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>

1 files changed, 49 insertions, 22 deletions

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;
 }