diff options
| author | Bill Spitzak <spitzak@gmail.com> | 2016-08-30 22:03:11 -0700 |
|---|---|---|
| committer | Søren Sandmann Pedersen <soren.sandmann@gmail.com> | 2016-09-02 00:40:12 -0400 |
| commit | 8855b3a2a231ab348c02c0d92f0051b079eabfa3 (patch) | |
| tree | 96713c3b64be2661e957b8e781dc395a297b1fe4 | |
| parent | 6ae281fbb7a02b94a3900b6677a51cdd28096ed7 (diff) | |
pixman-filter: integral splitting is only needed for triangle filter
Only the triangle is discontinuous at 0. The other filters resemble a
cubic closely enough that Simpsons integration works without
splitting.
Changes by Søren: Rebase without the changes to the integral function,
update comment to match the new code.
Signed-off-by: Bill Spitzak <spitzak@gmail.com>
Signed-off-by: Søren Sandmann <soren.sandmann@gmail.com>
Reviewed-by: Søren Sandmann <soren.sandmann@gmail.com>
| -rw-r--r-- | pixman/pixman-filter.c | 11 |
1 files changed, 5 insertions, 6 deletions
diff --git a/pixman/pixman-filter.c b/pixman/pixman-filter.c index ecff852..878cf9d 100644 --- a/pixman/pixman-filter.c +++ b/pixman/pixman-filter.c @@ -160,18 +160,17 @@ integral (pixman_kernel_t kernel1, double x1, pixman_kernel_t kernel2, double scale, double x2, double width) { - /* If the integration interval crosses zero, break it into - * two separate integrals. This ensures that filters such - * as LINEAR that are not differentiable at 0 will still - * integrate properly. + /* The LINEAR filter is not differentiable at 0, so if the + * integration interval crosses zero, break it into two + * separate integrals. */ - if (x1 < 0 && x1 + width > 0) + if (kernel1 == PIXMAN_KERNEL_LINEAR && x1 < 0 && x1 + width > 0) { return integral (kernel1, x1, kernel2, scale, x2, - x1) + integral (kernel1, 0, kernel2, scale, x2 - x1, width + x1); } - else if (x2 < 0 && x2 + width > 0) + else if (kernel2 == PIXMAN_KERNEL_LINEAR && x2 < 0 && x2 + width > 0) { return integral (kernel1, x1, kernel2, scale, x2, - x2) + |