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gimp/app/core/gimphistogram.c

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/* GIMP - The GNU Image Manipulation Program
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* gimphistogram module Copyright (C) 1999 Jay Cox <jaycox@gimp.org>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <string.h>
#include <gegl.h>
#include "libgimpmath/gimpmath.h"
#include "core-types.h"
#include "gegl/gimp-babl.h"
#include "gimphistogram.h"
struct _GimpHistogram
{
gint ref_count;
gint n_channels;
gdouble *values;
};
/* local function prototypes */
static void gimp_histogram_alloc_values (GimpHistogram *histogram,
gint bytes);
/* public functions */
GimpHistogram *
gimp_histogram_new (void)
{
GimpHistogram *histogram = g_slice_new0 (GimpHistogram);
histogram->ref_count = 1;
return histogram;
}
GimpHistogram *
gimp_histogram_ref (GimpHistogram *histogram)
{
g_return_val_if_fail (histogram != NULL, NULL);
histogram->ref_count++;
return histogram;
}
void
gimp_histogram_unref (GimpHistogram *histogram)
{
g_return_if_fail (histogram != NULL);
histogram->ref_count--;
if (histogram->ref_count == 0)
{
gimp_histogram_clear_values (histogram);
g_slice_free (GimpHistogram, histogram);
}
}
/**
* gimp_histogram_duplicate:
* @histogram: a %GimpHistogram
*
* Creates a duplicate of @histogram. The duplicate has a reference
* count of 1 and contains the values from @histogram.
*
* Return value: a newly allocated %GimpHistogram
**/
GimpHistogram *
gimp_histogram_duplicate (GimpHistogram *histogram)
{
GimpHistogram *dup;
g_return_val_if_fail (histogram != NULL, NULL);
dup = gimp_histogram_new ();
dup->n_channels = histogram->n_channels;
dup->values = g_memdup (histogram->values,
sizeof (gdouble) * dup->n_channels * 256);
return dup;
}
void
gimp_histogram_calculate (GimpHistogram *histogram,
GeglBuffer *buffer,
const GeglRectangle *buffer_rect,
GeglBuffer *mask,
const GeglRectangle *mask_rect)
{
GeglBufferIterator *iter;
const Babl *format;
gint n_components;
g_return_if_fail (histogram != NULL);
g_return_if_fail (GEGL_IS_BUFFER (buffer));
g_return_if_fail (buffer_rect != NULL);
format = gegl_buffer_get_format (buffer);
if (babl_format_is_palette (format))
format = gimp_babl_format (GIMP_RGB, GIMP_PRECISION_U8,
babl_format_has_alpha (format));
else
format = gimp_babl_format (gimp_babl_format_get_base_type (format),
GIMP_PRECISION_U8,
babl_format_has_alpha (format));
n_components = babl_format_get_n_components (format);
gimp_histogram_alloc_values (histogram, n_components);
iter = gegl_buffer_iterator_new (buffer, buffer_rect, 0, format,
GEGL_BUFFER_READ, GEGL_ABYSS_NONE);
if (mask)
gegl_buffer_iterator_add (iter, mask, mask_rect, 0,
babl_format ("Y float"),
GEGL_BUFFER_READ, GEGL_ABYSS_NONE);
#define VALUE(c,i) (histogram->values[(c) * 256 + (i)])
while (gegl_buffer_iterator_next (iter))
{
const guchar *data = iter->data[0];
gint max;
if (mask)
{
const gfloat *mask_data = iter->data[1];
switch (n_components)
{
case 1:
while (iter->length--)
{
const gdouble masked = *mask_data;
VALUE (0, data[0]) += masked;
data += n_components;
mask_data += 1;
}
break;
case 2:
while (iter->length--)
{
const gdouble masked = *mask_data;
const gdouble weight = data[1] / 255.0;
VALUE (0, data[0]) += weight * masked;
VALUE (1, data[1]) += masked;
data += n_components;
mask_data += 1;
}
break;
case 3: /* calculate separate value values */
while (iter->length--)
{
const gdouble masked = *mask_data;
VALUE (1, data[0]) += masked;
VALUE (2, data[1]) += masked;
VALUE (3, data[2]) += masked;
max = MAX (data[0], data[1]);
max = MAX (data[2], max);
VALUE (0, max) += masked;
data += n_components;
mask_data += 1;
}
break;
case 4: /* calculate separate value values */
while (iter->length--)
{
const gdouble masked = *mask_data;
const gdouble weight = data[3] / 255.0;
VALUE (1, data[0]) += weight * masked;
VALUE (2, data[1]) += weight * masked;
VALUE (3, data[2]) += weight * masked;
VALUE (4, data[3]) += masked;
max = MAX (data[0], data[1]);
max = MAX (data[2], max);
VALUE (0, max) += weight * masked;
data += n_components;
mask_data += 1;
}
break;
}
}
else /* no mask */
{
switch (n_components)
{
case 1:
while (iter->length--)
{
VALUE (0, data[0]) += 1.0;
data += n_components;
}
break;
case 2:
while (iter->length--)
{
const gdouble weight = data[1] / 255.0;
VALUE (0, data[0]) += weight;
VALUE (1, data[1]) += 1.0;
data += n_components;
}
break;
case 3: /* calculate separate value values */
while (iter->length--)
{
VALUE (1, data[0]) += 1.0;
VALUE (2, data[1]) += 1.0;
VALUE (3, data[2]) += 1.0;
max = MAX (data[0], data[1]);
max = MAX (data[2], max);
VALUE (0, max) += 1.0;
data += n_components;
}
break;
case 4: /* calculate separate value values */
while (iter->length--)
{
const gdouble weight = data[3] / 255.0;
VALUE (1, data[0]) += weight;
VALUE (2, data[1]) += weight;
VALUE (3, data[2]) += weight;
VALUE (4, data[3]) += 1.0;
max = MAX (data[0], data[1]);
max = MAX (data[2], max);
VALUE (0, max) += weight;
data += n_components;
}
break;
}
}
}
#undef VALUE
}
void
gimp_histogram_clear_values (GimpHistogram *histogram)
{
g_return_if_fail (histogram != NULL);
if (histogram->values)
{
g_free (histogram->values);
histogram->values = NULL;
}
histogram->n_channels = 0;
}
#define HISTOGRAM_VALUE(c,i) (histogram->values[(c) * 256 + (i)])
gdouble
gimp_histogram_get_maximum (GimpHistogram *histogram,
GimpHistogramChannel channel)
{
gdouble max = 0.0;
gint x;
g_return_val_if_fail (histogram != NULL, 0.0);
/* the gray alpha channel is in slot 1 */
if (histogram->n_channels == 3 && channel == GIMP_HISTOGRAM_ALPHA)
channel = 1;
if (! histogram->values ||
(channel != GIMP_HISTOGRAM_RGB && channel >= histogram->n_channels))
return 0.0;
if (channel == GIMP_HISTOGRAM_RGB)
for (x = 0; x < 256; x++)
{
max = MAX (max, HISTOGRAM_VALUE (GIMP_HISTOGRAM_RED, x));
max = MAX (max, HISTOGRAM_VALUE (GIMP_HISTOGRAM_GREEN, x));
max = MAX (max, HISTOGRAM_VALUE (GIMP_HISTOGRAM_BLUE, x));
}
else
for (x = 0; x < 256; x++)
{
max = MAX (max, HISTOGRAM_VALUE (channel, x));
}
return max;
}
gdouble
gimp_histogram_get_value (GimpHistogram *histogram,
GimpHistogramChannel channel,
gint bin)
{
g_return_val_if_fail (histogram != NULL, 0.0);
/* the gray alpha channel is in slot 1 */
if (histogram->n_channels == 3 && channel == GIMP_HISTOGRAM_ALPHA)
channel = 1;
if (! histogram->values ||
bin < 0 || bin >= 256 ||
(channel == GIMP_HISTOGRAM_RGB && histogram->n_channels < 4) ||
(channel != GIMP_HISTOGRAM_RGB && channel >= histogram->n_channels))
return 0.0;
if (channel == GIMP_HISTOGRAM_RGB)
{
gdouble min = HISTOGRAM_VALUE (GIMP_HISTOGRAM_RED, bin);
min = MIN (min, HISTOGRAM_VALUE (GIMP_HISTOGRAM_GREEN, bin));
return MIN (min, HISTOGRAM_VALUE (GIMP_HISTOGRAM_BLUE, bin));
}
else
{
return HISTOGRAM_VALUE (channel, bin);
}
}
gdouble
gimp_histogram_get_channel (GimpHistogram *histogram,
GimpHistogramChannel channel,
gint bin)
{
g_return_val_if_fail (histogram != NULL, 0.0);
if (histogram->n_channels > 3)
channel++;
return gimp_histogram_get_value (histogram, channel, bin);
}
gint
gimp_histogram_n_channels (GimpHistogram *histogram)
{
g_return_val_if_fail (histogram != NULL, 0);
return histogram->n_channels - 1;
}
gdouble
gimp_histogram_get_count (GimpHistogram *histogram,
GimpHistogramChannel channel,
gint start,
gint end)
{
gint i;
gdouble count = 0.0;
g_return_val_if_fail (histogram != NULL, 0.0);
/* the gray alpha channel is in slot 1 */
if (histogram->n_channels == 3 && channel == GIMP_HISTOGRAM_ALPHA)
channel = 1;
if (channel == GIMP_HISTOGRAM_RGB)
return (gimp_histogram_get_count (histogram,
GIMP_HISTOGRAM_RED, start, end) +
gimp_histogram_get_count (histogram,
GIMP_HISTOGRAM_GREEN, start, end) +
gimp_histogram_get_count (histogram,
GIMP_HISTOGRAM_BLUE, start, end));
if (! histogram->values ||
start > end ||
channel >= histogram->n_channels)
return 0.0;
start = CLAMP (start, 0, 255);
end = CLAMP (end, 0, 255);
for (i = start; i <= end; i++)
count += HISTOGRAM_VALUE (channel, i);
return count;
}
gdouble
gimp_histogram_get_mean (GimpHistogram *histogram,
GimpHistogramChannel channel,
gint start,
gint end)
{
gint i;
gdouble mean = 0.0;
gdouble count;
g_return_val_if_fail (histogram != NULL, 0.0);
/* the gray alpha channel is in slot 1 */
if (histogram->n_channels == 3 && channel == GIMP_HISTOGRAM_ALPHA)
channel = 1;
if (! histogram->values ||
start > end ||
(channel == GIMP_HISTOGRAM_RGB && histogram->n_channels < 4) ||
(channel != GIMP_HISTOGRAM_RGB && channel >= histogram->n_channels))
return 0.0;
start = CLAMP (start, 0, 255);
end = CLAMP (end, 0, 255);
if (channel == GIMP_HISTOGRAM_RGB)
{
for (i = start; i <= end; i++)
mean += (i * HISTOGRAM_VALUE (GIMP_HISTOGRAM_RED, i) +
i * HISTOGRAM_VALUE (GIMP_HISTOGRAM_GREEN, i) +
i * HISTOGRAM_VALUE (GIMP_HISTOGRAM_BLUE, i));
}
else
{
for (i = start; i <= end; i++)
mean += i * HISTOGRAM_VALUE (channel, i);
}
count = gimp_histogram_get_count (histogram, channel, start, end);
if (count > 0.0)
return mean / count;
return mean;
}
gint
gimp_histogram_get_median (GimpHistogram *histogram,
GimpHistogramChannel channel,
gint start,
gint end)
{
gint i;
gdouble sum = 0.0;
gdouble count;
g_return_val_if_fail (histogram != NULL, -1);
/* the gray alpha channel is in slot 1 */
if (histogram->n_channels == 3 && channel == GIMP_HISTOGRAM_ALPHA)
channel = 1;
if (! histogram->values ||
start > end ||
(channel == GIMP_HISTOGRAM_RGB && histogram->n_channels < 4) ||
(channel != GIMP_HISTOGRAM_RGB && channel >= histogram->n_channels))
return 0;
start = CLAMP (start, 0, 255);
end = CLAMP (end, 0, 255);
count = gimp_histogram_get_count (histogram, channel, start, end);
if (channel == GIMP_HISTOGRAM_RGB)
for (i = start; i <= end; i++)
{
sum += (HISTOGRAM_VALUE (GIMP_HISTOGRAM_RED, i) +
HISTOGRAM_VALUE (GIMP_HISTOGRAM_GREEN, i) +
HISTOGRAM_VALUE (GIMP_HISTOGRAM_BLUE, i));
if (sum * 2 > count)
return i;
}
else
for (i = start; i <= end; i++)
{
sum += HISTOGRAM_VALUE (channel, i);
if (sum * 2 > count)
return i;
}
return -1;
}
/*
* adapted from GNU ocrad 0.14 : page_image_io.cc : otsu_th
*
* N. Otsu, "A threshold selection method from gray-level histograms,"
* IEEE Trans. Systems, Man, and Cybernetics, vol. 9, no. 1, pp. 62-66, 1979.
*/
gdouble
gimp_histogram_get_threshold (GimpHistogram *histogram,
GimpHistogramChannel channel,
gint start,
gint end)
{
gint i;
gint maxval;
gdouble *hist = NULL;
gdouble *chist = NULL;
gdouble *cmom = NULL;
gdouble hist_max = 0.0;
gdouble chist_max = 0.0;
gdouble cmom_max = 0.0;
gdouble bvar_max = 0.0;
gint threshold = 127;
g_return_val_if_fail (histogram != NULL, -1);
/* the gray alpha channel is in slot 1 */
if (histogram->n_channels == 3 && channel == GIMP_HISTOGRAM_ALPHA)
channel = 1;
if (! histogram->values ||
start > end ||
(channel == GIMP_HISTOGRAM_RGB && histogram->n_channels < 4) ||
(channel != GIMP_HISTOGRAM_RGB && channel >= histogram->n_channels))
return 0;
start = CLAMP (start, 0, 255);
end = CLAMP (end, 0, 255);
maxval = end - start;
hist = g_newa (gdouble, maxval + 1);
chist = g_newa (gdouble, maxval + 1);
cmom = g_newa (gdouble, maxval + 1);
if (channel == GIMP_HISTOGRAM_RGB)
{
for (i = start; i <= end; i++)
hist[i - start] = (HISTOGRAM_VALUE (GIMP_HISTOGRAM_RED, i) +
HISTOGRAM_VALUE (GIMP_HISTOGRAM_GREEN, i) +
HISTOGRAM_VALUE (GIMP_HISTOGRAM_BLUE, i));
}
else
{
for (i = start; i <= end; i++)
hist[i - start] = HISTOGRAM_VALUE (channel, i);
}
hist_max = hist[0];
chist[0] = hist[0];
cmom[0] = 0;
for (i = 1; i <= maxval; i++)
{
if (hist[i] > hist_max)
hist_max = hist[i];
chist[i] = chist[i-1] + hist[i];
cmom[i] = cmom[i-1] + i * hist[i];
}
chist_max = chist[maxval];
cmom_max = cmom[maxval];
bvar_max = 0;
for (i = 0; i < maxval; ++i)
if (chist[i] > 0 && chist[i] < chist_max)
{
gdouble bvar;
bvar = (gdouble) cmom[i] / chist[i];
bvar -= (cmom_max - cmom[i]) / (chist_max - chist[i]);
bvar *= bvar;
bvar *= chist[i];
bvar *= chist_max - chist[i];
if (bvar > bvar_max)
{
bvar_max = bvar;
threshold = start + i;
}
}
return threshold;
}
gdouble
gimp_histogram_get_std_dev (GimpHistogram *histogram,
GimpHistogramChannel channel,
gint start,
gint end)
{
gint i;
gdouble dev = 0.0;
gdouble count;
gdouble mean;
g_return_val_if_fail (histogram != NULL, 0.0);
/* the gray alpha channel is in slot 1 */
if (histogram->n_channels == 3 && channel == GIMP_HISTOGRAM_ALPHA)
channel = 1;
if (! histogram->values ||
start > end ||
(channel == GIMP_HISTOGRAM_RGB && histogram->n_channels < 4) ||
(channel != GIMP_HISTOGRAM_RGB && channel >= histogram->n_channels))
return 0.0;
mean = gimp_histogram_get_mean (histogram, channel, start, end);
count = gimp_histogram_get_count (histogram, channel, start, end);
if (count == 0.0)
count = 1.0;
for (i = start; i <= end; i++)
{
gdouble value;
if (channel == GIMP_HISTOGRAM_RGB)
{
value = (HISTOGRAM_VALUE (GIMP_HISTOGRAM_RED, i) +
HISTOGRAM_VALUE (GIMP_HISTOGRAM_GREEN, i) +
HISTOGRAM_VALUE (GIMP_HISTOGRAM_BLUE, i));
}
else
{
value = gimp_histogram_get_value (histogram, channel, i);
}
dev += value * SQR (i - mean);
}
return sqrt (dev / count);
}
/* private functions */
static void
gimp_histogram_alloc_values (GimpHistogram *histogram,
gint bytes)
{
if (bytes + 1 != histogram->n_channels)
{
gimp_histogram_clear_values (histogram);
histogram->n_channels = bytes + 1;
histogram->values = g_new0 (gdouble, histogram->n_channels * 256);
}
else
{
memset (histogram->values,
0, histogram->n_channels * 256 * sizeof (gdouble));
}
}
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