Fixes for 18029 and 16723 -- fix image drawing on Mac to use GWorlds, and put in api to lock and unlock pixels. r=pnunn, a=chofmann.

gfx/public/nsIImage.h

@@ -105,10 +105,18 @@ public:
   /**
    * Get the number of bytes needed to get to the next scanline for the pixelmap
    * @update - dwc 2/1/99
-   @return The number of bytes in each scanline
+   * @return The number of bytes in each scanline
    */
   virtual PRInt32 GetLineStride() = 0;
 
+  /**
+   * Get whether this image has an alpha mask. Preferable to testing
+   * if GetAlphaBits() is non-null.
+   * @update - sfraser 10/19/99
+   * @return PR_TRUE if the image has an alpha mask, PR_FALSE otherwise
+   */
+  virtual PRBool GetHasAlphaMask() = 0;
+
   /**
    * Get a pointer to the bits for the alpha mask
    * @update - dwc 2/1/99
@@ -217,6 +225,34 @@ public:
    */
   virtual void* GetBitInfo() = 0;
 
+
+  /**
+   * LockImagePixels
+   * Lock the image pixels so that we can access them directly,
+   * with safely. May be a noop on some platforms.
+   *
+   * aMaskPixels = PR_TRUE for the mask, PR_FALSE for the image
+   *
+   * Must be balanced by a call to UnlockImagePixels().
+   *
+   * @update - sfraser 10/18/99
+   * @return error result
+   */
+  NS_IMETHOD LockImagePixels(PRBool aMaskPixels) = 0;
+  
+  /**
+   * UnlockImagePixels
+   * Unlock the image pixels. May be a noop on some platforms.
+   *
+   * Should balance an earlier call to LockImagePixels().
+   *
+   * aMaskPixels = PR_TRUE for the mask, PR_FALSE for the image
+   *
+   * @update - sfraser 10/18/99
+   * @return error result
+   */
+  NS_IMETHOD UnlockImagePixels(PRBool aMaskPixels) = 0;
+  
   //get the color space metrics for this image
   //virtual NI_ColorSpec * GetColorSpec() = 0;                       fix
 
@@ -224,7 +260,7 @@ public:
   //if this image is color mapped, this value will be an
   //index into the color map. hokey? yes, but it avoids
   //another silly api or struct.
-  //virtual nscolor GetTransparentColor() = 0;                              fix.
+  //virtual nscolor GetTransparentColor() = 0;                       fix.
 };
 
 //change notification API flag bits

gfx/src/beos/nsImageBeOS.cpp

@@ -463,3 +463,19 @@ nsresult nsImageBeOS::Optimize(nsIDeviceContext* aContext)
   mStaticImage = PR_TRUE;
   return NS_OK;
 }
+
+//------------------------------------------------------------
+// lock the image pixels. Implement this if you need it.
+NS_IMETHODIMP
+nsImageBeOS::LockImagePixels(PRBool aMaskPixels)
+{
+  return NS_OK;
+}
+
+//------------------------------------------------------------
+// unlock the image pixels.  Implement this if you need it.
+NS_IMETHODIMP
+nsImageBeOS::UnlockImagePixels(PRBool aMaskPixels)
+{
+  return NS_OK;
+}

gfx/src/beos/nsImageBeOS.h

@@ -43,6 +43,8 @@ public:
   virtual void*       GetBitInfo();
   virtual PRInt32     GetLineStride();
   virtual nsColorMap* GetColorMap();
+  virtual PRBool      GetHasAlphaMask()     { return mAlphaBits != nsnull; }        
+
   NS_IMETHOD Draw(nsIRenderingContext &aContext,
                   nsDrawingSurface aSurface,
                   PRInt32 aX, PRInt32 aY,
@@ -76,6 +78,9 @@ public:
   virtual PRInt32 GetAlphaLevel();
   virtual void  MoveAlphaMask(PRInt32 aX, PRInt32 aY);
 
+  NS_IMETHOD   LockImagePixels(PRBool aMaskPixels);
+  NS_IMETHOD   UnlockImagePixels(PRBool aMaskPixels);    
+
 private:
   /**
    * Calculate the amount of memory needed for the initialization of the image

gfx/src/gtk/nsImageGTK.cpp

@@ -599,3 +599,19 @@ nsresult nsImageGTK::Optimize(nsIDeviceContext* aContext)
 {
   return NS_OK;
 }
+
+//------------------------------------------------------------
+// lock the image pixels. nothing to do on gtk
+NS_IMETHODIMP
+nsImageGTK::LockImagePixels(PRBool aMaskPixels)
+{
+  return NS_OK;
+}
+
+//------------------------------------------------------------
+// unlock the image pixels. nothing to do on gtk
+NS_IMETHODIMP
+nsImageGTK::UnlockImagePixels(PRBool aMaskPixels)
+{
+  return NS_OK;
+} 

gfx/src/gtk/nsImageGTK.h

@@ -62,6 +62,8 @@ public:
   virtual PRBool      IsOptimized();
 
   virtual nsresult    Optimize(nsIDeviceContext* aContext);
+
+  virtual PRBool      GetHasAlphaMask()     { return mAlphaBits != nsnull; }        
   virtual PRUint8*    GetAlphaBits();
   virtual PRInt32     GetAlphaWidth();
   virtual PRInt32     GetAlphaHeight();
@@ -78,6 +80,9 @@ public:
   virtual PRInt32 GetAlphaLevel();
   virtual void  MoveAlphaMask(PRInt32 aX, PRInt32 aY);
 
+  NS_IMETHOD   LockImagePixels(PRBool aMaskPixels);
+  NS_IMETHOD   UnlockImagePixels(PRBool aMaskPixels);    
+
 private:
   /**
    * Calculate the amount of memory needed for the initialization of the image

gfx/src/mac/nsImageMac.cpp

@@ -2,7 +2,7 @@
  *
  * The contents of this file are subject to the Netscape Public License
  * Version 1.0 (the "NPL"); you may not use this file except in
- * compliance with the NPL.  You may obtain a copy of the NPL at
+ * compliance with the NPL.	 You may obtain a copy of the NPL at
  * http://www.mozilla.org/NPL/
  *
  * Software distributed under the NPL is distributed on an "AS IS" basis,
@@ -11,8 +11,8 @@
  * NPL.
  *
  * The Initial Developer of this code under the NPL is Netscape
- * Communications Corporation.  Portions created by Netscape are
+ * Communications Corporation.	Portions created by Netscape are
- * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
+ * Copyright (C) 1998 Netscape Communications Corporation.	All Rights
  * Reserved.
  */
 #include "nsImageMac.h"
@@ -25,244 +25,477 @@
 
 static NS_DEFINE_IID(kIImageIID, NS_IIMAGE_IID);
 
+
+/** ------------------------------------------------------------
+ *	Utility class for saving, locking, and restoring pixel state
+ */
+
+class StPixelLocker
+{
+public:
+				
+										StPixelLocker(PixMapHandle thePixMap)
+										:	mPixMap(thePixMap)
+										{
+											mPixelState = ::GetPixelsState(mPixMap);
+											::LockPixels(mPixMap);
+										}
+										
+										~StPixelLocker()
+										{
+											::SetPixelsState(mPixMap, mPixelState);
+										}
+
+protected:
+
+
+		PixMapHandle		mPixMap;
+		GWorldFlags			mPixelState;
+
+};
+
+
 /** ---------------------------------------------------
- *  See documentation in nsImageMac.h
+ *	See documentation in nsImageMac.h
  *	@update 
  */
-nsImageMac :: nsImageMac()
+nsImageMac::nsImageMac()
+:	mImageGWorld(nsnull)
+,	mWidth(0)
+,	mHeight(0)
+,	mRowBytes(0)
+,	mBytesPerPixel(0)
+,	mAlphaGWorld(nsnull)
+,	mAlphaDepth(0)
+,	mAlphaWidth(0)
+,	mAlphaHeight(0)
+,	mARowBytes(0)
+,	mIsTopToBottom(PR_TRUE)
+,	mPixelDataSize(0)
 {
-
 	NS_INIT_REFCNT();
-	mThePixelmap.baseAddr = nsnull;
-	mImageBits = nsnull;
-  mWidth = 0;
-  mHeight = 0;	
 }
 
 /** ---------------------------------------------------
- *  See documentation in nsImageMac.h
+ *	See documentation in nsImageMac.h
  *	@update 
  */
-nsImageMac :: ~nsImageMac()
+nsImageMac::~nsImageMac()
 {
-	if(mImageBits)
+	if (mImageGWorld)
-		delete[] mImageBits;
+		::DisposeGWorld(mImageGWorld);
+		
+	if (mAlphaGWorld)
+		::DisposeGWorld(mAlphaGWorld);
 		
-	if(mAlphaBits){
-    delete mAlphaPix;
-    delete [] mAlphaBits;
-	}
 }
 
 NS_IMPL_ISUPPORTS(nsImageMac, kIImageIID);
 
 /** ---------------------------------------------------
- *  See documentation in nsImageMac.h
+ *	See documentation in nsImageMac.h
  *	@update 
  */
 PRUint8* 
 nsImageMac::GetBits()
-{ 
+{
-	return mImageBits; 
+	if (!mImageGWorld)
+	{
+		NS_ASSERTION(0, "Getting bits for non-existent image");
+		return nsnull;
+	}
+
+	PixMapHandle		thePixMap = ::GetGWorldPixMap(mImageGWorld);
+	
+	// pixels should be locked here!
+#if DEBUG
+	GWorldFlags		pixelFlags = GetPixelsState(thePixMap);
+	NS_ASSERTION(pixelFlags & pixelsLocked, "Pixels must be locked here");
+#endif
+	
+	Ptr			pixels = ::GetPixBaseAddr(thePixMap);
+	NS_ASSERTION(pixels, "Getting bits for image failed");
+	return (PRUint8 *)pixels;
 }
 
+
 /** ---------------------------------------------------
- *  See documentation in nsImageMac.h
+ *	See documentation in nsImageMac.h
+ *	@update 
+ */
+PRUint8* 
+nsImageMac::GetAlphaBits()
+{
+	if (!mAlphaGWorld)
+	{
+		NS_ASSERTION(0, "Getting alpha bits for non-existent mask");
+		return nsnull;
+	}
+
+	PixMapHandle		thePixMap = GetGWorldPixMap(mAlphaGWorld);
+	
+	// pixels should be locked here!
+#if DEBUG
+	GWorldFlags		pixelFlags = GetPixelsState(thePixMap);
+	NS_ASSERTION(pixelFlags & pixelsLocked, "Pixels must be locked here");
+#endif
+
+	Ptr	pixels = GetPixBaseAddr(thePixMap);
+	NS_ASSERTION(pixels, "Getting alpha bits failed");
+	return (PRUint8 *)pixels;
+}
+
+
+/** ---------------------------------------------------
+ *	See documentation in nsImageMac.h
  *	@update 08/03/99 -- cleared out the image pointer - dwc
  */
 nsresult 
-nsImageMac :: Init(PRInt32 aWidth, PRInt32 aHeight, PRInt32 aDepth,nsMaskRequirements aMaskRequirements)
+nsImageMac::Init(PRInt32 aWidth, PRInt32 aHeight, PRInt32 aDepth, nsMaskRequirements aMaskRequirements)
-{
-PRInt32	bufferdepth;
-
-	if(nsnull==mImageBits){
-		delete [] mImageBits;
-		}
-
-		switch(aDepth){
-			case 8:
-				mThePixelmap.pixelType = 0;
-				mThePixelmap.cmpCount = 1;
-				mThePixelmap.cmpSize = 8;
-				mThePixelmap.pmTable = GetCTable(8);
-				bufferdepth = 8;
-				break;
-			case 16:
-				mThePixelmap.pixelType = 16;
-				mThePixelmap.cmpCount = 3;
-				mThePixelmap.cmpSize = 5;
-				mThePixelmap.pmTable = 0;
-				bufferdepth = 16;
-				break;
-			case 24:			// 24 and 32 bit are basically the same
-			case 32:
-				mThePixelmap.pixelType = 16;
-				mThePixelmap.cmpCount = 3;
-				mThePixelmap.cmpSize = 8;
-				mThePixelmap.pmTable = 0;
-				bufferdepth = 32;
-				break;
-			default:
-				mThePixelmap.cmpCount = 0;
-				break;
-			}
-	
-	if(mThePixelmap.cmpCount){
-		mRowBytes = CalcBytesSpan(aWidth,bufferdepth);
-		mSizeImage = mRowBytes*aHeight;
-		mImageBits = new unsigned char[mSizeImage];
-		}
-		
-	if(mImageBits){
-		memset(mImageBits,0,mSizeImage);						// clear out any garbage
-		
-		mThePixelmap.baseAddr = (char*) mImageBits;
-		mThePixelmap.rowBytes = mRowBytes | 0x8000;
-		mThePixelmap.bounds.top = 0;
-		mThePixelmap.bounds.left = 0;
-		mThePixelmap.bounds.bottom = aHeight;
-		mThePixelmap.bounds.right = aWidth;
-		mThePixelmap.pixelSize = bufferdepth;
-		mThePixelmap.packType = 0;
-		mThePixelmap.packSize = 0;
-		mThePixelmap.hRes = nsDeviceContextMac::GetScreenResolution()<<16;
-		mThePixelmap.vRes = nsDeviceContextMac::GetScreenResolution()<<16;
-#if TARGET_CARBON
-		mThePixelmap.pixelFormat = 0;				/*fourCharCode representation*/
-		mThePixelmap.pmTable	= 0;					/*color map for this pixMap*/
-		mThePixelmap.pmExt = 0;	
-#else
-  		mThePixelmap.planeBytes = 0;
-  		mThePixelmap.pmReserved = 0;
-#endif
-		mThePixelmap.pmVersion = 0;
-		mWidth = aWidth;
-		mHeight = aHeight;
-		}
-
-
-  // Allocate mask image bits if requested
-  if (aMaskRequirements != nsMaskRequirements_kNoMask){
-  	mAlphaPix = new BitMap();
-    if (nsMaskRequirements_kNeeds1Bit == aMaskRequirements){
-    	mARowBytes = (aWidth + 7) / 8;					// 1 bit rowbytes
-    	mARowBytes = (mARowBytes + 3) & ~0x3;		// 32 bit align
-    	mAlphaBits = new unsigned char[mARowBytes * aHeight];
-      mAlphaDepth = 1;
-      bufferdepth = 1;
-      mAlphaPix->baseAddr = (char*) mAlphaBits;
-      mAlphaPix->rowBytes = mARowBytes;
-      mAlphaPix->bounds.top = 0;
-      mAlphaPix->bounds.left = 0;
-      mAlphaPix->bounds.bottom = aHeight;
-      mAlphaPix->bounds.right = aWidth;      
-      mAlphaWidth = aWidth;
-      mAlphaHeight = aHeight;
-    }else{
-      NS_ASSERTION(nsMaskRequirements_kNeeds8Bit == aMaskRequirements, "unexpected mask depth");
-      mAlphaBits = nsnull;
-      mAlphaWidth = 0;
-      mAlphaHeight = 0;
-    }
-
-  } else{
-    mAlphaBits = nsnull;
-    mAlphaWidth = 0;
-    mAlphaHeight = 0;
-  }
-  mIsTopToBottom = PR_TRUE;
-  return NS_OK;
-}
-
-/** ---------------------------------------------------
- *  See documentation in nsImageMac.h
- *	@update 
- */
-PRInt32  nsImageMac :: CalcBytesSpan(PRUint32  aWidth,PRUint32	aDepth)
-{
-PRInt32 spanbytes;
-
-  spanbytes = (aWidth * aDepth) >> 5;
-
-  if (((PRUint32)aWidth * aDepth) & 0x1F) 
-    spanbytes++;
-  spanbytes <<= 2;
-  return(spanbytes);
-  return 0;
-}
-
-/** ---------------------------------------------------
- *  See documentation in nsImageMac.h
- *	@update 
- */
-void nsImageMac :: ImageUpdated(nsIDeviceContext *aContext, PRUint8 aFlags, nsRect *aUpdateRect)
 {
 
-  /*if (nsnull == mImage)
+	// have we already been initted?
-    return;
+	if (mImageGWorld)
-
+	{
-  if (IsFlagSet(nsImageUpdateFlags_kBitsChanged, aFlags)){
+		NS_ASSERTION(0, "Initting image twice");
-  }
+		::DisposeGWorld(mImageGWorld);
-*/
+		mImageGWorld = nsnull;
-}
-
-
-/** ---------------------------------------------------
- *  See documentation in nsImageMac.h
- *	@update 
- */
-NS_IMETHODIMP nsImageMac :: Draw(nsIRenderingContext &aContext, nsDrawingSurface aSurface, PRInt32 aSX, PRInt32 aSY, PRInt32 aSWidth, PRInt32 aSHeight,
-                                 PRInt32 aDX, PRInt32 aDY, PRInt32 aDWidth, PRInt32 aDHeight)
-{
-  PixMapPtr	destpix;
-  RGBColor	rgbblack = {0x0000,0x0000,0x0000};
-  RGBColor	rgbwhite = {0xFFFF,0xFFFF,0xFFFF};
-  Rect			srcrect,dstrect,maskrect;;
-
-  if (nsnull == mThePixelmap.baseAddr)
-    return NS_ERROR_FAILURE;
-
-	::SetRect(&srcrect,aSX,aSY,aSX+aSWidth,aSY+aSHeight);
-	::SetRect(&maskrect,aSX,aSY,aSX+aSWidth,aSY+aSHeight);
-	::SetRect(&dstrect,aDX,aDY,aDX+aDWidth,aDY+aDHeight);
-
-#if TARGET_CARBON
-	destpix = *::GetPortPixMap((CGrafPtr)aSurface);
-#else
-	destpix = *((CGrafPtr)aSurface)->portPixMap;
-#endif
-
-	::RGBForeColor(&rgbblack);
-	::RGBBackColor(&rgbwhite);
-	if(mAlphaBits){
-	  ::CopyDeepMask((BitMap*)&mThePixelmap,(BitMap*)mAlphaPix,(BitMap*)destpix,&srcrect,&maskrect,&dstrect,srcCopy,0L);
-	} else {
-	  ::CopyBits((BitMap*)&mThePixelmap, (BitMap*)destpix, &srcrect, &dstrect, ditherCopy, 0L);
 	}
 
-  return NS_OK;
+  mWidth = aWidth;
+  mHeight = aHeight;
+  
+	PRInt16 bufferdepth;
+
+	switch(aDepth)
+	{
+		case 8:
+			//mThePixelmap.pmTable = ::GetCTable(8);
+			bufferdepth = 8;
+			break;
+
+		case 16:
+			bufferdepth = 16;
+			break;
+
+		case 24:			// 24 and 32 bit are basically the same
+		case 32:
+			bufferdepth = 32;
+			break;
+
+		default:
+			NS_NOTREACHED("Unexpected buffer depth");
+			bufferdepth = 32;
+			break;
+	}
+
+
+	// allocate the GWorld
+	Rect		bounds = {0, 0, 0, 0};
+	bounds.right = aWidth;
+	bounds.bottom = aHeight;
+		
+	OSErr		err = AllocateGWorld(bufferdepth, nsnull, bounds, &mImageGWorld);
+	if (err != noErr)
+	{
+		NS_WARNING("GWorld allocation failed");
+		return NS_ERROR_OUT_OF_MEMORY;
+	}
+	
+	ClearGWorld(mImageGWorld);
+	
+	// calculate the pixel data size
+	PixMapHandle	thePixMap = ::GetGWorldPixMap(mImageGWorld);
+
+	mRowBytes = (**thePixMap).rowBytes & 0x3FFF;
+	mPixelDataSize = mRowBytes * aHeight;
+	mBytesPerPixel = (**thePixMap).cmpCount;
+		
+	if (aMaskRequirements != nsMaskRequirements_kNoMask)
+	{
+		PRInt16 mAlphaDepth = 0;
+
+		switch (aMaskRequirements)
+		{
+			case nsMaskRequirements_kNeeds1Bit:
+				mAlphaDepth = 1;
+				err = AllocateGWorld(mAlphaDepth, nsnull, bounds, &mAlphaGWorld);
+				if (err != noErr)
+					return NS_ERROR_OUT_OF_MEMORY;
+				break;
+				
+			case nsMaskRequirements_kNeeds8Bit:
+				mAlphaDepth = 8;
+				
+				// make 8-bit grayscale color table
+				CTabHandle		grayRamp = nsnull;
+				err = MakeGrayscaleColorTable(256, &grayRamp);
+				if (err != noErr)
+					return NS_ERROR_OUT_OF_MEMORY;				
+				
+				err = AllocateGWorld(mAlphaDepth, grayRamp, bounds, &mAlphaGWorld);
+				if (err != noErr)
+					return NS_ERROR_OUT_OF_MEMORY;
+					
+				::DisposeHandle((Handle)grayRamp);
+				break;
+				
+			default:
+				NS_NOTREACHED("Uknown mask depth");
+				break;
+		}
+		
+		if (mAlphaGWorld)
+		{
+			ClearGWorld(mAlphaGWorld);
+
+			// calculate the pixel data size
+			PixMapHandle	maskPixMap = GetGWorldPixMap(mAlphaGWorld);
+
+			mARowBytes = (**maskPixMap).rowBytes & 0x3FFF;
+		  mAlphaWidth = aWidth;
+		  mAlphaHeight = aHeight;
+		}		
+	}
+	
+	return NS_OK;
 }
 
 /** ---------------------------------------------------
- *  See documentation in nsImageMac.h
+ *	See documentation in nsImageMac.h
+ *	@update 
+ */
+void nsImageMac::ImageUpdated(nsIDeviceContext *aContext, PRUint8 aFlags, nsRect *aUpdateRect)
+{
+	// NS_NOTYETIMPLEMENTED("nsImageMac::ImageUpdated not implemented");
+}
+
+
+/** ---------------------------------------------------
+ *	See documentation in nsImageMac.h
+ *	@update 
+ */
+NS_IMETHODIMP nsImageMac::Draw(nsIRenderingContext &aContext, nsDrawingSurface aSurface, PRInt32 aSX, PRInt32 aSY,
+								 PRInt32 aSWidth, PRInt32 aSHeight, PRInt32 aDX, PRInt32 aDY, PRInt32 aDWidth, PRInt32 aDHeight)
+{
+	PixMapHandle	imagePixMap;
+	Rect					srcRect, dstRect, maskRect;
+
+	if (!mImageGWorld)
+		return NS_ERROR_FAILURE;
+
+	::SetRect(&srcRect, aSX, aSY, aSX + aSWidth, aSY + aSHeight);
+	maskRect = srcRect;
+	::SetRect(&dstRect, aDX, aDY, aDX + aDWidth, aDY + aDHeight);
+
+	::ForeColor(blackColor);
+	::BackColor(whiteColor);
+	
+	imagePixMap = GetGWorldPixMap(mImageGWorld);
+	
+	StPixelLocker		pixelLocker(imagePixMap);			// locks the pixels
+	
+	// get the destination pix map
+	nsDrawingSurfaceMac* surface = static_cast<nsDrawingSurfaceMac*>(aSurface);
+	CGrafPtr		destPort;
+	nsresult		rv = surface->GetGrafPtr((GrafPtr *)&destPort);
+	if (NS_FAILED(rv)) return rv;
+	
+	PixMapHandle		destPixels = GetGWorldPixMap(destPort);
+	NS_ASSERTION(destPixels, "No dest pixels!");
+	
+	// XXX printing???
+	
+	if(mAlphaGWorld)
+	{
+		PixMapHandle		maskPixMap = GetGWorldPixMap(mAlphaGWorld);
+		StPixelLocker		pixelLocker(maskPixMap);
+		
+		// 1-bit masks?
+		
+		::CopyDeepMask((BitMap*)*imagePixMap, (BitMap*)*maskPixMap, (BitMap*)*destPixels, &srcRect, &maskRect, &dstRect, srcCopy, nsnull);
+	}
+	else
+	{
+		::CopyBits((BitMap*)*imagePixMap, (BitMap*)*destPixels, &srcRect, &dstRect, ditherCopy, 0L);
+	}
+
+	return NS_OK;
+}
+
+/** ---------------------------------------------------
+ *	See documentation in nsImageMac.h
  *	@update 
  */
 NS_IMETHODIMP nsImageMac :: Draw(nsIRenderingContext &aContext, 
-                                 nsDrawingSurface aSurface,
+								 nsDrawingSurface aSurface,
-                                 PRInt32 aX, PRInt32 aY, 
+								 PRInt32 aX, PRInt32 aY, 
-                                 PRInt32 aWidth, PRInt32 aHeight)
+								 PRInt32 aWidth, PRInt32 aHeight)
 {
 
-  return Draw(aContext,aSurface,0,0,mWidth,mHeight,aX,aY,aWidth,aHeight);
+	return Draw(aContext,aSurface,0,0,mWidth,mHeight,aX,aY,aWidth,aHeight);
 }
-
+ 
 /** ---------------------------------------------------
- *  See documentation in nsImageMac.h
+ *	See documentation in nsImageMac.h
  *	@update 
  */
 nsresult nsImageMac::Optimize(nsIDeviceContext* aContext)
 {
-  return NS_OK;
+	return NS_OK;
 }
 
-//------------------------------------------------------------
+
+#pragma mark -
+
+/** ---------------------------------------------------
+ *	See documentation in nsImageMac.h
+ *	@update 
+ */
+void nsImageMac::SetAlphaLevel(PRInt32 aAlphaLevel)
+{
+	NS_NOTYETIMPLEMENTED("nsImageMac::SetAlphaLevel not implemented");
+}
+
+
+/** ---------------------------------------------------
+ *	See documentation in nsImageMac.h
+ *	@update 
+ */
+PRInt32 nsImageMac::GetAlphaLevel()
+{
+	NS_NOTYETIMPLEMENTED("nsImageMac::GetAlphaLevel not implemented");
+	return 0;
+}
+
+#pragma mark -
+
+/** ---------------------------------------------------
+ *	Lock down the image pixels
+ */
+NS_IMETHODIMP
+nsImageMac::LockImagePixels(PRBool aMaskPixels)
+{
+  if (!mImageGWorld)
+    return NS_ERROR_NOT_INITIALIZED;
+  
+  if (aMaskPixels && !mAlphaGWorld)
+  	return NS_ERROR_NOT_INITIALIZED;
+  	
+	PixMapHandle		thePixMap = ::GetGWorldPixMap(aMaskPixels ? mAlphaGWorld : mImageGWorld);
+	::LockPixels(thePixMap);
+	return NS_OK;
+}
+
+/** ---------------------------------------------------
+ *	Unlock the pixels
+ */
+NS_IMETHODIMP
+nsImageMac::UnlockImagePixels(PRBool aMaskPixels)
+{
+  if (!mImageGWorld)
+    return NS_ERROR_NOT_INITIALIZED;
+  
+  if (aMaskPixels && !mAlphaGWorld)
+  	return NS_ERROR_NOT_INITIALIZED;
+
+	PixMapHandle		thePixMap = ::GetGWorldPixMap(aMaskPixels ? mAlphaGWorld : mImageGWorld);
+	::UnlockPixels(thePixMap);
+	return NS_OK;
+}
+
+#pragma mark -
+
+/** ---------------------------------------------------
+ *	Erase the GWorld contents
+ */
+void nsImageMac::ClearGWorld(GWorldPtr theGWorld)
+{
+	PixMapHandle	thePixels;
+	GWorldPtr			curPort;
+	GDHandle			curDev;
+	OSErr					err = noErr;
+
+	thePixels = ::GetGWorldPixMap(theGWorld);
+	::GetGWorld(&curPort, &curDev);
+
+	// Black the offscreen
+	if (LockPixels(thePixels))
+	{
+		::SetGWorld(theGWorld, nil);
+
+		::BackColor(whiteColor);
+		::EraseRect(&theGWorld->portRect);
+
+		::UnlockPixels(thePixels);
+	}
+
+	::SetGWorld(curPort, curDev);
+}
+
+/** -----------------------------------------------------------------
+ *	Allocate a GWorld, trying first in the heap, and then in temp mem.
+ */
+#define kReserveHeapFreeSpace			(256 * 1024)
+#define kReserverHeapContigSpace	(64 * 1024)
+
+OSErr nsImageMac::AllocateGWorld(PRInt16 depth, CTabHandle colorTable, const Rect& bounds, GWorldPtr *outGWorld)
+{
+	*outGWorld = nsnull;
+	
+	// Quick and dirty check to make sure there is some memory available.
+	// GWorld allocations in temp mem can still fail if the heap is totally
+	// full, because some stuff is allocated in the heap
+	long	totalSpace, contiguousSpace;
+	::PurgeSpace(&totalSpace, &contiguousSpace);		// this does not purge memory!
+	
+	QDErr		err = noErr;
+	
+	if (totalSpace > kReserveHeapFreeSpace && contiguousSpace > kReserverHeapContigSpace)
+	{
+		err = ::NewGWorld(outGWorld, depth, &bounds, colorTable, nsnull, 0);
+		if (err == noErr || err != memFullErr) return err;
+	}
+	
+	err = ::NewGWorld(outGWorld, depth, &bounds, colorTable, nsnull, useTempMem);
+	return err;
+}
+
+
+/** ----------------------------------------------------------
+ *	Make a 256-level grayscale color table, for alpha blending.
+ *  Caller must free the color table with ::DisposeHandle((Handle)colorTable)
+ *  when done.
+ */
+
+OSErr nsImageMac::MakeGrayscaleColorTable(PRInt16 numColors, CTabHandle *outColorTable)
+{
+	CTabHandle	colorTable = nil;
+
+	colorTable = (CTabHandle)::NewHandleClear (8 * numColors + 8);	/* Allocate memory for the table */
+	if (!colorTable) return memFullErr;
+						
+	(**colorTable).ctSeed = ::GetCTSeed();				// not sure about this one
+	(**colorTable).ctFlags = 0;										// not sure about this one
+	(**colorTable).ctSize = numColors - 1;					
+
+	RGBColor		tempColor = { 0xFFFF, 0xFFFF, 0xFFFF};			// starts at white
+	PRUint16		colorInc = 0xFFFF / numColors;
+	
+	for (PRInt16 i = 0; i < numColors; i++)
+	{
+		(**colorTable).ctTable[i].value = i;
+				
+		(**colorTable).ctTable[i].rgb = tempColor;
+		
+		tempColor.red -= colorInc;
+		tempColor.green -= colorInc;
+		tempColor.blue -= colorInc;
+	}
+
+	*outColorTable = colorTable;
+	return noErr;
+}
+
+
+

gfx/src/mac/nsImageMac.h

@@ -2,7 +2,7 @@
  *
  * The contents of this file are subject to the Netscape Public License
  * Version 1.0 (the "NPL"); you may not use this file except in
- * compliance with the NPL.  You may obtain a copy of the NPL at
+ * compliance with the NPL.	 You may obtain a copy of the NPL at
  * http://www.mozilla.org/NPL/
  *
  * Software distributed under the NPL is distributed on an "AS IS" basis,
@@ -11,8 +11,8 @@
  * NPL.
  *
  * The Initial Developer of this code under the NPL is Netscape
- * Communications Corporation.  Portions created by Netscape are
+ * Communications Corporation.	Portions created by Netscape are
- * Copyright (C) 1998 Netscape Communications Corporation.  All Rights
+ * Copyright (C) 1998 Netscape Communications Corporation.	All Rights
  * Reserved.
  */
 
@@ -25,81 +25,81 @@
 class nsImageMac : public nsIImage
 {
 public:
-  nsImageMac();
+											nsImageMac();
-  ~nsImageMac();
+	virtual							~nsImageMac();
 
-  NS_DECL_ISUPPORTS
+	NS_DECL_ISUPPORTS
 
-  /**
+	/**
-  @see nsIImage.h
+	@see nsIImage.h
-  */
+	*/
-  virtual PRInt32     GetBytesPix()       { return mThePixelmap.cmpCount; }
+	virtual nsresult		Init(PRInt32 aWidth, PRInt32 aHeight, PRInt32 aDepth, nsMaskRequirements aMaskRequirements);
-  virtual PRInt32     GetHeight()         { return mHeight;}
+	virtual PRInt32			GetBytesPix()					{ return mBytesPerPixel; }
-  virtual PRInt32     GetWidth()          { return mWidth; }
+	virtual PRBool			GetIsRowOrderTopToBottom() { return mIsTopToBottom; }
-  virtual PRUint8*    GetBits() ;          //{ return mImageBits; }
-  virtual void*       GetBitInfo()        { return nsnull; }
-  virtual PRBool      GetIsRowOrderTopToBottom() { return mIsTopToBottom; }
-  virtual PRInt32     GetLineStride()     {return mRowBytes; }
-  NS_IMETHOD Draw(nsIRenderingContext &aContext, nsDrawingSurface aSurface, PRInt32 aX, PRInt32 aY, PRInt32 aWidth, PRInt32 aHeight);
-  NS_IMETHOD Draw(nsIRenderingContext &aContext, nsDrawingSurface aSurface, PRInt32 aSX, PRInt32 aSY, PRInt32 aSWidth, PRInt32 aSHeight,
-                  PRInt32 aDX, PRInt32 aDY, PRInt32 aDWidth, PRInt32 aDHeight);
-  virtual nsColorMap* GetColorMap() {return nsnull;}
-  virtual void ImageUpdated(nsIDeviceContext *aContext, PRUint8 aFlags, nsRect *aUpdateRect);
-  virtual nsresult    Init(PRInt32 aWidth, PRInt32 aHeight, PRInt32 aDepth, nsMaskRequirements aMaskRequirements);
-  virtual PRBool      IsOptimized()       { return false; }
-  virtual nsresult    Optimize(nsIDeviceContext* aContext);
-  virtual PRUint8*    GetAlphaBits()      { return mAlphaBits; }
-  virtual PRInt32     GetAlphaWidth()   { return mAlphaWidth;}
-  virtual PRInt32     GetAlphaHeight()   {return mAlphaHeight;}
-  virtual PRInt32     GetAlphaLineStride(){ return mARowBytes; }
-  virtual nsIImage*   DuplicateImage() {return(nsnull);}
 
-  void AllocConvertedBits(PRUint32 aSize);
+	virtual PRInt32			GetWidth()						{ return mWidth; }
+	virtual PRInt32			GetHeight()						{ return mHeight;}
 
-  /** 
+	virtual PRUint8*		GetBits();
-    * Return the image size of the Device Independent Bitmap(DIB).
+	virtual PRInt32			GetLineStride()				{ return mRowBytes; }
-    * @return size of image in bytes
+	virtual PRBool			GetHasAlphaMask()     { return mAlphaGWorld != nsnull; }
-    */
-  PRIntn      GetSizeImage(){ return mSizeImage; }
 
-  /** 
+	virtual PRUint8*		GetAlphaBits();
-   * Make a palette for the DIB.
+	virtual PRInt32			GetAlphaWidth() 			{ return mAlphaWidth; }
-   * @return true or false if the palette was created
+	virtual PRInt32			GetAlphaHeight()	 		{ return mAlphaHeight; }
-   */
+	virtual PRInt32			GetAlphaLineStride()	{ return mARowBytes; }
-  PRBool      MakePalette();
 
-  /** 
+	virtual void				ImageUpdated(nsIDeviceContext *aContext, PRUint8 aFlags, nsRect *aUpdateRect);
-   * Calculate the number of bytes spaned for this image for a given width
+	virtual PRBool			IsOptimized()					{ return PR_FALSE; }
-   * @param aWidth is the width to calculate the number of bytes for
+	virtual nsresult		Optimize(nsIDeviceContext* aContext);
-   * @return the number of bytes in this span
+	virtual nsColorMap*	GetColorMap() 				{ return nsnull;}
-   */
-  PRInt32  					CalcBytesSpan(PRUint32  aWidth,PRUint32	aDepth);
-  virtual void  		SetAlphaLevel(PRInt32 aAlphaLevel) {}
-  virtual PRInt32 	GetAlphaLevel() {return(0);}
-  virtual void  		MoveAlphaMask(PRInt32 aX, PRInt32 aY) {}
 
-private:
+	NS_IMETHOD 					Draw(nsIRenderingContext &aContext, nsDrawingSurface aSurface,
-  PixMap			mThePixelmap;
+															PRInt32 aX, PRInt32 aY, PRInt32 aWidth, PRInt32 aHeight);
-  PRInt32			mWidth;
-  PRInt32			mHeight;
-  PRInt32			mSizeImage;
-  PRInt32           mRowBytes;          // number of bytes per row
-  PRUint8*          mImageBits;         // starting address of the bits
 
+	NS_IMETHOD 					Draw(nsIRenderingContext &aContext, nsDrawingSurface aSurface,
+															PRInt32 aSX, PRInt32 aSY, PRInt32 aSWidth, PRInt32 aSHeight,
+															PRInt32 aDX, PRInt32 aDY, PRInt32 aDWidth, PRInt32 aDHeight);
+
+	virtual void				SetAlphaLevel(PRInt32 aAlphaLevel);
+	virtual PRInt32			GetAlphaLevel();
+	virtual void*				GetBitInfo()					{ return nsnull; }
+
+	NS_IMETHOD					LockImagePixels(PRBool aMaskPixels);
+	NS_IMETHOD					UnlockImagePixels(PRBool aMaskPixels);
+
+protected:
 	
-  nsColorMap*       mColorMap;          // Redundant with mColorTable, but necessary
+	void							ClearGWorld(GWorldPtr);
-    
+	OSErr							MakeGrayscaleColorTable(PRInt16 numColors, CTabHandle *outColorTable);
-  // alpha layer members
+	OSErr							AllocateGWorld(PRInt16 depth, CTabHandle colorTable, const Rect& bounds, GWorldPtr *outGWorld);
-  BitMap			*mAlphaPix;			// the alpha level pixel map
+	
-  PRBool 			mIsTopToBottom;
+private:
-  PRUint8			*mAlphaBits;        // the bits to set for the mask
+
-  PRInt32			mARowBytes;			// rowbytes for the alpha layer
+	GWorldPtr				mImageGWorld;
-  PRInt8            mAlphaDepth;        // alpha layer depth
+	
-  PRInt16			mAlphaWidth;        // alpha layer width
+	PRInt32					mWidth;
-  PRInt16			mAlphaHeight;       // alpha layer height
+	PRInt32					mHeight;
-  nsPoint			mLocation;          // alpha mask location
+
-  PRInt8			mImageCache;        // place to save off the old image for fast animation
+	PRInt32					mRowBytes;
-  PRInt16			mAlphaLevel;        // an alpha level every pixel uses
+	PRInt32					mBytesPerPixel;
+		
+	// alpha layer members
+	GWorldPtr				mAlphaGWorld;
+
+	PRInt16					mAlphaDepth;		// alpha layer depth
+	PRInt16					mAlphaWidth;		// alpha layer width
+	PRInt16					mAlphaHeight;		// alpha layer height
+	PRInt32					mARowBytes;			// alpha row bytes
+	
+	//nsPoint					mLocation;			// alpha mask location
+
+	//PRInt8					mImageCache;		// place to save off the old image for fast animation
+	//PRInt16					mAlphaLevel;		// an alpha level every pixel uses
+
+	PRIntn					mPixelDataSize;
+	PRBool					mIsTopToBottom;
+
 };
 
 #endif

gfx/src/motif/nsImageMotif.cpp

@@ -399,3 +399,19 @@ printf("Format XYPixmap\n");
   }	
   return ;
 }
+
+//------------------------------------------------------------
+// lock the image pixels. nothing to do on gtk
+NS_IMETHODIMP
+nsImageMotif::LockImagePixels(PRBool aMaskPixels)
+{
+  return NS_OK;
+}
+
+//------------------------------------------------------------
+// unlock the image pixels. nothing to do on gtk
+NS_IMETHODIMP
+nsImageMotif::UnlockImagePixels(PRBool aMaskPixels)
+{
+  return NS_OK;
+} 

gfx/src/motif/nsImageMotif.h

@@ -62,6 +62,7 @@ public:
 
   virtual  nsresult   BuildImage(nsDrawingSurface aDrawingSurface);
   virtual nsresult    Optimize(nsIDeviceContext* aContext);
+  virtual PRBool      GetHasAlphaMask()   { return mAlphaBits != nsnull; }        
   virtual PRUint8*    GetAlphaBits()      { return mAlphaBits; }
   virtual PRInt32     GetAlphaWidth()   { return 0;}
   virtual PRInt32     GetAlphaHeight()   {return 0;}
@@ -95,6 +96,9 @@ public:
   virtual PRInt32 GetAlphaLevel() {return(0);}
   virtual void  MoveAlphaMask(PRInt32 /* aX */, PRInt32 /* aY */) {}
 
+  NS_IMETHOD   LockImagePixels(PRBool aMaskPixels);
+  NS_IMETHOD   UnlockImagePixels(PRBool aMaskPixels);    
+
 private:
   void CreateImage(nsDrawingSurface aSurface);
   void ConvertImage(nsDrawingSurface aSurface);

gfx/src/os2/nsImageOS2.cpp

@@ -354,3 +354,19 @@ void nsImageOS2::DrawBitmap( HPS hps, LONG lCount, PPOINTL pPoints,
       delete pMaskInfo;
    }
 }
+
+//------------------------------------------------------------
+// lock the image pixels. implement this if you need it
+NS_IMETHODIMP
+nsImageOS2::LockImagePixels(PRBool aMaskPixels)
+{
+  return NS_OK;
+}
+
+//------------------------------------------------------------
+// unlock the image pixels. implement this if you need it
+NS_IMETHODIMP
+nsImageOS2::UnlockImagePixels(PRBool aMaskPixels)
+{
+  return NS_OK;
+} 

gfx/src/os2/nsImageOS2.h

@@ -50,6 +50,7 @@ class nsImageOS2 : public nsIImage
    PRInt32  GetAlphaWidth()      { return mInfo ? mInfo->cx : 0; }
    PRInt32  GetAlphaHeight()     { return mInfo ? mInfo->cy : 0; }
    PRInt32  GetAlphaLineStride() { return mAStride; }
+   PRBool   GetHasAlphaMask()     { return mAImageBits != nsnull; }        
    PRUint8 *GetAlphaBits()       { return mAImageBits; }
 
    void    SetAlphaLevel(PRInt32 aAlphaLevel)      {}
@@ -67,6 +68,9 @@ class nsImageOS2 : public nsIImage
    void ImageUpdated( nsIDeviceContext *aContext,
                       PRUint8 aFlags, nsRect *aUpdateRect);
 
+  NS_IMETHOD   LockImagePixels(PRBool aMaskPixels);
+  NS_IMETHOD   UnlockImagePixels(PRBool aMaskPixels);    
+
  private:
    BITMAPINFO2 *mInfo;
    PRInt32      mStride;

gfx/src/photon/nsImagePh.cpp

@@ -606,3 +606,19 @@ void* nsImagePh::GetBitInfo()
   return nsnull;
 }
 
+//------------------------------------------------------------
+// lock the image pixels. Implement this if you need it.
+NS_IMETHODIMP
+nsImagePh::LockImagePixels(PRBool aMaskPixels)
+{
+  return NS_OK;
+}
+
+//------------------------------------------------------------
+// unlock the image pixels.  Implement this if you need it.
+NS_IMETHODIMP
+nsImagePh::UnlockImagePixels(PRBool aMaskPixels)
+{
+  return NS_OK;
+}
+

gfx/src/photon/nsImagePh.h

@@ -46,6 +46,7 @@ public:
   virtual PRBool      IsOptimized();
   virtual nsresult    Optimize(nsIDeviceContext* aContext);
   virtual PRUint8*    GetAlphaBits();
+  virtual PRBool      GetHasAlphaMask()     { return mAlphaBits != nsnull; }        
   virtual PRInt32     GetAlphaWidth();
   virtual PRInt32     GetAlphaHeight();
   virtual PRInt32     GetAlphaLineStride();
@@ -85,7 +86,14 @@ public:
    * @return VOID
    */
   void* GetBitInfo();
+  
 
+  /** 
+   * Lock and unlock the image pixels (for platforms on which this is necessary)
+   * @param aMaskPixels true to lock the mask, false to lock the image
+   */
+  NS_IMETHOD   LockImagePixels(PRBool aMaskPixels);
+  NS_IMETHOD   UnlockImagePixels(PRBool aMaskPixels);    
 
 private:
   /** 

gfx/src/qt/nsImageQT.cpp

@@ -499,3 +499,19 @@ PRBool nsImageQT::GetIsRowOrderTopToBottom()
     PR_LOG(QtGfxLM, PR_LOG_DEBUG, ("nsImageQT::GetIsRowOrderTopToBottom()\n"));
     return PR_TRUE;
 }
+
+//------------------------------------------------------------
+// lock the image pixels. Implement this if you need it.
+NS_IMETHODIMP
+nsImageQT::LockImagePixels(PRBool aMaskPixels)
+{
+  return NS_OK;
+}
+
+//------------------------------------------------------------
+// unlock the image pixels.  Implement this if you need it.
+NS_IMETHODIMP
+nsImageQT::UnlockImagePixels(PRBool aMaskPixels)
+{
+  return NS_OK;
+}

gfx/src/qt/nsImageQT.h

@@ -66,6 +66,7 @@ public:
     virtual PRBool      IsOptimized();
 
     virtual nsresult    Optimize(nsIDeviceContext* aContext);
+    virtual PRBool      GetHasAlphaMask()     { return mAlphaBits != nsnull; }        
     virtual PRUint8*    GetAlphaBits();
     virtual PRInt32     GetAlphaWidth();
     virtual PRInt32     GetAlphaHeight();
@@ -82,6 +83,9 @@ public:
     virtual PRInt32 GetAlphaLevel();
     virtual void  MoveAlphaMask(PRInt32 aX, PRInt32 aY);
 
+  NS_IMETHOD   LockImagePixels(PRBool aMaskPixels);
+  NS_IMETHOD   UnlockImagePixels(PRBool aMaskPixels);    
+
 private:
     /**
      * Calculate the amount of memory needed for the initialization of the 

gfx/src/windows/nsImageWin.cpp

@@ -795,3 +795,38 @@ PRInt16 numPaletteColors;
   return NS_OK;
 }
 
+/** ---------------------------------------------------
+ *	Lock down the image pixels
+ */
+NS_IMETHODIMP
+nsImageWin::LockImagePixels(PRBool aMaskPixels)
+{
+    /*
+  if (!mHBitmap)
+    return NS_ERROR_NOT_INITIALIZED;
+  
+  if (aMaskPixels && !mAlphaHBitmap)
+  	return NS_ERROR_NOT_INITIALIZED;
+
+   ... and do Windows locking of image pixels here, if necessary
+*/
+	return NS_OK;
+}
+
+/** ---------------------------------------------------
+ *	Unlock the pixels
+ */
+NS_IMETHODIMP
+nsImageWin::UnlockImagePixels(PRBool aMaskPixels)
+{
+    /*
+  if (!mHBitmap)
+    return NS_ERROR_NOT_INITIALIZED;
+  
+  if (aMaskPixels && !mAlphamHBitmap)
+  	return NS_ERROR_NOT_INITIALIZED;
+
+   ... and do Windows unlocking of image pixels here, if necessary
+    */
+	return NS_OK;
+}

gfx/src/windows/nsImageWin.h

@@ -37,7 +37,9 @@ public:
   virtual PRBool      GetIsRowOrderTopToBottom() { return mIsTopToBottom; }
   virtual PRInt32     GetWidth()          { return mBHead->biWidth; }
   virtual PRUint8*    GetBits()           { return mImageBits; }
-  virtual PRInt32     GetLineStride()     {return mRowBytes; }
+  virtual PRInt32     GetLineStride()     { return mRowBytes; }
+  virtual PRBool      GetHasAlphaMask()   { return mAlphaBits != nsnull; }
+
   NS_IMETHOD          Draw(nsIRenderingContext &aContext, nsDrawingSurface aSurface, PRInt32 aX, PRInt32 aY, PRInt32 aWidth, PRInt32 aHeight);
   NS_IMETHOD          Draw(nsIRenderingContext &aContext, nsDrawingSurface aSurface, PRInt32 aSX, PRInt32 aSY, PRInt32 aSWidth, PRInt32 aSHeight,
                       PRInt32 aDX, PRInt32 aDY, PRInt32 aDWidth, PRInt32 aDHeight);
@@ -87,6 +89,10 @@ public:
    */
   void* GetBitInfo() {return mBHead;}
 
+  NS_IMETHOD   LockImagePixels(PRBool aMaskPixels);
+  NS_IMETHOD   UnlockImagePixels(PRBool aMaskPixels);
+
+
   static PRBool gIsWinNT;
 
 private:

gfx/src/xlib/nsImageXlib.cpp

@@ -414,3 +414,20 @@ nsImageXlib::ComputeMetrics()
   mRowBytes = CalcBytesSpan(mWidth);
   mSizeImage = mRowBytes * mHeight;
 }
+
+//------------------------------------------------------------
+// lock the image pixels. Implement this if you need it.
+NS_IMETHODIMP
+nsImageXlib::LockImagePixels(PRBool aMaskPixels)
+{
+  return NS_OK;
+}
+
+//------------------------------------------------------------
+// unlock the image pixels.  Implement this if you need it.
+NS_IMETHODIMP
+nsImageXlib::UnlockImagePixels(PRBool aMaskPixels)
+{
+  return NS_OK;
+}
+

gfx/src/xlib/nsImageXlib.h

@@ -53,6 +53,7 @@ public:
                            PRInt32 aDepth, nsMaskRequirements aMaskRequirements);
   virtual PRBool      IsOptimized();
   virtual nsresult    Optimize(nsIDeviceContext* aContext);
+  virtual PRBool      GetHasAlphaMask()     { return mAlphaBits != nsnull; }        
   virtual PRUint8*    GetAlphaBits();
   virtual PRInt32     GetAlphaWidth();
   virtual PRInt32     GetAlphaHeight();
@@ -68,6 +69,10 @@ public:
 
   void*               GetBitInfo();
   virtual PRBool      GetIsRowOrderTopToBottom() { return PR_TRUE; }
+
+  NS_IMETHOD   LockImagePixels(PRBool aMaskPixels);
+  NS_IMETHOD   UnlockImagePixels(PRBool aMaskPixels);    
+
 private:
   PRInt32   mWidth;
   PRInt32   mHeight;

layout/base/nsCSSRendering.cpp

@@ -1929,8 +1929,7 @@ nsCSSRendering::PaintBackground(nsIPresContext& aPresContext,
       xDistance = dirtyRect.width;
       yDistance = dirtyRect.height;
       // We need to render the background color if the image is transparent
-      PRUint8*  alphaBits = image->GetAlphaBits();
+      needBackgroundColor = image->GetHasAlphaMask();
-      needBackgroundColor = alphaBits != nsnull;
       break;
     }
 

layout/html/style/src/nsCSSRendering.cpp

@@ -1929,8 +1929,7 @@ nsCSSRendering::PaintBackground(nsIPresContext& aPresContext,
       xDistance = dirtyRect.width;
       yDistance = dirtyRect.height;
       // We need to render the background color if the image is transparent
-      PRUint8*  alphaBits = image->GetAlphaBits();
+      needBackgroundColor = image->GetHasAlphaMask();
-      needBackgroundColor = alphaBits != nsnull;
       break;
     }