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-rw-r--r--render/picture.c16
1 files changed, 14 insertions, 2 deletions
diff --git a/render/picture.c b/render/picture.c
index 2fbd09e8b..b7874bb64 100644
--- a/render/picture.c
+++ b/render/picture.c
@@ -1548,12 +1548,24 @@ FreePictFormat (pointer pPictFormat,
* being careful to avoid these cases.
*/
static CARD8
-ReduceCompositeOp (CARD8 op, PicturePtr pSrc, PicturePtr pMask, PicturePtr pDst)
+ReduceCompositeOp (CARD8 op, PicturePtr pSrc, PicturePtr pMask, PicturePtr pDst,
+ INT16 xSrc, INT16 ySrc, CARD16 width, CARD16 height)
{
Bool no_src_alpha, no_dst_alpha;
+ /* Sampling off the edge of a RepeatNone picture introduces alpha
+ * even if the picture itself doesn't have alpha. We don't try to
+ * detect every case where we don't sample off the edge, just the
+ * simplest case where there is no transform on the source
+ * picture.
+ */
no_src_alpha = PICT_FORMAT_COLOR(pSrc->format) &&
PICT_FORMAT_A(pSrc->format) == 0 &&
+ (pSrc->repeatType != RepeatNone ||
+ (!pSrc->transform &&
+ xSrc >= 0 && ySrc >= 0 &&
+ xSrc + width <= pSrc->pDrawable->width &&
+ ySrc + height <= pSrc->pDrawable->height)) &&
pSrc->alphaMap == NULL &&
pMask == NULL;
no_dst_alpha = PICT_FORMAT_COLOR(pDst->format) &&
@@ -1655,7 +1667,7 @@ CompositePicture (CARD8 op,
ValidatePicture (pMask);
ValidatePicture (pDst);
- op = ReduceCompositeOp (op, pSrc, pMask, pDst);
+ op = ReduceCompositeOp (op, pSrc, pMask, pDst, xSrc, ySrc, width, height);
if (op == PictOpDst)
return;