PIKApp/app/operations/layer-modes/pikaoperationlayermode-blend.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
*
* pikaoperationlayermode-blend.c
* Copyright (C) 2017 Michael Natterer <mitch@gimp.org>
* 2017 Øyvind Kolås <pippin@gimp.org>
* 2017 Ell
*
* 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 <cairo.h>
#include <gdk-pixbuf/gdk-pixbuf.h>
#include "libpikacolor/pikacolor.h"
#include "libpikabase/pikabase.h"
#include "libpikamath/pikamath.h"
#include "../operations-types.h"
#include "pikaoperationlayermode-blend.h"
#define EPSILON 1e-6f
#define SAFE_DIV_MIN EPSILON
#define SAFE_DIV_MAX (1.0f / SAFE_DIV_MIN)
/* local function prototypes */
static inline gfloat safe_div (gfloat a,
gfloat b);
/* private functions */
/* returns a / b, clamped to [-SAFE_DIV_MAX, SAFE_DIV_MAX].
* if -SAFE_DIV_MIN <= a <= SAFE_DIV_MIN, returns 0.
*/
static inline gfloat
safe_div (gfloat a,
gfloat b)
{
gfloat result = 0.0f;
if (fabsf (a) > SAFE_DIV_MIN)
{
result = a / b;
result = CLAMP (result, -SAFE_DIV_MAX, SAFE_DIV_MAX);
}
return result;
}
/* public functions */
/* non-subtractive blending functions. these functions must set comp[ALPHA]
* to the same value as layer[ALPHA]. when in[ALPHA] or layer[ALPHA] are
* zero, the value of comp[RED..BLUE] is unconstrained (in particular, it may
* be NaN).
*/
void /* aka linear_dodge */
pika_operation_layer_mode_blend_addition (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = in[c] + layer[c];
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_burn (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = 1.0f - safe_div (1.0f - in[c], layer[c]);
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_darken_only (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = MIN (in[c], layer[c]);
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_difference (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = fabsf (in[c] - layer[c]);
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_divide (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = safe_div (in[c], layer[c]);
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_dodge (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = safe_div (in[c], 1.0f - layer[c]);
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_exclusion (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = 0.5f - 2.0f * (in[c] - 0.5f) * (layer[c] - 0.5f);
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_grain_extract (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = in[c] - layer[c] + 0.5f;
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_grain_merge (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = in[c] + layer[c] - 0.5f;
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_hard_mix (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = in[c] + layer[c] < 1.0f ? 0.0f : 1.0f;
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_hardlight (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
{
gfloat val;
if (layer[c] > 0.5f)
{
val = (1.0f - in[c]) * (1.0f - (layer[c] - 0.5f) * 2.0f);
val = MIN (1.0f - val, 1.0f);
}
else
{
val = in[c] * (layer[c] * 2.0f);
val = MIN (val, 1.0f);
}
comp[c] = val;
}
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_hsl_color (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gfloat dest_min, dest_max, dest_l;
gfloat src_min, src_max, src_l;
dest_min = MIN (in[0], in[1]);
dest_min = MIN (dest_min, in[2]);
dest_max = MAX (in[0], in[1]);
dest_max = MAX (dest_max, in[2]);
dest_l = (dest_min + dest_max) / 2.0f;
src_min = MIN (layer[0], layer[1]);
src_min = MIN (src_min, layer[2]);
src_max = MAX (layer[0], layer[1]);
src_max = MAX (src_max, layer[2]);
src_l = (src_min + src_max) / 2.0f;
if (fabs (src_l) > EPSILON && fabs (1.0 - src_l) > EPSILON)
{
gboolean dest_high;
gboolean src_high;
gfloat ratio;
gfloat offset;
gint c;
dest_high = dest_l > 0.5f;
src_high = src_l > 0.5f;
dest_l = MIN (dest_l, 1.0f - dest_l);
src_l = MIN (src_l, 1.0f - src_l);
ratio = dest_l / src_l;
offset = 0.0f;
if (dest_high) offset += 1.0f - 2.0f * dest_l;
if (src_high) offset += 2.0f * dest_l - ratio;
for (c = 0; c < 3; c++)
comp[c] = layer[c] * ratio + offset;
}
else
{
comp[RED] = dest_l;
comp[GREEN] = dest_l;
comp[BLUE] = dest_l;
}
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_hsv_hue (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gfloat src_min, src_max, src_delta;
gfloat dest_min, dest_max, dest_delta, dest_s;
src_min = MIN (layer[0], layer[1]);
src_min = MIN (src_min, layer[2]);
src_max = MAX (layer[0], layer[1]);
src_max = MAX (src_max, layer[2]);
src_delta = src_max - src_min;
if (src_delta > EPSILON)
{
gfloat ratio;
gfloat offset;
gint c;
dest_min = MIN (in[0], in[1]);
dest_min = MIN (dest_min, in[2]);
dest_max = MAX (in[0], in[1]);
dest_max = MAX (dest_max, in[2]);
dest_delta = dest_max - dest_min;
dest_s = dest_max ? dest_delta / dest_max : 0.0f;
ratio = dest_s * dest_max / src_delta;
offset = dest_max - src_max * ratio;
for (c = 0; c < 3; c++)
comp[c] = layer[c] * ratio + offset;
}
else
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = in[c];
}
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_hsv_saturation (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gfloat src_min, src_max, src_delta, src_s;
gfloat dest_min, dest_max, dest_delta;
dest_min = MIN (in[0], in[1]);
dest_min = MIN (dest_min, in[2]);
dest_max = MAX (in[0], in[1]);
dest_max = MAX (dest_max, in[2]);
dest_delta = dest_max - dest_min;
if (dest_delta > EPSILON)
{
gfloat ratio;
gfloat offset;
gint c;
src_min = MIN (layer[0], layer[1]);
src_min = MIN (src_min, layer[2]);
src_max = MAX (layer[0], layer[1]);
src_max = MAX (src_max, layer[2]);
src_delta = src_max - src_min;
src_s = src_max ? src_delta / src_max : 0.0f;
ratio = src_s * dest_max / dest_delta;
offset = (1.0f - ratio) * dest_max;
for (c = 0; c < 3; c++)
comp[c] = in[c] * ratio + offset;
}
else
{
comp[RED] = dest_max;
comp[GREEN] = dest_max;
comp[BLUE] = dest_max;
}
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_hsv_value (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gfloat dest_v;
gfloat src_v;
dest_v = MAX (in[0], in[1]);
dest_v = MAX (dest_v, in[2]);
src_v = MAX (layer[0], layer[1]);
src_v = MAX (src_v, layer[2]);
if (fabs (dest_v) > EPSILON)
{
gfloat ratio = src_v / dest_v;
gint c;
for (c = 0; c < 3; c++)
comp[c] = in[c] * ratio;
}
else
{
comp[RED] = src_v;
comp[GREEN] = src_v;
comp[BLUE] = src_v;
}
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_lch_chroma (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gfloat A1 = in[1];
gfloat B1 = in[2];
gfloat c1 = hypotf (A1, B1);
if (c1 > EPSILON)
{
gfloat A2 = layer[1];
gfloat B2 = layer[2];
gfloat c2 = hypotf (A2, B2);
gfloat A = c2 * A1 / c1;
gfloat B = c2 * B1 / c1;
comp[0] = in[0];
comp[1] = A;
comp[2] = B;
}
else
{
comp[0] = in[0];
comp[1] = in[1];
comp[2] = in[2];
}
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_lch_color (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
comp[0] = in[0];
comp[1] = layer[1];
comp[2] = layer[2];
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_lch_hue (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gfloat A2 = layer[1];
gfloat B2 = layer[2];
gfloat c2 = hypotf (A2, B2);
if (c2 > EPSILON)
{
gfloat A1 = in[1];
gfloat B1 = in[2];
gfloat c1 = hypotf (A1, B1);
gfloat A = c1 * A2 / c2;
gfloat B = c1 * B2 / c2;
comp[0] = in[0];
comp[1] = A;
comp[2] = B;
}
else
{
comp[0] = in[0];
comp[1] = in[1];
comp[2] = in[2];
}
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_lch_lightness (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
comp[0] = layer[0];
comp[1] = in[1];
comp[2] = in[2];
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_lighten_only (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = MAX (in[c], layer[c]);
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_linear_burn (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = in[c] + layer[c] - 1.0f;
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
/* added according to:
http://www.deepskycolors.com/archivo/2010/04/21/formulas-for-Photoshop-blending-modes.html */
void
pika_operation_layer_mode_blend_linear_light (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
{
gfloat val;
if (layer[c] <= 0.5f)
val = in[c] + 2.0f * layer[c] - 1.0f;
else
val = in[c] + 2.0f * (layer[c] - 0.5f);
comp[c] = val;
}
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_luma_darken_only (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
const Babl *space = gegl_operation_get_source_space (operation, "input");
double red_luminance, green_luminance, blue_luminance;
babl_space_get_rgb_luminance (space,
&red_luminance, &green_luminance, &blue_luminance);
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gfloat dest_luminance;
gfloat src_luminance;
gint c;
dest_luminance = (in[0] * red_luminance) +
(in[1] * green_luminance) +
(in[2] * blue_luminance);
src_luminance = (layer[0] * red_luminance) +
(layer[1] * green_luminance) +
(layer[2] * blue_luminance);
if (dest_luminance <= src_luminance)
{
for (c = 0; c < 3; c++)
comp[c] = in[c];
}
else
{
for (c = 0; c < 3; c++)
comp[c] = layer[c];
}
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_luma_lighten_only (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
const Babl *space = gegl_operation_get_source_space (operation, "input");
double red_luminance, green_luminance, blue_luminance;
babl_space_get_rgb_luminance (space,
&red_luminance, &green_luminance, &blue_luminance);
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gfloat dest_luminance;
gfloat src_luminance;
gint c;
dest_luminance = (in[0] * red_luminance) +
(in[1] * green_luminance) +
(in[2] * blue_luminance);
src_luminance = (layer[0] * red_luminance) +
(layer[1] * green_luminance) +
(layer[2] * blue_luminance);
if (dest_luminance >= src_luminance)
{
for (c = 0; c < 3; c++)
comp[c] = in[c];
}
else
{
for (c = 0; c < 3; c++)
comp[c] = layer[c];
}
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_luminance (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
const Babl *fish;
gfloat *scratch;
gfloat *in_Y;
gfloat *layer_Y;
const Babl *space = gegl_operation_get_source_space (operation, "input");
fish = babl_fish (babl_format_with_space ("RGBA float", space),
babl_format_with_space ("Y float", space));
scratch = gegl_scratch_new (gfloat, 2 * samples);
in_Y = scratch;
layer_Y = scratch + samples;
babl_process (fish, in, in_Y, samples);
babl_process (fish, layer, layer_Y, samples);
while (samples--)
{
if (layer[ALPHA] != 0.0f && in[ALPHA] != 0.0f)
{
gfloat ratio = safe_div (layer_Y[0], in_Y[0]);
gint c;
for (c = 0; c < 3; c ++)
comp[c] = in[c] * ratio;
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
in += 4;
layer += 4;
in_Y ++;
layer_Y ++;
}
gegl_scratch_free (scratch);
}
void
pika_operation_layer_mode_blend_multiply (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = in[c] * layer[c];
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_overlay (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
{
gfloat val;
if (in[c] < 0.5f)
val = 2.0f * in[c] * layer[c];
else
val = 1.0f - 2.0f * (1.0f - layer[c]) * (1.0f - in[c]);
comp[c] = val;
}
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
/* added according to:
http://www.deepskycolors.com/archivo/2010/04/21/formulas-for-Photoshop-blending-modes.html */
void
pika_operation_layer_mode_blend_pin_light (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
{
gfloat val;
if (layer[c] > 0.5f)
val = MAX(in[c], 2.0f * (layer[c] - 0.5f));
else
val = MIN(in[c], 2.0f * layer[c]);
comp[c] = val;
}
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_screen (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = 1.0f - (1.0f - in[c]) * (1.0f - layer[c]);
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_softlight (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
{
gfloat multiply = in[c] * layer[c];
gfloat screen = 1.0f - (1.0f - in[c]) * (1.0f - layer[c]);
gfloat val = (1.0f - in[c]) * multiply + in[c] * screen;
comp[c] = val;
}
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
void
pika_operation_layer_mode_blend_subtract (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
comp[c] = in[c] - layer[c];
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
/* added according to:
http://www.simplefilter.de/en/basics/mixmods.html */
void
pika_operation_layer_mode_blend_vivid_light (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
gint c;
for (c = 0; c < 3; c++)
{
gfloat val;
if (layer[c] <= 0.5f)
{
val = 1.0f - safe_div (1.0f - in[c], 2.0f * layer[c]);
val = MAX (val, 0.0f);
}
else
{
val = safe_div (in[c], 2.0f * (1.0f - layer[c]));
val = MIN (val, 1.0f);
}
comp[c] = val;
}
}
comp[ALPHA] = layer[ALPHA];
comp += 4;
layer += 4;
in += 4;
}
}
/* subtractive blending functions. these functions must set comp[ALPHA] to
* the modified alpha of the overlapping content, as a fraction of the
* original overlapping content (i.e., an alpha of 1.0 specifies that no
* content is subtracted.) when in[ALPHA] or layer[ALPHA] are zero, the value
* of comp[RED..BLUE] is unconstrained (in particular, it may be NaN).
*/
void
pika_operation_layer_mode_blend_color_erase (GeglOperation *operation,
const gfloat *in,
const gfloat *layer,
gfloat *comp,
gint samples)
{
while (samples--)
{
if (in[ALPHA] != 0.0f && layer[ALPHA] != 0.0f)
{
const gfloat *color = in;
const gfloat *bgcolor = layer;
gfloat alpha;
gint c;
alpha = 0.0f;
for (c = 0; c < 3; c++)
{
gfloat col = CLAMP (color[c], 0.0f, 1.0f);
gfloat bgcol = CLAMP (bgcolor[c], 0.0f, 1.0f);
if (fabs (col - bgcol) > EPSILON)
{
gfloat a;
if (col > bgcol)
a = (col - bgcol) / (1.0f - bgcol);
else
a = (bgcol - col) / bgcol;
alpha = MAX (alpha, a);
}
}
if (alpha > EPSILON)
{
gfloat alpha_inv = 1.0f / alpha;
for (c = 0; c < 3; c++)
comp[c] = (color[c] - bgcolor[c]) * alpha_inv + bgcolor[c];
}
else
{
comp[RED] = comp[GREEN] = comp[BLUE] = 0.0f;
}
comp[ALPHA] = alpha;
}
else
comp[ALPHA] = 0.0f;
comp += 4;
layer += 4;
in += 4;
}
}