mirror of https://github.com/GNOME/gimp.git
317 lines
8.0 KiB
C
317 lines
8.0 KiB
C
/* The GIMP -- an image manipulation program
|
|
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
|
|
*
|
|
* 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 2 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, write to the Free Software
|
|
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
|
|
*/
|
|
|
|
#include "config.h"
|
|
|
|
#include <glib-object.h>
|
|
|
|
#include "libgimpmath/gimpmath.h"
|
|
|
|
#include "libgimpcolor/gimpcolortypes.h"
|
|
#include "libgimpcolor/gimprgb.h"
|
|
|
|
#include "base-types.h"
|
|
|
|
#include "gimphistogram.h"
|
|
#include "levels.h"
|
|
|
|
|
|
/* public functions */
|
|
|
|
void
|
|
levels_init (Levels *levels)
|
|
{
|
|
GimpHistogramChannel channel;
|
|
|
|
g_return_if_fail (levels != NULL);
|
|
|
|
for (channel = GIMP_HISTOGRAM_VALUE;
|
|
channel <= GIMP_HISTOGRAM_ALPHA;
|
|
channel++)
|
|
{
|
|
levels_channel_reset (levels, channel);
|
|
}
|
|
}
|
|
|
|
void
|
|
levels_channel_reset (Levels *levels,
|
|
GimpHistogramChannel channel)
|
|
{
|
|
g_return_if_fail (levels != NULL);
|
|
|
|
levels->gamma[channel] = 1.0;
|
|
levels->low_input[channel] = 0;
|
|
levels->high_input[channel] = 255;
|
|
levels->low_output[channel] = 0;
|
|
levels->high_output[channel] = 255;
|
|
}
|
|
|
|
void
|
|
levels_stretch (Levels *levels,
|
|
GimpHistogram *hist,
|
|
gboolean is_color)
|
|
{
|
|
GimpHistogramChannel channel;
|
|
|
|
g_return_if_fail (levels != NULL);
|
|
g_return_if_fail (hist != NULL);
|
|
|
|
if (is_color)
|
|
{
|
|
/* Set the overall value to defaults */
|
|
levels_channel_reset (levels, GIMP_HISTOGRAM_VALUE);
|
|
|
|
for (channel = GIMP_HISTOGRAM_RED;
|
|
channel <= GIMP_HISTOGRAM_BLUE;
|
|
channel++)
|
|
levels_channel_stretch (levels, hist, channel);
|
|
}
|
|
else
|
|
{
|
|
levels_channel_stretch (levels, hist, GIMP_HISTOGRAM_VALUE);
|
|
}
|
|
}
|
|
|
|
void
|
|
levels_channel_stretch (Levels *levels,
|
|
GimpHistogram *hist,
|
|
GimpHistogramChannel channel)
|
|
{
|
|
gint i;
|
|
gdouble count, new_count, percentage, next_percentage;
|
|
|
|
g_return_if_fail (levels != NULL);
|
|
g_return_if_fail (hist != NULL);
|
|
|
|
levels->gamma[channel] = 1.0;
|
|
levels->low_output[channel] = 0;
|
|
levels->high_output[channel] = 255;
|
|
|
|
count = gimp_histogram_get_count (hist, channel, 0, 255);
|
|
|
|
if (count == 0.0)
|
|
{
|
|
levels->low_input[channel] = 0;
|
|
levels->high_input[channel] = 0;
|
|
}
|
|
else
|
|
{
|
|
/* Set the low input */
|
|
new_count = 0.0;
|
|
|
|
for (i = 0; i < 255; i++)
|
|
{
|
|
new_count += gimp_histogram_get_value (hist, channel, i);
|
|
percentage = new_count / count;
|
|
next_percentage =
|
|
(new_count + gimp_histogram_get_value (hist,
|
|
channel,
|
|
i + 1)) / count;
|
|
if (fabs (percentage - 0.006) < fabs (next_percentage - 0.006))
|
|
{
|
|
levels->low_input[channel] = i + 1;
|
|
break;
|
|
}
|
|
}
|
|
/* Set the high input */
|
|
new_count = 0.0;
|
|
for (i = 255; i > 0; i--)
|
|
{
|
|
new_count += gimp_histogram_get_value (hist, channel, i);
|
|
percentage = new_count / count;
|
|
next_percentage =
|
|
(new_count + gimp_histogram_get_value (hist,
|
|
channel,
|
|
i - 1)) / count;
|
|
if (fabs (percentage - 0.006) < fabs (next_percentage - 0.006))
|
|
{
|
|
levels->high_input[channel] = i - 1;
|
|
break;
|
|
}
|
|
}
|
|
}
|
|
}
|
|
|
|
static gint
|
|
levels_input_from_color (GimpHistogramChannel channel,
|
|
guchar *color)
|
|
{
|
|
switch (channel)
|
|
{
|
|
case GIMP_HISTOGRAM_VALUE:
|
|
return MAX (MAX (color[RED_PIX], color[GREEN_PIX]), color[BLUE_PIX]);
|
|
case GIMP_HISTOGRAM_RED:
|
|
return color[RED_PIX];
|
|
case GIMP_HISTOGRAM_GREEN:
|
|
return color[GREEN_PIX];
|
|
case GIMP_HISTOGRAM_BLUE:
|
|
return color[BLUE_PIX];
|
|
case GIMP_HISTOGRAM_ALPHA:
|
|
return color[ALPHA_PIX];
|
|
case GIMP_HISTOGRAM_RGB:
|
|
return MIN (MIN (color[RED_PIX], color[GREEN_PIX]), color[BLUE_PIX]);
|
|
}
|
|
|
|
return 0; /* just to please the compiler */
|
|
}
|
|
|
|
void
|
|
levels_adjust_by_colors (Levels *levels,
|
|
GimpHistogramChannel channel,
|
|
guchar *black,
|
|
guchar *gray,
|
|
guchar *white)
|
|
{
|
|
g_return_if_fail (levels != NULL);
|
|
|
|
if (black)
|
|
levels->low_input[channel] = levels_input_from_color (channel, black);
|
|
|
|
if (white)
|
|
levels->high_input[channel] = levels_input_from_color (channel, white);
|
|
|
|
if (gray)
|
|
{
|
|
gint input;
|
|
gint range;
|
|
gdouble inten;
|
|
gdouble out_light;
|
|
guchar lightness;
|
|
|
|
/* Calculate lightness value */
|
|
lightness = GIMP_RGB_INTENSITY (gray[0], gray[1], gray[2]);
|
|
|
|
input = levels_input_from_color (channel, gray);
|
|
|
|
range = levels->high_input[channel] - levels->low_input[channel];
|
|
if (range <= 0)
|
|
return;
|
|
|
|
input -= levels->low_input[channel];
|
|
if (input < 0)
|
|
return;
|
|
|
|
/* Normalize input and lightness */
|
|
inten = (gdouble) input / (gdouble) range;
|
|
out_light = (gdouble) lightness/ (gdouble) range;
|
|
|
|
if (out_light <= 0)
|
|
return;
|
|
|
|
/* Map selected color to corresponding lightness */
|
|
levels->gamma[channel] = log (inten) / log (out_light);
|
|
}
|
|
}
|
|
|
|
void
|
|
levels_calculate_transfers (Levels *levels)
|
|
{
|
|
gdouble inten;
|
|
gint i, j;
|
|
|
|
g_return_if_fail (levels != NULL);
|
|
|
|
/* Recalculate the levels arrays */
|
|
for (j = 0; j < 5; j++)
|
|
{
|
|
for (i = 0; i < 256; i++)
|
|
{
|
|
/* determine input intensity */
|
|
if (levels->high_input[j] != levels->low_input[j])
|
|
{
|
|
inten = ((gdouble) (i - levels->low_input[j]) /
|
|
(double) (levels->high_input[j] - levels->low_input[j]));
|
|
}
|
|
else
|
|
{
|
|
inten = (gdouble) (i - levels->low_input[j]);
|
|
}
|
|
|
|
inten = CLAMP (inten, 0.0, 1.0);
|
|
|
|
if (levels->gamma[j] != 0.0)
|
|
inten = pow (inten, (1.0 / levels->gamma[j]));
|
|
|
|
levels->input[j][i] = (guchar) (inten * 255.0 + 0.5);
|
|
}
|
|
}
|
|
}
|
|
|
|
gfloat
|
|
levels_lut_func (Levels *levels,
|
|
gint n_channels,
|
|
gint channel,
|
|
gfloat value)
|
|
{
|
|
gdouble inten;
|
|
gint j;
|
|
|
|
if (n_channels <= 2)
|
|
j = channel;
|
|
else
|
|
j = channel + 1;
|
|
|
|
inten = value;
|
|
|
|
/* For RGB and RGBA images this runs through the loop with j = channel + 1
|
|
* the first time and j = 0 the second time
|
|
*
|
|
* For GRAY images this runs through the loop with j = 0 the first and
|
|
* only time
|
|
*/
|
|
for (; j >= 0; j -= (channel + 1))
|
|
{
|
|
/* don't apply the overall curve to the alpha channel */
|
|
if (j == 0 && (n_channels == 2 || n_channels == 4) &&
|
|
channel == n_channels - 1)
|
|
return inten;
|
|
|
|
/* determine input intensity */
|
|
if (levels->high_input[j] != levels->low_input[j])
|
|
{
|
|
inten = ((gdouble) (255.0 * inten - levels->low_input[j]) /
|
|
(gdouble) (levels->high_input[j] - levels->low_input[j]));
|
|
}
|
|
else
|
|
{
|
|
inten = (gdouble) (255.0 * inten - levels->low_input[j]);
|
|
}
|
|
|
|
if (levels->gamma[j] != 0.0)
|
|
{
|
|
if (inten >= 0.0)
|
|
inten = pow ( inten, (1.0 / levels->gamma[j]));
|
|
else
|
|
inten = -pow (-inten, (1.0 / levels->gamma[j]));
|
|
}
|
|
|
|
/* determine the output intensity */
|
|
if (levels->high_output[j] >= levels->low_output[j])
|
|
inten = (gdouble) (inten * (levels->high_output[j] -
|
|
levels->low_output[j]) +
|
|
levels->low_output[j]);
|
|
else if (levels->high_output[j] < levels->low_output[j])
|
|
inten = (gdouble) (levels->low_output[j] - inten *
|
|
(levels->low_output[j] - levels->high_output[j]));
|
|
|
|
inten /= 255.0;
|
|
}
|
|
|
|
return inten;
|
|
}
|