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Initial checkin of Pika from heckimp
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
*
* 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 <stdlib.h>
#include <cairo.h>
#include <gegl.h>
#include <gdk-pixbuf/gdk-pixbuf.h>
#include "libpikacolor/pikacolor.h"
#include "libpikamath/pikamath.h"
extern "C"
{
#include "core-types.h"
#include "gegl/pika-babl.h"
#include "gegl/pika-gegl-utils.h"
#include "pika-parallel.h"
#include "pika-utils.h" /* PIKA_TIMER */
#include "pikaasync.h"
#include "pikalineart.h"
#include "pikapickable.h"
#include "pikapickable-contiguous-region.h"
#define EPSILON 1e-6
#define PIXELS_PER_THREAD \
(/* each thread costs as much as */ 64.0 * 64.0 /* pixels */)
typedef struct
{
gint x;
gint y;
gint level;
} BorderPixel;
/* local function prototypes */
static const Babl * choose_format (GeglBuffer *buffer,
PikaSelectCriterion select_criterion,
gint *n_components,
gboolean *has_alpha);
static gfloat pixel_difference (const gfloat *col1,
const gfloat *col2,
gboolean antialias,
gfloat threshold,
gint n_components,
gboolean has_alpha,
gboolean select_transparent,
PikaSelectCriterion select_criterion);
static void push_segment (GQueue *segment_queue,
gint y,
gint old_y,
gint start,
gint end,
gint new_y,
gint new_start,
gint new_end);
static void pop_segment (GQueue *segment_queue,
gint *y,
gint *old_y,
gint *start,
gint *end);
static gboolean find_contiguous_segment (const gfloat *col,
GeglBuffer *src_buffer,
GeglSampler *src_sampler,
const GeglRectangle *src_extent,
GeglBuffer *mask_buffer,
const Babl *src_format,
const Babl *mask_format,
gint n_components,
gboolean has_alpha,
gboolean select_transparent,
PikaSelectCriterion select_criterion,
gboolean antialias,
gfloat threshold,
gint initial_x,
gint initial_y,
gint *start,
gint *end,
gfloat *row);
static void find_contiguous_region (GeglBuffer *src_buffer,
GeglBuffer *mask_buffer,
const Babl *format,
gint n_components,
gboolean has_alpha,
gboolean select_transparent,
PikaSelectCriterion select_criterion,
gboolean antialias,
gfloat threshold,
gboolean diagonal_neighbors,
gint x,
gint y,
const gfloat *col);
static void line_art_queue_pixel (GQueue *queue,
gint x,
gint y,
gint level);
/* public functions */
GeglBuffer *
pika_pickable_contiguous_region_by_seed (PikaPickable *pickable,
gboolean antialias,
gfloat threshold,
gboolean select_transparent,
PikaSelectCriterion select_criterion,
gboolean diagonal_neighbors,
gint x,
gint y)
{
GeglBuffer *src_buffer;
GeglBuffer *mask_buffer;
const Babl *format;
GeglRectangle extent;
gint n_components;
gboolean has_alpha;
gfloat start_col[MAX_CHANNELS];
g_return_val_if_fail (PIKA_IS_PICKABLE (pickable), NULL);
pika_pickable_flush (pickable);
src_buffer = pika_pickable_get_buffer (pickable);
format = choose_format (src_buffer, select_criterion,
&n_components, &has_alpha);
gegl_buffer_sample (src_buffer, x, y, NULL, start_col, format,
GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
if (has_alpha)
{
if (select_transparent)
{
/* don't select transparent regions if the start pixel isn't
* fully transparent
*/
if (start_col[n_components - 1] > 0)
select_transparent = FALSE;
}
}
else
{
select_transparent = FALSE;
}
extent = *gegl_buffer_get_extent (src_buffer);
mask_buffer = gegl_buffer_new (&extent, babl_format ("Y float"));
if (x >= extent.x && x < (extent.x + extent.width) &&
y >= extent.y && y < (extent.y + extent.height))
{
PIKA_TIMER_START();
find_contiguous_region (src_buffer, mask_buffer,
format, n_components, has_alpha,
select_transparent, select_criterion,
antialias, threshold, diagonal_neighbors,
x, y, start_col);
PIKA_TIMER_END("foo");
}
return mask_buffer;
}
GeglBuffer *
pika_pickable_contiguous_region_by_color (PikaPickable *pickable,
gboolean antialias,
gfloat threshold,
gboolean select_transparent,
PikaSelectCriterion select_criterion,
const PikaRGB *color)
{
/* Scan over the pickable's active layer, finding pixels within the
* specified threshold from the given R, G, & B values. If
* antialiasing is on, use the same antialiasing scheme as in
* fuzzy_select. Modify the pickable's mask to reflect the
* additional selection
*/
GeglBuffer *src_buffer;
GeglBuffer *mask_buffer;
const Babl *format;
gint n_components;
gboolean has_alpha;
gfloat start_col[MAX_CHANNELS];
g_return_val_if_fail (PIKA_IS_PICKABLE (pickable), NULL);
g_return_val_if_fail (color != NULL, NULL);
/* increase the threshold by EPSILON, to allow for conversion errors,
* especially when threshold == 0 (see issue #1554.) we need to do this
* here, but not in the other functions, since the input color gets converted
* to the format in which we perform the comparison through a different path
* than the pickable's pixels, which can introduce error.
*/
threshold += EPSILON;
pika_pickable_flush (pickable);
src_buffer = pika_pickable_get_buffer (pickable);
format = choose_format (src_buffer, select_criterion,
&n_components, &has_alpha);
pika_rgba_get_pixel (color, format, start_col);
if (has_alpha)
{
if (select_transparent)
{
/* don't select transparency if "color" isn't fully transparent
*/
if (start_col[n_components - 1] > 0.0)
select_transparent = FALSE;
}
}
else
{
select_transparent = FALSE;
}
mask_buffer = gegl_buffer_new (gegl_buffer_get_extent (src_buffer),
babl_format ("Y float"));
gegl_parallel_distribute_area (
gegl_buffer_get_extent (src_buffer), PIXELS_PER_THREAD,
[=] (const GeglRectangle *area)
{
GeglBufferIterator *iter;
iter = gegl_buffer_iterator_new (src_buffer,
area, 0, format,
GEGL_ACCESS_READ, GEGL_ABYSS_NONE, 2);
gegl_buffer_iterator_add (iter, mask_buffer,
area, 0, babl_format ("Y float"),
GEGL_ACCESS_WRITE, GEGL_ABYSS_NONE);
while (gegl_buffer_iterator_next (iter))
{
const gfloat *src = (const gfloat *) iter->items[0].data;
gfloat *dest = ( gfloat *) iter->items[1].data;
gint count = iter->length;
while (count--)
{
/* Find how closely the colors match */
*dest = pixel_difference (start_col, src,
antialias,
threshold,
n_components,
has_alpha,
select_transparent,
select_criterion);
src += n_components;
dest += 1;
}
}
});
return mask_buffer;
}
GeglBuffer *
pika_pickable_contiguous_region_by_line_art (PikaPickable *pickable,
PikaLineArt *line_art,
GeglBuffer *fill_buffer,
const PikaRGB *fill_color,
gfloat fill_threshold,
gint fill_offset_x,
gint fill_offset_y,
gint x,
gint y)
{
GeglBuffer *src_buffer;
GeglBuffer *mask_buffer;
const Babl *format = babl_format ("Y float");
gfloat *distmap = NULL;
GeglRectangle extent;
gboolean free_line_art = FALSE;
gboolean free_src_buffer = FALSE;
gboolean filled = FALSE;
guchar start_col;
g_return_val_if_fail (PIKA_IS_PICKABLE (pickable) || PIKA_IS_LINE_ART (line_art), NULL);
if (! line_art)
{
/* It is much better experience to pre-compute the line art,
* but it may not be always possible (for instance when
* selecting/filling through a PDB call).
*/
line_art = pika_line_art_new ();
pika_line_art_set_input (line_art, pickable);
free_line_art = TRUE;
}
src_buffer = pika_line_art_get (line_art, &distmap);
g_return_val_if_fail (src_buffer && distmap, NULL);
if (fill_buffer != NULL)
{
GeglBufferIterator *gi;
const Babl *fill_format;
const GeglRectangle *fill_extent;
gfloat fill_col[MAX_CHANNELS];
gboolean has_alpha;
gint n_components;
fill_extent = gegl_buffer_get_extent (fill_buffer);
fill_format = choose_format (fill_buffer,
PIKA_SELECT_CRITERION_COMPOSITE,
&n_components, &has_alpha);
pika_rgba_get_pixel (fill_color, fill_format, fill_col);
src_buffer = pika_gegl_buffer_dup (src_buffer);
gi = gegl_buffer_iterator_new (src_buffer, NULL, 0, NULL,
GEGL_ACCESS_READWRITE, GEGL_ABYSS_NONE, 2);
gegl_buffer_iterator_add (gi, fill_buffer,
GEGL_RECTANGLE (-fill_offset_x, -fill_offset_y,
fill_extent->width + fill_offset_x,
fill_extent->height + fill_offset_y),
0, fill_format, GEGL_ACCESS_READ, GEGL_ABYSS_NONE);
while (gegl_buffer_iterator_next (gi))
{
guchar *data = (guchar*) gi->items[0].data;
const gfloat *fill = (const gfloat *) gi->items[1].data;
gint k;
for (k = 0; k < gi->length; k++)
{
/* Only consider if the line art source hasn't filled yet,
* and also if this the fill target has full opacity.
*/
if (! *data &&
( ! has_alpha ||
fill[n_components - 1] == 1.0))
{
gfloat diff;
diff = pixel_difference (fill, fill_col,
FALSE,
fill_threshold,
n_components, has_alpha, FALSE,
PIKA_SELECT_CRITERION_COMPOSITE);
/* Make the additional fill pixel a closure pixel. */
if (diff == 1.0)
*data = 2;
}
data++;
fill += n_components;
}
}
free_src_buffer = TRUE;
}
gegl_buffer_sample (src_buffer, x, y, NULL, &start_col, NULL,
GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
extent = *gegl_buffer_get_extent (src_buffer);
mask_buffer = gegl_buffer_new (&extent, format);
if (start_col)
{
if (start_col == 1)
{
/* As a special exception, if you fill over a line art pixel, only
* fill the pixel and exit
*/
gfloat col = 1.0;
gegl_buffer_set (mask_buffer, GEGL_RECTANGLE (x, y, 1, 1),
0, format, &col, GEGL_AUTO_ROWSTRIDE);
}
else /* start_col == 2 */
{
/* If you fill over a closure pixel, let's fill on all sides
* of the start point. Otherwise we get a very weird result
* with only a single pixel filled in the middle of an empty
* region (since closure pixels are invisible by nature).
*/
gfloat col = 0.0;
if (x - 1 >= extent.x && x - 1 < extent.x + extent.width &&
y - 1 >= extent.y && y - 1 < (extent.y + extent.height))
find_contiguous_region (src_buffer, mask_buffer,
format, 1, FALSE,
FALSE, PIKA_SELECT_CRITERION_COMPOSITE,
FALSE, 0.0, FALSE,
x - 1, y - 1, &col);
if (x - 1 >= extent.x && x - 1 < extent.x + extent.width &&
y >= extent.y && y < (extent.y + extent.height))
find_contiguous_region (src_buffer, mask_buffer,
format, 1, FALSE,
FALSE, PIKA_SELECT_CRITERION_COMPOSITE,
FALSE, 0.0, FALSE,
x - 1, y, &col);
if (x - 1 >= extent.x && x - 1 < extent.x + extent.width &&
y + 1 >= extent.y && y + 1 < (extent.y + extent.height))
find_contiguous_region (src_buffer, mask_buffer,
format, 1, FALSE,
FALSE, PIKA_SELECT_CRITERION_COMPOSITE,
FALSE, 0.0, FALSE,
x - 1, y + 1, &col);
if (x >= extent.x && x < extent.x + extent.width &&
y - 1 >= extent.y && y - 1 < (extent.y + extent.height))
find_contiguous_region (src_buffer, mask_buffer,
format, 1, FALSE,
FALSE, PIKA_SELECT_CRITERION_COMPOSITE,
FALSE, 0.0, FALSE,
x, y - 1, &col);
if (x >= extent.x && x < extent.x + extent.width &&
y + 1 >= extent.y && y + 1 < (extent.y + extent.height))
find_contiguous_region (src_buffer, mask_buffer,
format, 1, FALSE,
FALSE, PIKA_SELECT_CRITERION_COMPOSITE,
FALSE, 0.0, FALSE,
x, y + 1, &col);
if (x + 1 >= extent.x && x + 1 < extent.x + extent.width &&
y - 1 >= extent.y && y - 1 < (extent.y + extent.height))
find_contiguous_region (src_buffer, mask_buffer,
format, 1, FALSE,
FALSE, PIKA_SELECT_CRITERION_COMPOSITE,
FALSE, 0.0, FALSE,
x + 1, y - 1, &col);
if (x + 1 >= extent.x && x + 1 < extent.x + extent.width &&
y >= extent.y && y < (extent.y + extent.height))
find_contiguous_region (src_buffer, mask_buffer,
format, 1, FALSE,
FALSE, PIKA_SELECT_CRITERION_COMPOSITE,
FALSE, 0.0, FALSE,
x + 1, y, &col);
if (x + 1 >= extent.x && x + 1 < extent.x + extent.width &&
y + 1 >= extent.y && y + 1 < (extent.y + extent.height))
find_contiguous_region (src_buffer, mask_buffer,
format, 1, FALSE,
FALSE, PIKA_SELECT_CRITERION_COMPOSITE,
FALSE, 0.0, FALSE,
x + 1, y + 1, &col);
filled = TRUE;
}
}
else if (x >= extent.x && x < (extent.x + extent.width) &&
y >= extent.y && y < (extent.y + extent.height))
{
gfloat col = 0.0;
find_contiguous_region (src_buffer, mask_buffer,
format, 1, FALSE,
FALSE, PIKA_SELECT_CRITERION_COMPOSITE,
FALSE, 0.0, FALSE,
x, y, &col);
filled = TRUE;
}
if (filled)
{
GQueue *queue = g_queue_new ();
gfloat *mask;
gint width = gegl_buffer_get_width (src_buffer);
gint height = gegl_buffer_get_height (src_buffer);
gint line_art_max_grow;
gint nx, ny;
PIKA_TIMER_START();
/* The last step of the line art algorithm is to make sure that
* selections does not leave "holes" between its borders and the
* line arts, while not stepping over as well.
* I used to run the "gegl:watershed-transform" operation to flood
* the stroke pixels, but for such simple need, this simple code
* is so much faster while producing better results.
*/
mask = g_new (gfloat, width * height);
gegl_buffer_get (mask_buffer, NULL, 1.0, NULL,
mask, GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);
for (y = 0; y < height; y++)
for (x = 0; x < width; x++)
{
if (distmap[x + y * width] == 1.0)
{
if (x > 0)
{
nx = x - 1;
if (y > 0)
{
ny = y - 1;
if (mask[nx + ny * width] != 0.0)
{
line_art_queue_pixel (queue, x, y, 1);
continue;
}
}
ny = y;
if (mask[nx + ny * width] != 0.0)
{
line_art_queue_pixel (queue, x, y, 1);
continue;
}
if (y < height - 1)
{
ny = y + 1;
if (mask[nx + ny * width] != 0.0)
{
line_art_queue_pixel (queue, x, y, 1);
continue;
}
}
}
if (x < width - 1)
{
nx = x + 1;
if (y > 0)
{
ny = y - 1;
if (mask[nx + ny * width] != 0.0)
{
line_art_queue_pixel (queue, x, y, 1);
continue;
}
}
ny = y;
if (mask[nx + ny * width] != 0.0)
{
line_art_queue_pixel (queue, x, y, 1);
continue;
}
if (y < height - 1)
{
ny = y + 1;
if (mask[nx + ny * width] != 0.0)
{
line_art_queue_pixel (queue, x, y, 1);
continue;
}
}
}
nx = x;
if (y > 0)
{
ny = y - 1;
if (mask[nx + ny * width] != 0.0)
{
line_art_queue_pixel (queue, x, y, 1);
continue;
}
}
if (y < height - 1)
{
ny = y + 1;
if (mask[nx + ny * width] != 0.0)
{
line_art_queue_pixel (queue, x, y, 1);
continue;
}
}
}
}
g_object_get (line_art,
"max-grow", &line_art_max_grow,
NULL);
while (! g_queue_is_empty (queue))
{
BorderPixel *c = (BorderPixel *) g_queue_pop_head (queue);
if (mask[c->x + c->y * width] != 1.0)
{
mask[c->x + c->y * width] = 1.0;
if (c->level >= line_art_max_grow)
{
/* Do not overflood under line arts. */
g_free (c);
continue;
}
if (c->x > 0)
{
nx = c->x - 1;
if (c->y > 0)
{
ny = c->y - 1;
if (mask[nx + ny * width] == 0.0 &&
distmap[nx + ny * width] > distmap[c->x + c->y * width])
line_art_queue_pixel (queue, nx, ny, c->level + 1);
}
ny = c->y;
if (mask[nx + ny * width] == 0.0 &&
distmap[nx + ny * width] > distmap[c->x + c->y * width])
line_art_queue_pixel (queue, nx, ny, c->level + 1);
if (c->y < height - 1)
{
ny = c->y + 1;
if (mask[nx + ny * width] == 0.0 &&
distmap[nx + ny * width] > distmap[c->x + c->y * width])
line_art_queue_pixel (queue, nx, ny, c->level + 1);
}
}
if (c->x < width - 1)
{
nx = c->x + 1;
if (c->y > 0)
{
ny = c->y - 1;
if (mask[nx + ny * width] == 0.0 &&
distmap[nx + ny * width] > distmap[c->x + c->y * width])
line_art_queue_pixel (queue, nx, ny, c->level + 1);
}
ny = c->y;
if (mask[nx + ny * width] == 0.0 &&
distmap[nx + ny * width] > distmap[c->x + c->y * width])
line_art_queue_pixel (queue, nx, ny, c->level + 1);
if (c->y < height - 1)
{
ny = c->y + 1;
if (mask[nx + ny * width] == 0.0 &&
distmap[nx + ny * width] > distmap[c->x + c->y * width])
line_art_queue_pixel (queue, nx, ny, c->level + 1);
}
}
nx = c->x;
if (c->y > 0)
{
ny = c->y - 1;
if (mask[nx + ny * width] == 0.0 &&
distmap[nx + ny * width] > distmap[c->x + c->y * width])
line_art_queue_pixel (queue, nx, ny, c->level + 1);
}
if (c->y < height - 1)
{
ny = c->y + 1;
if (mask[nx + ny * width] == 0.0 &&
distmap[nx + ny * width] > distmap[c->x + c->y * width])
line_art_queue_pixel (queue, nx, ny, c->level + 1);
}
}
g_free (c);
}
g_queue_free (queue);
gegl_buffer_set (mask_buffer, gegl_buffer_get_extent (mask_buffer),
0, NULL, mask, GEGL_AUTO_ROWSTRIDE);
g_free (mask);
PIKA_TIMER_END("watershed line art");
}
if (free_line_art)
g_clear_object (&line_art);
if (free_src_buffer)
g_object_unref (src_buffer);
return mask_buffer;
}
/* private functions */
static const Babl *
choose_format (GeglBuffer *buffer,
PikaSelectCriterion select_criterion,
gint *n_components,
gboolean *has_alpha)
{
const Babl *format = gegl_buffer_get_format (buffer);
*has_alpha = babl_format_has_alpha (format);
switch (select_criterion)
{
case PIKA_SELECT_CRITERION_COMPOSITE:
if (babl_format_is_palette (format))
format = babl_format ("R'G'B'A float");
else
format = pika_babl_format (pika_babl_format_get_base_type (format),
PIKA_PRECISION_FLOAT_NON_LINEAR,
*has_alpha,
NULL);
break;
case PIKA_SELECT_CRITERION_RGB_RED:
case PIKA_SELECT_CRITERION_RGB_GREEN:
case PIKA_SELECT_CRITERION_RGB_BLUE:
case PIKA_SELECT_CRITERION_ALPHA:
format = babl_format ("R'G'B'A float");
break;
case PIKA_SELECT_CRITERION_HSV_HUE:
case PIKA_SELECT_CRITERION_HSV_SATURATION:
case PIKA_SELECT_CRITERION_HSV_VALUE:
format = babl_format ("HSVA float");
break;
case PIKA_SELECT_CRITERION_LCH_LIGHTNESS:
format = babl_format ("CIE L alpha float");
break;
case PIKA_SELECT_CRITERION_LCH_CHROMA:
case PIKA_SELECT_CRITERION_LCH_HUE:
format = babl_format ("CIE LCH(ab) alpha float");
break;
default:
g_return_val_if_reached (NULL);
break;
}
*n_components = babl_format_get_n_components (format);
return format;
}
static gfloat
pixel_difference (const gfloat *col1,
const gfloat *col2,
gboolean antialias,
gfloat threshold,
gint n_components,
gboolean has_alpha,
gboolean select_transparent,
PikaSelectCriterion select_criterion)
{
gfloat max = 0.0;
/* if there is an alpha channel, never select transparent regions */
if (! select_transparent && has_alpha && col2[n_components - 1] == 0.0)
return 0.0;
if (select_transparent && has_alpha)
{
max = fabs (col1[n_components - 1] - col2[n_components - 1]);
}
else
{
gfloat diff;
gint b;
if (has_alpha)
n_components--;
switch (select_criterion)
{
case PIKA_SELECT_CRITERION_COMPOSITE:
for (b = 0; b < n_components; b++)
{
diff = fabs (col1[b] - col2[b]);
if (diff > max)
max = diff;
}
break;
case PIKA_SELECT_CRITERION_RGB_RED:
max = fabs (col1[0] - col2[0]);
break;
case PIKA_SELECT_CRITERION_RGB_GREEN:
max = fabs (col1[1] - col2[1]);
break;
case PIKA_SELECT_CRITERION_RGB_BLUE:
max = fabs (col1[2] - col2[2]);
break;
case PIKA_SELECT_CRITERION_ALPHA:
max = fabs (col1[3] - col2[3]);
break;
case PIKA_SELECT_CRITERION_HSV_HUE:
if (col1[1] > EPSILON)
{
if (col2[1] > EPSILON)
{
max = fabs (col1[0] - col2[0]);
max = MIN (max, 1.0 - max);
}
else
{
/* "infinite" difference. anything >> 1 will do. */
max = 10.0;
}
}
else
{
if (col2[1] > EPSILON)
{
/* "infinite" difference. anything >> 1 will do. */
max = 10.0;
}
else
{
max = 0.0;
}
}
break;
case PIKA_SELECT_CRITERION_HSV_SATURATION:
max = fabs (col1[1] - col2[1]);
break;
case PIKA_SELECT_CRITERION_HSV_VALUE:
max = fabs (col1[2] - col2[2]);
break;
case PIKA_SELECT_CRITERION_LCH_LIGHTNESS:
max = fabs (col1[0] - col2[0]) / 100.0;
break;
case PIKA_SELECT_CRITERION_LCH_CHROMA:
max = fabs (col1[1] - col2[1]) / 100.0;
break;
case PIKA_SELECT_CRITERION_LCH_HUE:
if (col1[1] > 100.0 * EPSILON)
{
if (col2[1] > 100.0 * EPSILON)
{
max = fabs (col1[2] - col2[2]) / 360.0;
max = MIN (max, 1.0 - max);
}
else
{
/* "infinite" difference. anything >> 1 will do. */
max = 10.0;
}
}
else
{
if (col2[1] > 100.0 * EPSILON)
{
/* "infinite" difference. anything >> 1 will do. */
max = 10.0;
}
else
{
max = 0.0;
}
}
break;
}
}
if (antialias && threshold > 0.0)
{
gfloat aa = 1.5 - (max / threshold);
if (aa <= 0.0)
return 0.0;
else if (aa < 0.5)
return aa * 2.0;
else
return 1.0;
}
else
{
if (max > threshold)
return 0.0;
else
return 1.0;
}
}
static void
push_segment (GQueue *segment_queue,
gint y,
gint old_y,
gint start,
gint end,
gint new_y,
gint new_start,
gint new_end)
{
/* To avoid excessive memory allocation (y, old_y, start, end) tuples are
* stored in interleaved format:
*
* [y1] [old_y1] [start1] [end1] [y2] [old_y2] [start2] [end2]
*/
if (new_y != old_y)
{
/* If the new segment's y-coordinate is different than the old (source)
* segment's y-coordinate, push the entire segment.
*/
g_queue_push_tail (segment_queue, GINT_TO_POINTER (new_y));
g_queue_push_tail (segment_queue, GINT_TO_POINTER (y));
g_queue_push_tail (segment_queue, GINT_TO_POINTER (new_start));
g_queue_push_tail (segment_queue, GINT_TO_POINTER (new_end));
}
else
{
/* Otherwise, only push the set-difference between the new segment and
* the source segment (since we've already scanned the source segment.)
* Note that the `+ 1` and `- 1` terms of the end/start coordinates below
* are only necessary when `diagonal_neighbors` is on (and otherwise make
* the segments slightly larger than necessary), but, meh...
*/
if (new_start < start)
{
g_queue_push_tail (segment_queue, GINT_TO_POINTER (new_y));
g_queue_push_tail (segment_queue, GINT_TO_POINTER (y));
g_queue_push_tail (segment_queue, GINT_TO_POINTER (new_start));
g_queue_push_tail (segment_queue, GINT_TO_POINTER (start + 1));
}
if (new_end > end)
{
g_queue_push_tail (segment_queue, GINT_TO_POINTER (new_y));
g_queue_push_tail (segment_queue, GINT_TO_POINTER (y));
g_queue_push_tail (segment_queue, GINT_TO_POINTER (end - 1));
g_queue_push_tail (segment_queue, GINT_TO_POINTER (new_end));
}
}
}
static void
pop_segment (GQueue *segment_queue,
gint *y,
gint *old_y,
gint *start,
gint *end)
{
*y = GPOINTER_TO_INT (g_queue_pop_head (segment_queue));
*old_y = GPOINTER_TO_INT (g_queue_pop_head (segment_queue));
*start = GPOINTER_TO_INT (g_queue_pop_head (segment_queue));
*end = GPOINTER_TO_INT (g_queue_pop_head (segment_queue));
}
/* #define FETCH_ROW 1 */
static gboolean
find_contiguous_segment (const gfloat *col,
GeglBuffer *src_buffer,
GeglSampler *src_sampler,
const GeglRectangle *src_extent,
GeglBuffer *mask_buffer,
const Babl *src_format,
const Babl *mask_format,
gint n_components,
gboolean has_alpha,
gboolean select_transparent,
PikaSelectCriterion select_criterion,
gboolean antialias,
gfloat threshold,
gint initial_x,
gint initial_y,
gint *start,
gint *end,
gfloat *row)
{
gfloat *s;
gfloat mask_row_buf[src_extent->width];
gfloat *mask_row = mask_row_buf - src_extent->x;
gfloat diff;
#ifdef FETCH_ROW
gegl_buffer_get (src_buffer, GEGL_RECTANGLE (0, initial_y, width, 1), 1.0,
src_format,
row, GEGL_AUTO_ROWSTRIDE, GEGL_ABYSS_NONE);
s = row + initial_x * n_components;
#else
s = (gfloat *) g_alloca (n_components * sizeof (gfloat));
gegl_sampler_get (src_sampler,
initial_x, initial_y, NULL, s, GEGL_ABYSS_NONE);
#endif
diff = pixel_difference (col, s, antialias, threshold,
n_components, has_alpha, select_transparent,
select_criterion);
/* check the starting pixel */
if (! diff)
return FALSE;
mask_row[initial_x] = diff;
*start = initial_x - 1;
#ifdef FETCH_ROW
s = row + *start * n_components;
#endif
while (*start >= src_extent->x)
{
#ifndef FETCH_ROW
gegl_sampler_get (src_sampler,
*start, initial_y, NULL, s, GEGL_ABYSS_NONE);
#endif
diff = pixel_difference (col, s, antialias, threshold,
n_components, has_alpha, select_transparent,
select_criterion);
if (diff == 0.0)
break;
mask_row[*start] = diff;
(*start)--;
#ifdef FETCH_ROW
s -= n_components;
#endif
}
*end = initial_x + 1;
#ifdef FETCH_ROW
s = row + *end * n_components;
#endif
while (*end < src_extent->x + src_extent->width)
{
#ifndef FETCH_ROW
gegl_sampler_get (src_sampler,
*end, initial_y, NULL, s, GEGL_ABYSS_NONE);
#endif
diff = pixel_difference (col, s, antialias, threshold,
n_components, has_alpha, select_transparent,
select_criterion);
if (diff == 0.0)
break;
mask_row[*end] = diff;
(*end)++;
#ifdef FETCH_ROW
s += n_components;
#endif
}
gegl_buffer_set (mask_buffer, GEGL_RECTANGLE (*start + 1, initial_y,
*end - *start - 1, 1),
0, mask_format, &mask_row[*start + 1],
GEGL_AUTO_ROWSTRIDE);
return TRUE;
}
static void
find_contiguous_region (GeglBuffer *src_buffer,
GeglBuffer *mask_buffer,
const Babl *format,
gint n_components,
gboolean has_alpha,
gboolean select_transparent,
PikaSelectCriterion select_criterion,
gboolean antialias,
gfloat threshold,
gboolean diagonal_neighbors,
gint x,
gint y,
const gfloat *col)
{
const Babl *mask_format = babl_format ("Y float");
GeglSampler *src_sampler;
const GeglRectangle *src_extent;
gint old_y;
gint start, end;
gint new_start, new_end;
GQueue *segment_queue;
gfloat *row = NULL;
src_extent = gegl_buffer_get_extent (src_buffer);
#ifdef FETCH_ROW
row = g_new (gfloat, src_extent->width * n_components);
#endif
src_sampler = gegl_buffer_sampler_new (src_buffer,
format, GEGL_SAMPLER_NEAREST);
segment_queue = g_queue_new ();
push_segment (segment_queue,
y, /* dummy values: */ -1, 0, 0,
y, x - 1, x + 1);
do
{
pop_segment (segment_queue,
&y, &old_y, &start, &end);
for (x = start + 1; x < end; x++)
{
gfloat val;
gegl_buffer_get (mask_buffer, GEGL_RECTANGLE (x, y, 1, 1), 1.0,
mask_format, &val, GEGL_AUTO_ROWSTRIDE,
GEGL_ABYSS_NONE);
if (val != 0.0)
{
/* If the current pixel is selected, then we've already visited
* the next pixel. (Note that we assume that the maximal image
* width is sufficiently low that `x` won't overflow.)
*/
x++;
continue;
}
if (! find_contiguous_segment (col,
src_buffer, src_sampler, src_extent,
mask_buffer,
format, mask_format,
n_components,
has_alpha,
select_transparent, select_criterion,
antialias, threshold, x, y,
&new_start, &new_end,
row))
continue;
/* We can skip directly to `new_end + 1` on the next iteration, since
* we've just selected all pixels in the range `[x, new_end)`, and
* the pixel at `new_end` is above threshold. (Note that we assume
* that the maximal image width is sufficiently low that `x` won't
* overflow.)
*/
x = new_end;
if (diagonal_neighbors)
{
if (new_start >= src_extent->x)
new_start--;
if (new_end < src_extent->x + src_extent->width)
new_end++;
}
if (y + 1 < src_extent->y + src_extent->height)
{
push_segment (segment_queue,
y, old_y, start, end,
y + 1, new_start, new_end);
}
if (y - 1 >= src_extent->y)
{
push_segment (segment_queue,
y, old_y, start, end,
y - 1, new_start, new_end);
}
}
}
while (! g_queue_is_empty (segment_queue));
g_queue_free (segment_queue);
g_object_unref (src_sampler);
#ifdef FETCH_ROW
g_free (row);
#endif
}
static void
line_art_queue_pixel (GQueue *queue,
gint x,
gint y,
gint level)
{
BorderPixel *p = g_new (BorderPixel, 1);
p->x = x;
p->y = y;
p->level = level;
g_queue_push_head (queue, p);
}
} /* extern "C" */