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));
}
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)
return;
input -= config->low_input[channel];
if (input < 0)
return;
/* Normalize input and lightness */
inten = input / range;
out_light = lightness/ range;
if (out_light <= 0)
return;
/* Map selected color to corresponding lightness */
config->gamma[channel] = log (inten) / log (out_light);
g_object_notify (G_OBJECT (config), "gamma");
}
g_object_thaw_notify (G_OBJECT (config));
}
