Fix rounding issue in DrawTile() and remove a bogus assertion. Bug 194791, Author=paper@animecity.nu, r=smontagu, sr=roc+moz

gfx/public/nsIRenderingContext.h

@@ -812,8 +812,16 @@ public:
   /* [noscript] void drawScaledImage (in imgIContainer aImage, [const] in nsRect aSrcRect, [const] in nsRect aDestRect); */
   NS_IMETHOD DrawScaledImage(imgIContainer *aImage, const nsRect * aSrcRect, const nsRect * aDestRect) = 0;
 
-  /* [noscript] void drawTile (in imgIContainer aImage, in nscoord aXOffset, in nscoord aYOffset, [const] in nsRect aTargetRect); */
-  NS_IMETHOD DrawTile(imgIContainer *aImage, nscoord aXOffset, nscoord aYOffset, const nsRect * aTargetRect) = 0;
+  /*
+   * Tiles an image over an area
+   * @param aImage       Image to tile
+   * @param aXImageStart x location where the origin (0,0) of the image starts
+   * @param aYImageStart y location where the origin (0,0) of the image starts
+   * @param aTargetRect  area to draw to
+   */
+  NS_IMETHOD DrawTile(imgIContainer *aImage,
+                      nscoord aXImageStart, nscoord aYImageStart,
+                      const nsRect * aTargetRect) = 0;
 
 };
 

gfx/src/shared/nsRenderingContextImpl.cpp

@@ -880,16 +880,25 @@ NS_IMETHODIMP nsRenderingContextImpl::DrawScaledImage(imgIContainer *aImage, con
                    dr.x, dr.y, dr.width, dr.height);
 }
 
-/* [noscript] void drawTile (in imgIContainer aImage, in nscoord aXOffset, in nscoord aYOffset, [const] in nsRect aTargetRect); */
-NS_IMETHODIMP nsRenderingContextImpl::DrawTile(imgIContainer *aImage, nscoord aXOffset, nscoord aYOffset, const nsRect * aTargetRect)
+/* [noscript] void drawTile (in imgIContainer aImage, in nscoord aXImageStart, in nscoord aYImageStart, [const] in nsRect aTargetRect); */
+NS_IMETHODIMP
+nsRenderingContextImpl::DrawTile(imgIContainer *aImage,
+                                 nscoord aXImageStart, nscoord aYImageStart,
+                                 const nsRect * aTargetRect)
 {
   nsRect dr(*aTargetRect);
-  nsRect so(0, 0, aXOffset, aYOffset);
-
   mTranMatrix->TransformCoord(&dr.x, &dr.y, &dr.width, &dr.height);
+  mTranMatrix->TransformCoord(&aXImageStart, &aYImageStart);
 
-  // i want one of these...
-  mTranMatrix->TransformCoord(&so.x, &so.y, &so.width, &so.height);
+  nscoord width, height;
+  aImage->GetWidth(&width);
+  aImage->GetHeight(&height);
+
+  if (width == 0 || height == 0)
+    return PR_FALSE;
+
+  nscoord xOffset = (dr.x - aXImageStart) % width;
+  nscoord yOffset = (dr.y - aYImageStart) % height;
 
   nsCOMPtr<gfxIImageFrame> iframe;
   aImage->GetCurrentFrame(getter_AddRefs(iframe));
@@ -902,7 +911,7 @@ NS_IMETHODIMP nsRenderingContextImpl::DrawTile(imgIContainer *aImage, nscoord aX
   GetDrawingSurface((void**)&surface);
   if (!surface) return NS_ERROR_FAILURE;
 
-  return img->DrawTile(*this, surface, so.width, so.height, dr);
+  return img->DrawTile(*this, surface, xOffset, yOffset, dr);
 }
 
 NS_IMETHODIMP

gfx/src/windows/nsImageWin.cpp

@@ -735,9 +735,6 @@ NS_IMETHODIMP nsImageWin::DrawTile(nsIRenderingContext &aContext,
                                    PRInt32 aSXOffset, PRInt32 aSYOffset,
                                    const nsRect &aDestRect)
 {
-  NS_ASSERTION(aSXOffset < mBHead->biWidth && aSYOffset < mBHead->biHeight,
-               "Offset(s) are bigger than image.  Caller to DrawTile needs to do more thinking!");
-
   if (mDecodedX2 < mDecodedX1 || mDecodedY2 < mDecodedY1)
     return NS_OK;
 

layout/base/nsCSSRendering.cpp

@@ -3375,11 +3375,8 @@ nsCSSRendering::PaintBackgroundWithSC(nsIPresContext* aPresContext,
   nsRect tileRect(x0, y0, (x1 - x0), (y1 - y0));
   nsRect drawRect;
 
-  if (drawRect.IntersectRect(tileRect, dirtyRect)) {
-    PRInt32 xOffset = drawRect.x - x0,
-            yOffset = drawRect.y - y0;
-    aRenderingContext.DrawTile(image, xOffset, yOffset, &drawRect);
-  }
+  if (drawRect.IntersectRect(tileRect, dirtyRect))
+    aRenderingContext.DrawTile(image, x0, y0, &drawRect);
 
 #if (!defined(XP_UNIX) && !defined(XP_BEOS)) || defined(XP_MACOSX)
   // Restore clipping

layout/html/style/src/nsCSSRendering.cpp

@@ -3375,11 +3375,8 @@ nsCSSRendering::PaintBackgroundWithSC(nsIPresContext* aPresContext,
   nsRect tileRect(x0, y0, (x1 - x0), (y1 - y0));
   nsRect drawRect;
 
-  if (drawRect.IntersectRect(tileRect, dirtyRect)) {
-    PRInt32 xOffset = drawRect.x - x0,
-            yOffset = drawRect.y - y0;
-    aRenderingContext.DrawTile(image, xOffset, yOffset, &drawRect);
-  }
+  if (drawRect.IntersectRect(tileRect, dirtyRect))
+    aRenderingContext.DrawTile(image, x0, y0, &drawRect);
 
 #if (!defined(XP_UNIX) && !defined(XP_BEOS)) || defined(XP_MACOSX)
   // Restore clipping