callisto-debian/gimp
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

Bug 667368: Bug in Histogram egalization

Browse Source
This commit is contained in:
Massimo Valentini
2012-03-08 18:20:45 +01:00
parent c7c752f5df
commit 71cb4fbd71
1 changed files with 11 additions and 36 deletions
Download Patch File Download Diff File Expand all files Collapse all files

47
app/base/lut-funcs.c
View File

@ -287,7 +287,7 @@ posterize_lut_new (gint levels,
typedef struct
{
GimpHistogram *histogram;
gint part[5][257];
gint part[5][256];
} hist_lut_struct;
static gfloat
@ -296,19 +296,15 @@ equalize_lut_func (hist_lut_struct *hlut,
gint channel,
gfloat value)
{
gint i = 0;
gint j;
/* don't equalize the alpha channel */
if ((nchannels == 2 || nchannels == 4) && channel == nchannels - 1)
return value;
j = (gint) (value * 255.0 + 0.5);
j = RINT (CLAMP (value * 255.0, 0, 255));
while (hlut->part[channel][i + 1] <= j)
i++;
return i / 255.0;
return hlut->part[channel][j] / 255.;
}
static void
@ -316,48 +312,27 @@ equalize_lut_setup (GimpLut *lut,
GimpHistogram *hist,
gint n_channels)
{
gint i, k, j;
gint i, k;
hist_lut_struct hlut;
gdouble pixels_per_value;
gdouble desired;
gdouble sum, dif;
gdouble pixels;
g_return_if_fail (lut != NULL);
g_return_if_fail (hist != NULL);
/* Find partition points */
pixels_per_value = gimp_histogram_get_count (hist,
GIMP_HISTOGRAM_VALUE,
0, 255) / 256.0;
pixels = gimp_histogram_get_count (hist, GIMP_HISTOGRAM_VALUE, 0, 255);
for (k = 0; k < n_channels; k++)
{
/* First and last points in partition */
hlut.part[k][0] = 0;
hlut.part[k][256] = 256;
gdouble sum = 0;
/* Find intermediate points */
j = 0;
sum = (gimp_histogram_get_channel (hist, k, 0) +
gimp_histogram_get_channel (hist, k, 1));
for (i = 1; i < 256; i++)
for (i = 0; i < 256; i++)
{
desired = i * pixels_per_value;
gdouble histi = gimp_histogram_get_channel (hist, k, i);
while (sum < desired && j < 256)
{
j++;
sum += gimp_histogram_get_channel (hist, k, j + 1);
}
sum += histi;
/* Nearest sum */
dif = sum - gimp_histogram_get_channel (hist, k, j);
if ((sum - desired) > (dif / 2.0))
hlut.part[k][i] = j;
else
hlut.part[k][i] = j + 1;
hlut.part[k][i] = RINT (sum * 255. / pixels);
}
}