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| author | Manuel Stoeckl <code@mstoeckl.com> | 2021-08-02 21:48:38 -0400 |
|---|---|---|
| committer | Manuel Stoeckl <code@mstoeckl.com> | 2021-08-09 21:43:58 -0400 |
| commit | 5f5e752f15acff7f39c861f2defed8ca10fa041c (patch) | |
| tree | a9022bbd653584f663850b9c5d0a62e3059aaf08 | |
| parent | aaf59b0338fbd4b9142794254261f8d0a018b60c (diff) | |
| download | pixman-5f5e752f15acff7f39c861f2defed8ca10fa041c.tar.gz | |
Fix masked pixel fetching with wide format
In __bits_image_fetch_affine_no_alpha and __bits_image_fetch_general,
when `wide` is true, the mask is actually an array of argb_t instead
of the array of uint32_t it was cast to, and the access to `mask[i]`
does not correctly detect when the pixel is nontrivial. The code now
uses a check appropriate for argb_t when `wide` is true.
One caveat: this new check only skips entries when the mask pixel data
is binary all zero; this misses cases like `-0.f` which would be caught
by the FLOAT_IS_ZERO macro. As the mask check only appears to be a
performance optimization to avoid loading inconsequential pixels, it
erring on the side of loading more pixels is safe.
Signed-off-by: Manuel Stoeckl <code@mstoeckl.com>
| -rw-r--r-- | pixman/pixman-bits-image.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/pixman/pixman-bits-image.c b/pixman/pixman-bits-image.c index 8f3d9f2..a0d9441 100644 --- a/pixman/pixman-bits-image.c +++ b/pixman/pixman-bits-image.c @@ -482,6 +482,7 @@ __bits_image_fetch_affine_no_alpha (pixman_iter_t * iter, int width = iter->width; uint32_t * buffer = iter->buffer; + const uint32_t wide_zero[4] = {0}; pixman_fixed_t x, y; pixman_fixed_t ux, uy; pixman_vector_t v; @@ -513,7 +514,8 @@ __bits_image_fetch_affine_no_alpha (pixman_iter_t * iter, for (i = 0; i < width; ++i) { - if (!mask || mask[i]) + if (!mask || (!wide && mask[i]) || + (wide && memcmp(&mask[4 * i], wide_zero, 16) != 0)) { bits_image_fetch_pixel_filtered ( &image->bits, wide, x, y, get_pixel, buffer); @@ -636,6 +638,7 @@ __bits_image_fetch_general (pixman_iter_t *iter, get_pixel_t get_pixel = wide ? fetch_pixel_general_float : fetch_pixel_general_32; + const uint32_t wide_zero[4] = {0}; pixman_fixed_t x, y, w; pixman_fixed_t ux, uy, uw; pixman_vector_t v; @@ -670,7 +673,8 @@ __bits_image_fetch_general (pixman_iter_t *iter, { pixman_fixed_t x0, y0; - if (!mask || mask[i]) + if (!mask || (!wide && mask[i]) || + (wide && memcmp(&mask[4 * i], wide_zero, 16) != 0)) { if (w != 0) { |