Files
gimp/app/operations/gimplevelsconfig.c
Michael Natterer e09e563a70 Initial space invasion commit in GIMP
All babl formats now have a space equivalent to a color profile,
determining the format's primaries and TRCs. This commit makes GIMP
aware of this.

libgimp:

- enum GimpPrecision: rename GAMMA values to NON_LINEAR and keep GAMMA
  as deprecated aliases, add PERCEPTUAL values so we now have LINEAR,
  NON_LINEAR and PERCPTUAL for each encoding, matching the babl
  encoding variants RGB, R'G'B' and R~G~B~.

- gimp_color_transform_can_gegl_copy() now returns TRUE if both
  profiles can return a babl space, increasing the amount of fast babl
  color conversions significantly.

- TODO: no solution yet for getting libgimp drawable proxy buffers in
  the right format with space.

plug-ins:

- follow the GimpPrecision change.

- TODO: everything else unchanged and partly broken or sub-optimal,
  like setting a new image's color profile too late.

app:

- add enum GimpTRCType { LINEAR, NON_LINEAR, PERCEPTUAL } as
  replacement for all "linear" booleans.

- change gimp-babl functions to take babl spaces and GimpTRCType
  parameters and support all sorts of new perceptual ~ formats.

- a lot of places changed in the early days of goat invasion didn't
  take advantage of gimp-babl utility functions and constructed
  formats manually. They all needed revisiting and many now use much
  simpler code calling gimp-babl API.

- change gimp_babl_format_get_color_profile() to really extract a
  newly allocated color profile from the format, and add
  gimp_babl_get_builtin_color_profile() which does the same as
  gimp_babl_format_get_color_profile() did before. Visited all callers
  to decide whether they are looking for the format's actual profile,
  or for one of the builtin profiles, simplifying code that only needs
  builtin profiles.

- drawables have a new get_space_api(), get_linear() is now get_trc().

- images now have a "layer space" and an API to get it,
  gimp_image_get_layer_format() returns formats in that space.

- an image's layer space is created from the image's color profile,
  change gimpimage-color-profile to deal with that correctly

- change many babl_format() calls to babl_format_with_space() and take
  the space from passed formats or drawables

- add function gimp_layer_fix_format_space() which replaces the
  layer's buffer with one that has the image's layer format, but
  doesn't change pixel values

- use gimp_layer_fix_format_space() to make sure layers loaded from
  XCF and created by plug-ins have the right space when added to the
  image, because it's impossible to always assign the right space upon
  layer creation

- "assign color profile" and "discard color profile" now require use
  of gimp_layer_fix_format_space() too because the profile is now
  embedded in all formats via the space.  Add
  gimp_image_assign_color_profile() which does all that and call it
  instead of a simple gimp_image_set_color_profile(), also from the
  PDB set-color-profile functions, which are essentially "assign" and
  "discard" calls.

- generally, make sure a new image's color profile is set before
  adding layers to it, gimp_image_set_color_profile() is more than
  before considered know-what-you-are-doing API.

- take special precaution in all places that call
  gimp_drawable_convert_type(), we now must pass a new_profile from
  all callers that convert layers within the same image (such as
  image_convert_type, image_convert_precision), because the layer's
  new space can't be determined from the image's layer format during
  the call.

- change all "linear" properties to "trc", in all config objects like
  for levels and curves, in the histogram, in the widgets. This results
  in some GUI that now has three choices instead of two.
  TODO: we might want to reduce that back to two later.

- keep "linear" boolean properties around as compat if needed for file
  pasring, but always convert the parsed parsed boolean to
  GimpTRCType.

- TODO: the image's "enable color management" switch is currently
  broken, will fix that in another commit.
2018-07-21 16:42:57 +02:00

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/* GIMP - The GNU Image Manipulation Program
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* gimplevelsconfig.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 <errno.h>
#include <cairo.h>
#include <gegl.h>
#include <gdk-pixbuf/gdk-pixbuf.h>
#include "libgimpbase/gimpbase.h"
#include "libgimpcolor/gimpcolor.h"
#include "libgimpmath/gimpmath.h"
#include "libgimpconfig/gimpconfig.h"
#include "operations-types.h"
#include "core/gimp-utils.h"
#include "core/gimpcurve.h"
#include "core/gimphistogram.h"
#include "gimpcurvesconfig.h"
#include "gimplevelsconfig.h"
#include "gimpoperationlevels.h"
#include "gimp-intl.h"
enum
{
PROP_0,
PROP_TRC,
PROP_LINEAR,
PROP_CHANNEL,
PROP_LOW_INPUT,
PROP_HIGH_INPUT,
PROP_CLAMP_INPUT,
PROP_GAMMA,
PROP_LOW_OUTPUT,
PROP_HIGH_OUTPUT,
PROP_CLAMP_OUTPUT
};
static void gimp_levels_config_iface_init (GimpConfigInterface *iface);
static void gimp_levels_config_get_property (GObject *object,
guint property_id,
GValue *value,
GParamSpec *pspec);
static void gimp_levels_config_set_property (GObject *object,
guint property_id,
const GValue *value,
GParamSpec *pspec);
static gboolean gimp_levels_config_serialize (GimpConfig *config,
GimpConfigWriter *writer,
gpointer data);
static gboolean gimp_levels_config_deserialize (GimpConfig *config,
GScanner *scanner,
gint nest_level,
gpointer data);
static gboolean gimp_levels_config_equal (GimpConfig *a,
GimpConfig *b);
static void gimp_levels_config_reset (GimpConfig *config);
static gboolean gimp_levels_config_copy (GimpConfig *src,
GimpConfig *dest,
GParamFlags flags);
G_DEFINE_TYPE_WITH_CODE (GimpLevelsConfig, gimp_levels_config,
GIMP_TYPE_SETTINGS,
G_IMPLEMENT_INTERFACE (GIMP_TYPE_CONFIG,
gimp_levels_config_iface_init))
#define parent_class gimp_levels_config_parent_class
static void
gimp_levels_config_class_init (GimpLevelsConfigClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
GimpViewableClass *viewable_class = GIMP_VIEWABLE_CLASS (klass);
object_class->set_property = gimp_levels_config_set_property;
object_class->get_property = gimp_levels_config_get_property;
viewable_class->default_icon_name = "gimp-tool-levels";
GIMP_CONFIG_PROP_ENUM (object_class, PROP_TRC,
"trc",
_("Linear/Perceptual"),
_("Work on linear or perceptual RGB"),
GIMP_TYPE_TRC_TYPE,
GIMP_TRC_NON_LINEAR, 0);
/* compat */
GIMP_CONFIG_PROP_BOOLEAN (object_class, PROP_LINEAR,
"linear",
_("Linear"),
_("Work on linear RGB"),
FALSE, 0);
GIMP_CONFIG_PROP_ENUM (object_class, PROP_CHANNEL,
"channel",
_("Channel"),
_("The affected channel"),
GIMP_TYPE_HISTOGRAM_CHANNEL,
GIMP_HISTOGRAM_VALUE, 0);
GIMP_CONFIG_PROP_DOUBLE (object_class, PROP_LOW_INPUT,
"low-input",
_("Low Input"),
_("Low Input"),
0.0, 1.0, 0.0, 0);
GIMP_CONFIG_PROP_DOUBLE (object_class, PROP_HIGH_INPUT,
"high-input",
_("High Input"),
_("High Input"),
0.0, 1.0, 1.0, 0);
GIMP_CONFIG_PROP_BOOLEAN (object_class, PROP_CLAMP_INPUT,
"clamp-input",
_("Clamp Input"),
_("Clamp input values before applying output mapping."),
FALSE, 0);
GIMP_CONFIG_PROP_DOUBLE (object_class, PROP_GAMMA,
"gamma",
_("Gamma"),
_("Gamma"),
0.1, 10.0, 1.0, 0);
GIMP_CONFIG_PROP_DOUBLE (object_class, PROP_LOW_OUTPUT,
"low-output",
_("Low Output"),
_("Low Output"),
0.0, 1.0, 0.0, 0);
GIMP_CONFIG_PROP_DOUBLE (object_class, PROP_HIGH_OUTPUT,
"high-output",
_("High Output"),
_("High Output"),
0.0, 1.0, 1.0, 0);
GIMP_CONFIG_PROP_BOOLEAN (object_class, PROP_CLAMP_OUTPUT,
"clamp-output",
_("Clamp Output"),
_("Clamp final output values."),
FALSE, 0);
}
static void
gimp_levels_config_iface_init (GimpConfigInterface *iface)
{
iface->serialize = gimp_levels_config_serialize;
iface->deserialize = gimp_levels_config_deserialize;
iface->equal = gimp_levels_config_equal;
iface->reset = gimp_levels_config_reset;
iface->copy = gimp_levels_config_copy;
}
static void
gimp_levels_config_init (GimpLevelsConfig *self)
{
gimp_config_reset (GIMP_CONFIG (self));
}
static void
gimp_levels_config_get_property (GObject *object,
guint property_id,
GValue *value,
GParamSpec *pspec)
{
GimpLevelsConfig *self = GIMP_LEVELS_CONFIG (object);
switch (property_id)
{
case PROP_TRC:
g_value_set_enum (value, self->trc);
break;
case PROP_LINEAR:
g_value_set_boolean (value, self->trc == GIMP_TRC_LINEAR ? TRUE : FALSE);
break;
case PROP_CHANNEL:
g_value_set_enum (value, self->channel);
break;
case PROP_LOW_INPUT:
g_value_set_double (value, self->low_input[self->channel]);
break;
case PROP_HIGH_INPUT:
g_value_set_double (value, self->high_input[self->channel]);
break;
case PROP_CLAMP_INPUT:
g_value_set_boolean (value, self->clamp_input);
break;
case PROP_GAMMA:
g_value_set_double (value, self->gamma[self->channel]);
break;
case PROP_LOW_OUTPUT:
g_value_set_double (value, self->low_output[self->channel]);
break;
case PROP_HIGH_OUTPUT:
g_value_set_double (value, self->high_output[self->channel]);
break;
case PROP_CLAMP_OUTPUT:
g_value_set_boolean (value, self->clamp_output);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
break;
}
}
static void
gimp_levels_config_set_property (GObject *object,
guint property_id,
const GValue *value,
GParamSpec *pspec)
{
GimpLevelsConfig *self = GIMP_LEVELS_CONFIG (object);
switch (property_id)
{
case PROP_TRC:
self->trc = g_value_get_enum (value);
break;
case PROP_LINEAR:
self->trc = g_value_get_boolean (value) ?
GIMP_TRC_LINEAR : GIMP_TRC_NON_LINEAR;
g_object_notify (object, "trc");
break;
case PROP_CHANNEL:
self->channel = g_value_get_enum (value);
g_object_notify (object, "low-input");
g_object_notify (object, "high-input");
g_object_notify (object, "gamma");
g_object_notify (object, "low-output");
g_object_notify (object, "high-output");
break;
case PROP_LOW_INPUT:
self->low_input[self->channel] = g_value_get_double (value);
break;
case PROP_HIGH_INPUT:
self->high_input[self->channel] = g_value_get_double (value);
break;
case PROP_CLAMP_INPUT:
self->clamp_input = g_value_get_boolean (value);
break;
case PROP_GAMMA:
self->gamma[self->channel] = g_value_get_double (value);
break;
case PROP_LOW_OUTPUT:
self->low_output[self->channel] = g_value_get_double (value);
break;
case PROP_HIGH_OUTPUT:
self->high_output[self->channel] = g_value_get_double (value);
break;
case PROP_CLAMP_OUTPUT:
self->clamp_output = g_value_get_boolean (value);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
break;
}
}
static gboolean
gimp_levels_config_serialize (GimpConfig *config,
GimpConfigWriter *writer,
gpointer data)
{
GimpLevelsConfig *l_config = GIMP_LEVELS_CONFIG (config);
GimpHistogramChannel channel;
GimpHistogramChannel old_channel;
gboolean success = TRUE;
if (! gimp_config_serialize_property_by_name (config, "time", writer) ||
! gimp_config_serialize_property_by_name (config, "trc", writer) ||
! gimp_config_serialize_property_by_name (config, "clamp-input", writer) ||
! gimp_config_serialize_property_by_name (config, "clamp-output", writer))
return FALSE;
old_channel = l_config->channel;
for (channel = GIMP_HISTOGRAM_VALUE;
channel <= GIMP_HISTOGRAM_ALPHA;
channel++)
{
l_config->channel = channel;
/* serialize the channel properties manually (not using
* gimp_config_serialize_properties()), so the parent class'
* "time" property doesn't end up in the config file one per
* channel. See bug #700653.
*/
success =
(gimp_config_serialize_property_by_name (config, "channel", writer) &&
gimp_config_serialize_property_by_name (config, "low-input", writer) &&
gimp_config_serialize_property_by_name (config, "high-input", writer) &&
gimp_config_serialize_property_by_name (config, "gamma", writer) &&
gimp_config_serialize_property_by_name (config, "low-output", writer) &&
gimp_config_serialize_property_by_name (config, "high-output", writer));
if (! success)
break;
}
l_config->channel = old_channel;
return success;
}
static gboolean
gimp_levels_config_deserialize (GimpConfig *config,
GScanner *scanner,
gint nest_level,
gpointer data)
{
GimpLevelsConfig *l_config = GIMP_LEVELS_CONFIG (config);
GimpHistogramChannel old_channel;
gboolean success = TRUE;
old_channel = l_config->channel;
success = gimp_config_deserialize_properties (config, scanner, nest_level);
g_object_set (config, "channel", old_channel, NULL);
return success;
}
static gboolean
gimp_levels_config_equal (GimpConfig *a,
GimpConfig *b)
{
GimpLevelsConfig *config_a = GIMP_LEVELS_CONFIG (a);
GimpLevelsConfig *config_b = GIMP_LEVELS_CONFIG (b);
GimpHistogramChannel channel;
if (config_a->trc != config_b->trc ||
config_a->clamp_input != config_b->clamp_input ||
config_a->clamp_output != config_b->clamp_output)
return FALSE;
for (channel = GIMP_HISTOGRAM_VALUE;
channel <= GIMP_HISTOGRAM_ALPHA;
channel++)
{
if (config_a->gamma[channel] != config_b->gamma[channel] ||
config_a->low_input[channel] != config_b->low_input[channel] ||
config_a->high_input[channel] != config_b->high_input[channel] ||
config_a->low_output[channel] != config_b->low_output[channel] ||
config_a->high_output[channel] != config_b->high_output[channel])
return FALSE;
}
/* don't compare "channel" */
return TRUE;
}
static void
gimp_levels_config_reset (GimpConfig *config)
{
GimpLevelsConfig *l_config = GIMP_LEVELS_CONFIG (config);
GimpHistogramChannel channel;
for (channel = GIMP_HISTOGRAM_VALUE;
channel <= GIMP_HISTOGRAM_ALPHA;
channel++)
{
l_config->channel = channel;
gimp_levels_config_reset_channel (l_config);
}
gimp_config_reset_property (G_OBJECT (config), "trc");
gimp_config_reset_property (G_OBJECT (config), "channel");
gimp_config_reset_property (G_OBJECT (config), "clamp-input");
gimp_config_reset_property (G_OBJECT (config), "clamp_output");
}
static gboolean
gimp_levels_config_copy (GimpConfig *src,
GimpConfig *dest,
GParamFlags flags)
{
GimpLevelsConfig *src_config = GIMP_LEVELS_CONFIG (src);
GimpLevelsConfig *dest_config = GIMP_LEVELS_CONFIG (dest);
GimpHistogramChannel channel;
for (channel = GIMP_HISTOGRAM_VALUE;
channel <= GIMP_HISTOGRAM_ALPHA;
channel++)
{
dest_config->gamma[channel] = src_config->gamma[channel];
dest_config->low_input[channel] = src_config->low_input[channel];
dest_config->high_input[channel] = src_config->high_input[channel];
dest_config->low_output[channel] = src_config->low_output[channel];
dest_config->high_output[channel] = src_config->high_output[channel];
}
g_object_notify (G_OBJECT (dest), "gamma");
g_object_notify (G_OBJECT (dest), "low-input");
g_object_notify (G_OBJECT (dest), "high-input");
g_object_notify (G_OBJECT (dest), "low-output");
g_object_notify (G_OBJECT (dest), "high-output");
dest_config->trc = src_config->trc;
dest_config->channel = src_config->channel;
dest_config->clamp_input = src_config->clamp_input;
dest_config->clamp_output = src_config->clamp_output;
g_object_notify (G_OBJECT (dest), "trc");
g_object_notify (G_OBJECT (dest), "channel");
g_object_notify (G_OBJECT (dest), "clamp-input");
g_object_notify (G_OBJECT (dest), "clamp-output");
return TRUE;
}
/* public functions */
void
gimp_levels_config_reset_channel (GimpLevelsConfig *config)
{
g_return_if_fail (GIMP_IS_LEVELS_CONFIG (config));
g_object_freeze_notify (G_OBJECT (config));
gimp_config_reset_property (G_OBJECT (config), "gamma");
gimp_config_reset_property (G_OBJECT (config), "low-input");
gimp_config_reset_property (G_OBJECT (config), "high-input");
gimp_config_reset_property (G_OBJECT (config), "low-output");
gimp_config_reset_property (G_OBJECT (config), "high-output");
g_object_thaw_notify (G_OBJECT (config));
}
void
gimp_levels_config_stretch (GimpLevelsConfig *config,
GimpHistogram *histogram,
gboolean is_color)
{
g_return_if_fail (GIMP_IS_LEVELS_CONFIG (config));
g_return_if_fail (histogram != NULL);
g_object_freeze_notify (G_OBJECT (config));
if (is_color)
{
GimpHistogramChannel channel;
/* Set the overall value to defaults */
channel = config->channel;
config->channel = GIMP_HISTOGRAM_VALUE;
gimp_levels_config_reset_channel (config);
config->channel = channel;
for (channel = GIMP_HISTOGRAM_RED;
channel <= GIMP_HISTOGRAM_BLUE;
channel++)
{
gimp_levels_config_stretch_channel (config, histogram, channel);
}
}
else
{
gimp_levels_config_stretch_channel (config, histogram,
GIMP_HISTOGRAM_VALUE);
}
g_object_thaw_notify (G_OBJECT (config));
}
void
gimp_levels_config_stretch_channel (GimpLevelsConfig *config,
GimpHistogram *histogram,
GimpHistogramChannel channel)
{
gdouble count;
gdouble bias = 0.006;
gint n_bins;
gint i;
g_return_if_fail (GIMP_IS_LEVELS_CONFIG (config));
g_return_if_fail (histogram != NULL);
g_object_freeze_notify (G_OBJECT (config));
config->gamma[channel] = 1.0;
config->low_output[channel] = 0.0;
config->high_output[channel] = 1.0;
n_bins = gimp_histogram_n_bins (histogram);
count = gimp_histogram_get_count (histogram, channel, 0, n_bins - 1);
if (count == 0.0)
{
config->low_input[channel] = 0.0;
config->high_input[channel] = 0.0;
}
else
{
gdouble new_count;
gdouble percentage;
gdouble next_percentage;
/* Set the low input */
new_count = 0.0;
for (i = 0; i < (n_bins - 1); i++)
{
new_count += gimp_histogram_get_value (histogram, channel, i);
percentage = new_count / count;
next_percentage = (new_count +
gimp_histogram_get_value (histogram,
channel,
i + 1)) / count;
if (fabs (percentage - bias) < fabs (next_percentage - bias))
{
config->low_input[channel] = (gdouble) (i + 1) / (n_bins - 1);
break;
}
}
/* Set the high input */
new_count = 0.0;
for (i = (n_bins - 1); i > 0; i--)
{
new_count += gimp_histogram_get_value (histogram, channel, i);
percentage = new_count / count;
next_percentage = (new_count +
gimp_histogram_get_value (histogram,
channel,
i - 1)) / count;
if (fabs (percentage - bias) < fabs (next_percentage - bias))
{
config->high_input[channel] = (gdouble) (i - 1) / (n_bins - 1);
break;
}
}
}
g_object_notify (G_OBJECT (config), "gamma");
g_object_notify (G_OBJECT (config), "low-input");
g_object_notify (G_OBJECT (config), "high-input");
g_object_notify (G_OBJECT (config), "low-output");
g_object_notify (G_OBJECT (config), "high-output");
g_object_thaw_notify (G_OBJECT (config));
}
static gdouble
gimp_levels_config_input_from_color (GimpHistogramChannel channel,
const GimpRGB *color)
{
switch (channel)
{
case GIMP_HISTOGRAM_VALUE:
return MAX (MAX (color->r, color->g), color->b);
case GIMP_HISTOGRAM_RED:
return color->r;
case GIMP_HISTOGRAM_GREEN:
return color->g;
case GIMP_HISTOGRAM_BLUE:
return color->b;
case GIMP_HISTOGRAM_ALPHA:
return color->a;
case GIMP_HISTOGRAM_RGB:
return MIN (MIN (color->r, color->g), color->b);
case GIMP_HISTOGRAM_LUMINANCE:
return GIMP_RGB_LUMINANCE (color->r, color->g, color->b);
}
return 0.0;
}
void
gimp_levels_config_adjust_by_colors (GimpLevelsConfig *config,
GimpHistogramChannel channel,
const GimpRGB *black,
const GimpRGB *gray,
const GimpRGB *white)
{
g_return_if_fail (GIMP_IS_LEVELS_CONFIG (config));
g_object_freeze_notify (G_OBJECT (config));
if (black)
{
config->low_input[channel] = gimp_levels_config_input_from_color (channel,
black);
g_object_notify (G_OBJECT (config), "low-input");
}
if (white)
{
config->high_input[channel] = gimp_levels_config_input_from_color (channel,
white);
g_object_notify (G_OBJECT (config), "high-input");
}
if (gray)
{
gdouble input;
gdouble range;
gdouble inten;
gdouble out_light;
gdouble lightness;
/* Calculate lightness value */
lightness = GIMP_RGB_LUMINANCE (gray->r, gray->g, gray->b);
input = gimp_levels_config_input_from_color (channel, gray);
range = config->high_input[channel] - config->low_input[channel];
if (range <= 0)
goto out;
input -= config->low_input[channel];
if (input < 0)
goto out;
/* Normalize input and lightness */
inten = input / range;
out_light = lightness / range;
/* See bug 622054: picking pure black or white as gamma doesn't
* work. But we cannot compare to 0.0 or 1.0 because cpus and
* compilers are shit. If you try to check out_light using
* printf() it will give exact 0.0 or 1.0 anyway, probably
* because the generated code is different and out_light doesn't
* live in a register. That must be why the cpu/compiler mafia
* invented epsilon and defined this shit to be the programmer's
* responsibility.
*/
if (out_light <= 0.0001 || out_light >= 0.9999)
goto out;
/* Map selected color to corresponding lightness */
config->gamma[channel] = log (inten) / log (out_light);
config->gamma[channel] = CLAMP (config->gamma[channel], 0.1, 10.0);
g_object_notify (G_OBJECT (config), "gamma");
}
out:
g_object_thaw_notify (G_OBJECT (config));
}
GimpCurvesConfig *
gimp_levels_config_to_curves_config (GimpLevelsConfig *config)
{
GimpCurvesConfig *curves;
GimpHistogramChannel channel;
g_return_val_if_fail (GIMP_IS_LEVELS_CONFIG (config), NULL);
curves = g_object_new (GIMP_TYPE_CURVES_CONFIG, NULL);
curves->trc = config->trc;
for (channel = GIMP_HISTOGRAM_VALUE;
channel <= GIMP_HISTOGRAM_ALPHA;
channel++)
{
GimpCurve *curve = curves->curve[channel];
const gint n_points = gimp_curve_get_n_points (curve);
static const gint n = 8;
gint point = -1;
gdouble gamma = config->gamma[channel];
gdouble delta_in;
gdouble delta_out;
gdouble x, y;
/* clear the points set by default */
gimp_curve_set_point (curve, 0, -1, -1);
gimp_curve_set_point (curve, n_points - 1, -1, -1);
delta_in = config->high_input[channel] - config->low_input[channel];
delta_out = config->high_output[channel] - config->low_output[channel];
x = config->low_input[channel];
y = config->low_output[channel];
point = CLAMP (n_points * x, point + 1, n_points - 1 - n);
gimp_curve_set_point (curve, point, x, y);
if (delta_out != 0 && gamma != 1.0)
{
/* The Levels tool performs gamma adjustment, which is a
* power law, while the Curves tool uses cubic Bézier
* curves. Here we try to approximate this gamma adjustment
* with a Bézier curve with 5 control points. Two of them
* must be (low_input, low_output) and (high_input,
* high_output), so we need to add 3 more control points in
* the middle.
*/
gint i;
if (gamma > 1)
{
/* Case no. 1: γ > 1
*
* The curve should look like a horizontal
* parabola. Since its curvature is greatest when x is
* small, we add more control points there, so the
* approximation is more accurate. I decided to set the
* length of the consecutive segments to x₀, γ⋅x₀, γ²⋅x₀
* and γ³⋅x₀ and I saw that the curves looked
* good. Still, this is completely arbitrary.
*/
gdouble dx = 0;
gdouble x0;
for (i = 0; i < n; ++i)
dx = dx * gamma + 1;
x0 = delta_in / dx;
dx = 0;
for (i = 1; i < n; ++i)
{
dx = dx * gamma + x0;
x = config->low_input[channel] + dx;
y = config->low_output[channel] + delta_out *
gimp_operation_levels_map_input (config, channel, x);
point = CLAMP (n_points * x, point + 1, n_points - 1 - n + i);
gimp_curve_set_point (curve, point, x, y);
}
}
else
{
/* Case no. 2: γ < 1
*
* The curve is the same as the one in case no. 1,
* observed through a reflexion along the y = x axis. So
* if we invert γ and swap the x and y axes we can use
* the same method as in case no. 1.
*/
GimpLevelsConfig *config_inv;
gdouble dy = 0;
gdouble y0;
const gdouble gamma_inv = 1 / gamma;
config_inv = gimp_config_duplicate (GIMP_CONFIG (config));
config_inv->gamma[channel] = gamma_inv;
config_inv->low_input[channel] = config->low_output[channel];
config_inv->low_output[channel] = config->low_input[channel];
config_inv->high_input[channel] = config->high_output[channel];
config_inv->high_output[channel] = config->high_input[channel];
for (i = 0; i < n; ++i)
dy = dy * gamma_inv + 1;
y0 = delta_out / dy;
dy = 0;
for (i = 1; i < n; ++i)
{
dy = dy * gamma_inv + y0;
y = config->low_output[channel] + dy;
x = config->low_input[channel] + delta_in *
gimp_operation_levels_map_input (config_inv, channel, y);
point = CLAMP (n_points * x, point + 1, n_points - 1 - n + i);
gimp_curve_set_point (curve, point, x, y);
}
g_object_unref (config_inv);
}
}
x = config->high_input[channel];
y = config->high_output[channel];
point = CLAMP (n_points * x, point + 1, n_points - 1);
gimp_curve_set_point (curve, point, x, y);
}
return curves;
}
gboolean
gimp_levels_config_load_cruft (GimpLevelsConfig *config,
GInputStream *input,
GError **error)
{
GDataInputStream *data_input;
gint low_input[5];
gint high_input[5];
gint low_output[5];
gint high_output[5];
gdouble gamma[5];
gchar *line;
gsize line_len;
gint i;
g_return_val_if_fail (GIMP_IS_LEVELS_CONFIG (config), FALSE);
g_return_val_if_fail (G_IS_INPUT_STREAM (input), FALSE);
g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
data_input = g_data_input_stream_new (input);
line_len = 64;
line = gimp_data_input_stream_read_line_always (data_input, &line_len,
NULL, error);
if (! line)
return FALSE;
if (strcmp (line, "# GIMP Levels File") != 0)
{
g_set_error_literal (error, GIMP_CONFIG_ERROR, GIMP_CONFIG_ERROR_PARSE,
_("not a GIMP Levels file"));
g_object_unref (data_input);
g_free (line);
return FALSE;
}
g_free (line);
for (i = 0; i < 5; i++)
{
gchar float_buf[32];
gchar *endp;
gint fields;
line_len = 64;
line = gimp_data_input_stream_read_line_always (data_input, &line_len,
NULL, error);
if (! line)
{
g_object_unref (data_input);
return FALSE;
}
fields = sscanf (line, "%d %d %d %d %31s",
&low_input[i],
&high_input[i],
&low_output[i],
&high_output[i],
float_buf);
g_free (line);
if (fields != 5)
goto error;
gamma[i] = g_ascii_strtod (float_buf, &endp);
if (endp == float_buf || errno == ERANGE)
goto error;
}
g_object_unref (data_input);
g_object_freeze_notify (G_OBJECT (config));
for (i = 0; i < 5; i++)
{
config->low_input[i] = low_input[i] / 255.0;
config->high_input[i] = high_input[i] / 255.0;
config->gamma[i] = gamma[i];
config->low_output[i] = low_output[i] / 255.0;
config->high_output[i] = high_output[i] / 255.0;
}
config->trc = GIMP_TRC_NON_LINEAR;
config->clamp_input = TRUE;
config->clamp_output = TRUE;
g_object_notify (G_OBJECT (config), "trc");
g_object_notify (G_OBJECT (config), "low-input");
g_object_notify (G_OBJECT (config), "high-input");
g_object_notify (G_OBJECT (config), "clamp-input");
g_object_notify (G_OBJECT (config), "gamma");
g_object_notify (G_OBJECT (config), "low-output");
g_object_notify (G_OBJECT (config), "high-output");
g_object_notify (G_OBJECT (config), "clamp-output");
g_object_thaw_notify (G_OBJECT (config));
return TRUE;
error:
g_object_unref (data_input);
g_set_error_literal (error, GIMP_CONFIG_ERROR, GIMP_CONFIG_ERROR_PARSE,
_("parse error"));
return FALSE;
}
gboolean
gimp_levels_config_save_cruft (GimpLevelsConfig *config,
GOutputStream *output,
GError **error)
{
GString *string;
gint i;
g_return_val_if_fail (GIMP_IS_LEVELS_CONFIG (config), FALSE);
g_return_val_if_fail (G_IS_OUTPUT_STREAM (output), FALSE);
g_return_val_if_fail (error == NULL || *error == NULL, FALSE);
string = g_string_new ("# GIMP Levels File\n");
for (i = 0; i < 5; i++)
{
gchar buf[G_ASCII_DTOSTR_BUF_SIZE];
g_string_append_printf (string,
"%d %d %d %d %s\n",
(gint) (config->low_input[i] * 255.999),
(gint) (config->high_input[i] * 255.999),
(gint) (config->low_output[i] * 255.999),
(gint) (config->high_output[i] * 255.999),
g_ascii_formatd (buf, G_ASCII_DTOSTR_BUF_SIZE, "%f",
config->gamma[i]));
}
if (! g_output_stream_write_all (output, string->str, string->len,
NULL, NULL, error))
{
g_prefix_error (error, _("Writing levels file failed: "));
g_string_free (string, TRUE);
return FALSE;
}
g_string_free (string, TRUE);
return TRUE;
}