PIKApp/app/operations/layer-modes/pikaoperationerase.c

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2023-09-26 00:35:21 +02:00
/* PIKA - Photo and Image Kooker Application
* a rebranding of The GNU Image Manipulation Program (created with heckimp)
* A derived work which may be trivial. However, any changes may be (C)2023 by Aldercone Studio
*
* Original copyright, applying to most contents (license remains unchanged):
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* pikaoperationerase.c
* Copyright (C) 2008 Michael Natterer <mitch@gimp.org>
* 2012 Ville Sokk <ville.sokk@gmail.com>
*
* 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 <gegl-plugin.h>
#include "../operations-types.h"
#include "pikaoperationerase.h"
static gboolean pika_operation_erase_process (GeglOperation *op,
void *in,
void *layer,
void *mask,
void *out,
glong samples,
const GeglRectangle *roi,
gint level);
G_DEFINE_TYPE (PikaOperationErase, pika_operation_erase,
PIKA_TYPE_OPERATION_LAYER_MODE)
static void
pika_operation_erase_class_init (PikaOperationEraseClass *klass)
{
GeglOperationClass *operation_class = GEGL_OPERATION_CLASS (klass);
PikaOperationLayerModeClass *layer_mode_class = PIKA_OPERATION_LAYER_MODE_CLASS (klass);
gegl_operation_class_set_keys (operation_class,
"name", "pika:erase",
"description", "PIKA erase mode operation",
NULL);
layer_mode_class->process = pika_operation_erase_process;
}
static void
pika_operation_erase_init (PikaOperationErase *self)
{
}
static gboolean
pika_operation_erase_process (GeglOperation *op,
void *in_p,
void *layer_p,
void *mask_p,
void *out_p,
glong samples,
const GeglRectangle *roi,
gint level)
{
PikaOperationLayerMode *layer_mode = (gpointer) op;
gfloat *in = in_p;
gfloat *out = out_p;
gfloat *layer = layer_p;
gfloat *mask = mask_p;
gfloat opacity = layer_mode->opacity;
const gboolean has_mask = mask != NULL;
switch (layer_mode->composite_mode)
{
case PIKA_LAYER_COMPOSITE_UNION:
while (samples--)
{
gfloat layer_alpha;
gfloat new_alpha;
gint b;
layer_alpha = layer[ALPHA] * opacity;
if (has_mask)
layer_alpha *= (*mask);
new_alpha = in[ALPHA] + layer_alpha - 2.0f * in[ALPHA] * layer_alpha;
if (new_alpha != 0.0f)
{
gfloat ratio;
ratio = (1.0f - in[ALPHA]) * layer_alpha / new_alpha;
for (b = RED; b < ALPHA; b++)
{
out[b] = ratio * layer[b] + (1.0f - ratio) * in[b];
}
}
else
{
for (b = RED; b < ALPHA; b++)
{
out[b] = in[b];
}
}
out[ALPHA] = new_alpha;
in += 4;
layer += 4;
out += 4;
if (has_mask)
mask ++;
}
break;
case PIKA_LAYER_COMPOSITE_CLIP_TO_BACKDROP:
case PIKA_LAYER_COMPOSITE_AUTO:
while (samples--)
{
gfloat layer_alpha;
gfloat new_alpha;
gint b;
layer_alpha = layer[ALPHA] * opacity;
if (has_mask)
layer_alpha *= (*mask);
new_alpha = (1.0f - layer_alpha) * in[ALPHA];
for (b = RED; b < ALPHA; b++)
{
out[b] = in[b];
}
out[ALPHA] = new_alpha;
in += 4;
layer += 4;
out += 4;
if (has_mask)
mask ++;
}
break;
case PIKA_LAYER_COMPOSITE_CLIP_TO_LAYER:
while (samples--)
{
gfloat layer_alpha;
gfloat new_alpha;
const gfloat *src;
gint b;
layer_alpha = layer[ALPHA] * opacity;
if (has_mask)
layer_alpha *= (*mask);
new_alpha = (1.0f - in[ALPHA]) * layer_alpha;
src = layer;
if (new_alpha == 0.0f)
src = in;
for (b = RED; b < ALPHA; b++)
{
out[b] = src[b];
}
out[ALPHA] = new_alpha;
in += 4;
layer += 4;
out += 4;
if (has_mask)
mask ++;
}
break;
case PIKA_LAYER_COMPOSITE_INTERSECTION:
while (samples--)
{
gint b;
for (b = RED; b < ALPHA; b++)
{
out[b] = in[b];
}
out[ALPHA] = 0.0f;
in += 4;
out += 4;
}
break;
}
return TRUE;
}