fb: Adjust transform or composite coordinates for pixman operations

Windows (or even pixmaps, in some cases) may not sit at the origin of
the containing pixmap, so any coordinates relative to the drawable
must be adjusted. For destinations and untransformed sources, the
operation coordinates are adjusted. For transformed sources, the
transform matrix is adjusted.

Signed-off-by: Keith Packard <keithp@keithp.com>
Acked-by: Soeren Sandmann <sandmann@daimi.au.dk>

3 files changed, 58 insertions, 26 deletions

diff --git a/fb/fb.h b/fb/fb.h
index ed21f9eb6..02d6c0372 100644
--- a/fb/fb.h
+++ b/fb/fb.h
@@ -2082,8 +2082,11 @@ fbFillRegionSolid (DrawablePtr	pDrawable,
 		   FbBits	xor);
 
 extern _X_EXPORT pixman_image_t *
-image_from_pict (PicturePtr pict,
-		 Bool       has_clip);
+image_from_pict (PicturePtr	pict,
+		 Bool		has_clip,
+		 int		*xoff,
+		 int		*yoff);
+
 extern _X_EXPORT void free_pixman_pict (PicturePtr, pixman_image_t *);
 
 #endif /* _FB_H_ */
diff --git a/fb/fbpict.c b/fb/fbpict.c
index 07a22869d..251754b3f 100644
--- a/fb/fbpict.c
+++ b/fb/fbpict.c
@@ -158,19 +158,24 @@ fbComposite (CARD8      op,
 	     CARD16     height)
 {
     pixman_image_t *src, *mask, *dest;
+    int src_xoff, src_yoff;
+    int msk_xoff, msk_yoff;
+    int dst_xoff, dst_yoff;
     
     miCompositeSourceValidate (pSrc, xSrc - xDst, ySrc - yDst, width, height);
     if (pMask)
 	miCompositeSourceValidate (pMask, xMask - xDst, yMask - yDst, width, height);
     
-    src = image_from_pict (pSrc, TRUE);
-    mask = image_from_pict (pMask, TRUE);
-    dest = image_from_pict (pDst, TRUE);
+    src = image_from_pict (pSrc, FALSE, &src_xoff, &src_yoff);
+    mask = image_from_pict (pMask, FALSE, &msk_xoff, &msk_yoff);
+    dest = image_from_pict (pDst, TRUE, &dst_xoff, &dst_yoff);
 
     if (src && dest && !(pMask && !mask))
     {
 	pixman_image_composite (op, src, mask, dest,
-				xSrc, ySrc, xMask, yMask, xDst, yDst,
+				xSrc + src_xoff, ySrc + src_yoff,
+				xMask + msk_xoff, yMask + msk_yoff,
+				xDst + dst_xoff, yDst + dst_yoff,
 				width, height);
     }
 
@@ -270,22 +275,22 @@ create_conical_gradient_image (PictGradient *gradient)
 
 static pixman_image_t *
 create_bits_picture (PicturePtr pict,
-		     Bool       has_clip)
+		     Bool       has_clip,
+		     int	*xoff,
+		     int	*yoff)
 {
+    PixmapPtr pixmap;
     FbBits *bits;
     FbStride stride;
-    int bpp, xoff, yoff;
+    int bpp;
     pixman_image_t *image;
     
-    fbGetDrawable (pict->pDrawable, bits, stride, bpp, xoff, yoff);
-
-    bits = (FbBits*)((CARD8*)bits +
-		     (pict->pDrawable->y + yoff) * stride * sizeof(FbBits) +
-		     (pict->pDrawable->x + xoff) * (bpp / 8));
+    fbGetDrawablePixmap (pict->pDrawable, pixmap, *xoff, *yoff);
+    fbGetPixmapBitsData(pixmap, bits, stride, bpp);
 
     image = pixman_image_create_bits (
 	pict->format,
-	pict->pDrawable->width, pict->pDrawable->height,
+	pixmap->drawable.width, pixmap->drawable.height,
 	(uint32_t *)bits, stride * sizeof (FbStride));
     
     
@@ -311,30 +316,52 @@ create_bits_picture (PicturePtr pict,
 	if (pict->clientClipType != CT_NONE)
 	    pixman_image_set_has_client_clip (image, TRUE);
 
-	pixman_region_translate (pict->pCompositeClip, - pict->pDrawable->x, - pict->pDrawable->y);
+	if (*xoff || *yoff)
+	    pixman_region_translate (pict->pCompositeClip, *xoff, *yoff);
 
 	pixman_image_set_clip_region (image, pict->pCompositeClip);
 
-	pixman_region_translate (pict->pCompositeClip, pict->pDrawable->x, pict->pDrawable->y);
+	if (*xoff || *yoff)
+	    pixman_region_translate (pict->pCompositeClip, -*xoff, -*yoff);
     }
     
     /* Indexed table */
     if (pict->pFormat->index.devPrivate)
 	pixman_image_set_indexed (image, pict->pFormat->index.devPrivate);
 
+    /* Add in drawable origin to position within the image */
+    *xoff += pict->pDrawable->x;
+    *yoff += pict->pDrawable->y;
+
     return image;
 }
 
 static void
-set_image_properties (pixman_image_t *image, PicturePtr pict)
+set_image_properties (pixman_image_t *image, PicturePtr pict, Bool has_clip, int *xoff, int *yoff)
 {
     pixman_repeat_t repeat;
     pixman_filter_t filter;
     
     if (pict->transform)
     {
-	pixman_image_set_transform (
-	    image, (pixman_transform_t *)pict->transform);
+	/* For source images, adjust the transform to account
+	 * for the drawable offset within the pixman image,
+	 * then set the offset to 0 as it will be used
+	 * to compute positions within the transformed image.
+	 */
+	if (!has_clip) {
+	    struct pixman_transform	adjusted;
+
+	    adjusted = *pict->transform;
+	    pixman_transform_translate(&adjusted,
+				       NULL,
+				       pixman_int_to_fixed(*xoff),
+				       pixman_int_to_fixed(*yoff));
+	    pixman_image_set_transform (image, &adjusted);
+	    *xoff = 0;
+	    *yoff = 0;
+	} else
+	    pixman_image_set_transform (image, pict->transform);
     }
     
     switch (pict->repeatType)
@@ -361,7 +388,8 @@ set_image_properties (pixman_image_t *image, PicturePtr pict)
     
     if (pict->alphaMap)
     {
-	pixman_image_t *alpha_map = image_from_pict (pict->alphaMap, TRUE);
+	int alpha_xoff, alpha_yoff;
+	pixman_image_t *alpha_map = image_from_pict (pict->alphaMap, FALSE, &alpha_xoff, &alpha_yoff);
 	
 	pixman_image_set_alpha_map (
 	    image, alpha_map, pict->alphaOrigin.x, pict->alphaOrigin.y);
@@ -394,8 +422,7 @@ set_image_properties (pixman_image_t *image, PicturePtr pict)
 }
 
 pixman_image_t *
-image_from_pict (PicturePtr pict,
-		 Bool has_clip)
+image_from_pict (PicturePtr pict, Bool has_clip, int *xoff, int *yoff)
 {
     pixman_image_t *image = NULL;
 
@@ -404,7 +431,7 @@ image_from_pict (PicturePtr pict,
 
     if (pict->pDrawable)
     {
-	image = create_bits_picture (pict, has_clip);
+	image = create_bits_picture (pict, has_clip, xoff, yoff);
     }
     else if (pict->pSourcePict)
     {
@@ -428,7 +455,7 @@ image_from_pict (PicturePtr pict,
     }
     
     if (image)
-	set_image_properties (image, pict);
+	set_image_properties (image, pict, has_clip, xoff, yoff);
     
     return image;
 }
diff --git a/fb/fbtrap.c b/fb/fbtrap.c
index 830603ae7..515e2e1c1 100644
--- a/fb/fbtrap.c
+++ b/fb/fbtrap.c
@@ -40,7 +40,8 @@ fbAddTraps (PicturePtr	pPicture,
 	    int		ntrap,
 	    xTrap	*traps)
 {
-    pixman_image_t *image = image_from_pict (pPicture, FALSE);
+    int image_xoff, image_yoff;
+    pixman_image_t *image = image_from_pict (pPicture, FALSE, &image_xoff, &image_yoff);
 
     if (!image)
 	return;
@@ -56,7 +57,8 @@ fbRasterizeTrapezoid (PicturePtr    pPicture,
 		      int	    x_off,
 		      int	    y_off)
 {
-    pixman_image_t *image = image_from_pict (pPicture, FALSE);
+    int	mask_xoff, mask_yoff;
+    pixman_image_t *image = image_from_pict (pPicture, FALSE, &mask_xoff, &mask_yoff);
 
     if (!image)
 	return;