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more hist_local fixups

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add tests, add restrict
This commit is contained in:
John Cupitt 2017-01-22 10:36:07 +00:00
parent 9660036216
commit c963678549
2 changed files with 19 additions and 9 deletions
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21
libvips/histogram/hist_local.c
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@ -172,10 +172,12 @@ vips_hist_local_generate( VipsRegion *or,
for( y = 0; y < r->height; y++ ) {
/* Get input and output pointers for this line.
*/
VipsPel *p = VIPS_REGION_ADDR( seq->ir, r->left, r->top + y );
VipsPel *q = VIPS_REGION_ADDR( or, r->left, r->top + y );
VipsPel * restrict p =
VIPS_REGION_ADDR( seq->ir, r->left, r->top + y );
VipsPel * restrict q =
VIPS_REGION_ADDR( or, r->left, r->top + y );
VipsPel *p1;
VipsPel * restrict p1;
int x, i, j, b;
/* Find histogram for start of this line.
@ -197,8 +199,8 @@ vips_hist_local_generate( VipsRegion *or,
for( b = 0; b < bands; b++ ) {
/* Sum histogram up to current pel.
*/
unsigned int *hist = seq->hist[b];
const int target = p[centre];
unsigned int * restrict hist = seq->hist[b];
const int target = p[centre + b];
const int max_slope = local->max_slope;
int sum;
@ -251,23 +253,24 @@ vips_hist_local_generate( VipsRegion *or,
* Scale by 255, not 256, or we'll get
* overflow.
*/
*q++ = 255 * sum /
q[b] = 255 * sum /
(local->width * local->height);
/* Adapt histogram --- remove the pels from
* the left hand column, add in pels for a
* new right-hand column.
*/
p1 = p;
p1 = p + b;
for( j = 0; j < local->height; j++ ) {
hist[p1[0]] -= 1;
hist[p1[bands * local->width]] += 1;
p1 += lsk;
}
p += 1;
}
p += bands;
q += bands;
}
}

7
test/test_histogram.py
View File

@ -74,6 +74,13 @@ class TestHistogram(unittest.TestCase):
self.assertTrue(im.avg() < im2.avg())
self.assertTrue(im.deviate() < im2.deviate())
im3 = im.hist_local(10, 10, max_slope = 3)
self.assertEqual(im.width, im2.width)
self.assertEqual(im.height, im2.height)
self.assertTrue(im3.deviate() < im2.deviate())
def test_hist_match(self):
im = Vips.Image.identity()
im2 = Vips.Image.identity()