Adding support for XOR selection. Updated nsIRenderingContext interface

to support InvertRect() for the XOR-ing of rectangles.  Makes selection
work as expected on windows and unix as opposed to the rectangle hack.
Stubs added for all other platforms.

gfx/public/nsIRenderingContext.h

@@ -325,6 +325,21 @@ public:
    */
   NS_IMETHOD FillRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight) = 0;
 
+  /**
+   * XOR Invert a rectangle in the current foreground color
+   * @param aRect The rectangle to draw
+   */
+  NS_IMETHOD InvertRect(const nsRect& aRect) = 0;
+
+  /**
+   * XOR Invert a rectangle in the current foreground color
+   * @param aX Horizontal left Coordinate in twips
+   * @param aY Vertical top Coordinate in twips
+   * @param aWidth Width of rectangle in twips
+   * @param aHeight Height of rectangle in twips
+   */
+  NS_IMETHOD InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight) = 0;
+
   /**
    * Draw a poly in the current foreground color
    * @param aPoints points to use for the drawing, last must equal first

gfx/src/beos/nsRenderingContextBeOS.cpp

@@ -823,6 +823,22 @@ NS_IMETHODIMP nsRenderingContextBeOS::FillRect(nscoord aX, nscoord aY, nscoord a
 	return NS_OK;
 }
 
+NS_IMETHODIMP 
+nsRenderingContextBeOS :: InvertRect(const nsRect& aRect)
+{
+	NS_NOTYETIMPLEMENTED("nsRenderingContextBeOS::InvertRect");
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP 
+nsRenderingContextBeOS :: InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight)
+{
+	NS_NOTYETIMPLEMENTED("nsRenderingContextBeOS::InvertRect");
+
+  return NS_OK;
+}
+
 NS_IMETHODIMP nsRenderingContextBeOS::DrawPolygon(const nsPoint aPoints[], PRInt32 aNumPoints)
 {
 	// First transform nsPoint's into BPoint's; perform coordinate space

gfx/src/beos/nsRenderingContextBeOS.h

@@ -96,9 +96,13 @@ public:
 
   NS_IMETHOD DrawRect(const nsRect& aRect);
   NS_IMETHOD DrawRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+
   NS_IMETHOD FillRect(const nsRect& aRect);
   NS_IMETHOD FillRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
 
+  NS_IMETHOD InvertRect(const nsRect& aRect);
+  NS_IMETHOD InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+  
   NS_IMETHOD DrawPolygon(const nsPoint aPoints[], PRInt32 aNumPoints);
   NS_IMETHOD FillPolygon(const nsPoint aPoints[], PRInt32 aNumPoints);
 

gfx/src/gtk/nsRenderingContextGTK.cpp

@@ -745,6 +745,40 @@ NS_IMETHODIMP nsRenderingContextGTK::FillRect(nscoord aX, nscoord aY, nscoord aW
   return NS_OK;
 }
 
+NS_IMETHODIMP nsRenderingContextGTK::InvertRect(const nsRect& aRect)
+{
+  return InvertRect(aRect.x, aRect.y, aRect.width, aRect.height);
+}
+
+NS_IMETHODIMP nsRenderingContextGTK::InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight)
+{
+  if (nsnull == mTMatrix || nsnull == mSurface) {
+    return NS_ERROR_FAILURE;
+  }
+
+  nscoord x,y,w,h;
+
+  x = aX;
+  y = aY;
+  w = aWidth;
+  h = aHeight;
+
+  mTMatrix->TransformCoord(&x,&y,&w,&h);
+
+  // Set XOR drawing mode
+  ::gdk_gc_set_function(mSurface->GetGC(),GDK_XOR);  
+
+  // Fill the rect
+  ::gdk_draw_rectangle(mSurface->GetDrawable(), mSurface->GetGC(),
+                       TRUE,
+                       x, y, w, h);
+
+  // Back to normal copy drawing mode
+  ::gdk_gc_set_function(mSurface->GetGC(),GDK_COPY);
+
+  return NS_OK;
+}
+
 NS_IMETHODIMP nsRenderingContextGTK::DrawPolygon(const nsPoint aPoints[], PRInt32 aNumPoints)
 {
   g_return_val_if_fail(mTMatrix != NULL, NS_ERROR_FAILURE);

gfx/src/gtk/nsRenderingContextGTK.h

@@ -98,9 +98,13 @@ public:
 
   NS_IMETHOD DrawRect(const nsRect& aRect);
   NS_IMETHOD DrawRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+
   NS_IMETHOD FillRect(const nsRect& aRect);
   NS_IMETHOD FillRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
 
+  NS_IMETHOD InvertRect(const nsRect& aRect);
+  NS_IMETHOD InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+
   NS_IMETHOD DrawPolygon(const nsPoint aPoints[], PRInt32 aNumPoints);
   NS_IMETHOD FillPolygon(const nsPoint aPoints[], PRInt32 aNumPoints);
 

gfx/src/motif/nsRenderingContextMotif.cpp

@@ -992,6 +992,21 @@ NS_IMETHODIMP nsRenderingContextMotif :: FillRect(nscoord aX, nscoord aY, nscoor
   return NS_OK;
 }
 
+NS_IMETHODIMP 
+nsRenderingContextMotif :: InvertRect(const nsRect& aRect)
+{
+	NS_NOTYETIMPLEMENTED("nsRenderingContextMotif::InvertRect");
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP 
+nsRenderingContextMotif :: InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight)
+{
+	NS_NOTYETIMPLEMENTED("nsRenderingContextMotif::InvertRect");
+
+  return NS_OK;
+}
 
 NS_IMETHODIMP nsRenderingContextMotif::DrawPolygon(const nsPoint aPoints[], PRInt32 aNumPoints)
 {

gfx/src/motif/nsRenderingContextMotif.h

@@ -106,9 +106,13 @@ public:
 
   NS_IMETHOD DrawRect(const nsRect& aRect);
   NS_IMETHOD DrawRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+
   NS_IMETHOD FillRect(const nsRect& aRect);
   NS_IMETHOD FillRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
 
+  NS_IMETHOD InvertRect(const nsRect& aRect);
+  NS_IMETHOD InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+
   NS_IMETHOD DrawPolygon(const nsPoint aPoints[], PRInt32 aNumPoints);
   NS_IMETHOD FillPolygon(const nsPoint aPoints[], PRInt32 aNumPoints);
 

gfx/src/os2/nsRenderingContextOS2.cpp

@@ -1003,6 +1003,22 @@ nsresult nsRenderingContextOS2::FillRect( nscoord aX, nscoord aY, nscoord aWidth
    return NS_OK;
 }
 
+NS_IMETHODIMP 
+nsRenderingContextOS2 :: InvertRect(const nsRect& aRect)
+{
+	NS_NOTYETIMPLEMENTED("nsRenderingContextOS2::InvertRect");
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP 
+nsRenderingContextOS2 :: InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight)
+{
+	NS_NOTYETIMPLEMENTED("nsRenderingContextOS2::InvertRect");
+
+  return NS_OK;
+}
+
 void nsRenderingContextOS2::PMDrawRect( nsRect &rect, BOOL fill)
 {
    mTMatrix.TransformCoord( &rect.x, &rect.y, &rect.width, &rect.height);

gfx/src/os2/nsRenderingContextOS2.h

@@ -112,6 +112,9 @@ class nsRenderingContextOS2 : public nsIRenderingContext,
    NS_IMETHOD FillRect( const nsRect& aRect);
    NS_IMETHOD FillRect( nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
 
+   NS_IMETHOD InvertRect(const nsRect& aRect);
+   NS_IMETHOD InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+
    NS_IMETHOD DrawPolygon( const nsPoint aPoints[], PRInt32 aNumPoints);
    NS_IMETHOD FillPolygon( const nsPoint aPoints[], PRInt32 aNumPoints);
 

gfx/src/photon/nsRenderingContextPh.cpp

@@ -996,6 +996,21 @@ NS_IMETHODIMP nsRenderingContextPh :: FillRect(nscoord aX, nscoord aY, nscoord a
   return NS_OK;
 }
 
+NS_IMETHODIMP 
+nsRenderingContextPh :: InvertRect(const nsRect& aRect)
+{
+	NS_NOTYETIMPLEMENTED("nsRenderingContextPh::InvertRect");
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP 
+nsRenderingContextPh :: InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight)
+{
+	NS_NOTYETIMPLEMENTED("nsRenderingContextPh::InvertRect");
+
+  return NS_OK;
+}
 
 NS_IMETHODIMP nsRenderingContextPh :: DrawPolygon(const nsPoint aPoints[], PRInt32 aNumPoints)
 {

gfx/src/photon/nsRenderingContextPh.h

@@ -106,9 +106,13 @@ public:
 
   NS_IMETHOD DrawRect(const nsRect& aRect);
   NS_IMETHOD DrawRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+
   NS_IMETHOD FillRect(const nsRect& aRect);
   NS_IMETHOD FillRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
 
+  NS_IMETHOD InvertRect(const nsRect& aRect);
+  NS_IMETHOD InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+
   NS_IMETHOD DrawPolygon(const nsPoint aPoints[], PRInt32 aNumPoints);
   NS_IMETHOD FillPolygon(const nsPoint aPoints[], PRInt32 aNumPoints);
 

gfx/src/ps/nsRenderingContextPS.cpp

@@ -724,6 +724,22 @@ nsRenderingContextPS :: FillRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord
   return NS_OK;
 }
 
+NS_IMETHODIMP 
+nsRenderingContextPS :: InvertRect(const nsRect& aRect)
+{
+	NS_NOTYETIMPLEMENTED("nsRenderingContextPS::InvertRect");
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP 
+nsRenderingContextPS :: InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight)
+{
+	NS_NOTYETIMPLEMENTED("nsRenderingContextPS::InvertRect");
+
+  return NS_OK;
+}
+
 /** ---------------------------------------------------
  *  See documentation in nsIRenderingContext.h
  *	@update 12/21/98 dwc

gfx/src/ps/nsRenderingContextPS.h

@@ -104,9 +104,13 @@ public:
 
   NS_IMETHOD DrawRect(const nsRect& aRect);
   NS_IMETHOD DrawRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+
   NS_IMETHOD FillRect(const nsRect& aRect);
   NS_IMETHOD FillRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
 
+  NS_IMETHOD InvertRect(const nsRect& aRect);
+  NS_IMETHOD InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+
   NS_IMETHOD DrawPolygon(const nsPoint aPoints[], PRInt32 aNumPoints);
   NS_IMETHOD FillPolygon(const nsPoint aPoints[], PRInt32 aNumPoints);
 

gfx/src/windows/nsRenderingContextWin.cpp

@@ -1202,6 +1202,35 @@ NS_IMETHODIMP nsRenderingContextWin :: FillRect(nscoord aX, nscoord aY, nscoord
   return NS_OK;
 }
 
+NS_IMETHODIMP nsRenderingContextWin :: InvertRect(const nsRect& aRect)
+{
+  RECT nr;
+	nsRect tr;
+
+	tr = aRect;
+	mTMatrix->TransformCoord(&tr.x,&tr.y,&tr.width,&tr.height);
+  ConditionRect(tr, nr);
+  ::InvertRect(mDC, &nr);
+
+  return NS_OK;
+}
+
+NS_IMETHODIMP nsRenderingContextWin :: InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight)
+{
+  RECT nr;
+	nsRect	tr;
+
+	mTMatrix->TransformCoord(&aX,&aY,&aWidth,&aHeight);
+	nr.left = aX;
+	nr.top = aY;
+	nr.right = aX+aWidth;
+	nr.bottom = aY+aHeight;
+
+  ::InvertRect(mDC, &nr);
+
+  return NS_OK;
+}
+
 NS_IMETHODIMP nsRenderingContextWin :: DrawPolygon(const nsPoint aPoints[], PRInt32 aNumPoints)
 {
   // First transform nsPoint's into POINT's; perform coordinate space

gfx/src/windows/nsRenderingContextWin.h

@@ -102,9 +102,13 @@ public:
 
   NS_IMETHOD DrawRect(const nsRect& aRect);
   NS_IMETHOD DrawRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+
   NS_IMETHOD FillRect(const nsRect& aRect);
   NS_IMETHOD FillRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
 
+  NS_IMETHOD InvertRect(const nsRect& aRect);
+  NS_IMETHOD InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+
   NS_IMETHOD DrawPolygon(const nsPoint aPoints[], PRInt32 aNumPoints);
   NS_IMETHOD FillPolygon(const nsPoint aPoints[], PRInt32 aNumPoints);
 

gfx/src/xlib/nsRenderingContextXlib.cpp

@@ -826,6 +826,49 @@ nsRenderingContextXlib::FillRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord
   return NS_OK;
 }
 
+NS_IMETHODIMP 
+nsRenderingContextXlib :: InvertRect(const nsRect& aRect)
+{
+  return InvertRect(aRect.x, aRect.y, aRect.width, aRect.height);
+}
+
+NS_IMETHODIMP 
+nsRenderingContextXlib :: InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight)
+{
+  if (nsnull == mTMatrix || nsnull == mRenderingSurface) 
+    return NS_ERROR_FAILURE;
+  
+  nscoord x,y,w,h;
+
+  x = aX;
+  y = aY;
+  w = aWidth;
+  h = aHeight;
+
+  mTMatrix->TransformCoord(&x,&y,&w,&h);
+
+  // Set XOR drawing mode
+  ::XSetFunction(mDisplay,
+                 mRenderingSurface->GetGC(),
+                 GXxor);  
+
+  ::XFillRectangle(mDisplay,
+                   mRenderingSurface->GetDrawable(),
+                   mRenderingSurface->GetGC(),
+                   x,
+                   y,
+                   w,
+                   h);
+  
+  // Back to normal copy drawing mode
+  // Set XOR drawing mode
+  ::XSetFunction(mDisplay,
+                 mRenderingSurface->GetGC(),
+                 GXcopy);  
+
+  return NS_OK;
+}
+
 NS_IMETHODIMP
 nsRenderingContextXlib::DrawPolygon(const nsPoint aPoints[], PRInt32 aNumPoints)
 {

gfx/src/xlib/nsRenderingContextXlib.h

@@ -101,9 +101,13 @@ class nsRenderingContextXlib : public nsIRenderingContext,
 
   NS_IMETHOD DrawRect(const nsRect& aRect);
   NS_IMETHOD DrawRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+
   NS_IMETHOD FillRect(const nsRect& aRect);
   NS_IMETHOD FillRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
 
+  NS_IMETHOD InvertRect(const nsRect& aRect);
+  NS_IMETHOD InvertRect(nscoord aX, nscoord aY, nscoord aWidth, nscoord aHeight);
+
   NS_IMETHOD DrawPolygon(const nsPoint aPoints[], PRInt32 aNumPoints);
   NS_IMETHOD FillPolygon(const nsPoint aPoints[], PRInt32 aNumPoints);
 

layout/generic/nsTextFrame.cpp

@@ -864,8 +864,20 @@ nsTextFrame::PaintTextDecorations(nsIRenderingContext& aRenderingContext,
           switch (aDetails->mType)
           {
           case SELECTION_NORMAL:{
+//
+// XOR InvertRect is currently implemented only in the unix and windows
+// rendering contexts.  When other platforms implement InvertRect(), they
+// can be added here.  Eventually this #ifdef should die.
+//
+// For platforms that dont implement InvertRect(), the selection will be 
+// a non-filled rectangle.
+#if defined(XP_PC) || defined(XP_UNIX)
+              aRenderingContext.SetColor(NS_RGB(255,255,255));
+              aRenderingContext.InvertRect(aX + startOffset, aY, textWidth, rect.height);
+#else
               aRenderingContext.SetColor(NS_RGB(0,0,0));
               aRenderingContext.DrawRect(aX + startOffset, aY, textWidth, rect.height);
+#endif
                                 }break;
           case SELECTION_SPELLCHECK:{
               aTextStyle.mNormalFont->GetUnderline(offset, size);

layout/html/base/src/nsTextFrame.cpp

@@ -864,8 +864,20 @@ nsTextFrame::PaintTextDecorations(nsIRenderingContext& aRenderingContext,
           switch (aDetails->mType)
           {
           case SELECTION_NORMAL:{
+//
+// XOR InvertRect is currently implemented only in the unix and windows
+// rendering contexts.  When other platforms implement InvertRect(), they
+// can be added here.  Eventually this #ifdef should die.
+//
+// For platforms that dont implement InvertRect(), the selection will be 
+// a non-filled rectangle.
+#if defined(XP_PC) || defined(XP_UNIX)
+              aRenderingContext.SetColor(NS_RGB(255,255,255));
+              aRenderingContext.InvertRect(aX + startOffset, aY, textWidth, rect.height);
+#else
               aRenderingContext.SetColor(NS_RGB(0,0,0));
               aRenderingContext.DrawRect(aX + startOffset, aY, textWidth, rect.height);
+#endif
                                 }break;
           case SELECTION_SPELLCHECK:{
               aTextStyle.mNormalFont->GetUnderline(offset, size);