pixman-filter: Made Gaussian a bit wider
Expanded the size slightly (from ~4.25 to 5) to make the cutoff less
noticable. Previouly the value at the cutoff was
gaussian_filter(sqrt(2)*3/2) = 0.00626 which is larger than the
difference between 8-bit pixels (1/255 = 0.003921). New cutoff is
gaussian_filter(2.5) = 0.001089 which is smaller.
v11: added some math to commit message
v14: left SIGMA in there
Signed-off-by: Bill Spitzak <spitzak@gmail.com>
Acked-by: Oded Gabbay <oded.gabbay@gmail.com>
Reviewed-by: Søren Sandmann <soren.sandmann@gmail.com>
diff --git a/pixman/pixman-filter.c b/pixman/pixman-filter.c
index 3318893..5f3b752 100644
--- a/pixman/pixman-filter.c
+++ b/pixman/pixman-filter.c
@@ -143,7 +143,7 @@
{ PIXMAN_KERNEL_BOX, box_kernel, 1.0 },
{ PIXMAN_KERNEL_LINEAR, linear_kernel, 2.0 },
{ PIXMAN_KERNEL_CUBIC, cubic_kernel, 4.0 },
- { PIXMAN_KERNEL_GAUSSIAN, gaussian_kernel, 6 * SIGMA },
+ { PIXMAN_KERNEL_GAUSSIAN, gaussian_kernel, 5.0 },
{ PIXMAN_KERNEL_LANCZOS2, lanczos2_kernel, 4.0 },
{ PIXMAN_KERNEL_LANCZOS3, lanczos3_kernel, 6.0 },
{ PIXMAN_KERNEL_LANCZOS3_STRETCHED, nice_kernel, 8.0 },
