The contiguous put routines in the RGBA read path use the fromskew
argument to advance the source pointer over the source columns that are
skipped between two output rows (the clipped part of an edge tile, or the
columns beyond the requested raster width for a strip). fromskew is
expressed in pixels, so it has to be multiplied by the per-pixel sample
stride, exactly as the inner loops advance pp by samplesperpixel for every
pixel.
put8bitcmaptile(), putgreytile() and putagreytile() instead did
pp += fromskew;
without multiplying by samplesperpixel. For greyscale or palette images
that have more than one sample per pixel (i.e. extra samples in a
contiguous configuration) and where fromskew is non-zero - a tiled image
whose width is not a multiple of the tile width, or a sub-region read via
img->col_offset - the source pointer is advanced by too few bytes between
rows, and every row after the first reads its samples from the wrong
offset inside the decoded tile/strip buffer. The result is corrupted pixel
data in the affected columns.
putRGBcontig8bittile() and, more recently, put16bitbwtile() already scale
fromskew by the sample stride; apply the same conversion here so all of
the contiguous put routines are consistent.
Signed-off-by: Nashit Hayat <[email protected]>
---
diff --git a/libtiff/tif_getimage.c b/libtiff/tif_getimage.c
index 4a759a6..80f68a5 100644
--- a/libtiff/tif_getimage.c
+++ b/libtiff/tif_getimage.c
@@ -1626,6 +1626,8 @@ DECLAREContigPutFunc(put8bitcmaptile)
{
uint32_t **PALmap = img->PALmap;
int samplesperpixel = img->samplesperpixel;
+ /* Convert pixel skew to sample skew */
+ const tmsize_t fromskewLocal = (tmsize_t)fromskew *
(tmsize_t)samplesperpixel;
(void)y;
for (; h > 0; --h)
@@ -1636,7 +1638,7 @@ DECLAREContigPutFunc(put8bitcmaptile)
pp += samplesperpixel;
}
cp += toskew;
- pp += fromskew;
+ pp += fromskewLocal;
}
}
@@ -1704,6 +1706,8 @@ DECLAREContigPutFunc(putgreytile)
{
int samplesperpixel = img->samplesperpixel;
uint32_t **BWmap = img->BWmap;
+ /* Convert pixel skew to sample skew */
+ const tmsize_t fromskewLocal = (tmsize_t)fromskew *
(tmsize_t)samplesperpixel;
(void)y;
for (; h > 0; --h)
@@ -1714,7 +1718,7 @@ DECLAREContigPutFunc(putgreytile)
pp += samplesperpixel;
}
cp += toskew;
- pp += fromskew;
+ pp += fromskewLocal;
}
}
@@ -1725,6 +1729,8 @@ DECLAREContigPutFunc(putagreytile)
{
int samplesperpixel = img->samplesperpixel;
uint32_t **BWmap = img->BWmap;
+ /* Convert pixel skew to sample skew */
+ const tmsize_t fromskewLocal = (tmsize_t)fromskew *
(tmsize_t)samplesperpixel;
(void)y;
for (; h > 0; --h)
@@ -1735,7 +1741,7 @@ DECLAREContigPutFunc(putagreytile)
pp += samplesperpixel;
}
cp += toskew;
- pp += fromskew;
+ pp += fromskewLocal;
}
}
--
2.50.1 (Apple Git-155)
_______________________________________________
Tiff mailing list
[email protected]
https://lists.osgeo.org/mailman/listinfo/tiff
