diff --git a/ChangeLog b/ChangeLog
index c475ea87c..f661f5c2f 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,11 @@
+2009-12-12 Eric Wasylishen <ewasylishen@gmail.com>
+
+	* Source/NSBitmapImageRep.m:
+	* Source/GSThemeTools.m: 
+	Change the colorAtX:y: and related methods in NSBitmapImageRep
+	to use flipped coordinates, matching OS X. colorAtX:0 y:0 now 
+	returns the top-left pixel instead of the bottom left.
+
 2009-12-12 Fred Kiefer <FredKiefer@gmx.de>
 
 	* Source/NSApplication (-setWindowsMenu:): Only add windows that 
diff --git a/Source/GSThemeTools.m b/Source/GSThemeTools.m
index af5d0e007..d931d4c2a 100644
--- a/Source/GSThemeTools.m
+++ b/Source/GSThemeTools.m
@@ -791,7 +791,7 @@ withRepeatedImage: (NSImage*)image
 
   for (i = 0; i < s.width; i++)
     {
-      NSColor	*pixelColor = [rep colorAtX: i y: s.height - 1];
+      NSColor	*pixelColor = [rep colorAtX: i y: 0];
 
       [pixelColor getRed: &r green: &g blue: &b alpha: &a];
       if (a > 0 && x1 == -1)
diff --git a/Source/NSBitmapImageRep.m b/Source/NSBitmapImageRep.m
index c10b045d0..49ab821e7 100644
--- a/Source/NSBitmapImageRep.m
+++ b/Source/NSBitmapImageRep.m
@@ -756,6 +756,10 @@ _get_bit_value(unsigned char *base, long msb_off, int bit_width)
   return value & ((1<<bit_width)-1);
 }
 
+/**
+ * Returns the values of the components of pixel (x,y), where (0,0) is the 
+ * top-left pixel in the image, by storing them in the array pixelData.
+ */
 - (void) getPixel: (unsigned int[])pixelData atX: (int)x y: (int)y
 {
   int i;
@@ -768,9 +772,7 @@ _get_bit_value(unsigned char *base, long msb_off, int bit_width)
       return;
     }
 
-  // FIXME: The y value is taken from the bottom of the image. 
-  // Not sure if this is correct.
-  line_offset = _bytesPerRow * (_pixelsHigh - 1 - y);
+  line_offset = _bytesPerRow * y;
   if (_isPlanar)
     {
       if (_bitsPerSample == 8)
@@ -847,6 +849,10 @@ _set_bit_value(unsigned char *base, long msb_off, int bit_width,
   base[byte2] = (value & 255) | (base[byte2] ^ (all & 255));
 }
 
+/**
+ * Sets the components of pixel (x,y), where (0,0) is the top-left pixel in
+ * the image, to the given array of pixel components. 
+ */
 - (void) setPixel: (unsigned int[])pixelData atX: (int)x y: (int)y
 {
   int i;
@@ -865,9 +871,7 @@ _set_bit_value(unsigned char *base, long msb_off, int bit_width,
       [self bitmapData];
     }
 
-  // FIXME: The y value is taken from the bottom of the image. 
-  // Not sure if this is correct.
-  line_offset = _bytesPerRow * (_pixelsHigh - 1 - y);
+  line_offset = _bytesPerRow * y;
   if(_isPlanar)
     {
       if (_bitsPerSample == 8)
@@ -911,6 +915,10 @@ _set_bit_value(unsigned char *base, long msb_off, int bit_width,
     }
 }
 
+/**
+ * Returns an NSColor object representing the color of the pixel (x,y), where
+ * (0,0) is the top-left pixel in the image.
+ */
 - (NSColor*) colorAtX: (int)x y: (int)y
 {
 	unsigned int pixelData[5];
@@ -1159,6 +1167,10 @@ _set_bit_value(unsigned char *base, long msb_off, int bit_width,
 	return nil;
 }
 
+/**
+ * Sets the color of pixel (x,y), where (0,0) is the top-left pixel in the
+ * image.
+ */
 - (void) setColor: (NSColor*)color atX: (int)x y: (int)y
 {
 	unsigned int pixelData[5];