From 29967153c376561bda73f6361ea59724bdd84629 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 10:49:43 +0100
Subject: [PATCH 01/16] Clean up TODO comments...

---
 src/color/Gradient.js      |  4 ++--
 src/item/Item.js           |  8 +++-----
 src/item/Raster.js         | 14 +++++++-------
 src/path/CompoundPath.js   |  2 +-
 src/project/Project.js     | 10 +++++-----
 src/project/Symbol.js      |  2 +-
 src/text/PointText.js      |  4 ++--
 src/tool/ToolEvent.js      |  2 +-
 src/ui/Key.js              |  2 +-
 src/util/CanvasProvider.js |  4 ++--
 10 files changed, 25 insertions(+), 27 deletions(-)

diff --git a/src/color/Gradient.js b/src/color/Gradient.js
index 639cdc3c..1231e961 100644
--- a/src/color/Gradient.js
+++ b/src/color/Gradient.js
@@ -19,8 +19,8 @@ var Gradient = this.Gradient = Base.extend({
 
 	beans: true,
 
-	// TODO: Should type here be called 'radial' and have it
-	// receive a boolean value?
+	// TODO: Should type here be called 'radial' and have it receive a
+	// boolean value?
 	/**
 	 * Creates a gradient object
 	 * 
diff --git a/src/item/Item.js b/src/item/Item.js
index 7c54e1a7..9a43c996 100644
--- a/src/item/Item.js
+++ b/src/item/Item.js
@@ -1043,8 +1043,8 @@ var Item = this.Item = Base.extend({
 	 */
 	transform: function(matrix, flags) {
 		// TODO: Handle flags, add TransformFlag class and convert to bit mask
-		// for quicker checking
-		// TODO: Call transform on chidren only if 'children' flag is provided
+		// for quicker checking.
+		// TODO: Call transform on chidren only if 'children' flag is provided.
 		if (this._transform)
 			this._transform(matrix, flags);
 		// Transform position as well. Do not modify _position directly,
@@ -1085,7 +1085,7 @@ var Item = this.Item = Base.extend({
 			}
 		},
 
-		// TODO: Implement View into the drawing
+		// TODO: Implement View into the drawing.
 		// TODO: Optimize temporary canvas drawing to ignore parts that are
 		// outside of the visible view.
 		draw: function(item, ctx, param) {
@@ -1241,8 +1241,6 @@ var Item = this.Item = Base.extend({
 		moveBelow: move(false)
 	};
 }, new function() {
-	//DOCS: document removeOn(param)
-
 	/**
 	 * {@grouptitle Remove On Event}
 	 * Removes the item when the next {@link Tool#onMouseMove} event is fired.
diff --git a/src/item/Raster.js b/src/item/Raster.js
index 51020109..bb8cc9f7 100644
--- a/src/item/Raster.js
+++ b/src/item/Raster.js
@@ -19,9 +19,9 @@ var Raster = this.Raster = Item.extend({
 
 	beans: true,
 
-	// TODO: implement url / type, width, height
-	// TODO: have PlacedSymbol & Raster inherit from a shared class?
-	// DOCS: document Raster constructor
+	// TODO: Implement url / type, width, height.
+	// TODO: Have PlacedSymbol & Raster inherit from a shared class?
+	// DOCS: Document Raster constructor.
 	/**
 	 * Creates a new raster item and places it in the active layer.
 	 * 
@@ -163,12 +163,12 @@ var Raster = this.Raster = Item.extend({
 		return this._image || this.getCanvas();
 	},
 
-	// TODO: support string id of image element
+	// TODO: Support string id of image element.
 	setImage: function(image) {
 		if (this._canvas)
 			CanvasProvider.returnCanvas(this._canvas);
 		this._image = image;
-		// TODO: cross browser compatible?
+		// TODO: Cross browser compatible?
 		this._size = new Size(image.naturalWidth, image.naturalHeight);
 		this._canvas = null;
 		this._context = null;
@@ -216,8 +216,8 @@ var Raster = this.Raster = Item.extend({
 			object = this.getBounds();
 		var bounds, path;
 		if (object instanceof PathItem) {
-			// TODO: what if the path is smaller than 1 px?
-			// TODO: how about rounding of bounds.size?
+			// TODO: What if the path is smaller than 1 px?
+			// TODO: How about rounding of bounds.size?
 			path = object;
 			bounds = object.getBounds();
 		} else if (object.width) {
diff --git a/src/path/CompoundPath.js b/src/path/CompoundPath.js
index bca3b713..4b03128c 100644
--- a/src/path/CompoundPath.js
+++ b/src/path/CompoundPath.js
@@ -54,7 +54,7 @@ var CompoundPath = this.CompoundPath = PathItem.extend({
 			// clockwise orientation when creating a compound path, so that they
 			// appear as holes, but only if their orientation was not already
 			// specified before (= _clockwise is defined).
-			// TODO: This should really be handled in appendTop / Bottom, right?
+			// TODO: Should this be handled in appendTop / Bottom instead?
 			if (path._clockwise === undefined)
 				path.setClockwise(i < l - 1);
 			this.appendTop(path);
diff --git a/src/project/Project.js b/src/project/Project.js
index 589451eb..89e4bffd 100644
--- a/src/project/Project.js
+++ b/src/project/Project.js
@@ -20,7 +20,7 @@ var Project = this.Project = Base.extend({
 	beans: true,
 
 	// TODO: Add arguments to define pages
-	// DOCS: document Project constructor and class
+	// DOCS: Document Project constructor and class
 	/**
 	 * Creates a Paper.js project
 	 *
@@ -90,7 +90,7 @@ var Project = this.Project = Base.extend({
 	},
 
 	setCurrentStyle: function(style) {
-		// TODO: style selected items with the style:
+		// TODO: Style selected items with the style:
 		this._currentStyle.initialize(style);
 	},
 
@@ -129,9 +129,9 @@ var Project = this.Project = Base.extend({
 	 * @bean
 	 */
 	getSelectedItems: function() {
-		// TODO: return groups if their children are all selected,
+		// TODO: Return groups if their children are all selected,
 		// and filter out their children from the list.
-		// TODO: the order of these items should be that of their
+		// TODO: The order of these items should be that of their
 		// drawing order.
 		var items = [];
 		Base.each(this._selectedItems, function(item) {
@@ -140,7 +140,7 @@ var Project = this.Project = Base.extend({
 		return items;
 	},
 
-	// TODO: implement setSelectedItems?
+	// TODO: Implement setSelectedItems?
 	
 	_selectItem: function(item, select) {
 		if (select) {
diff --git a/src/project/Symbol.js b/src/project/Symbol.js
index 5ed4f5a4..f35de100 100644
--- a/src/project/Symbol.js
+++ b/src/project/Symbol.js
@@ -57,7 +57,7 @@ var Symbol = this.Symbol = Base.extend({
 	},
 
 	// TODO: Symbol#remove()
-	// TODO: Size#name (accessible by name through project#symbols)
+	// TODO: Symbol#name (accessible by name through project#symbols)
 
 	/**
 	 * The project that this symbol belongs to.
diff --git a/src/text/PointText.js b/src/text/PointText.js
index 535cb2e3..1f341f6e 100644
--- a/src/text/PointText.js
+++ b/src/text/PointText.js
@@ -69,8 +69,8 @@ var PointText = this.PointText = TextItem.extend({
 				Point.read(arguments).subtract(this._point)));
 	},
 	
-	// TODO: position should be the center point of the bounds
-	// but we currently don't support bounds for PointText.
+	// TODO: Position should be the center point of the bounds but we currently
+	// don't support bounds for PointText.
 	getPosition: function() {
 		return this._point;
 	},
diff --git a/src/tool/ToolEvent.js b/src/tool/ToolEvent.js
index f49a5ec6..b3d76363 100644
--- a/src/tool/ToolEvent.js
+++ b/src/tool/ToolEvent.js
@@ -172,7 +172,7 @@ var ToolEvent = this.ToolEvent = Base.extend({
 		return Key.modifiers;
 	},
 
-	// TODO: implement hitTest first
+	// TODO: Implement hitTest first
 	// getItem: function() {
 	// 	if (this.item == null) {
 	// 		var result = Project.getActiveProject().hitTest(this.getPoint());
diff --git a/src/ui/Key.js b/src/ui/Key.js
index fa0a645b..019e7c61 100644
--- a/src/ui/Key.js
+++ b/src/ui/Key.js
@@ -19,7 +19,7 @@
  * @name Key
  */
 var Key = this.Key = new function() {
-	// TODO: make sure the keys are called the same as in Scriptographer
+	// TODO: Make sure the keys are called the same as in Scriptographer
 	// Missing: tab, cancel, clear, page-down, page-up, comma, minus, period,
 	// slash, etc etc etc.
 
diff --git a/src/util/CanvasProvider.js b/src/util/CanvasProvider.js
index 8bbdca93..49b352f8 100644
--- a/src/util/CanvasProvider.js
+++ b/src/util/CanvasProvider.js
@@ -14,8 +14,8 @@
  * All rights reserved.
  */
 
-// TODO: it might be better to make a ContextProvider class, since you
-// can always find the canvas through context.canvas. This saves code and 
+// TODO: It might be better to make a ContextProvider class, since you
+// can always find the canvas through context.canvas. This saves code and
 // speed by not having to do canvas.getContext('2d')
 // TODO: Run through the canvas array to find a canvas with the requested
 // width / height, so we don't need to resize it?

From c47d281308484180957099e4cf9005a76ffc38e4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 13:37:36 +0100
Subject: [PATCH 02/16] Speed up blend-modes by using a lookup table for
 process functions rather than a switch() statement for each pixel.

---
 src/util/BlendMode.js | 186 ++++++++++++++++++++++--------------------
 1 file changed, 98 insertions(+), 88 deletions(-)

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index 7d462103..c620a14a 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -51,56 +51,95 @@ var BlendMode = {
 					sourceCanvas.width, sourceCanvas.height),
 			src  = srcD.data,
 			dst  = dstD.data,
-			sA, dA, len = dst.length,
-			sRA, sGA, sBA, dRA, dGA, dBA, dA2,
-			demultiply,
-			min = Math.min;
+			min = Math.min,
+			sA, dA, dA2, sRA, sGA, sBA, dRA, dGA, dBA, demultiply;
 
-		for (var i = 0; i < len; i += 4) {
-			sA  = src[i + 3] / 255 * opacity;
-			dA  = dst[i + 3] / 255;
-			dA2 = sA + dA - sA * dA;
-			dst[i + 3] = dA2 * 255;
+		// TODO: Some blend modes seem broken at the moment, e.g.
+		// dodge, burn
+		// TODO: This could be optimised by not diving everything by 255 and
+		// keeping it integer instead, with one divide at the end.
+		var modes = {
+			unsupported: function(i) {
+				// Render checker pattern
+				dst[i] = dst[i + 3] = 255;
+				dst[i + 1] = i % 8 == 0 ? 255 : 0;
+				dst[i + 2] = i % 8 == 0 ? 0 : 255;
+			},
 
-			sRA = src[i] / 255 * sA;
-			dRA = dst[i] / 255 * dA;
-			sGA = src[i + 1] / 255 * sA;
-			dGA = dst[i + 1] / 255 * dA;
-			sBA = src[i + 2] / 255 * sA;
-			dBA = dst[i + 2] / 255 * dA;
-
-			demultiply = 255 / dA2;
-
-			// TODO: Some blend modes seem broken at the moment, e.g.
-			// dodge, burn
-			// TODO: This could be optimised by not diving everything by 255 and
-			// keeping it integer instead, with one divide at the end.
-
-			switch (blendMode) {
-			// Very close match to Photoshop
-			case 'normal':
-			case 'src-over':
+			normal: function(i) {
 				dst[i]     = (sRA + dRA - dRA * sA) * demultiply;
 				dst[i + 1] = (sGA + dGA - dGA * sA) * demultiply;
 				dst[i + 2] = (sBA + dBA - dBA * sA) * demultiply;
-				break;
-			case 'screen':
-				dst[i]     = (sRA + dRA - sRA * dRA) * demultiply;
-				dst[i + 1] = (sGA + dGA - sGA * dGA) * demultiply;
-				dst[i + 2] = (sBA + dBA - sBA * dBA) * demultiply;
-				break;
-			case 'multiply':
+			},
+
+			multiply: function(i) {
 				dst[i]     = (sRA * dRA + sRA * (1 - dA) + dRA * (1 - sA)) * demultiply;
 				dst[i + 1] = (sGA * dGA + sGA * (1 - dA) + dGA * (1 - sA)) * demultiply;
 				dst[i + 2] = (sBA * dBA + sBA * (1 - dA) + dBA * (1 - sA)) * demultiply;
-				break;
-			case 'difference':
+			},
+
+			screen: function(i) {
+				dst[i]     = (sRA + dRA - sRA * dRA) * demultiply;
+				dst[i + 1] = (sGA + dGA - sGA * dGA) * demultiply;
+				dst[i + 2] = (sBA + dBA - sBA * dBA) * demultiply;
+			},
+
+			overlay: function(i) {
+				// Correct for 100% opacity case; colors get clipped as opacity falls
+				dst[i]     = dRA <= 0.5 ? (2 * src[i]     * dRA / dA) : 255 - (2 - 2 * dRA / dA) * (255 - src[i]);
+				dst[i + 1] = dGA <= 0.5 ? (2 * src[i + 1] * dGA / dA) : 255 - (2 - 2 * dGA / dA) * (255 - src[i + 1]);
+				dst[i + 2] = dBA <= 0.5 ? (2 * src[i + 2] * dBA / dA) : 255 - (2 - 2 * dBA / dA) * (255 - src[i + 2]);
+			},
+
+			// TODO: Missing: soft-light
+
+			'hard-light': function(i) {
+				dst[i] =     sRA <= 0.5 ? (2 * dst[i]     * sRA / dA) : 255 - (2 - 2 * sRA / sA) * (255 - dst[i]);
+				dst[i + 1] = sGA <= 0.5 ? (2 * dst[i + 1] * sGA / dA) : 255 - (2 - 2 * sGA / sA) * (255 - dst[i + 1]);
+				dst[i + 2] = sBA <= 0.5 ? (2 * dst[i + 2] * sBA / dA) : 255 - (2 - 2 * sBA / sA) * (255 - dst[i + 2]);
+			},
+
+			'color-dodge': function(i) {
+				dst[i] =     src[i]     == 255 && dRA == 0 ? 255 : min(255, dst[i]     / (255 - src[i]    )) * demultiply;
+				dst[i + 1] = src[i + 1] == 255 && dGA == 0 ? 255 : min(255, dst[i + 1] / (255 - src[i + 1])) * demultiply;
+				dst[i + 2] = src[i + 2] == 255 && dBA == 0 ? 255 : min(255, dst[i + 2] / (255 - src[i + 2])) * demultiply;
+			},
+
+			'color-burn': function(i) {
+				dst[i] =     src[i]     == 0 && dRA == 0 ? 0 : (1 - min(1, (1 - dRA) / sRA)) * demultiply;
+				dst[i + 1] = src[i + 1] == 0 && dGA == 0 ? 0 : (1 - min(1, (1 - dGA) / sGA)) * demultiply;
+				dst[i + 2] = src[i + 2] == 0 && dBA == 0 ? 0 : (1 - min(1, (1 - dBA) / sBA)) * demultiply;
+			},
+
+			darken: function(i) {
+				dst[i] =     (sRA > dRA ? dRA : sRA) * demultiply;
+				dst[i + 1] = (sGA > dGA ? dGA : sGA) * demultiply;
+				dst[i + 2] = (sBA > dBA ? dBA : sBA) * demultiply;
+			},
+
+			lighten: function(i) {
+				dst[i] =     (sRA < dRA ? dRA : sRA) * demultiply;
+				dst[i + 1] = (sGA < dGA ? dGA : sGA) * demultiply;
+				dst[i + 2] = (sBA < dBA ? dBA : sBA) * demultiply;
+			},
+
+			difference: function(i) {
 				dst[i]     = (sRA + dRA - 2 * min(sRA * dA, dRA * sA)) * demultiply;
 				dst[i + 1] = (sGA + dGA - 2 * min(sGA * dA, dGA * sA)) * demultiply;
 				dst[i + 2] = (sBA + dBA - 2 * min(sBA * dA, dBA * sA)) * demultiply;
-				break;
-			// Slightly different from Photoshop, where alpha is concerned
-			case 'src-in':
+			},
+
+			exclusion: function(i) {
+				dst[i] =     (dRA + sRA - 2 * dRA * sRA) * demultiply;
+				dst[i + 1] = (dGA + sGA - 2 * dGA * sGA) * demultiply;
+				dst[i + 2] = (dBA + sBA - 2 * dBA * sBA) * demultiply;
+			},
+
+			// TODO: Missing: hue, saturation, color, luminosity
+
+			// Not in Illustrator:
+			
+			'src-in': function(i) {
 				// Only differs from Photoshop in low - opacity areas
 				dA2 = sA * dA;
 				demultiply = 255 / dA2;
@@ -108,9 +147,9 @@ var BlendMode = {
 				dst[i]     = sRA * dA * demultiply;
 				dst[i + 1] = sGA * dA * demultiply;
 				dst[i + 2] = sBA * dA * demultiply;
-				break;
-			case 'plus':
-			case 'add':
+			},
+
+			add: function(i) {
 				// Photoshop doesn't simply add the alpha channels; this might be correct wrt SVG 1.2
 				dA2 = min(1, sA + dA);
 				dst[i + 3] = dA2 * 255;
@@ -118,54 +157,25 @@ var BlendMode = {
 				dst[i]     = min(sRA + dRA, 1) * demultiply;
 				dst[i + 1] = min(sGA + dGA, 1) * demultiply;
 				dst[i + 2] = min(sBA + dBA, 1) * demultiply;
-				break;
-			case 'overlay':
-				// Correct for 100% opacity case; colors get clipped as opacity falls
-				dst[i]     = dRA <= 0.5 ? (2 * src[i]     * dRA / dA) : 255 - (2 - 2 * dRA / dA) * (255 - src[i]);
-				dst[i + 1] = dGA <= 0.5 ? (2 * src[i + 1] * dGA / dA) : 255 - (2 - 2 * dGA / dA) * (255 - src[i + 1]);
-				dst[i + 2] = dBA <= 0.5 ? (2 * src[i + 2] * dBA / dA) : 255 - (2 - 2 * dBA / dA) * (255 - src[i + 2]);
-				break;
-			case 'hard-light':
-				dst[i] =     sRA <= 0.5 ? (2 * dst[i]     * sRA / dA) : 255 - (2 - 2 * sRA / sA) * (255 - dst[i]);
-				dst[i + 1] = sGA <= 0.5 ? (2 * dst[i + 1] * sGA / dA) : 255 - (2 - 2 * sGA / sA) * (255 - dst[i + 1]);
-				dst[i + 2] = sBA <= 0.5 ? (2 * dst[i + 2] * sBA / dA) : 255 - (2 - 2 * sBA / sA) * (255 - dst[i + 2]);
-				break;
-			case 'color-dodge':
-			case 'dodge':
-				dst[i] =     src[i]     == 255 && dRA == 0 ? 255 : min(255, dst[i]     / (255 - src[i]    )) * demultiply;
-				dst[i + 1] = src[i + 1] == 255 && dGA == 0 ? 255 : min(255, dst[i + 1] / (255 - src[i + 1])) * demultiply;
-				dst[i + 2] = src[i + 2] == 255 && dBA == 0 ? 255 : min(255, dst[i + 2] / (255 - src[i + 2])) * demultiply;
-				break;
-			case 'color-burn':
-			case 'burn':
-				dst[i] =     src[i]     == 0 && dRA == 0 ? 0 : (1 - min(1, (1 - dRA) / sRA)) * demultiply;
-				dst[i + 1] = src[i + 1] == 0 && dGA == 0 ? 0 : (1 - min(1, (1 - dGA) / sGA)) * demultiply;
-				dst[i + 2] = src[i + 2] == 0 && dBA == 0 ? 0 : (1 - min(1, (1 - dBA) / sBA)) * demultiply;
-				break;
-			case 'darken':
-			case 'darker':
-				dst[i] =     (sRA > dRA ? dRA : sRA) * demultiply;
-				dst[i + 1] = (sGA > dGA ? dGA : sGA) * demultiply;
-				dst[i + 2] = (sBA > dBA ? dBA : sBA) * demultiply;
-				break;
-			case 'lighten':
-			case 'lighter':
-				dst[i] =     (sRA < dRA ? dRA : sRA) * demultiply;
-				dst[i + 1] = (sGA < dGA ? dGA : sGA) * demultiply;
-				dst[i + 2] = (sBA < dBA ? dBA : sBA) * demultiply;
-				break;
-			case 'exclusion':
-				dst[i] =     (dRA + sRA - 2 * dRA * sRA) * demultiply;
-				dst[i + 1] = (dGA + sGA - 2 * dGA * sGA) * demultiply;
-				dst[i + 2] = (dBA + sBA - 2 * dBA * sBA) * demultiply;
-				break;
-			// Unsupported
-			default:
-				dst[i] = dst[i + 3] = 255;
-				dst[i + 1] = i % 8 == 0 ? 255 : 0;
-				dst[i + 2] = i % 8 == 0 ? 0 : 255;
 			}
 		}
+
+		var process = modes[blendMode] || modes.unsupported;
+
+		for (var i = 0, l = dst.length; i < l; i += 4) {
+			sA  = src[i + 3] / 255 * opacity;
+			dA  = dst[i + 3] / 255;
+			dA2 = sA + dA - sA * dA;
+			sRA = src[i] / 255 * sA;
+			dRA = dst[i] / 255 * dA;
+			sGA = src[i + 1] / 255 * sA;
+			dGA = dst[i + 1] / 255 * dA;
+			sBA = src[i + 2] / 255 * sA;
+			dBA = dst[i + 2] / 255 * dA;
+			demultiply = 255 / dA2;
+			process(i);
+			dst[i + 3] = dA2 * 255;
+		}
 		destContext.putImageData(dstD, offset.x, offset.y);
 	}
 };

From 69e989f8343811f4edb0457d49c20d8af88191ec Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 13:42:22 +0100
Subject: [PATCH 03/16] No need to set dst[i + 3] again after changing dA2,
 since we are now only setting it after calling process() from the main loop.

---
 src/util/BlendMode.js | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index c620a14a..bf5e5d70 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -143,22 +143,21 @@ var BlendMode = {
 				// Only differs from Photoshop in low - opacity areas
 				dA2 = sA * dA;
 				demultiply = 255 / dA2;
-				dst[i + 3] = dA2 * 255;
 				dst[i]     = sRA * dA * demultiply;
 				dst[i + 1] = sGA * dA * demultiply;
 				dst[i + 2] = sBA * dA * demultiply;
 			},
 
 			add: function(i) {
-				// Photoshop doesn't simply add the alpha channels; this might be correct wrt SVG 1.2
+				// Photoshop doesn't simply add the alpha channels,
+				// this might be correct wrt SVG 1.2
 				dA2 = min(1, sA + dA);
-				dst[i + 3] = dA2 * 255;
 				demultiply = 255 / dA2;
 				dst[i]     = min(sRA + dRA, 1) * demultiply;
 				dst[i + 1] = min(sGA + dGA, 1) * demultiply;
 				dst[i + 2] = min(sBA + dBA, 1) * demultiply;
 			}
-		}
+		};
 
 		var process = modes[blendMode] || modes.unsupported;
 

From a1d996df05e41d469633e5515b7ec6f5dac1ad7f Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 13:42:34 +0100
Subject: [PATCH 04/16] Clean up formating.

---
 src/util/BlendMode.js | 12 ++++++------
 1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index bf5e5d70..8138bb31 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -94,31 +94,31 @@ var BlendMode = {
 			// TODO: Missing: soft-light
 
 			'hard-light': function(i) {
-				dst[i] =     sRA <= 0.5 ? (2 * dst[i]     * sRA / dA) : 255 - (2 - 2 * sRA / sA) * (255 - dst[i]);
+				dst[i]     = sRA <= 0.5 ? (2 * dst[i]     * sRA / dA) : 255 - (2 - 2 * sRA / sA) * (255 - dst[i]);
 				dst[i + 1] = sGA <= 0.5 ? (2 * dst[i + 1] * sGA / dA) : 255 - (2 - 2 * sGA / sA) * (255 - dst[i + 1]);
 				dst[i + 2] = sBA <= 0.5 ? (2 * dst[i + 2] * sBA / dA) : 255 - (2 - 2 * sBA / sA) * (255 - dst[i + 2]);
 			},
 
 			'color-dodge': function(i) {
-				dst[i] =     src[i]     == 255 && dRA == 0 ? 255 : min(255, dst[i]     / (255 - src[i]    )) * demultiply;
+				dst[i]     = src[i]     == 255 && dRA == 0 ? 255 : min(255, dst[i]     / (255 - src[i]    )) * demultiply;
 				dst[i + 1] = src[i + 1] == 255 && dGA == 0 ? 255 : min(255, dst[i + 1] / (255 - src[i + 1])) * demultiply;
 				dst[i + 2] = src[i + 2] == 255 && dBA == 0 ? 255 : min(255, dst[i + 2] / (255 - src[i + 2])) * demultiply;
 			},
 
 			'color-burn': function(i) {
-				dst[i] =     src[i]     == 0 && dRA == 0 ? 0 : (1 - min(1, (1 - dRA) / sRA)) * demultiply;
+				dst[i]     = src[i]     == 0 && dRA == 0 ? 0 : (1 - min(1, (1 - dRA) / sRA)) * demultiply;
 				dst[i + 1] = src[i + 1] == 0 && dGA == 0 ? 0 : (1 - min(1, (1 - dGA) / sGA)) * demultiply;
 				dst[i + 2] = src[i + 2] == 0 && dBA == 0 ? 0 : (1 - min(1, (1 - dBA) / sBA)) * demultiply;
 			},
 
 			darken: function(i) {
-				dst[i] =     (sRA > dRA ? dRA : sRA) * demultiply;
+				dst[i]     = (sRA > dRA ? dRA : sRA) * demultiply;
 				dst[i + 1] = (sGA > dGA ? dGA : sGA) * demultiply;
 				dst[i + 2] = (sBA > dBA ? dBA : sBA) * demultiply;
 			},
 
 			lighten: function(i) {
-				dst[i] =     (sRA < dRA ? dRA : sRA) * demultiply;
+				dst[i]     = (sRA < dRA ? dRA : sRA) * demultiply;
 				dst[i + 1] = (sGA < dGA ? dGA : sGA) * demultiply;
 				dst[i + 2] = (sBA < dBA ? dBA : sBA) * demultiply;
 			},
@@ -130,7 +130,7 @@ var BlendMode = {
 			},
 
 			exclusion: function(i) {
-				dst[i] =     (dRA + sRA - 2 * dRA * sRA) * demultiply;
+				dst[i]     = (dRA + sRA - 2 * dRA * sRA) * demultiply;
 				dst[i + 1] = (dGA + sGA - 2 * dGA * sGA) * demultiply;
 				dst[i + 2] = (dBA + sBA - 2 * dBA * sBA) * demultiply;
 			},

From 4a9f0d726f1e48b230033b5a2532f9a9618c389d Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 14:00:02 +0100
Subject: [PATCH 05/16] Pre-calculate opacity value.

---
 src/util/BlendMode.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index 8138bb31..4f0300c3 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -53,6 +53,7 @@ var BlendMode = {
 			dst  = dstD.data,
 			min = Math.min,
 			sA, dA, dA2, sRA, sGA, sBA, dRA, dGA, dBA, demultiply;
+			opacity = opacity / 255,
 
 		// TODO: Some blend modes seem broken at the moment, e.g.
 		// dodge, burn
@@ -162,7 +163,7 @@ var BlendMode = {
 		var process = modes[blendMode] || modes.unsupported;
 
 		for (var i = 0, l = dst.length; i < l; i += 4) {
-			sA  = src[i + 3] / 255 * opacity;
+			sA  = src[i + 3] * opacity;
 			dA  = dst[i + 3] / 255;
 			dA2 = sA + dA - sA * dA;
 			sRA = src[i] / 255 * sA;

From b9739aa26a5052c1c076ae61761914e903cfddad Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 14:00:50 +0100
Subject: [PATCH 06/16] Optimise blend mode loop by pre-calculating divisions.

---
 src/util/BlendMode.js | 16 +++++++++-------
 1 file changed, 9 insertions(+), 7 deletions(-)

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index 4f0300c3..d81b81be 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -52,8 +52,8 @@ var BlendMode = {
 			src  = srcD.data,
 			dst  = dstD.data,
 			min = Math.min,
-			sA, dA, dA2, sRA, sGA, sBA, dRA, dGA, dBA, demultiply;
 			opacity = opacity / 255,
+			sA, dA, sAM, dAM, dA2, sRA, sGA, sBA, dRA, dGA, dBA, demultiply;
 
 		// TODO: Some blend modes seem broken at the moment, e.g.
 		// dodge, burn
@@ -166,12 +166,14 @@ var BlendMode = {
 			sA  = src[i + 3] * opacity;
 			dA  = dst[i + 3] / 255;
 			dA2 = sA + dA - sA * dA;
-			sRA = src[i] / 255 * sA;
-			dRA = dst[i] / 255 * dA;
-			sGA = src[i + 1] / 255 * sA;
-			dGA = dst[i + 1] / 255 * dA;
-			sBA = src[i + 2] / 255 * sA;
-			dBA = dst[i + 2] / 255 * dA;
+			sAM = sA / 255;
+			dAM = dA / 255;
+			sRA = src[i] * sAM;
+			dRA = dst[i] * dAM;
+			sGA = src[i + 1] * sAM;
+			dGA = dst[i + 1] * dAM;
+			sBA = src[i + 2] * sAM;
+			dBA = dst[i + 2] * dAM;
 			demultiply = 255 / dA2;
 			process(i);
 			dst[i + 3] = dA2 * 255;

From acecb1a2c1c278afdf4eab92c2346e5cf183925e Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 14:01:22 +0100
Subject: [PATCH 07/16] Clean up variable names.

---
 src/util/BlendMode.js | 11 +++++------
 1 file changed, 5 insertions(+), 6 deletions(-)

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index d81b81be..55b719f2 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -45,12 +45,11 @@ var BlendMode = {
 	// we can easily encorporate changes?
 	process: function(blendMode, sourceContext, destContext, opacity, offset) {
 		var sourceCanvas = sourceContext.canvas,
-			dstD = destContext.getImageData(offset.x, offset.y,
+			dstData = destContext.getImageData(offset.x, offset.y,
 					sourceCanvas.width, sourceCanvas.height),
-			srcD = sourceContext.getImageData(0, 0,
-					sourceCanvas.width, sourceCanvas.height),
-			src  = srcD.data,
-			dst  = dstD.data,
+			dst  = dstData.data,
+			src  = sourceContext.getImageData(0, 0,
+					sourceCanvas.width, sourceCanvas.height).data,
 			min = Math.min,
 			opacity = opacity / 255,
 			sA, dA, sAM, dAM, dA2, sRA, sGA, sBA, dRA, dGA, dBA, demultiply;
@@ -178,6 +177,6 @@ var BlendMode = {
 			process(i);
 			dst[i + 3] = dA2 * 255;
 		}
-		destContext.putImageData(dstD, offset.x, offset.y);
+		destContext.putImageData(dstData, offset.x, offset.y);
 	}
 };

From 117a828b2ba347636e94d8159daccd5398f33ed4 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 14:01:46 +0100
Subject: [PATCH 08/16] Don't set dst[i + 3] directly, set dA2 instead.

---
 src/util/BlendMode.js | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index 55b719f2..f6991095 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -61,7 +61,8 @@ var BlendMode = {
 		var modes = {
 			unsupported: function(i) {
 				// Render checker pattern
-				dst[i] = dst[i + 3] = 255;
+				dA2 = 1;
+				dst[i] = 255;
 				dst[i + 1] = i % 8 == 0 ? 255 : 0;
 				dst[i + 2] = i % 8 == 0 ? 0 : 255;
 			},

From 9fa193d26f372b647c7638b4db8e254586855ea5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 15:31:02 +0100
Subject: [PATCH 09/16] Move opacity precalculation out of variable definition.

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

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index f6991095..6e7b4db8 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -51,7 +51,6 @@ var BlendMode = {
 			src  = sourceContext.getImageData(0, 0,
 					sourceCanvas.width, sourceCanvas.height).data,
 			min = Math.min,
-			opacity = opacity / 255,
 			sA, dA, sAM, dAM, dA2, sRA, sGA, sBA, dRA, dGA, dBA, demultiply;
 
 		// TODO: Some blend modes seem broken at the moment, e.g.
@@ -161,7 +160,7 @@ var BlendMode = {
 		};
 
 		var process = modes[blendMode] || modes.unsupported;
-
+		opacity /= 255;
 		for (var i = 0, l = dst.length; i < l; i += 4) {
 			sA  = src[i + 3] * opacity;
 			dA  = dst[i + 3] / 255;

From 44605433d14c0051f8ab204477eaa7ffbf07c2cd Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 16:34:57 +0100
Subject: [PATCH 10/16] Further shorten and simplify BlendMode cide by having
 process() only process one pixel value at a time.

---
 src/util/BlendMode.js | 123 ++++++++++++++++++------------------------
 1 file changed, 51 insertions(+), 72 deletions(-)

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index 6e7b4db8..79e650d4 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -39,10 +39,6 @@
  */
 
 var BlendMode = {
-	// TODO: Should we remove the blend modes that are not in Scriptographer?
-	// TODO: Add missing blendmodes like hue / saturation / color / luminosity
-	// TODO: Clean up codespacing of original code, or keep it as is, so 
-	// we can easily encorporate changes?
 	process: function(blendMode, sourceContext, destContext, opacity, offset) {
 		var sourceCanvas = sourceContext.canvas,
 			dstData = destContext.getImageData(offset.x, offset.y,
@@ -51,131 +47,114 @@ var BlendMode = {
 			src  = sourceContext.getImageData(0, 0,
 					sourceCanvas.width, sourceCanvas.height).data,
 			min = Math.min,
-			sA, dA, sAM, dAM, dA2, sRA, sGA, sBA, dRA, dGA, dBA, demultiply;
+			sA, dA, rA, sM, dM, demultiply;
 
 		// TODO: Some blend modes seem broken at the moment, e.g.
 		// dodge, burn
-		// TODO: This could be optimised by not diving everything by 255 and
-		// keeping it integer instead, with one divide at the end.
 		var modes = {
-			unsupported: function(i) {
-				// Render checker pattern
-				dA2 = 1;
-				dst[i] = 255;
-				dst[i + 1] = i % 8 == 0 ? 255 : 0;
-				dst[i + 2] = i % 8 == 0 ? 0 : 255;
-			},
-
 			normal: function(i) {
-				dst[i]     = (sRA + dRA - dRA * sA) * demultiply;
-				dst[i + 1] = (sGA + dGA - dGA * sA) * demultiply;
-				dst[i + 2] = (sBA + dBA - dBA * sA) * demultiply;
+				var s = src[i] * sM, d = dst[i] * dM;
+				dst[i] = (s + d * (1 - sA)) * demultiply;
 			},
 
 			multiply: function(i) {
-				dst[i]     = (sRA * dRA + sRA * (1 - dA) + dRA * (1 - sA)) * demultiply;
-				dst[i + 1] = (sGA * dGA + sGA * (1 - dA) + dGA * (1 - sA)) * demultiply;
-				dst[i + 2] = (sBA * dBA + sBA * (1 - dA) + dBA * (1 - sA)) * demultiply;
+				var s = src[i] * sM, d = dst[i] * dM;
+				dst[i] = (s * d + s * (1 - dA) + d * (1 - sA)) * demultiply;
 			},
 
 			screen: function(i) {
-				dst[i]     = (sRA + dRA - sRA * dRA) * demultiply;
-				dst[i + 1] = (sGA + dGA - sGA * dGA) * demultiply;
-				dst[i + 2] = (sBA + dBA - sBA * dBA) * demultiply;
+				var s = src[i] * sM, d = dst[i] * dM;
+				dst[i] = (s * (1 - d) + d) * demultiply;
 			},
 
 			overlay: function(i) {
 				// Correct for 100% opacity case; colors get clipped as opacity falls
-				dst[i]     = dRA <= 0.5 ? (2 * src[i]     * dRA / dA) : 255 - (2 - 2 * dRA / dA) * (255 - src[i]);
-				dst[i + 1] = dGA <= 0.5 ? (2 * src[i + 1] * dGA / dA) : 255 - (2 - 2 * dGA / dA) * (255 - src[i + 1]);
-				dst[i + 2] = dBA <= 0.5 ? (2 * src[i + 2] * dBA / dA) : 255 - (2 - 2 * dBA / dA) * (255 - src[i + 2]);
+				var s = src[i], d = dst[i] * dM; // src is unmultiplied
+				dst[i] = d <= 0.5 ? (2 * s * d / dA) : 255 - (2 - 2 * d / dA) * (255 - s);
 			},
 
 			// TODO: Missing: soft-light
 
 			'hard-light': function(i) {
-				dst[i]     = sRA <= 0.5 ? (2 * dst[i]     * sRA / dA) : 255 - (2 - 2 * sRA / sA) * (255 - dst[i]);
-				dst[i + 1] = sGA <= 0.5 ? (2 * dst[i + 1] * sGA / dA) : 255 - (2 - 2 * sGA / sA) * (255 - dst[i + 1]);
-				dst[i + 2] = sBA <= 0.5 ? (2 * dst[i + 2] * sBA / dA) : 255 - (2 - 2 * sBA / sA) * (255 - dst[i + 2]);
+				var s = src[i] * sM, d = dst[i]; // dst is unmultiplied
+				dst[i] = s <= 0.5 ? (2 * d * s / dA) : 255 - (2 - 2 * s / sA) * (255 - d);
 			},
 
 			'color-dodge': function(i) {
-				dst[i]     = src[i]     == 255 && dRA == 0 ? 255 : min(255, dst[i]     / (255 - src[i]    )) * demultiply;
-				dst[i + 1] = src[i + 1] == 255 && dGA == 0 ? 255 : min(255, dst[i + 1] / (255 - src[i + 1])) * demultiply;
-				dst[i + 2] = src[i + 2] == 255 && dBA == 0 ? 255 : min(255, dst[i + 2] / (255 - src[i + 2])) * demultiply;
+				var s = src[i], d = dst[i]; // both unmultiplied
+				dst[i] = s == 255 && d * dM == 0 ? 255 : min(255, d / (255 - s)) * demultiply;
 			},
 
 			'color-burn': function(i) {
-				dst[i]     = src[i]     == 0 && dRA == 0 ? 0 : (1 - min(1, (1 - dRA) / sRA)) * demultiply;
-				dst[i + 1] = src[i + 1] == 0 && dGA == 0 ? 0 : (1 - min(1, (1 - dGA) / sGA)) * demultiply;
-				dst[i + 2] = src[i + 2] == 0 && dBA == 0 ? 0 : (1 - min(1, (1 - dBA) / sBA)) * demultiply;
+				var s = src[i] * sM, d = dst[i] * dM;
+				dst[i] = src[i] == 0 && d == 0 ? 0 : (1 - min(1, (1 - d) / s)) * demultiply;
 			},
 
 			darken: function(i) {
-				dst[i]     = (sRA > dRA ? dRA : sRA) * demultiply;
-				dst[i + 1] = (sGA > dGA ? dGA : sGA) * demultiply;
-				dst[i + 2] = (sBA > dBA ? dBA : sBA) * demultiply;
+				var s = src[i] * sM, d = dst[i] * dM;
+				dst[i] = (s > d ? d : s) * demultiply;
 			},
 
 			lighten: function(i) {
-				dst[i]     = (sRA < dRA ? dRA : sRA) * demultiply;
-				dst[i + 1] = (sGA < dGA ? dGA : sGA) * demultiply;
-				dst[i + 2] = (sBA < dBA ? dBA : sBA) * demultiply;
+				var s = src[i] * sM, d = dst[i] * dM;
+				dst[i] = (s < d ? d : s) * demultiply;
 			},
 
 			difference: function(i) {
-				dst[i]     = (sRA + dRA - 2 * min(sRA * dA, dRA * sA)) * demultiply;
-				dst[i + 1] = (sGA + dGA - 2 * min(sGA * dA, dGA * sA)) * demultiply;
-				dst[i + 2] = (sBA + dBA - 2 * min(sBA * dA, dBA * sA)) * demultiply;
+				var s = src[i] * sM, d = dst[i] * dM;
+				dst[i] = (s + d - 2 * min(s * dA, d * sA)) * demultiply;
 			},
 
 			exclusion: function(i) {
-				dst[i]     = (dRA + sRA - 2 * dRA * sRA) * demultiply;
-				dst[i + 1] = (dGA + sGA - 2 * dGA * sGA) * demultiply;
-				dst[i + 2] = (dBA + sBA - 2 * dBA * sBA) * demultiply;
+				var s = src[i] * sM, d = dst[i] * dM;
+				dst[i] = (d + s - 2 * d * s) * demultiply;
 			},
 
 			// TODO: Missing: hue, saturation, color, luminosity
 
-			// Not in Illustrator:
-			
+			// TODO: Not in Illustrator. Remove these?
 			'src-in': function(i) {
 				// Only differs from Photoshop in low - opacity areas
-				dA2 = sA * dA;
-				demultiply = 255 / dA2;
-				dst[i]     = sRA * dA * demultiply;
-				dst[i + 1] = sGA * dA * demultiply;
-				dst[i + 2] = sBA * dA * demultiply;
+				dst[i] = sRA * dA * demultiply;
 			},
 
 			add: function(i) {
 				// Photoshop doesn't simply add the alpha channels,
 				// this might be correct wrt SVG 1.2
-				dA2 = min(1, sA + dA);
-				demultiply = 255 / dA2;
-				dst[i]     = min(sRA + dRA, 1) * demultiply;
-				dst[i + 1] = min(sGA + dGA, 1) * demultiply;
-				dst[i + 2] = min(sBA + dBA, 1) * demultiply;
+				dst[i] = min(sRA + dRA, 1) * demultiply;
 			}
 		};
 
-		var process = modes[blendMode] || modes.unsupported;
+		var alphas = {
+			'src-in': function(sA, dA) {
+				return sA * dA;
+			},
+
+			add: function(sA, dA) {
+				return min(1, sA + dA);
+			}
+		};
+
+		var process = modes[blendMode];
+		var alpha = alphas[blendMode];
+		if (!process)
+			return;
+		// Divide opacity by 255 so it can be multiplied straight into pixel
+		// values to get 0 .. 1 range.
 		opacity /= 255;
 		for (var i = 0, l = dst.length; i < l; i += 4) {
 			sA  = src[i + 3] * opacity;
 			dA  = dst[i + 3] / 255;
-			dA2 = sA + dA - sA * dA;
-			sAM = sA / 255;
-			dAM = dA / 255;
-			sRA = src[i] * sAM;
-			dRA = dst[i] * dAM;
-			sGA = src[i + 1] * sAM;
-			dGA = dst[i + 1] * dAM;
-			sBA = src[i + 2] * sAM;
-			dBA = dst[i + 2] * dAM;
-			demultiply = 255 / dA2;
+			// Result alpha:
+			rA = alpha ? alpha(sA, dA) : sA + dA - sA * dA;
+			demultiply = 255 / rA;
+			// Multipliers:
+			sM = sA / 255;
+			dM = dA / 255;
 			process(i);
-			dst[i + 3] = dA2 * 255;
+			process(i + 1);
+			process(i + 2);
+			dst[i + 3] = rA * 255;
 		}
 		destContext.putImageData(dstData, offset.x, offset.y);
 	}

From 62f5204810d1aae143260301c827260df5f1c0a2 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 16:45:42 +0100
Subject: [PATCH 11/16] Shorten variable names.

---
 src/util/BlendMode.js | 26 +++++++++++++-------------
 1 file changed, 13 insertions(+), 13 deletions(-)

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index 79e650d4..1a18eb43 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -47,24 +47,24 @@ var BlendMode = {
 			src  = sourceContext.getImageData(0, 0,
 					sourceCanvas.width, sourceCanvas.height).data,
 			min = Math.min,
-			sA, dA, rA, sM, dM, demultiply;
+			sA, dA, rA, sM, dM, rM;
 
 		// TODO: Some blend modes seem broken at the moment, e.g.
 		// dodge, burn
 		var modes = {
 			normal: function(i) {
 				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = (s + d * (1 - sA)) * demultiply;
+				dst[i] = (s + d * (1 - sA)) * rM;
 			},
 
 			multiply: function(i) {
 				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = (s * d + s * (1 - dA) + d * (1 - sA)) * demultiply;
+				dst[i] = (s * d + s * (1 - dA) + d * (1 - sA)) * rM;
 			},
 
 			screen: function(i) {
 				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = (s * (1 - d) + d) * demultiply;
+				dst[i] = (s * (1 - d) + d) * rM;
 			},
 
 			overlay: function(i) {
@@ -82,32 +82,32 @@ var BlendMode = {
 
 			'color-dodge': function(i) {
 				var s = src[i], d = dst[i]; // both unmultiplied
-				dst[i] = s == 255 && d * dM == 0 ? 255 : min(255, d / (255 - s)) * demultiply;
+				dst[i] = s == 255 && d * dM == 0 ? 255 : min(255, d / (255 - s)) * rM;
 			},
 
 			'color-burn': function(i) {
 				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = src[i] == 0 && d == 0 ? 0 : (1 - min(1, (1 - d) / s)) * demultiply;
+				dst[i] = src[i] == 0 && d == 0 ? 0 : (1 - min(1, (1 - d) / s)) * rM;
 			},
 
 			darken: function(i) {
 				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = (s > d ? d : s) * demultiply;
+				dst[i] = (s > d ? d : s) * rM;
 			},
 
 			lighten: function(i) {
 				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = (s < d ? d : s) * demultiply;
+				dst[i] = (s < d ? d : s) * rM;
 			},
 
 			difference: function(i) {
 				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = (s + d - 2 * min(s * dA, d * sA)) * demultiply;
+				dst[i] = (s + d - 2 * min(s * dA, d * sA)) * rM;
 			},
 
 			exclusion: function(i) {
 				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = (d + s - 2 * d * s) * demultiply;
+				dst[i] = (d + s - 2 * d * s) * rM;
 			},
 
 			// TODO: Missing: hue, saturation, color, luminosity
@@ -115,13 +115,13 @@ var BlendMode = {
 			// TODO: Not in Illustrator. Remove these?
 			'src-in': function(i) {
 				// Only differs from Photoshop in low - opacity areas
-				dst[i] = sRA * dA * demultiply;
+				dst[i] = sRA * dA * rM;
 			},
 
 			add: function(i) {
 				// Photoshop doesn't simply add the alpha channels,
 				// this might be correct wrt SVG 1.2
-				dst[i] = min(sRA + dRA, 1) * demultiply;
+				dst[i] = min(sRA + dRA, 1) * rM;
 			}
 		};
 
@@ -147,7 +147,7 @@ var BlendMode = {
 			dA  = dst[i + 3] / 255;
 			// Result alpha:
 			rA = alpha ? alpha(sA, dA) : sA + dA - sA * dA;
-			demultiply = 255 / rA;
+			rM = 255 / rA;
 			// Multipliers:
 			sM = sA / 255;
 			dM = dA / 255;

From 9142c974c35140d1d9a0e248a53b7ec6a338f0b9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 16:49:48 +0100
Subject: [PATCH 12/16] Revert to longer version of blend mode code as it is
 faster.

---
 src/util/BlendMode.js | 114 ++++++++++++++++++++++++------------------
 1 file changed, 64 insertions(+), 50 deletions(-)

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index 1a18eb43..96c6cc27 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -47,113 +47,127 @@ var BlendMode = {
 			src  = sourceContext.getImageData(0, 0,
 					sourceCanvas.width, sourceCanvas.height).data,
 			min = Math.min,
-			sA, dA, rA, sM, dM, rM;
+			sA, dA, rA, sM, dM, rM, sRA, sGA, sBA, dRA, dGA, dBA;
 
-		// TODO: Some blend modes seem broken at the moment, e.g.
-		// dodge, burn
+		// TODO: Some blend modes seem broken at the moment, e.g. dodge, burn
 		var modes = {
+			unsupported: function(i) {
+				// Render checker pattern
+				rA = 1;
+				dst[i] = 255;
+				dst[i + 1] = i % 8 == 0 ? 255 : 0;
+				dst[i + 2] = i % 8 == 0 ? 0 : 255;
+			},
+
 			normal: function(i) {
-				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = (s + d * (1 - sA)) * rM;
+				dst[i]     = (sRA + dRA - dRA * sA) * rM;
+				dst[i + 1] = (sGA + dGA - dGA * sA) * rM;
+				dst[i + 2] = (sBA + dBA - dBA * sA) * rM;
 			},
 
 			multiply: function(i) {
-				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = (s * d + s * (1 - dA) + d * (1 - sA)) * rM;
+				dst[i]     = (sRA * dRA + sRA * (1 - dA) + dRA * (1 - sA)) * rM;
+				dst[i + 1] = (sGA * dGA + sGA * (1 - dA) + dGA * (1 - sA)) * rM;
+				dst[i + 2] = (sBA * dBA + sBA * (1 - dA) + dBA * (1 - sA)) * rM;
 			},
 
 			screen: function(i) {
-				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = (s * (1 - d) + d) * rM;
+				dst[i]     = (sRA + dRA - sRA * dRA) * rM;
+				dst[i + 1] = (sGA + dGA - sGA * dGA) * rM;
+				dst[i + 2] = (sBA + dBA - sBA * dBA) * rM;
 			},
 
 			overlay: function(i) {
 				// Correct for 100% opacity case; colors get clipped as opacity falls
-				var s = src[i], d = dst[i] * dM; // src is unmultiplied
-				dst[i] = d <= 0.5 ? (2 * s * d / dA) : 255 - (2 - 2 * d / dA) * (255 - s);
+				dst[i]     = dRA <= 0.5 ? (2 * src[i]     * dRA / dA) : 255 - (2 - 2 * dRA / dA) * (255 - src[i]);
+				dst[i + 1] = dGA <= 0.5 ? (2 * src[i + 1] * dGA / dA) : 255 - (2 - 2 * dGA / dA) * (255 - src[i + 1]);
+				dst[i + 2] = dBA <= 0.5 ? (2 * src[i + 2] * dBA / dA) : 255 - (2 - 2 * dBA / dA) * (255 - src[i + 2]);
 			},
 
 			// TODO: Missing: soft-light
 
 			'hard-light': function(i) {
-				var s = src[i] * sM, d = dst[i]; // dst is unmultiplied
-				dst[i] = s <= 0.5 ? (2 * d * s / dA) : 255 - (2 - 2 * s / sA) * (255 - d);
+				dst[i]     = sRA <= 0.5 ? (2 * dst[i]     * sRA / dA) : 255 - (2 - 2 * sRA / sA) * (255 - dst[i]);
+				dst[i + 1] = sGA <= 0.5 ? (2 * dst[i + 1] * sGA / dA) : 255 - (2 - 2 * sGA / sA) * (255 - dst[i + 1]);
+				dst[i + 2] = sBA <= 0.5 ? (2 * dst[i + 2] * sBA / dA) : 255 - (2 - 2 * sBA / sA) * (255 - dst[i + 2]);
 			},
 
 			'color-dodge': function(i) {
-				var s = src[i], d = dst[i]; // both unmultiplied
-				dst[i] = s == 255 && d * dM == 0 ? 255 : min(255, d / (255 - s)) * rM;
+				dst[i]     = src[i]     == 255 && dRA == 0 ? 255 : min(255, dst[i]     / (255 - src[i]    )) * rM;
+				dst[i + 1] = src[i + 1] == 255 && dGA == 0 ? 255 : min(255, dst[i + 1] / (255 - src[i + 1])) * rM;
+				dst[i + 2] = src[i + 2] == 255 && dBA == 0 ? 255 : min(255, dst[i + 2] / (255 - src[i + 2])) * rM;
 			},
 
 			'color-burn': function(i) {
-				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = src[i] == 0 && d == 0 ? 0 : (1 - min(1, (1 - d) / s)) * rM;
+				dst[i]     = src[i]     == 0 && dRA == 0 ? 0 : (1 - min(1, (1 - dRA) / sRA)) * rM;
+				dst[i + 1] = src[i + 1] == 0 && dGA == 0 ? 0 : (1 - min(1, (1 - dGA) / sGA)) * rM;
+				dst[i + 2] = src[i + 2] == 0 && dBA == 0 ? 0 : (1 - min(1, (1 - dBA) / sBA)) * rM;
 			},
 
 			darken: function(i) {
-				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = (s > d ? d : s) * rM;
+				dst[i]     = (sRA > dRA ? dRA : sRA) * rM;
+				dst[i + 1] = (sGA > dGA ? dGA : sGA) * rM;
+				dst[i + 2] = (sBA > dBA ? dBA : sBA) * rM;
 			},
 
 			lighten: function(i) {
-				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = (s < d ? d : s) * rM;
+				dst[i]     = (sRA < dRA ? dRA : sRA) * rM;
+				dst[i + 1] = (sGA < dGA ? dGA : sGA) * rM;
+				dst[i + 2] = (sBA < dBA ? dBA : sBA) * rM;
 			},
 
 			difference: function(i) {
-				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = (s + d - 2 * min(s * dA, d * sA)) * rM;
+				dst[i]     = (sRA + dRA - 2 * min(sRA * dA, dRA * sA)) * rM;
+				dst[i + 1] = (sGA + dGA - 2 * min(sGA * dA, dGA * sA)) * rM;
+				dst[i + 2] = (sBA + dBA - 2 * min(sBA * dA, dBA * sA)) * rM;
 			},
 
 			exclusion: function(i) {
-				var s = src[i] * sM, d = dst[i] * dM;
-				dst[i] = (d + s - 2 * d * s) * rM;
+				dst[i]     = (dRA + sRA - 2 * dRA * sRA) * rM;
+				dst[i + 1] = (dGA + sGA - 2 * dGA * sGA) * rM;
+				dst[i + 2] = (dBA + sBA - 2 * dBA * sBA) * rM;
 			},
 
 			// TODO: Missing: hue, saturation, color, luminosity
 
-			// TODO: Not in Illustrator. Remove these?
+			// Not in Illustrator:
+			
 			'src-in': function(i) {
 				// Only differs from Photoshop in low - opacity areas
-				dst[i] = sRA * dA * rM;
+				rA = sA * dA;
+				rM = 255 / rA;
+				dst[i]     = sRA * dA * rM;
+				dst[i + 1] = sGA * dA * rM;
+				dst[i + 2] = sBA * dA * rM;
 			},
 
 			add: function(i) {
 				// Photoshop doesn't simply add the alpha channels,
 				// this might be correct wrt SVG 1.2
-				dst[i] = min(sRA + dRA, 1) * rM;
+				rA = min(1, sA + dA);
+				rM = 255 / rA;
+				dst[i]     = min(sRA + dRA, 1) * rM;
+				dst[i + 1] = min(sGA + dGA, 1) * rM;
+				dst[i + 2] = min(sBA + dBA, 1) * rM;
 			}
 		};
 
-		var alphas = {
-			'src-in': function(sA, dA) {
-				return sA * dA;
-			},
-
-			add: function(sA, dA) {
-				return min(1, sA + dA);
-			}
-		};
-
-		var process = modes[blendMode];
-		var alpha = alphas[blendMode];
-		if (!process)
-			return;
-		// Divide opacity by 255 so it can be multiplied straight into pixel
-		// values to get 0 .. 1 range.
+		var process = modes[blendMode] || modes.unsupported;
 		opacity /= 255;
 		for (var i = 0, l = dst.length; i < l; i += 4) {
 			sA  = src[i + 3] * opacity;
 			dA  = dst[i + 3] / 255;
-			// Result alpha:
-			rA = alpha ? alpha(sA, dA) : sA + dA - sA * dA;
-			rM = 255 / rA;
-			// Multipliers:
+			rA = sA + dA - sA * dA;
 			sM = sA / 255;
 			dM = dA / 255;
+			sRA = src[i] * sM;
+			dRA = dst[i] * dM;
+			sGA = src[i + 1] * sM;
+			dGA = dst[i + 1] * dM;
+			sBA = src[i + 2] * sM;
+			dBA = dst[i + 2] * dM;
+			rM = 255 / rA;
 			process(i);
-			process(i + 1);
-			process(i + 2);
 			dst[i + 3] = rA * 255;
 		}
 		destContext.putImageData(dstData, offset.x, offset.y);

From b08abcdd6933f802d7d9f55e9467845344aee9fb Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 16:50:14 +0100
Subject: [PATCH 13/16] Remove 'unsupported' blend mode.

---
 src/util/BlendMode.js | 12 +++---------
 1 file changed, 3 insertions(+), 9 deletions(-)

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index 96c6cc27..ded19181 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -51,14 +51,6 @@ var BlendMode = {
 
 		// TODO: Some blend modes seem broken at the moment, e.g. dodge, burn
 		var modes = {
-			unsupported: function(i) {
-				// Render checker pattern
-				rA = 1;
-				dst[i] = 255;
-				dst[i + 1] = i % 8 == 0 ? 255 : 0;
-				dst[i + 2] = i % 8 == 0 ? 0 : 255;
-			},
-
 			normal: function(i) {
 				dst[i]     = (sRA + dRA - dRA * sA) * rM;
 				dst[i + 1] = (sGA + dGA - dGA * sA) * rM;
@@ -152,7 +144,9 @@ var BlendMode = {
 			}
 		};
 
-		var process = modes[blendMode] || modes.unsupported;
+		var process = modes[blendMode];
+		if (!process)
+			return;
 		opacity /= 255;
 		for (var i = 0, l = dst.length; i < l; i += 4) {
 			sA  = src[i + 3] * opacity;

From 8bbb3744fe33a299329a85c79fc8428aa57a3b69 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 17:09:32 +0100
Subject: [PATCH 14/16] Use min() / max() in darken / lighten for shorter code.

---
 src/util/BlendMode.js | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index ded19181..bf0f153d 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -47,6 +47,7 @@ var BlendMode = {
 			src  = sourceContext.getImageData(0, 0,
 					sourceCanvas.width, sourceCanvas.height).data,
 			min = Math.min,
+			max = Math.max,
 			sA, dA, rA, sM, dM, rM, sRA, sGA, sBA, dRA, dGA, dBA;
 
 		// TODO: Some blend modes seem broken at the moment, e.g. dodge, burn
@@ -97,15 +98,15 @@ var BlendMode = {
 			},
 
 			darken: function(i) {
-				dst[i]     = (sRA > dRA ? dRA : sRA) * rM;
-				dst[i + 1] = (sGA > dGA ? dGA : sGA) * rM;
-				dst[i + 2] = (sBA > dBA ? dBA : sBA) * rM;
+				dst[i]     = min(sRA, dRA) * rM;
+				dst[i + 1] = min(sGA, dGA) * rM;
+				dst[i + 2] = min(sBA, dBA) * rM;
 			},
 
 			lighten: function(i) {
-				dst[i]     = (sRA < dRA ? dRA : sRA) * rM;
-				dst[i + 1] = (sGA < dGA ? dGA : sGA) * rM;
-				dst[i + 2] = (sBA < dBA ? dBA : sBA) * rM;
+				dst[i]     = max(sRA, dRA) * rM;
+				dst[i + 1] = max(sGA, dGA) * rM;
+				dst[i + 2] = max(sBA, dBA) * rM;
 			},
 
 			difference: function(i) {

From 3850e4a53b9e3ee6296455b5bd79a07d9944f789 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 17:10:40 +0100
Subject: [PATCH 15/16] Optimise code for normal and multiply blend modes by
 precalculating values.

---
 src/util/BlendMode.js | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index bf0f153d..b1b20a02 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -53,15 +53,17 @@ var BlendMode = {
 		// TODO: Some blend modes seem broken at the moment, e.g. dodge, burn
 		var modes = {
 			normal: function(i) {
-				dst[i]     = (sRA + dRA - dRA * sA) * rM;
-				dst[i + 1] = (sGA + dGA - dGA * sA) * rM;
-				dst[i + 2] = (sBA + dBA - dBA * sA) * rM;
+				var sA1 = 1 - sA;
+				dst[i]     = (sRA + dRA * sA1) * rM;
+				dst[i + 1] = (sGA + dGA * sA1) * rM;
+				dst[i + 2] = (sBA + dRA * sA1) * rM;
 			},
 
 			multiply: function(i) {
-				dst[i]     = (sRA * dRA + sRA * (1 - dA) + dRA * (1 - sA)) * rM;
-				dst[i + 1] = (sGA * dGA + sGA * (1 - dA) + dGA * (1 - sA)) * rM;
-				dst[i + 2] = (sBA * dBA + sBA * (1 - dA) + dBA * (1 - sA)) * rM;
+				var sA1 = 1 - sA, dA1 = 1 - dA;
+				dst[i]     = (sRA * dRA + sRA * dA1 + dRA * sA1) * rM;
+				dst[i + 1] = (sGA * dGA + sGA * dA1 + dGA * sA1) * rM;
+				dst[i + 2] = (sBA * dBA + sBA * dA1 + dBA * sA1) * rM;
 			},
 
 			screen: function(i) {

From f58aa2a23be3a571be879c97b8d7e4bb214ca051 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?J=C3=BCrg=20Lehni?= <juerg@scratchdisk.com>
Date: Wed, 1 Jun 2011 17:11:06 +0100
Subject: [PATCH 16/16] Add comment about overlay mode being the reverse of
 hard-light.

---
 src/util/BlendMode.js | 1 +
 1 file changed, 1 insertion(+)

diff --git a/src/util/BlendMode.js b/src/util/BlendMode.js
index b1b20a02..b5fc7d11 100644
--- a/src/util/BlendMode.js
+++ b/src/util/BlendMode.js
@@ -73,6 +73,7 @@ var BlendMode = {
 			},
 
 			overlay: function(i) {
+				// = Reverse of hard-light
 				// Correct for 100% opacity case; colors get clipped as opacity falls
 				dst[i]     = dRA <= 0.5 ? (2 * src[i]     * dRA / dA) : 255 - (2 - 2 * dRA / dA) * (255 - src[i]);
 				dst[i + 1] = dGA <= 0.5 ? (2 * src[i + 1] * dGA / dA) : 255 - (2 - 2 * dGA / dA) * (255 - src[i + 1]);