Samples are multiplied in a 1,4,2,4,2,4,1 pattern, previous version
did 1,2,4,4,4,2,1.
I also reduced the number of samples greatly as there is no
numerical difference with the filter functions.
---
pixman/pixman-filter.c | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/pixman/pixman-filter.c b/pixman/pixman-filter.c
index b2bf53f..a9af72c 100644
--- a/pixman/pixman-filter.c
+++ b/pixman/pixman-filter.c
@@ -190,7 +190,7 @@ integral (pixman_kernel_t kernel1, double x1,
else
{
/* Integration via Simpson's rule */
-#define N_SEGMENTS 128
+#define N_SEGMENTS 16
#define SAMPLE(a1, a2) \
(filters[kernel1].func ((a1)) * filters[kernel2].func ((a2) * scale))
@@ -204,11 +204,14 @@ integral (pixman_kernel_t kernel1, double x1,
{
double a1 = x1 + h * i;
double a2 = x2 + h * i;
+ s += 4 * SAMPLE(a1, a2);
+ }
- s += 2 * SAMPLE (a1, a2);
-
- if (i >= 2 && i < N_SEGMENTS - 1)
- s += 4 * SAMPLE (a1, a2);
+ for (i = 2; i < N_SEGMENTS; i += 2)
+ {
+ double a1 = x1 + h * i;
+ double a2 = x2 + h * i;
+ s += 2 * SAMPLE(a1, a2);
}
s += SAMPLE (x1 + width, x2 + width);
--
1.7.9.5
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