improved version. Still need to refactor
 default decode stuff.

---
 src/image.js | 87 ++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 70 insertions(+), 17 deletions(-)

diff --git a/src/image.js b/src/image.js
index 8adae5030..f848b12ae 100644
--- a/src/image.js
+++ b/src/image.js
@@ -24,6 +24,16 @@ var PDFImage = (function PDFImageClosure() {
       promise.resolve(image);
     }
   }
+  /**
+   * Decode and clamp a value.
+   */
+  function decode(value, addend, coefficient, max) {
+    // This formula is different from the spec because we don't decode to
+    // float range [0,1], we decode it in the [0,max] range.
+    value = addend + value * coefficient;
+    // Clamp the value to the range
+    return value < 0 ? 0 : value > max ? max : value;
+  }
   function PDFImage(xref, res, image, inline, smask) {
     this.image = image;
     if (image.getParams) {
@@ -69,6 +79,18 @@ var PDFImage = (function PDFImageClosure() {
     }
 
     this.decode = dict.get('Decode', 'D');
+    if (this.decode && !this.hasDefaultDecode()) {
+      // Do some preprocessing to avoid more math.
+      var max = (1 << bitsPerComponent) - 1;
+      this.decodeCoefficients = [];
+      this.decodeAddends = [];
+      for (var i = 0, j = 0; i < this.decode.length; i += 2, ++j) {
+        var dmin = this.decode[i];
+        var dmax = this.decode[i + 1];
+        this.decodeCoefficients[j] = dmax - dmin;
+        this.decodeAddends[j] = max * dmin;
+      }
+    }
 
     var mask = xref.fetchIfRef(dict.get('Mask'));
 
@@ -106,23 +128,40 @@ var PDFImage = (function PDFImageClosure() {
   PDFImage.prototype = {
     getComponents: function getComponents(buffer) {
       var bpc = this.bpc;
+      var defaultDecode = this.hasDefaultDecode();
       var decodeMap = this.decode;
-      //if (decodeMap)
-      //  debugger;
-      //if (bpc == 8)
-      //  return buffer;
-
+      if (decodeMap) console.time('getComps');
+      // This image doesn't require extra work
+      if (bpc == 8 && defaultDecode)
+        return buffer;
+      var bufferLength = buffer.length;
       var width = this.width;
       var height = this.height;
       var numComps = this.numComps;
 
-      var length = width * height;
+      var length = width * height * numComps;
       var bufferPos = 0;
       var output = bpc <= 8 ? new Uint8Array(length) :
         bpc <= 16 ? new Uint16Array(length) : new Uint32Array(length);
       var rowComps = width * numComps;
+      var decodeAddends, decodeCoefficients;
+      if (!defaultDecode) {
+        decodeAddends = this.decodeAddends;
+        decodeCoefficients = this.decodeCoefficients;
+      }
+      var max = (1 << bpc) - 1;
 
-      if (bpc == 1) {
+      if (bpc == 8) {
+        // Optimization for reading 8 bpc images that have a decode.
+        for (var i = 0, ii = length; i < ii; ++i) {
+          var compIndex = i % numComps;
+          var value = buffer[i];
+          value = decode(value, decodeAddends[compIndex],
+                          decodeCoefficients[compIndex], max);
+          output[i] = value;
+        }
+      } else if (bpc == 1) {
+        // Optimization for reading 1 bpc images.
         var valueZero = 0, valueOne = 1;
         if (decodeMap) {
           valueZero = decodeMap[0] ? 1 : 0;
@@ -147,8 +186,7 @@ var PDFImage = (function PDFImageClosure() {
           output[i] = !(buf & mask) ? valueZero : valueOne;
         }
       } else {
-        if (decodeMap != null)
-          TODO('interpolate component values');
+        // The general case that handles all other bpc values.
         var bits = 0, buf = 0;
         for (var i = 0, ii = length; i < ii; ++i) {
           if (i % rowComps == 0) {
@@ -162,19 +200,18 @@ var PDFImage = (function PDFImageClosure() {
           }
 
           var remainingBits = bits - bpc;
-          output[i] = buf >> remainingBits;
-          if (decodeMap) {
-            var x = output[i];
-            var dmin = decodeMap[0];
-            var dmax = decodeMap[1];
-            var max = Math.pow(2, bpc) - 1;
-            var val = max * (dmin + x * ((dmax - dmin)/(max)));
-            output[i] = val;
+          var value = buf >> remainingBits;
+          if (!defaultDecode) {
+            var compIndex = i % numComps;
+            value = decode(value, decodeAddends[compIndex],
+                            decodeCoefficients[compIndex], max);
           }
+          output[i] = value;
           buf = buf & ((1 << remainingBits) - 1);
           bits = remainingBits;
         }
       }
+      if(decodeMap) console.timeEnd('getComps');
       return output;
     },
     getOpacity: function getOpacity() {
@@ -267,6 +304,22 @@ var PDFImage = (function PDFImageClosure() {
     getImageBytes: function getImageBytes(length) {
       this.image.reset();
       return this.image.getBytes(length);
+    },
+    hasDefaultDecode: function hasDefaultDecode() {
+      // TODO lab color as a way different decode map
+      if (!this.decode)
+        return true;
+      var numComps = this.numComps;
+      var decode = this.decode;
+      if (numComps * 2 !== decode.length) {
+        warning('The decode map is not the correct length');
+        return true;
+      }
+      for (var i = 0, ii = decode.length; i < ii; i += 2) {
+        if (decode[i] != 0 || decode[i + 1] != 1)
+          return false;
+      }
+      return true;
     }
   };
   return PDFImage;

From ff1d804fd706e709ab240364a862e5c2557fd30f Mon Sep 17 00:00:00 2001
From: Brendan Dahl <brendan.dahl@gmail.com>
Date: Tue, 13 Dec 2011 14:35:46 -0800
Subject: [PATCH 03/18] Move the default decode to logic to the colorspace.

---
 src/colorspace.js | 40 ++++++++++++++++++++++++++++++++++++++++
 src/image.js      | 45 ++++++++++++++++-----------------------------
 2 files changed, 56 insertions(+), 29 deletions(-)

diff --git a/src/colorspace.js b/src/colorspace.js
index 231ff6923..87d0083c0 100644
--- a/src/colorspace.js
+++ b/src/colorspace.js
@@ -154,6 +154,29 @@ var ColorSpace = (function ColorSpaceClosure() {
     }
     return null;
   };
+  /**
+   * Checks if a decode map matches the default decode map for a color space.
+   * This handles the general decode maps where there are two values per
+   * component. e.g. [0, 1, 0, 1, 0, 1] for a RGB color.
+   * This does not handle Lab, Indexed, or Pattern decode maps since they are
+   * slightly different.
+   * @param {Array} decode Decode map (usually from an image).
+   * @param {Number} n Number of components the color space has.
+   */
+  ColorSpace.isDefaultDecode = function colorSpaceIsDefaultDecode(decode, n) {
+    if (!decode)
+      return true;
+
+    if (n * 2 !== decode.length) {
+      warning('The decode map is not the correct length');
+      return true;
+    }
+    for (var i = 0, ii = decode.length; i < ii; i += 2) {
+      if (decode[i] != 0 || decode[i + 1] != 1)
+        return false;
+    }
+    return true;
+  };
 
   return ColorSpace;
 })();
@@ -200,6 +223,9 @@ var AlternateCS = (function AlternateCSClosure() {
           baseBuf[pos++] = 255 * tinted[j];
       }
       return base.getRgbBuffer(baseBuf, 8);
+    },
+    isDefaultDecode: function altcs_isDefaultDecode(decodeMap) {
+      ColorSpace.isDefaultDecode(decodeMap, this.numComps);
     }
   };
 
@@ -267,6 +293,10 @@ var IndexedCS = (function IndexedCSClosure() {
       }
 
       return base.getRgbBuffer(baseBuf, 8);
+    },
+    isDefaultDecode: function indexcs_isDefaultDecode(decodeMap) {
+      // indexed color maps shouldn't be changed
+      return true;
     }
   };
   return IndexedCS;
@@ -295,6 +325,9 @@ var DeviceGrayCS = (function DeviceGrayCSClosure() {
         rgbBuf[j++] = c;
       }
       return rgbBuf;
+    },
+    isDefaultDecode: function graycs_isDefaultDecode(decodeMap) {
+      ColorSpace.isDefaultDecode(decodeMap, this.numComps);
     }
   };
   return DeviceGrayCS;
@@ -319,6 +352,10 @@ var DeviceRgbCS = (function DeviceRgbCSClosure() {
       for (i = 0; i < length; ++i)
         rgbBuf[i] = (scale * input[i]) | 0;
       return rgbBuf;
+    },
+    isDefaultDecode: function rgbcs_isDefaultDecode(decodeMap) {
+      return 0 == decodeMap[0] == decodeMap[2] == decodeMap[4] &&
+             1 == decodeMap[1] == decodeMap[3] == decoeMap[5];
     }
   };
   return DeviceRgbCS;
@@ -403,6 +440,9 @@ var DeviceCmykCS = (function DeviceCmykCSClosure() {
       }
 
       return rgbBuf;
+    },
+    isDefaultDecode: function cmykcs_isDefaultDecode(decodeMap) {
+      ColorSpace.isDefaultDecode(decodeMap, this.numComps);
     }
   };
 
diff --git a/src/image.js b/src/image.js
index f848b12ae..2f99dee54 100644
--- a/src/image.js
+++ b/src/image.js
@@ -25,11 +25,10 @@ var PDFImage = (function PDFImageClosure() {
     }
   }
   /**
-   * Decode and clamp a value.
+   * Decode and clamp a value. The formula is different from the spec because we
+   * don't decode to float range [0,1], we decode it in the [0,max] range.
    */
-  function decode(value, addend, coefficient, max) {
-    // This formula is different from the spec because we don't decode to
-    // float range [0,1], we decode it in the [0,max] range.
+  function decodeAndClamp(value, addend, coefficient, max) {
     value = addend + value * coefficient;
     // Clamp the value to the range
     return value < 0 ? 0 : value > max ? max : value;
@@ -79,7 +78,10 @@ var PDFImage = (function PDFImageClosure() {
     }
 
     this.decode = dict.get('Decode', 'D');
-    if (this.decode && !this.hasDefaultDecode()) {
+    this.needsDecode = false;
+    if (this.decode && this.colorSpace &&
+        !this.colorSpace.isDefaultDecode(this.decode)) {
+      this.needsDecode = true;
       // Do some preprocessing to avoid more math.
       var max = (1 << bitsPerComponent) - 1;
       this.decodeCoefficients = [];
@@ -128,12 +130,13 @@ var PDFImage = (function PDFImageClosure() {
   PDFImage.prototype = {
     getComponents: function getComponents(buffer) {
       var bpc = this.bpc;
-      var defaultDecode = this.hasDefaultDecode();
+      var needsDecode = this.needsDecode;
       var decodeMap = this.decode;
-      if (decodeMap) console.time('getComps');
-      // This image doesn't require extra work
-      if (bpc == 8 && defaultDecode)
+
+      // This image doesn't require any extra work.
+      if (bpc == 8 && !needsDecode)
         return buffer;
+
       var bufferLength = buffer.length;
       var width = this.width;
       var height = this.height;
@@ -145,7 +148,7 @@ var PDFImage = (function PDFImageClosure() {
         bpc <= 16 ? new Uint16Array(length) : new Uint32Array(length);
       var rowComps = width * numComps;
       var decodeAddends, decodeCoefficients;
-      if (!defaultDecode) {
+      if (needsDecode) {
         decodeAddends = this.decodeAddends;
         decodeCoefficients = this.decodeCoefficients;
       }
@@ -156,7 +159,7 @@ var PDFImage = (function PDFImageClosure() {
         for (var i = 0, ii = length; i < ii; ++i) {
           var compIndex = i % numComps;
           var value = buffer[i];
-          value = decode(value, decodeAddends[compIndex],
+          value = decodeAndClamp(value, decodeAddends[compIndex],
                           decodeCoefficients[compIndex], max);
           output[i] = value;
         }
@@ -201,9 +204,9 @@ var PDFImage = (function PDFImageClosure() {
 
           var remainingBits = bits - bpc;
           var value = buf >> remainingBits;
-          if (!defaultDecode) {
+          if (needsDecode) {
             var compIndex = i % numComps;
-            value = decode(value, decodeAddends[compIndex],
+            value = decodeAndClamp(value, decodeAddends[compIndex],
                             decodeCoefficients[compIndex], max);
           }
           output[i] = value;
@@ -304,22 +307,6 @@ var PDFImage = (function PDFImageClosure() {
     getImageBytes: function getImageBytes(length) {
       this.image.reset();
       return this.image.getBytes(length);
-    },
-    hasDefaultDecode: function hasDefaultDecode() {
-      // TODO lab color as a way different decode map
-      if (!this.decode)
-        return true;
-      var numComps = this.numComps;
-      var decode = this.decode;
-      if (numComps * 2 !== decode.length) {
-        warning('The decode map is not the correct length');
-        return true;
-      }
-      for (var i = 0, ii = decode.length; i < ii; i += 2) {
-        if (decode[i] != 0 || decode[i + 1] != 1)
-          return false;
-      }
-      return true;
     }
   };
   return PDFImage;

From 9d042ce16661b3453581786f701e172594ba5a13 Mon Sep 17 00:00:00 2001
From: Brendan Dahl <brendan.dahl@gmail.com>
Date: Wed, 14 Dec 2011 08:47:35 -0800
Subject: [PATCH 04/18] Use the general function for is default decode.

---
 src/colorspace.js | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/src/colorspace.js b/src/colorspace.js
index 87d0083c0..8088ab7df 100644
--- a/src/colorspace.js
+++ b/src/colorspace.js
@@ -354,8 +354,7 @@ var DeviceRgbCS = (function DeviceRgbCSClosure() {
       return rgbBuf;
     },
     isDefaultDecode: function rgbcs_isDefaultDecode(decodeMap) {
-      return 0 == decodeMap[0] == decodeMap[2] == decodeMap[4] &&
-             1 == decodeMap[1] == decodeMap[3] == decoeMap[5];
+      ColorSpace.isDefaultDecode(decodeMap, this.numComps);
     }
   };
   return DeviceRgbCS;

From ce57bac447cbe7cf9e264d8aaa3608a5e61c24be Mon Sep 17 00:00:00 2001
From: Adil Allawi <adil@diwan.com>
Date: Wed, 14 Dec 2011 22:28:34 +0000
Subject: [PATCH 05/18] Build Text Layer one div at a a time as an Interval
 instead of a all in a TimeOut to keep the browser responsive

---
 src/canvas.js | 28 ++++++++++++++++++----------
 1 file changed, 18 insertions(+), 10 deletions(-)

diff --git a/src/canvas.js b/src/canvas.js
index 4aaf75508..1efddbefa 100644
--- a/src/canvas.js
+++ b/src/canvas.js
@@ -259,7 +259,7 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
       this.textLayerQueue = [];
       // Prevent textLayerQueue from being rendered while rendering a new page
       if (this.textLayerTimer)
-        clearTimeout(this.textLayerTimer);
+        clearInterval(this.textLayerTimer);
     },
 
     executeIRQueue: function canvasGraphicsExecuteIRQueue(codeIR,
@@ -329,17 +329,21 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
 
       var self = this;
       var renderTextLayer = function canvasRenderTextLayer() {
+        var finished = true;
         var textDivs = self.textDivs;
-        for (var i = 0, length = textDivs.length; i < length; ++i) {
-          if (textDivs[i].dataset.textLength > 1) { // avoid div by zero
-            textLayer.appendChild(textDivs[i]);
+        if (textDivs.length > 0) {
+          var textDiv = textDivs.shift();
+          if (textDiv.dataset.textLength > 1) { // avoid div by zero
+            textLayer.appendChild(textDiv);
             // Adjust div width (via letterSpacing) to match canvas text
             // Due to the .offsetWidth calls, this is slow
-            textDivs[i].style.letterSpacing =
-              ((textDivs[i].dataset.canvasWidth - textDivs[i].offsetWidth) /
-               (textDivs[i].dataset.textLength - 1)) + 'px';
+            textDiv.style.letterSpacing =
+              ((textDiv.dataset.canvasWidth - textDiv.offsetWidth) /
+               (textDiv.dataset.textLength - 1)) + 'px';
           }
+          finished = false;
         }
+        return finished;
       }
       var textLayerQueue = this.textLayerQueue;
       textLayerQueue.push(renderTextLayer);
@@ -347,12 +351,16 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
       // Lazy textLayer rendering (to prevent UI hangs)
       // Only render queue if activity has stopped, where "no activity" ==
       // "no beginDrawing() calls in the last N ms"
-      this.textLayerTimer = setTimeout(function renderTextLayerQueue() {
+      this.textLayerTimer = setInterval(function renderTextLayerQueue() {
         // Render most recent (==most relevant) layers first
         for (var i = textLayerQueue.length - 1; i >= 0; i--) {
-          textLayerQueue.pop().call();
+          var finished = textLayerQueue[i].call();
+          if (finished)
+            textLayerQueue.splice(i,1);
         }
-      }, 500);
+        if (textLayerQueue.length == 0)
+          clearInterval(this.textLayerTimer);
+      }, 1);
     },
 
     // Graphics state

From cc007b539a73d0d96d7d34d48851a4aad7f95f75 Mon Sep 17 00:00:00 2001
From: Adil Allawi <adil@diwan.com>
Date: Thu, 15 Dec 2011 09:20:55 +0000
Subject: [PATCH 06/18] fix lint nitpick

---
 src/canvas.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/canvas.js b/src/canvas.js
index 1efddbefa..fbebc0aa2 100644
--- a/src/canvas.js
+++ b/src/canvas.js
@@ -356,7 +356,7 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
         for (var i = textLayerQueue.length - 1; i >= 0; i--) {
           var finished = textLayerQueue[i].call();
           if (finished)
-            textLayerQueue.splice(i,1);
+            textLayerQueue.splice(i, 1);
         }
         if (textLayerQueue.length == 0)
           clearInterval(this.textLayerTimer);

From 4a14a798845e42e946f41da89a4bdc6ceab4a08d Mon Sep 17 00:00:00 2001
From: Adil Allawi <adil@diwan.com>
Date: Thu, 15 Dec 2011 10:08:50 +0000
Subject: [PATCH 07/18] use array index instead of array.shift()

---
 src/canvas.js | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/src/canvas.js b/src/canvas.js
index fbebc0aa2..38b33d19d 100644
--- a/src/canvas.js
+++ b/src/canvas.js
@@ -328,11 +328,12 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
         return;
 
       var self = this;
+      var textDivIndex = 0;
       var renderTextLayer = function canvasRenderTextLayer() {
-        var finished = true;
+        var finished = false;
         var textDivs = self.textDivs;
-        if (textDivs.length > 0) {
-          var textDiv = textDivs.shift();
+        if (textDivIndex < textDivs.length) {
+          var textDiv = textDivs[textDivIndex++];
           if (textDiv.dataset.textLength > 1) { // avoid div by zero
             textLayer.appendChild(textDiv);
             // Adjust div width (via letterSpacing) to match canvas text
@@ -341,8 +342,9 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
               ((textDiv.dataset.canvasWidth - textDiv.offsetWidth) /
                (textDiv.dataset.textLength - 1)) + 'px';
           }
-          finished = false;
         }
+        else
+          finished = true;
         return finished;
       }
       var textLayerQueue = this.textLayerQueue;

From 5bd080fd0508197e34e03e2d73447b7cfe9a3c26 Mon Sep 17 00:00:00 2001
From: Adil Allawi <adil@diwan.com>
Date: Thu, 15 Dec 2011 11:32:58 +0000
Subject: [PATCH 08/18] oops, interval was not clearing because 'this' is not
 the same 'this' inside an interval. Should use local variable 'self' instead.
 Reviewers you should have spotted this! :)

---
 src/canvas.js | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/src/canvas.js b/src/canvas.js
index 2d1130b4f..50c762bca 100644
--- a/src/canvas.js
+++ b/src/canvas.js
@@ -361,7 +361,7 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
             textLayerQueue.splice(i, 1);
         }
         if (textLayerQueue.length == 0)
-          clearInterval(this.textLayerTimer);
+          clearInterval(self.textLayerTimer);
       }, 1);
     },
 

From 8096d747c0f0ff85f9a39b43e56d7c2153cc9913 Mon Sep 17 00:00:00 2001
From: Brendan Dahl <brendan.dahl@gmail.com>
Date: Thu, 15 Dec 2011 15:13:48 -0800
Subject: [PATCH 09/18] Fix nits.

---
 src/canvas.js | 4 ++--
 src/image.js  | 1 -
 2 files changed, 2 insertions(+), 3 deletions(-)

diff --git a/src/canvas.js b/src/canvas.js
index e056fe0f2..e42f53cf1 100644
--- a/src/canvas.js
+++ b/src/canvas.js
@@ -1106,9 +1106,9 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
 
     paintImageXObject: function canvasGraphicsPaintImageXObject(objId) {
       var imgData = this.objs.get(objId);
-      if (!imgData) {
+      if (!imgData)
         error('Dependent image isn\'t ready yet');
-      }
+
       this.save();
       var ctx = this.ctx;
       var w = imgData.width;
diff --git a/src/image.js b/src/image.js
index 2f99dee54..22a9f9eb4 100644
--- a/src/image.js
+++ b/src/image.js
@@ -214,7 +214,6 @@ var PDFImage = (function PDFImageClosure() {
           bits = remainingBits;
         }
       }
-      if(decodeMap) console.timeEnd('getComps');
       return output;
     },
     getOpacity: function getOpacity() {

From d6e4607fd039c0f2ccb7c863d048cd4d9235ec9d Mon Sep 17 00:00:00 2001
From: notmasteryet <async.processingjs@yahoo.com>
Date: Thu, 15 Dec 2011 20:44:55 -0600
Subject: [PATCH 10/18] Add compatibility for HTMLElement's dataset (#945)

---
 web/compatibility.js | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/web/compatibility.js b/web/compatibility.js
index 7d1d72553..e4e2f2440 100644
--- a/web/compatibility.js
+++ b/web/compatibility.js
@@ -205,3 +205,15 @@
   });
 })();
 
+// HTMLElement dataset property
+(function checkDatasetProperty() {
+  var div = document.createElement('div');
+  if ('dataset' in div)
+    return; // dataset property exists
+  Object.defineProperty(HTMLElement.prototype, 'dataset', {
+    get: function htmlElementDatasetGetter() {
+      // adding dataset field to the actual object
+      return (this.dataset = {});
+    }
+  });
+})();

From b921486bce08ef6cc2683989848b44f28861e2f4 Mon Sep 17 00:00:00 2001
From: Adil Allawi <adil@diwan.com>
Date: Fri, 16 Dec 2011 10:38:30 +0000
Subject: [PATCH 11/18] simplify adding of textdivs to DOM as queue is no
 longer needed

---
 src/canvas.js | 52 +++++++++++++++------------------------------------
 1 file changed, 15 insertions(+), 37 deletions(-)

diff --git a/src/canvas.js b/src/canvas.js
index 50c762bca..0e351c1b8 100644
--- a/src/canvas.js
+++ b/src/canvas.js
@@ -257,9 +257,6 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
       this.ctx.scale(cw / mediaBox.width, ch / mediaBox.height);
       this.textDivs = [];
       this.textLayerQueue = [];
-      // Prevent textLayerQueue from being rendered while rendering a new page
-      if (this.textLayerTimer)
-        clearInterval(this.textLayerTimer);
     },
 
     executeIRQueue: function canvasGraphicsExecuteIRQueue(codeIR,
@@ -328,41 +325,22 @@ var CanvasGraphics = (function CanvasGraphicsClosure() {
         return;
 
       var self = this;
-      var textDivIndex = 0;
-      var renderTextLayer = function canvasRenderTextLayer() {
-        var finished = false;
-        var textDivs = self.textDivs;
-        if (textDivIndex < textDivs.length) {
-          var textDiv = textDivs[textDivIndex++];
-          if (textDiv.dataset.textLength > 1) { // avoid div by zero
-            textLayer.appendChild(textDiv);
-            // Adjust div width (via letterSpacing) to match canvas text
-            // Due to the .offsetWidth calls, this is slow
-            textDiv.style.letterSpacing =
-              ((textDiv.dataset.canvasWidth - textDiv.offsetWidth) /
-               (textDiv.dataset.textLength - 1)) + 'px';
-          }
-        }
-        else
-          finished = true;
-        return finished;
-      }
-      var textLayerQueue = this.textLayerQueue;
-      textLayerQueue.push(renderTextLayer);
-
-      // Lazy textLayer rendering (to prevent UI hangs)
-      // Only render queue if activity has stopped, where "no activity" ==
-      // "no beginDrawing() calls in the last N ms"
-      this.textLayerTimer = setInterval(function renderTextLayerQueue() {
-        // Render most recent (==most relevant) layers first
-        for (var i = textLayerQueue.length - 1; i >= 0; i--) {
-          var finished = textLayerQueue[i].call();
-          if (finished)
-            textLayerQueue.splice(i, 1);
-        }
-        if (textLayerQueue.length == 0)
+      var textDivs = this.textDivs;
+      this.textLayerTimer = setInterval(function renderTextLayer() {
+        if (textDivs.length === 0) {
           clearInterval(self.textLayerTimer);
-      }, 1);
+          return;
+        }
+        var textDiv = textDivs.shift();
+        if (textDiv.dataset.textLength > 1) { // avoid div by zero
+          textLayer.appendChild(textDiv);
+          // Adjust div width (via letterSpacing) to match canvas text
+          // Due to the .offsetWidth calls, this is slow
+          textDiv.style.letterSpacing =
+            ((textDiv.dataset.canvasWidth - textDiv.offsetWidth) /
+              (textDiv.dataset.textLength - 1)) + 'px';
+        }
+      }, 0);
     },
 
     // Graphics state

From 156e20ca7398b34d5eeb10c98c9da879b61d3c3a Mon Sep 17 00:00:00 2001
From: Julian Viereck <julian.viereck@gmail.com>
Date: Sun, 18 Dec 2011 20:39:10 +0100
Subject: [PATCH 12/18] Cache Cmd object to reduce number of created objects

---
 src/obj.js    | 11 +++++++++++
 src/parser.js | 12 ++++++------
 2 files changed, 17 insertions(+), 6 deletions(-)

diff --git a/src/obj.js b/src/obj.js
index 2f7488a76..cb29f4c3c 100644
--- a/src/obj.js
+++ b/src/obj.js
@@ -22,6 +22,17 @@ var Cmd = (function CmdClosure() {
   Cmd.prototype = {
   };
 
+
+  var cmdCache = {};
+
+  Cmd.get = function(cmd) {
+    if (cmdCache[cmd]) {
+      return cmdCache[cmd];
+    } else {
+      return cmdCache[cmd] = new Cmd(cmd);
+    }
+  }
+
   return Cmd;
 })();
 
diff --git a/src/parser.js b/src/parser.js
index 695438379..e50b12b9b 100644
--- a/src/parser.js
+++ b/src/parser.js
@@ -157,7 +157,7 @@ var Parser = (function ParserClosure() {
       imageStream = this.filter(imageStream, dict, length);
       imageStream.parameters = dict;
 
-      this.buf2 = new Cmd('EI');
+      this.buf2 = Cmd.get('EI');
       this.shift();
 
       return imageStream;
@@ -496,14 +496,14 @@ var Lexer = (function LexerClosure() {
         // array punctuation
         case '[':
         case ']':
-          return new Cmd(ch);
+          return Cmd.get(ch);
         // hex string or dict punctuation
         case '<':
           ch = stream.lookChar();
           if (ch == '<') {
             // dict punctuation
             stream.skip();
-            return new Cmd('<<');
+            return Cmd.get('<<');
           }
           return this.getHexString(ch);
         // dict punctuation
@@ -511,11 +511,11 @@ var Lexer = (function LexerClosure() {
           ch = stream.lookChar();
           if (ch == '>') {
             stream.skip();
-            return new Cmd('>>');
+            return Cmd.get('>>');
           }
         case '{':
         case '}':
-          return new Cmd(ch);
+          return Cmd.get(ch);
         // fall through
         case ')':
           error('Illegal character: ' + ch);
@@ -538,7 +538,7 @@ var Lexer = (function LexerClosure() {
         return false;
       if (str == 'null')
         return null;
-      return new Cmd(str);
+      return Cmd.get(str);
     },
     skipToNextLine: function lexerSkipToNextLine() {
       var stream = this.stream;

From 3a86e047e05e12ab5544d9f0609a3b56153c44fd Mon Sep 17 00:00:00 2001
From: Julian Viereck <julian.viereck@gmail.com>
Date: Sun, 18 Dec 2011 20:42:06 +0100
Subject: [PATCH 13/18] Prevent default actions when zooming. Otherwise the
 browser performs a zoom of the entire page

---
 web/viewer.js | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/web/viewer.js b/web/viewer.js
index daf0174ab..d9732c2a3 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -895,18 +895,26 @@ window.addEventListener('keydown', function keydown(evt) {
       return; // ignoring if the 'controls' element is focused
     curElement = curElement.parentNode;
   }
+  var handled = false;
   switch (evt.keyCode) {
     case 61: // FF/Mac '='
     case 107: // FF '+' and '='
     case 187: // Chrome '+'
       PDFView.zoomIn();
+      handled = true;
       break;
     case 109: // FF '-'
     case 189: // Chrome '-'
       PDFView.zoomOut();
+      handled = true;
       break;
     case 48: // '0'
       PDFView.setScale(kDefaultScale, true);
+      handled = true;
       break;
   }
+
+  if (handled) {
+    evt.preventDefault();
+  }
 });

From aebb9946f8a653c83c5bdad1a79ab062d7d75321 Mon Sep 17 00:00:00 2001
From: Chris Peterson <cpeterso@cpeterso.com>
Date: Sun, 18 Dec 2011 20:39:41 -0800
Subject: [PATCH 14/18] Add keyboard shortcuts to navigate pages with left and
 right arrow keys

This is the behavior of Adobe Reader.app and Apple's Preview.app.
---
 web/viewer.js | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/web/viewer.js b/web/viewer.js
index d9732c2a3..e8b94af46 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -912,6 +912,14 @@ window.addEventListener('keydown', function keydown(evt) {
       PDFView.setScale(kDefaultScale, true);
       handled = true;
       break;
+    case 37: // left arrow
+      PDFView.page--;
+      handle = true;
+      break;
+    case 39: // right arrow
+      PDFView.page++;
+      handle = true;
+      break;
   }
 
   if (handled) {

From 4008ec69b832dd06f004dc2dcc59386c17e521a7 Mon Sep 17 00:00:00 2001
From: Chris Peterson <cpeterso@cpeterso.com>
Date: Sun, 18 Dec 2011 20:40:44 -0800
Subject: [PATCH 15/18] Add keyboard shortcuts to navigate pages with 'j' and
 'k' keys like vi

---
 web/viewer.js | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/web/viewer.js b/web/viewer.js
index e8b94af46..3404c6e42 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -913,10 +913,12 @@ window.addEventListener('keydown', function keydown(evt) {
       handled = true;
       break;
     case 37: // left arrow
+    case 75: // 'k'
       PDFView.page--;
       handle = true;
       break;
     case 39: // right arrow
+    case 74: // 'j'
       PDFView.page++;
       handle = true;
       break;

From 396daddefebc90edfb553e8d9f75fc373c438423 Mon Sep 17 00:00:00 2001
From: Chris Peterson <cpeterso@cpeterso.com>
Date: Sun, 18 Dec 2011 20:42:18 -0800
Subject: [PATCH 16/18] Add keyboard shortcuts to navigate pages with 'n' and
 'p' keys (Next/Previous)

---
 web/viewer.js | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/web/viewer.js b/web/viewer.js
index 3404c6e42..24c3458d7 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -914,11 +914,13 @@ window.addEventListener('keydown', function keydown(evt) {
       break;
     case 37: // left arrow
     case 75: // 'k'
+    case 80: // 'p'
       PDFView.page--;
       handle = true;
       break;
     case 39: // right arrow
     case 74: // 'j'
+    case 78: // 'n'
       PDFView.page++;
       handle = true;
       break;

From 8adb92a7092818462abe087c47f53a9d95e9d075 Mon Sep 17 00:00:00 2001
From: Chris Peterson <github.com@cpeterso.com>
Date: Sun, 18 Dec 2011 20:58:14 -0800
Subject: [PATCH 17/18] Fix typo: s/handle/handled/

---
 web/viewer.js | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/web/viewer.js b/web/viewer.js
index 24c3458d7..153de99aa 100644
--- a/web/viewer.js
+++ b/web/viewer.js
@@ -916,13 +916,13 @@ window.addEventListener('keydown', function keydown(evt) {
     case 75: // 'k'
     case 80: // 'p'
       PDFView.page--;
-      handle = true;
+      handled = true;
       break;
     case 39: // right arrow
     case 74: // 'j'
     case 78: // 'n'
       PDFView.page++;
-      handle = true;
+      handled = true;
       break;
   }
 

From e9c762a97fa9c7520f5b88a8a3b108f2372ddf99 Mon Sep 17 00:00:00 2001
From: Julian Viereck <julian.viereck@gmail.com>
Date: Mon, 19 Dec 2011 16:37:36 +0100
Subject: [PATCH 18/18] Address review comments by notmasteryet

---
 src/obj.js | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/src/obj.js b/src/obj.js
index cb29f4c3c..453014a91 100644
--- a/src/obj.js
+++ b/src/obj.js
@@ -25,13 +25,13 @@ var Cmd = (function CmdClosure() {
 
   var cmdCache = {};
 
-  Cmd.get = function(cmd) {
-    if (cmdCache[cmd]) {
-      return cmdCache[cmd];
-    } else {
-      return cmdCache[cmd] = new Cmd(cmd);
-    }
-  }
+  Cmd.get = function cmdGet(cmd) {
+    var cmdValue = cmdCache[cmd];
+    if (cmdValue)
+      return cmdValue;
+
+    return cmdCache[cmd] = new Cmd(cmd);
+  };
 
   return Cmd;
 })();