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/* GIMP - The GNU Image Manipulation Program
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* gimpoperationcolorbalance.c
* Copyright (C) 2007 Michael Natterer <mitch@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 <https://www.gnu.org/licenses/>.
*/
#include "config.h"
#include <cairo.h>
#include <gegl.h>
#include <gdk-pixbuf/gdk-pixbuf.h>
#include "libgimpcolor/gimpcolor.h"
#include "libgimpmath/gimpmath.h"
#include "operations-types.h"
#include "gimpcolorbalanceconfig.h"
#include "gimpoperationcolorbalance.h"
#include "gimp-intl.h"
static gboolean gimp_operation_color_balance_process (GeglOperation *operation,
void *in_buf,
void *out_buf,
glong samples,
const GeglRectangle *roi,
gint level);
G_DEFINE_TYPE (GimpOperationColorBalance, gimp_operation_color_balance,
GIMP_TYPE_OPERATION_POINT_FILTER)
#define parent_class gimp_operation_color_balance_parent_class
static void
gimp_operation_color_balance_class_init (GimpOperationColorBalanceClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
GeglOperationClass *operation_class = GEGL_OPERATION_CLASS (klass);
GeglOperationPointFilterClass *point_class = GEGL_OPERATION_POINT_FILTER_CLASS (klass);
object_class->set_property = gimp_operation_point_filter_set_property;
object_class->get_property = gimp_operation_point_filter_get_property;
gegl_operation_class_set_keys (operation_class,
"name", "gimp:color-balance",
"categories", "color",
"description", _("Adjust color distribution"),
NULL);
point_class->process = gimp_operation_color_balance_process;
g_object_class_install_property (object_class,
GIMP_OPERATION_POINT_FILTER_PROP_CONFIG,
g_param_spec_object ("config",
"Config",
"The config object",
GIMP_TYPE_COLOR_BALANCE_CONFIG,
G_PARAM_READWRITE |
G_PARAM_CONSTRUCT));
}
static void
gimp_operation_color_balance_init (GimpOperationColorBalance *self)
{
}
static inline gfloat
gimp_operation_color_balance_map (gfloat value,
gdouble lightness,
gdouble shadows,
gdouble midtones,
gdouble highlights)
{
/* Apply masks to the corrections for shadows, midtones and
* highlights so that each correction affects only one range.
* Those masks look like this:
* ‾\___
* _/‾\_
* ___/‾
* with ramps of width a at x = b and x = 1 - b.
*
* The sum of these masks equals 1 for x in 0..1, so applying the
* same correction in the shadows and in the midtones is equivalent
* to applying this correction on a virtual shadows_and_midtones
* range.
*/
static const gdouble a = 0.25, b = 0.333, scale = 0.7;
shadows *= CLAMP ((lightness - b) / -a + 0.5, 0, 1) * scale;
midtones *= CLAMP ((lightness - b) / a + 0.5, 0, 1) *
CLAMP ((lightness + b - 1) / -a + 0.5, 0, 1) * scale;
highlights *= CLAMP ((lightness + b - 1) / a + 0.5, 0, 1) * scale;
value += shadows;
value += midtones;
value += highlights;
value = CLAMP (value, 0.0, 1.0);
return value;
}
static gboolean
gimp_operation_color_balance_process (GeglOperation *operation,
void *in_buf,
void *out_buf,
glong samples,
const GeglRectangle *roi,
gint level)
{
GimpOperationPointFilter *point = GIMP_OPERATION_POINT_FILTER (operation);
GimpColorBalanceConfig *config = GIMP_COLOR_BALANCE_CONFIG (point->config);
gfloat *src = in_buf;
gfloat *dest = out_buf;
if (! config)
return FALSE;
while (samples--)
{
gfloat r = src[RED];
gfloat g = src[GREEN];
gfloat b = src[BLUE];
gfloat r_n;
gfloat g_n;
gfloat b_n;
GimpRGB rgb = { r, g, b};
GimpHSL hsl;
gimp_rgb_to_hsl (&rgb, &hsl);
r_n = gimp_operation_color_balance_map (r, hsl.l,
config->cyan_red[GIMP_TRANSFER_SHADOWS],
config->cyan_red[GIMP_TRANSFER_MIDTONES],
config->cyan_red[GIMP_TRANSFER_HIGHLIGHTS]);
g_n = gimp_operation_color_balance_map (g, hsl.l,
config->magenta_green[GIMP_TRANSFER_SHADOWS],
config->magenta_green[GIMP_TRANSFER_MIDTONES],
config->magenta_green[GIMP_TRANSFER_HIGHLIGHTS]);
b_n = gimp_operation_color_balance_map (b, hsl.l,
config->yellow_blue[GIMP_TRANSFER_SHADOWS],
config->yellow_blue[GIMP_TRANSFER_MIDTONES],
config->yellow_blue[GIMP_TRANSFER_HIGHLIGHTS]);
if (config->preserve_luminosity)
{
GimpHSL hsl2;
rgb.r = r_n;
rgb.g = g_n;
rgb.b = b_n;
gimp_rgb_to_hsl (&rgb, &hsl);
rgb.r = r;
rgb.g = g;
rgb.b = b;
gimp_rgb_to_hsl (&rgb, &hsl2);
hsl.l = hsl2.l;
gimp_hsl_to_rgb (&hsl, &rgb);
r_n = rgb.r;
g_n = rgb.g;
b_n = rgb.b;
}
dest[RED] = r_n;
dest[GREEN] = g_n;
dest[BLUE] = b_n;
dest[ALPHA] = src[ALPHA];
src += 4;
dest += 4;
}
return TRUE;
}
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