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PIKApp/app/core/pikalineart.c

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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
*
* Copyright (C) 2017 Sébastien Fourey & David Tchumperlé
* Copyright (C) 2018 Jehan
*
* 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 <gdk-pixbuf/gdk-pixbuf.h>
#include <gegl.h>
#include "libpikabase/pikabase.h"
#include "libpikamath/pikamath.h"
#include "core-types.h"
#include "gegl/pika-gegl-loops.h"
#include "gegl/pika-gegl-utils.h"
#include "pika-parallel.h"
#include "pika-priorities.h"
#include "pika-utils.h" /* PIKA_TIMER */
#include "pikaasync.h"
#include "pikacancelable.h"
#include "pikadrawable.h"
#include "pikaimage.h"
#include "pikalineart.h"
#include "pikapickable.h"
#include "pikaprojection.h"
#include "pikaviewable.h"
#include "pikawaitable.h"
#include "pika-intl.h"
enum
{
COMPUTING_START,
COMPUTING_END,
LAST_SIGNAL,
};
enum
{
PROP_0,
PROP_SELECT_TRANSPARENT,
PROP_MAX_GROW,
PROP_THRESHOLD,
PROP_AUTOMATIC_CLOSURE,
PROP_SPLINE_MAX_LEN,
PROP_SEGMENT_MAX_LEN,
};
typedef struct _PikaLineArtPrivate PikaLineArtPrivate;
struct _PikaLineArtPrivate
{
gboolean frozen;
gboolean compute_after_thaw;
PikaAsync *async;
gint idle_id;
PikaPickable *input;
GeglBuffer *closed;
gfloat *distmap;
/* Used in the closing step. */
gboolean select_transparent;
gdouble threshold;
gboolean automatic_closure;
gint spline_max_len;
gint segment_max_len;
gboolean max_len_bound;
/* Used in the grow step. */
gint max_grow;
};
typedef struct
{
GeglBuffer *buffer;
gboolean select_transparent;
gdouble threshold;
gboolean automatic_closure;
gint spline_max_len;
gint segment_max_len;
} LineArtData;
typedef struct
{
GeglBuffer *closed;
gfloat *distmap;
} LineArtResult;
static int DeltaX[4] = {+1, -1, 0, 0};
static int DeltaY[4] = {0, 0, +1, -1};
static const PikaVector2 Direction2Normal[4] =
{
{ 1.0f, 0.0f },
{ -1.0f, 0.0f },
{ 0.0f, 1.0f },
{ 0.0f, -1.0f }
};
typedef enum _Direction
{
XPlusDirection = 0,
XMinusDirection = 1,
YPlusDirection = 2,
YMinusDirection = 3
} Direction;
typedef PikaVector2 Pixel;
typedef struct _SplineCandidate
{
Pixel p1;
Pixel p2;
float quality;
} SplineCandidate;
typedef struct _Edgel
{
gint x, y;
Direction direction;
gfloat x_normal;
gfloat y_normal;
gfloat curvature;
guint next, previous;
} Edgel;
static void pika_line_art_finalize (GObject *object);
static void pika_line_art_set_property (GObject *object,
guint property_id,
const GValue *value,
GParamSpec *pspec);
static void pika_line_art_get_property (GObject *object,
guint property_id,
GValue *value,
GParamSpec *pspec);
/* Functions for asynchronous computation. */
static void pika_line_art_compute (PikaLineArt *line_art);
static void pika_line_art_compute_cb (PikaAsync *async,
PikaLineArt *line_art);
static PikaAsync * pika_line_art_prepare_async (PikaLineArt *line_art,
gint priority);
static void pika_line_art_prepare_async_func (PikaAsync *async,
LineArtData *data);
static LineArtData * line_art_data_new (GeglBuffer *buffer,
PikaLineArt *line_art);
static void line_art_data_free (LineArtData *data);
static LineArtResult * line_art_result_new (GeglBuffer *line_art,
gfloat *distmap);
static void line_art_result_free (LineArtResult *result);
static gboolean pika_line_art_idle (PikaLineArt *line_art);
static void pika_line_art_input_invalidate_preview (PikaViewable *viewable,
PikaLineArt *line_art);
/* All actual computation functions. */
static GeglBuffer * pika_line_art_close (GeglBuffer *buffer,
gboolean select_transparent,
gdouble stroke_threshold,
gboolean automatic_closure,
gint spline_max_length,
gint segment_max_length,
gint minimal_lineart_area,
gint normal_estimate_mask_size,
gfloat end_point_rate,
gfloat spline_max_angle,
gint end_point_connectivity,
gfloat spline_roundness,
gboolean allow_self_intersections,
gint created_regions_significant_area,
gint created_regions_minimum_area,
gboolean small_segments_from_spline_sources,
gfloat **lineart_distmap,
PikaAsync *async);
static void pika_lineart_denoise (GeglBuffer *buffer,
int size,
PikaAsync *async);
static void pika_lineart_compute_normals_curvatures (GeglBuffer *mask,
gfloat *normals,
gfloat *curvatures,
gfloat *smoothed_curvatures,
int normal_estimate_mask_size,
PikaAsync *async);
static gfloat * pika_lineart_get_smooth_curvatures (GArray *edgelset,
PikaAsync *async);
static GArray * pika_lineart_curvature_extremums (gfloat *curvatures,
gfloat *smoothed_curvatures,
gint curvatures_width,
gint curvatures_height,
PikaAsync *async);
static gint pika_spline_candidate_cmp (const SplineCandidate *a,
const SplineCandidate *b,
gpointer user_data);
static GList * pika_lineart_find_spline_candidates (GArray *max_positions,
gfloat *normals,
gint width,
gint distance_threshold,
gfloat max_angle_deg,
PikaAsync *async);
static GArray * pika_lineart_discrete_spline (Pixel p0,
PikaVector2 n0,
Pixel p1,
PikaVector2 n1);
static gint pika_number_of_transitions (GArray *pixels,
GeglBuffer *buffer);
static gboolean pika_line_art_allow_closure (GeglBuffer *mask,
GArray *pixels,
GList **fill_pixels,
int significant_size,
int minimum_size);
static GArray * pika_lineart_line_segment_until_hit (const GeglBuffer *buffer,
Pixel start,
PikaVector2 direction,
int size);
static gfloat * pika_lineart_estimate_strokes_radii (GeglBuffer *mask,
PikaAsync *async);
static void pika_line_art_simple_fill (GeglBuffer *buffer,
gint x,
gint y,
gint *counter);
/* Some callback-type functions. */
static guint visited_hash_fun (Pixel *key);
static gboolean visited_equal_fun (Pixel *e1,
Pixel *e2);
static inline gboolean border_in_direction (GeglBuffer *mask,
Pixel p,
int direction);
static inline PikaVector2 pair2normal (Pixel p,
gfloat *normals,
gint width);
/* Edgel */
static Edgel * pika_edgel_new (int x,
int y,
Direction direction);
static void pika_edgel_init (Edgel *edgel);
static void pika_edgel_clear (Edgel **edgel);
static int pika_edgel_cmp (const Edgel *e1,
const Edgel *e2);
static guint edgel2index_hash_fun (Edgel *key);
static gboolean edgel2index_equal_fun (Edgel *e1,
Edgel *e2);
static glong pika_edgel_track_mark (GeglBuffer *mask,
Edgel edgel,
long size_limit);
static glong pika_edgel_region_area (const GeglBuffer *mask,
Edgel start_edgel);
/* Edgel set */
static GArray * pika_edgelset_new (GeglBuffer *buffer,
PikaAsync *async);
static void pika_edgelset_add (GArray *set,
int x,
int y,
Direction direction,
GHashTable *edgel2index);
static void pika_edgelset_init_normals (GArray *set);
static void pika_edgelset_smooth_normals (GArray *set,
int mask_size,
PikaAsync *async);
static void pika_edgelset_compute_curvature (GArray *set,
PikaAsync *async);
static void pika_edgelset_build_graph (GArray *set,
GeglBuffer *buffer,
GHashTable *edgel2index,
PikaAsync *async);
static void pika_edgelset_next8 (const GeglBuffer *buffer,
Edgel *it,
Edgel *n);
G_DEFINE_TYPE_WITH_CODE (PikaLineArt, pika_line_art, PIKA_TYPE_OBJECT,
G_ADD_PRIVATE (PikaLineArt))
#define parent_class pika_line_art_parent_class
static guint pika_line_art_signals[LAST_SIGNAL] = { 0 };
static void
pika_line_art_class_init (PikaLineArtClass *klass)
{
GObjectClass *object_class = G_OBJECT_CLASS (klass);
pika_line_art_signals[COMPUTING_START] =
g_signal_new ("computing-start",
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (PikaLineArtClass, computing_start),
NULL, NULL, NULL,
G_TYPE_NONE, 0);
pika_line_art_signals[COMPUTING_END] =
g_signal_new ("computing-end",
G_TYPE_FROM_CLASS (klass),
G_SIGNAL_RUN_FIRST,
G_STRUCT_OFFSET (PikaLineArtClass, computing_end),
NULL, NULL, NULL,
G_TYPE_NONE, 0);
object_class->finalize = pika_line_art_finalize;
object_class->set_property = pika_line_art_set_property;
object_class->get_property = pika_line_art_get_property;
g_object_class_install_property (object_class, PROP_SELECT_TRANSPARENT,
g_param_spec_boolean ("select-transparent",
_("Select transparent pixels instead of gray ones"),
_("Select transparent pixels instead of gray ones"),
TRUE,
G_PARAM_CONSTRUCT | PIKA_PARAM_READWRITE));
g_object_class_install_property (object_class, PROP_THRESHOLD,
g_param_spec_double ("threshold",
_("Line art detection threshold"),
_("Threshold to detect contour (higher values will include more pixels)"),
0.0, 1.0, 0.92,
G_PARAM_CONSTRUCT | PIKA_PARAM_READWRITE));
g_object_class_install_property (object_class, PROP_MAX_GROW,
g_param_spec_int ("max-grow",
_("Maximum growing size"),
_("Maximum number of pixels grown under the line art"),
1, 100, 3,
G_PARAM_CONSTRUCT | PIKA_PARAM_READWRITE));
g_object_class_install_property (object_class, PROP_AUTOMATIC_CLOSURE,
g_param_spec_boolean ("automatic-closure",
_("Whether or not we should perform the closing step"),
_("Whether or not we should perform the closing step"),
TRUE,
G_PARAM_CONSTRUCT | PIKA_PARAM_READWRITE));
g_object_class_install_property (object_class, PROP_SPLINE_MAX_LEN,
g_param_spec_int ("spline-max-length",
_("Maximum curved closing length"),
_("Maximum curved length (in pixels) to close the line art"),
0, 1000, 100,
G_PARAM_CONSTRUCT | PIKA_PARAM_READWRITE));
g_object_class_install_property (object_class, PROP_SEGMENT_MAX_LEN,
g_param_spec_int ("segment-max-length",
_("Maximum straight closing length"),
_("Maximum straight length (in pixels) to close the line art"),
0, 1000, 100,
G_PARAM_CONSTRUCT | PIKA_PARAM_READWRITE));
}
static void
pika_line_art_init (PikaLineArt *line_art)
{
line_art->priv = pika_line_art_get_instance_private (line_art);
}
static void
pika_line_art_finalize (GObject *object)
{
PikaLineArt *line_art = PIKA_LINE_ART (object);
line_art->priv->frozen = FALSE;
pika_line_art_set_input (line_art, NULL);
G_OBJECT_CLASS (parent_class)->finalize (object);
}
static void
pika_line_art_set_property (GObject *object,
guint property_id,
const GValue *value,
GParamSpec *pspec)
{
PikaLineArt *line_art = PIKA_LINE_ART (object);
switch (property_id)
{
case PROP_SELECT_TRANSPARENT:
if (line_art->priv->select_transparent != g_value_get_boolean (value))
{
line_art->priv->select_transparent = g_value_get_boolean (value);
pika_line_art_compute (line_art);
}
break;
case PROP_MAX_GROW:
line_art->priv->max_grow = g_value_get_int (value);
break;
case PROP_THRESHOLD:
if (line_art->priv->threshold != g_value_get_double (value))
{
line_art->priv->threshold = g_value_get_double (value);
pika_line_art_compute (line_art);
}
break;
case PROP_AUTOMATIC_CLOSURE:
if (line_art->priv->automatic_closure != g_value_get_boolean (value))
{
line_art->priv->automatic_closure = g_value_get_boolean (value);
pika_line_art_compute (line_art);
}
break;
case PROP_SPLINE_MAX_LEN:
if (line_art->priv->spline_max_len != g_value_get_int (value))
{
line_art->priv->spline_max_len = g_value_get_int (value);
if (line_art->priv->max_len_bound)
line_art->priv->segment_max_len = line_art->priv->spline_max_len;
pika_line_art_compute (line_art);
}
break;
case PROP_SEGMENT_MAX_LEN:
if (line_art->priv->segment_max_len != g_value_get_int (value))
{
line_art->priv->segment_max_len = g_value_get_int (value);
if (line_art->priv->max_len_bound)
line_art->priv->spline_max_len = line_art->priv->segment_max_len;
pika_line_art_compute (line_art);
}
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
break;
}
}
static void
pika_line_art_get_property (GObject *object,
guint property_id,
GValue *value,
GParamSpec *pspec)
{
PikaLineArt *line_art = PIKA_LINE_ART (object);
switch (property_id)
{
case PROP_SELECT_TRANSPARENT:
g_value_set_boolean (value, line_art->priv->select_transparent);
break;
case PROP_MAX_GROW:
g_value_set_int (value, line_art->priv->max_grow);
break;
case PROP_THRESHOLD:
g_value_set_double (value, line_art->priv->threshold);
break;
case PROP_AUTOMATIC_CLOSURE:
g_value_set_boolean (value, line_art->priv->automatic_closure);
break;
case PROP_SPLINE_MAX_LEN:
g_value_set_int (value, line_art->priv->spline_max_len);
break;
case PROP_SEGMENT_MAX_LEN:
g_value_set_int (value, line_art->priv->segment_max_len);
break;
default:
G_OBJECT_WARN_INVALID_PROPERTY_ID (object, property_id, pspec);
break;
}
}
/* Public functions */
PikaLineArt *
pika_line_art_new (void)
{
return g_object_new (PIKA_TYPE_LINE_ART,
NULL);
}
void
pika_line_art_bind_gap_length (PikaLineArt *line_art,
gboolean bound)
{
line_art->priv->max_len_bound = bound;
}
void
pika_line_art_set_input (PikaLineArt *line_art,
PikaPickable *pickable)
{
g_return_if_fail (pickable == NULL || PIKA_IS_VIEWABLE (pickable));
if (pickable != line_art->priv->input)
{
if (line_art->priv->input)
g_signal_handlers_disconnect_by_data (line_art->priv->input, line_art);
g_set_object (&line_art->priv->input, pickable);
pika_line_art_compute (line_art);
if (pickable)
{
g_signal_connect (pickable, "invalidate-preview",
G_CALLBACK (pika_line_art_input_invalidate_preview),
line_art);
}
}
}
PikaPickable *
pika_line_art_get_input (PikaLineArt *line_art)
{
return line_art->priv->input;
}
void
pika_line_art_freeze (PikaLineArt *line_art)
{
g_return_if_fail (! line_art->priv->frozen);
line_art->priv->frozen = TRUE;
line_art->priv->compute_after_thaw = FALSE;
}
void
pika_line_art_thaw (PikaLineArt *line_art)
{
g_return_if_fail (line_art->priv->frozen);
line_art->priv->frozen = FALSE;
if (line_art->priv->compute_after_thaw)
{
pika_line_art_compute (line_art);
line_art->priv->compute_after_thaw = FALSE;
}
}
gboolean
pika_line_art_is_frozen (PikaLineArt *line_art)
{
return line_art->priv->frozen;
}
GeglBuffer *
pika_line_art_get (PikaLineArt *line_art,
gfloat **distmap)
{
g_return_val_if_fail (line_art->priv->input, NULL);
if (line_art->priv->async)
{
pika_waitable_wait (PIKA_WAITABLE (line_art->priv->async));
}
else if (! line_art->priv->closed)
{
pika_line_art_compute (line_art);
if (line_art->priv->async)
pika_waitable_wait (PIKA_WAITABLE (line_art->priv->async));
}
g_return_val_if_fail (line_art->priv->closed, NULL);
if (distmap)
*distmap = line_art->priv->distmap;
return line_art->priv->closed;
}
/* Functions for asynchronous computation. */
static void
pika_line_art_compute (PikaLineArt *line_art)
{
if (line_art->priv->frozen)
{
line_art->priv->compute_after_thaw = TRUE;
return;
}
if (line_art->priv->async)
{
/* we cancel the async, but don't wait for it to finish, since
* it might take a while to respond. instead pika_line_art_compute_cb()
* bails if the async has been canceled, to avoid accessing the line art.
*/
g_signal_emit (line_art, pika_line_art_signals[COMPUTING_END], 0);
pika_cancelable_cancel (PIKA_CANCELABLE (line_art->priv->async));
g_clear_object (&line_art->priv->async);
}
if (line_art->priv->idle_id)
{
g_source_remove (line_art->priv->idle_id);
line_art->priv->idle_id = 0;
}
g_clear_object (&line_art->priv->closed);
g_clear_pointer (&line_art->priv->distmap, g_free);
if (line_art->priv->input)
{
/* pika_line_art_prepare_async() will flush the pickable, which
* may trigger this signal handler, and will leak a line art (as
* line_art->priv->async has not been set yet).
*/
g_signal_handlers_block_by_func (
line_art->priv->input,
G_CALLBACK (pika_line_art_input_invalidate_preview),
line_art);
line_art->priv->async = pika_line_art_prepare_async (line_art, +1);
g_signal_emit (line_art, pika_line_art_signals[COMPUTING_START], 0);
g_signal_handlers_unblock_by_func (
line_art->priv->input,
G_CALLBACK (pika_line_art_input_invalidate_preview),
line_art);
pika_async_add_callback_for_object (line_art->priv->async,
(PikaAsyncCallback) pika_line_art_compute_cb,
line_art, line_art);
}
}
static void
pika_line_art_compute_cb (PikaAsync *async,
PikaLineArt *line_art)
{
if (pika_async_is_canceled (async))
return;
if (pika_async_is_finished (async))
{
LineArtResult *result;
result = pika_async_get_result (async);
line_art->priv->closed = g_object_ref (result->closed);
line_art->priv->distmap = result->distmap;
result->distmap = NULL;
g_signal_emit (line_art, pika_line_art_signals[COMPUTING_END], 0);
}
g_clear_object (&line_art->priv->async);
}
static PikaAsync *
pika_line_art_prepare_async (PikaLineArt *line_art,
gint priority)
{
GeglBuffer *buffer;
PikaAsync *async;
LineArtData *data;
g_return_val_if_fail (PIKA_IS_PICKABLE (line_art->priv->input), NULL);
pika_pickable_flush (line_art->priv->input);
buffer = pika_gegl_buffer_dup (
pika_pickable_get_buffer (line_art->priv->input));
data = line_art_data_new (buffer, line_art);
g_object_unref (buffer);
async = pika_parallel_run_async_full (
priority,
(PikaRunAsyncFunc) pika_line_art_prepare_async_func,
data, (GDestroyNotify) line_art_data_free);
return async;
}
static void
pika_line_art_prepare_async_func (PikaAsync *async,
LineArtData *data)
{
GeglBuffer *buffer;
GeglBuffer *closed = NULL;
gfloat *distmap = NULL;
gint buffer_x;
gint buffer_y;
gboolean has_alpha;
gboolean select_transparent = FALSE;
has_alpha = babl_format_has_alpha (gegl_buffer_get_format (data->buffer));
if (has_alpha)
{
if (data->select_transparent)
{
/* don't select transparent regions if there are no fully
* transparent pixels.
*/
GeglBufferIterator *gi;
gi = gegl_buffer_iterator_new (data->buffer, NULL, 0,
babl_format ("A u8"),
GEGL_ACCESS_READ, GEGL_ABYSS_NONE, 3);
while (gegl_buffer_iterator_next (gi))
{
guint8 *p = (guint8*) gi->items[0].data;
gint k;
if (pika_async_is_canceled (async))
{
gegl_buffer_iterator_stop (gi);
pika_async_abort (async);
line_art_data_free (data);
return;
}
for (k = 0; k < gi->length; k++)
{
if (! *p)
{
select_transparent = TRUE;
break;
}
p++;
}
if (select_transparent)
break;
}
if (select_transparent)
gegl_buffer_iterator_stop (gi);
}
}
buffer = data->buffer;
buffer_x = gegl_buffer_get_x (data->buffer);
buffer_y = gegl_buffer_get_y (data->buffer);
if (buffer_x != 0 || buffer_y != 0)
{
buffer = g_object_new (GEGL_TYPE_BUFFER,
"source", buffer,
"shift-x", buffer_x,
"shift-y", buffer_y,
NULL);
}
/* For smart selection, we generate a binarized image with close
* regions, then run a composite selection with no threshold on
* this intermediate buffer.
*/
PIKA_TIMER_START();
closed = pika_line_art_close (buffer,
select_transparent,
data->threshold,
data->automatic_closure,
data->spline_max_len,
data->segment_max_len,
/*minimal_lineart_area,*/
5,
/*normal_estimate_mask_size,*/
5,
/*end_point_rate,*/
0.85,
/*spline_max_angle,*/
90.0,
/*end_point_connectivity,*/
2,
/*spline_roundness,*/
1.0,
/*allow_self_intersections,*/
TRUE,
/*created_regions_significant_area,*/
4,
/*created_regions_minimum_area,*/
100,
/*small_segments_from_spline_sources,*/
TRUE,
&distmap,
async);
PIKA_TIMER_END("close line-art");
if (buffer != data->buffer)
g_object_unref (buffer);
if (! pika_async_is_stopped (async))
{
if (buffer_x != 0 || buffer_y != 0)
{
buffer = g_object_new (GEGL_TYPE_BUFFER,
"source", closed,
"shift-x", -buffer_x,
"shift-y", -buffer_y,
NULL);
g_object_unref (closed);
closed = buffer;
}
pika_async_finish_full (async,
line_art_result_new (closed, distmap),
(GDestroyNotify) line_art_result_free);
}
line_art_data_free (data);
}
static LineArtData *
line_art_data_new (GeglBuffer *buffer,
PikaLineArt *line_art)
{
LineArtData *data = g_slice_new (LineArtData);
data->buffer = g_object_ref (buffer);
data->select_transparent = line_art->priv->select_transparent;
data->threshold = line_art->priv->threshold;
data->automatic_closure = line_art->priv->automatic_closure;
data->spline_max_len = line_art->priv->spline_max_len;
data->segment_max_len = line_art->priv->segment_max_len;
return data;
}
static void
line_art_data_free (LineArtData *data)
{
g_object_unref (data->buffer);
g_slice_free (LineArtData, data);
}
static LineArtResult *
line_art_result_new (GeglBuffer *closed,
gfloat *distmap)
{
LineArtResult *data;
data = g_slice_new (LineArtResult);
data->closed = closed;
data->distmap = distmap;
return data;
}
static void
line_art_result_free (LineArtResult *data)
{
g_object_unref (data->closed);
g_clear_pointer (&data->distmap, g_free);
g_slice_free (LineArtResult, data);
}
static gboolean
pika_line_art_idle (PikaLineArt *line_art)
{
line_art->priv->idle_id = 0;
pika_line_art_compute (line_art);
return G_SOURCE_REMOVE;
}
static void
pika_line_art_input_invalidate_preview (PikaViewable *viewable,
PikaLineArt *line_art)
{
if (! line_art->priv->idle_id)
{
line_art->priv->idle_id = g_idle_add_full (
PIKA_PRIORITY_VIEWABLE_IDLE,
(GSourceFunc) pika_line_art_idle,
line_art, NULL);
}
}
/* All actual computation functions. */
/**
* pika_line_art_close:
* @buffer: the input #GeglBuffer.
* @select_transparent: whether we binarize the alpha channel or the
* luminosity.
* @stroke_threshold: [0-1] threshold value for detecting stroke pixels
* (higher values will detect more stroke pixels).
* @automatic_closure: whether the closing step should be performed or
* not. @spline_max_length and @segment_max_len are
* used only if @automatic_closure is %TRUE.
* @spline_max_length: the maximum length for creating splines between
* end points.
* @segment_max_length: the maximum length for creating segments
* between end points. Unlike splines, segments
* are straight lines.
* @minimal_lineart_area: the minimum size in number pixels for area to
* be considered as line art.
* @normal_estimate_mask_size:
* @end_point_rate: threshold to estimate if a curvature is an end-point
* in [0-1] range value.
* @spline_max_angle: the maximum angle between end point normals for
* creating splines between them.
* @end_point_connectivity:
* @spline_roundness:
* @allow_self_intersections: whether to allow created splines and
* segments to intersect.
* @created_regions_significant_area:
* @created_regions_minimum_area:
* @small_segments_from_spline_sources:
* @closed_distmap: a distance map of the closed line art pixels.
* @async: the #PikaAsync associated with the computation
*
* Creates a binarized version of the strokes of @buffer, detected either
* with luminosity (light means background) or alpha values depending on
* @select_transparent. This binary version of the strokes will have closed
* regions allowing adequate selection of "nearly closed regions".
* This algorithm is meant for digital painting (and in particular on the
* sketch-only step), and therefore will likely produce unexpected results on
* other types of input.
*
* The algorithm is the first step from the research paper "A Fast and
* Efficient Semi-guided Algorithm for Flat Coloring Line-arts", by Sébastian
* Fourey, David Tschumperlé, David Revoy.
* https://hal.archives-ouvertes.fr/hal-01891876
*
* Returns: a new #GeglBuffer of format "Y u8" representing the
* binarized @line_art. If @lineart_distmap is not %NULL, a
* newly allocated float buffer is returned, which can be used
* for overflowing created masks later.
*/
static GeglBuffer *
pika_line_art_close (GeglBuffer *buffer,
gboolean select_transparent,
gdouble stroke_threshold,
gboolean automatic_closure,
gint spline_max_length,
gint segment_max_length,
gint minimal_lineart_area,
gint normal_estimate_mask_size,
gfloat end_point_rate,
gfloat spline_max_angle,
gint end_point_connectivity,
gfloat spline_roundness,
gboolean allow_self_intersections,
gint created_regions_significant_area,
gint created_regions_minimum_area,
gboolean small_segments_from_spline_sources,
gfloat **closed_distmap,
PikaAsync *async)
{
const Babl *gray_format;
GeglBufferIterator *gi;
GeglBuffer *closed = NULL;
GeglBuffer *strokes = NULL;
guchar max_value = 0;
gint width = gegl_buffer_get_width (buffer);
gint height = gegl_buffer_get_height (buffer);
gint i;
if (select_transparent)
/* Keep alpha channel as gray levels */
gray_format = babl_format ("A u8");
else
/* Keep luminance */
gray_format = babl_format ("Y' u8");
/* Transform the line art from any format to gray. */
strokes = gegl_buffer_new (gegl_buffer_get_extent (buffer),
gray_format);
pika_gegl_buffer_copy (buffer, NULL, GEGL_ABYSS_NONE, strokes, NULL);
gegl_buffer_set_format (strokes, babl_format ("Y' u8"));
if (! select_transparent)
{
/* Compute the biggest value */
gi = gegl_buffer_iterator_new (strokes, NULL, 0, NULL,
GEGL_ACCESS_READ, GEGL_ABYSS_NONE, 1);
while (gegl_buffer_iterator_next (gi))
{
guchar *data = (guchar*) gi->items[0].data;
gint k;
if (pika_async_is_canceled (async))
{
gegl_buffer_iterator_stop (gi);
pika_async_abort (async);
goto end1;
}
for (k = 0; k < gi->length; k++)
{
if (*data > max_value)
max_value = *data;
data++;
}
}
}
/* Make the image binary: 1 is stroke, 0 background */
gi = gegl_buffer_iterator_new (strokes, NULL, 0, NULL,
GEGL_ACCESS_READWRITE, GEGL_ABYSS_NONE, 1);
while (gegl_buffer_iterator_next (gi))
{
guchar *data = (guchar*) gi->items[0].data;
gint k;
if (pika_async_is_canceled (async))
{
gegl_buffer_iterator_stop (gi);
pika_async_abort (async);
goto end1;
}
for (k = 0; k < gi->length; k++)
{
if (! select_transparent)
/* Negate the value. */
*data = max_value - *data;
/* Apply a threshold. */
if (*data > (guchar) (255.0f * (1.0f - stroke_threshold)))
*data = 1;
else
*data = 0;
data++;
}
}
/* Denoise (remove small connected components) */
pika_lineart_denoise (strokes, minimal_lineart_area, async);
if (pika_async_is_stopped (async))
goto end1;
closed = g_object_ref (strokes);
if (automatic_closure &&
(spline_max_length > 0 || segment_max_length > 0))
{
GArray *keypoints = NULL;
GHashTable *visited = NULL;
gfloat *radii = NULL;
gfloat *normals = NULL;
gfloat *curvatures = NULL;
gfloat *smoothed_curvatures = NULL;
gfloat threshold;
gfloat clamped_threshold;
GList *fill_pixels = NULL;
GList *iter;
normals = g_new0 (gfloat, width * height * 2);
curvatures = g_new0 (gfloat, width * height);
smoothed_curvatures = g_new0 (gfloat, width * height);
/* Estimate normals & curvature */
pika_lineart_compute_normals_curvatures (strokes, normals, curvatures,
smoothed_curvatures,
normal_estimate_mask_size,
async);
if (pika_async_is_stopped (async))
goto end2;
radii = pika_lineart_estimate_strokes_radii (strokes, async);
if (pika_async_is_stopped (async))
goto end2;
threshold = 1.0f - end_point_rate;
clamped_threshold = MAX (0.25f, threshold);
for (i = 0; i < width; i++)
{
gint j;
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
goto end2;
}
for (j = 0; j < height; j++)
{
if (smoothed_curvatures[i + j * width] >= (threshold / MAX (1.0f, radii[i + j * width])) ||
curvatures[i + j * width] >= clamped_threshold)
curvatures[i + j * width] = 1.0;
else
curvatures[i + j * width] = 0.0;
}
}
g_clear_pointer (&radii, g_free);
keypoints = pika_lineart_curvature_extremums (curvatures, smoothed_curvatures,
width, height, async);
if (pika_async_is_stopped (async))
goto end2;
visited = g_hash_table_new_full ((GHashFunc) visited_hash_fun,
(GEqualFunc) visited_equal_fun,
(GDestroyNotify) g_free, NULL);
if (spline_max_length > 0)
{
GList *candidates;
SplineCandidate *candidate;
candidates = pika_lineart_find_spline_candidates (keypoints, normals, width,
spline_max_length,
spline_max_angle,
async);
if (pika_async_is_stopped (async))
goto end3;
g_object_unref (closed);
closed = pika_gegl_buffer_dup (strokes);
/* Draw splines */
while (candidates)
{
Pixel *p1;
Pixel *p2;
gboolean inserted = FALSE;
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
goto end3;
}
p1 = g_new (Pixel, 1);
p2 = g_new (Pixel, 1);
candidate = (SplineCandidate *) candidates->data;
p1->x = candidate->p1.x;
p1->y = candidate->p1.y;
p2->x = candidate->p2.x;
p2->y = candidate->p2.y;
g_free (candidate);
candidates = g_list_delete_link (candidates, candidates);
if ((! g_hash_table_contains (visited, p1) ||
GPOINTER_TO_INT (g_hash_table_lookup (visited, p1)) < end_point_connectivity) &&
(! g_hash_table_contains (visited, p2) ||
GPOINTER_TO_INT (g_hash_table_lookup (visited, p2)) < end_point_connectivity))
{
GArray *discrete_curve;
PikaVector2 vect1 = pair2normal (*p1, normals, width);
PikaVector2 vect2 = pair2normal (*p2, normals, width);
gfloat distance = pika_vector2_length_val (pika_vector2_sub_val (*p1, *p2));
gint transitions;
pika_vector2_mul (&vect1, distance);
pika_vector2_mul (&vect1, spline_roundness);
pika_vector2_mul (&vect2, distance);
pika_vector2_mul (&vect2, spline_roundness);
discrete_curve = pika_lineart_discrete_spline (*p1, vect1, *p2, vect2);
transitions = allow_self_intersections ?
pika_number_of_transitions (discrete_curve, strokes) :
pika_number_of_transitions (discrete_curve, closed);
if (transitions == 2 &&
pika_line_art_allow_closure (closed, discrete_curve,
&fill_pixels,
created_regions_significant_area,
created_regions_minimum_area))
{
for (i = 0; i < discrete_curve->len; i++)
{
Pixel p = g_array_index (discrete_curve, Pixel, i);
if (p.x >= 0 && p.x < gegl_buffer_get_width (closed) &&
p.y >= 0 && p.y < gegl_buffer_get_height (closed))
{
guchar val = 2;
gegl_buffer_set (closed, GEGL_RECTANGLE ((gint) p.x, (gint) p.y, 1, 1), 0,
NULL, &val, GEGL_AUTO_ROWSTRIDE);
}
}
g_hash_table_replace (visited, p1,
GINT_TO_POINTER (GPOINTER_TO_INT (g_hash_table_lookup (visited, p1)) + 1));
g_hash_table_replace (visited, p2,
GINT_TO_POINTER (GPOINTER_TO_INT (g_hash_table_lookup (visited, p2)) + 1));
inserted = TRUE;
}
g_array_free (discrete_curve, TRUE);
}
if (! inserted)
{
g_free (p1);
g_free (p2);
}
}
end3:
g_list_free_full (candidates, g_free);
if (pika_async_is_stopped (async))
goto end2;
}
g_clear_object (&strokes);
/* Draw straight line segments */
if (segment_max_length > 0)
{
Pixel *point;
point = (Pixel *) keypoints->data;
for (i = 0; i < keypoints->len; i++)
{
Pixel *p;
gboolean inserted = FALSE;
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
goto end2;
}
p = g_new (Pixel, 1);
*p = *point;
if (! g_hash_table_contains (visited, p) ||
(small_segments_from_spline_sources &&
GPOINTER_TO_INT (g_hash_table_lookup (visited, p)) < end_point_connectivity))
{
GArray *segment = pika_lineart_line_segment_until_hit (closed, *point,
pair2normal (*point, normals, width),
segment_max_length);
if (segment->len &&
pika_line_art_allow_closure (closed, segment, &fill_pixels,
created_regions_significant_area,
created_regions_minimum_area))
{
gint j;
for (j = 0; j < segment->len; j++)
{
Pixel p2 = g_array_index (segment, Pixel, j);
guchar val = 2;
gegl_buffer_set (closed, GEGL_RECTANGLE ((gint) p2.x, (gint) p2.y, 1, 1), 0,
NULL, &val, GEGL_AUTO_ROWSTRIDE);
}
g_hash_table_replace (visited, p,
GINT_TO_POINTER (GPOINTER_TO_INT (g_hash_table_lookup (visited, p)) + 1));
inserted = TRUE;
}
g_array_free (segment, TRUE);
}
if (! inserted)
g_free (p);
point++;
}
}
for (iter = fill_pixels; iter; iter = iter->next)
{
Pixel *p = iter->data;
gint fill_max = created_regions_significant_area - 1;
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
goto end2;
}
/* XXX A best approach would be to generalize
* pika_drawable_bucket_fill() to work on any buffer (the code
* is already mostly there) rather than reimplementing a naive
* bucket fill.
* This is mostly a quick'n dirty first implementation which I
* will improve later.
*/
pika_line_art_simple_fill (closed, (gint) p->x, (gint) p->y, &fill_max);
}
end2:
g_list_free_full (fill_pixels, g_free);
g_free (normals);
g_free (curvatures);
g_free (smoothed_curvatures);
g_clear_pointer (&radii, g_free);
if (keypoints)
g_array_free (keypoints, TRUE);
g_clear_pointer (&visited, g_hash_table_destroy);
if (pika_async_is_stopped (async))
goto end1;
}
else
{
g_clear_object (&strokes);
}
if (closed_distmap)
{
GeglNode *graph;
GeglNode *input;
GeglNode *op;
/* Flooding needs a distance map for closed line art. */
*closed_distmap = g_new (gfloat, width * height);
graph = gegl_node_new ();
input = gegl_node_new_child (graph,
"operation", "gegl:buffer-source",
"buffer", closed,
NULL);
op = gegl_node_new_child (graph,
"operation", "gegl:distance-transform",
"metric", GEGL_DISTANCE_METRIC_EUCLIDEAN,
"normalize", FALSE,
NULL);
gegl_node_link (input, op);
gegl_node_blit (op, 1.0, gegl_buffer_get_extent (closed),
NULL, *closed_distmap,
GEGL_AUTO_ROWSTRIDE, GEGL_BLIT_DEFAULT);
g_object_unref (graph);
}
end1:
g_clear_object (&strokes);
if (pika_async_is_stopped (async))
g_clear_object (&closed);
return closed;
}
static void
pika_lineart_denoise (GeglBuffer *buffer,
int minimum_area,
PikaAsync *async)
{
/* Keep connected regions with significant area. */
GArray *region;
GQueue *q = g_queue_new ();
gint width = gegl_buffer_get_width (buffer);
gint height = gegl_buffer_get_height (buffer);
gboolean *visited = g_new0 (gboolean, width * height);
gint x, y;
region = g_array_sized_new (TRUE, TRUE, sizeof (Pixel *), minimum_area);
for (y = 0; y < height; ++y)
for (x = 0; x < width; ++x)
{
guchar has_stroke;
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
goto end;
}
gegl_buffer_sample (buffer, x, y, NULL, &has_stroke, NULL,
GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
if (has_stroke && ! visited[x + y * width])
{
Pixel *p = g_new (Pixel, 1);
gint regionSize = 0;
p->x = x;
p->y = y;
g_queue_push_tail (q, p);
visited[x + y * width] = TRUE;
while (! g_queue_is_empty (q))
{
Pixel *p;
gint p2x;
gint p2y;
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
goto end;
}
p = (Pixel *) g_queue_pop_head (q);
p2x = p->x + 1;
p2y = p->y;
if (p2x >= 0 && p2x < width && p2y >= 0 && p2y < height)
{
gegl_buffer_sample (buffer, p2x, p2y, NULL, &has_stroke, NULL,
GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
if (has_stroke && ! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x +p2y * width] = TRUE;
}
}
p2x = p->x - 1;
p2y = p->y;
if (p2x >= 0 && p2x < width && p2y >= 0 && p2y < height)
{
gegl_buffer_sample (buffer, p2x, p2y, NULL, &has_stroke, NULL,
GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
if (has_stroke && ! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
}
p2x = p->x;
p2y = p->y - 1;
if (p2x >= 0 && p2x < width && p2y >= 0 && p2y < height)
{
gegl_buffer_sample (buffer, p2x, p2y, NULL, &has_stroke, NULL,
GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
if (has_stroke && ! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
}
p2x = p->x;
p2y = p->y + 1;
if (p2x >= 0 && p2x < width && p2y >= 0 && p2y < height)
{
gegl_buffer_sample (buffer, p2x, p2y, NULL, &has_stroke, NULL,
GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
if (has_stroke && ! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
}
p2x = p->x + 1;
p2y = p->y + 1;
if (p2x >= 0 && p2x < width && p2y >= 0 && p2y < height)
{
gegl_buffer_sample (buffer, p2x, p2y, NULL, &has_stroke, NULL,
GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
if (has_stroke && ! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
}
p2x = p->x - 1;
p2y = p->y - 1;
if (p2x >= 0 && p2x < width && p2y >= 0 && p2y < height)
{
gegl_buffer_sample (buffer, p2x, p2y, NULL, &has_stroke, NULL,
GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
if (has_stroke && ! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
}
p2x = p->x - 1;
p2y = p->y + 1;
if (p2x >= 0 && p2x < width && p2y >= 0 && p2y < height)
{
gegl_buffer_sample (buffer, p2x, p2y, NULL, &has_stroke, NULL,
GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
if (has_stroke && ! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
}
p2x = p->x + 1;
p2y = p->y - 1;
if (p2x >= 0 && p2x < width && p2y >= 0 && p2y < height)
{
gegl_buffer_sample (buffer, p2x, p2y, NULL, &has_stroke, NULL,
GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
if (has_stroke && ! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
}
++regionSize;
if (regionSize < minimum_area)
g_array_append_val (region, *p);
g_free (p);
}
if (regionSize < minimum_area)
{
Pixel *pixel = (Pixel *) region->data;
gint i = 0;
for (; i < region->len; i++)
{
guchar val = 0;
gegl_buffer_set (buffer, GEGL_RECTANGLE (pixel->x, pixel->y, 1, 1), 0,
NULL, &val, GEGL_AUTO_ROWSTRIDE);
pixel++;
}
}
g_array_remove_range (region, 0, region->len);
}
}
end:
g_array_free (region, TRUE);
g_queue_free_full (q, g_free);
g_free (visited);
}
static void
pika_lineart_compute_normals_curvatures (GeglBuffer *mask,
gfloat *normals,
gfloat *curvatures,
gfloat *smoothed_curvatures,
int normal_estimate_mask_size,
PikaAsync *async)
{
gfloat *edgels_curvatures = NULL;
gfloat *smoothed_curvature;
GArray *es = NULL;
Edgel **e;
gint width = gegl_buffer_get_width (mask);
es = pika_edgelset_new (mask, async);
if (pika_async_is_stopped (async))
goto end;
e = (Edgel **) es->data;
pika_edgelset_smooth_normals (es, normal_estimate_mask_size, async);
if (pika_async_is_stopped (async))
goto end;
pika_edgelset_compute_curvature (es, async);
if (pika_async_is_stopped (async))
goto end;
while (*e)
{
const float curvature = ((*e)->curvature > 0.0f) ? (*e)->curvature : 0.0f;
const float w = MAX (1e-8f, curvature * curvature);
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
goto end;
}
normals[((*e)->x + (*e)->y * width) * 2] += w * (*e)->x_normal;
normals[((*e)->x + (*e)->y * width) * 2 + 1] += w * (*e)->y_normal;
curvatures[(*e)->x + (*e)->y * width] = MAX (curvature,
curvatures[(*e)->x + (*e)->y * width]);
e++;
}
for (int y = 0; y < gegl_buffer_get_height (mask); ++y)
{
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
goto end;
}
for (int x = 0; x < gegl_buffer_get_width (mask); ++x)
{
const float _angle = atan2f (normals[(x + y * width) * 2 + 1],
normals[(x + y * width) * 2]);
normals[(x + y * width) * 2] = cosf (_angle);
normals[(x + y * width) * 2 + 1] = sinf (_angle);
}
}
/* Smooth curvatures on edgels, then take maximum on each pixel. */
edgels_curvatures = pika_lineart_get_smooth_curvatures (es, async);
if (pika_async_is_stopped (async))
goto end;
smoothed_curvature = edgels_curvatures;
e = (Edgel **) es->data;
while (*e)
{
gfloat *pixel_curvature = &smoothed_curvatures[(*e)->x + (*e)->y * width];
if (*pixel_curvature < *smoothed_curvature)
*pixel_curvature = *smoothed_curvature;
++smoothed_curvature;
e++;
}
end:
g_free (edgels_curvatures);
if (es)
g_array_free (es, TRUE);
}
static gfloat *
pika_lineart_get_smooth_curvatures (GArray *edgelset,
PikaAsync *async)
{
Edgel **e;
gfloat *smoothed_curvatures = g_new0 (gfloat, edgelset->len);
gfloat weights[9];
gfloat smoothed_curvature;
gfloat weights_sum;
gint idx = 0;
weights[0] = 1.0f;
for (int i = 1; i <= 8; ++i)
weights[i] = expf (-(i * i) / 30.0f);
e = (Edgel **) edgelset->data;
while (*e)
{
Edgel *edgel_before = g_array_index (edgelset, Edgel*, (*e)->previous);
Edgel *edgel_after = g_array_index (edgelset, Edgel*, (*e)->next);
int n = 5;
int i = 1;
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
g_free (smoothed_curvatures);
return NULL;
}
smoothed_curvature = (*e)->curvature;
weights_sum = weights[0];
while (n-- && (edgel_after != edgel_before))
{
smoothed_curvature += weights[i] * edgel_before->curvature;
smoothed_curvature += weights[i] * edgel_after->curvature;
edgel_before = g_array_index (edgelset, Edgel*, edgel_before->previous);
edgel_after = g_array_index (edgelset, Edgel*, edgel_after->next);
weights_sum += 2 * weights[i];
i++;
}
smoothed_curvature /= weights_sum;
smoothed_curvatures[idx++] = smoothed_curvature;
e++;
}
return smoothed_curvatures;
}
/**
* Keep one pixel per connected component of curvature extremums.
*/
static GArray *
pika_lineart_curvature_extremums (gfloat *curvatures,
gfloat *smoothed_curvatures,
gint width,
gint height,
PikaAsync *async)
{
gboolean *visited = g_new0 (gboolean, width * height);
GQueue *q = g_queue_new ();
GArray *max_positions;
max_positions = g_array_new (FALSE, TRUE, sizeof (Pixel));
for (int y = 0; y < height; ++y)
{
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
goto end;
}
for (int x = 0; x < width; ++x)
{
if ((curvatures[x + y * width] > 0.0) && ! visited[x + y * width])
{
Pixel *p = g_new (Pixel, 1);
Pixel max_smoothed_curvature_pixel;
Pixel max_raw_curvature_pixel;
gfloat max_smoothed_curvature;
gfloat max_raw_curvature;
max_smoothed_curvature_pixel = pika_vector2_new (-1.0, -1.0);
max_smoothed_curvature = 0.0f;
max_raw_curvature_pixel = pika_vector2_new (x, y);
max_raw_curvature = curvatures[x + y * width];
p->x = x;
p->y = y;
g_queue_push_tail (q, p);
visited[x + y * width] = TRUE;
while (! g_queue_is_empty (q))
{
gfloat sc;
gfloat c;
gint p2x;
gint p2y;
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
goto end;
}
p = (Pixel *) g_queue_pop_head (q);
sc = smoothed_curvatures[(gint) p->x + (gint) p->y * width];
c = curvatures[(gint) p->x + (gint) p->y * width];
curvatures[(gint) p->x + (gint) p->y * width] = 0.0f;
p2x = (gint) p->x + 1;
p2y = (gint) p->y;
if (p2x >= 0 && p2x < width &&
p2y >= 0 && p2y < height &&
curvatures[p2x + p2y * width] > 0.0 &&
! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
p2x = p->x - 1;
p2y = p->y;
if (p2x >= 0 && p2x < width &&
p2y >= 0 && p2y < height &&
curvatures[p2x + p2y * width] > 0.0 &&
! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
p2x = p->x;
p2y = p->y - 1;
if (p2x >= 0 && p2x < width &&
p2y >= 0 && p2y < height &&
curvatures[p2x + p2y * width] > 0.0 &&
! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
p2x = p->x;
p2y = p->y + 1;
if (p2x >= 0 && p2x < width &&
p2y >= 0 && p2y < height &&
curvatures[p2x + p2y * width] > 0.0 &&
! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
p2x = p->x + 1;
p2y = p->y + 1;
if (p2x >= 0 && p2x < width &&
p2y >= 0 && p2y < height &&
curvatures[p2x + p2y * width] > 0.0 &&
! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
p2x = p->x - 1;
p2y = p->y - 1;
if (p2x >= 0 && p2x < width &&
p2y >= 0 && p2y < height &&
curvatures[p2x + p2y * width] > 0.0 &&
! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
p2x = p->x - 1;
p2y = p->y + 1;
if (p2x >= 0 && p2x < width &&
p2y >= 0 && p2y < height &&
curvatures[p2x + p2y * width] > 0.0 &&
! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
p2x = p->x + 1;
p2y = p->y - 1;
if (p2x >= 0 && p2x < width &&
p2y >= 0 && p2y < height &&
curvatures[p2x + p2y * width] > 0.0 &&
! visited[p2x + p2y * width])
{
Pixel *p2 = g_new (Pixel, 1);
p2->x = p2x;
p2->y = p2y;
g_queue_push_tail (q, p2);
visited[p2x + p2y * width] = TRUE;
}
if (sc > max_smoothed_curvature)
{
max_smoothed_curvature_pixel = *p;
max_smoothed_curvature = sc;
}
if (c > max_raw_curvature)
{
max_raw_curvature_pixel = *p;
max_raw_curvature = c;
}
g_free (p);
}
if (max_smoothed_curvature > 0.0f)
{
curvatures[(gint) max_smoothed_curvature_pixel.x + (gint) max_smoothed_curvature_pixel.y * width] = max_smoothed_curvature;
g_array_append_val (max_positions, max_smoothed_curvature_pixel);
}
else
{
curvatures[(gint) max_raw_curvature_pixel.x + (gint) max_raw_curvature_pixel.y * width] = max_raw_curvature;
g_array_append_val (max_positions, max_raw_curvature_pixel);
}
}
}
}
end:
g_queue_free_full (q, g_free);
g_free (visited);
if (pika_async_is_stopped (async))
{
g_array_free (max_positions, TRUE);
max_positions = NULL;
}
return max_positions;
}
static gint
pika_spline_candidate_cmp (const SplineCandidate *a,
const SplineCandidate *b,
gpointer user_data)
{
/* This comparison actually returns the opposite of common comparison
* functions on purpose, as we want the first element on the list to
* be the "bigger".
*/
if (a->quality < b->quality)
return 1;
else if (a->quality > b->quality)
return -1;
else
return 0;
}
static GList *
pika_lineart_find_spline_candidates (GArray *max_positions,
gfloat *normals,
gint width,
gint distance_threshold,
gfloat max_angle_deg,
PikaAsync *async)
{
GList *candidates = NULL;
const float CosMin = cosf (M_PI * (max_angle_deg / 180.0));
gint i;
for (i = 0; i < max_positions->len; i++)
{
Pixel p1 = g_array_index (max_positions, Pixel, i);
gint j;
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
g_list_free_full (candidates, g_free);
return NULL;
}
for (j = i + 1; j < max_positions->len; j++)
{
Pixel p2 = g_array_index (max_positions, Pixel, j);
const float distance = pika_vector2_length_val (pika_vector2_sub_val (p1, p2));
if (distance <= distance_threshold)
{
PikaVector2 normalP1;
PikaVector2 normalP2;
PikaVector2 p1f;
PikaVector2 p2f;
PikaVector2 p1p2;
float cosN;
float qualityA;
float qualityB;
float qualityC;
float quality;
normalP1 = pika_vector2_new (normals[((gint) p1.x + (gint) p1.y * width) * 2],
normals[((gint) p1.x + (gint) p1.y * width) * 2 + 1]);
normalP2 = pika_vector2_new (normals[((gint) p2.x + (gint) p2.y * width) * 2],
normals[((gint) p2.x + (gint) p2.y * width) * 2 + 1]);
p1f = pika_vector2_new (p1.x, p1.y);
p2f = pika_vector2_new (p2.x, p2.y);
p1p2 = pika_vector2_sub_val (p2f, p1f);
cosN = pika_vector2_inner_product_val (normalP1, (pika_vector2_neg_val (normalP2)));
qualityA = MAX (0.0f, 1 - distance / distance_threshold);
qualityB = MAX (0.0f,
(float) (pika_vector2_inner_product_val (normalP1, p1p2) - pika_vector2_inner_product_val (normalP2, p1p2)) /
distance);
qualityC = MAX (0.0f, cosN - CosMin);
quality = qualityA * qualityB * qualityC;
if (quality > 0)
{
SplineCandidate *candidate = g_new (SplineCandidate, 1);
candidate->p1 = p1;
candidate->p2 = p2;
candidate->quality = quality;
candidates = g_list_insert_sorted_with_data (candidates, candidate,
(GCompareDataFunc) pika_spline_candidate_cmp,
NULL);
}
}
}
}
return candidates;
}
static GArray *
pika_lineart_discrete_spline (Pixel p0,
PikaVector2 n0,
Pixel p1,
PikaVector2 n1)
{
GArray *points = g_array_new (FALSE, TRUE, sizeof (Pixel));
const double a0 = 2 * p0.x - 2 * p1.x + n0.x - n1.x;
const double b0 = -3 * p0.x + 3 * p1.x - 2 * n0.x + n1.x;
const double c0 = n0.x;
const double d0 = p0.x;
const double a1 = 2 * p0.y - 2 * p1.y + n0.y - n1.y;
const double b1 = -3 * p0.y + 3 * p1.y - 2 * n0.y + n1.y;
const double c1 = n0.y;
const double d1 = p0.y;
double t = 0.0;
const double dtMin = 1.0 / MAX (fabs (p0.x - p1.x), fabs (p0.y - p1.y));
Pixel point = pika_vector2_new ((gint) round (d0), (gint) round (d1));
g_array_append_val (points, point);
while (t <= 1.0)
{
const double t2 = t * t;
const double t3 = t * t2;
double dx;
double dy;
Pixel p = pika_vector2_new ((gint) round (a0 * t3 + b0 * t2 + c0 * t + d0),
(gint) round (a1 * t3 + b1 * t2 + c1 * t + d1));
/* create pika_vector2_neq () ? */
if (g_array_index (points, Pixel, points->len - 1).x != p.x ||
g_array_index (points, Pixel, points->len - 1).y != p.y)
{
g_array_append_val (points, p);
}
dx = fabs (3 * a0 * t * t + 2 * b0 * t + c0) + 1e-8;
dy = fabs (3 * a1 * t * t + 2 * b1 * t + c1) + 1e-8;
t += MIN (dtMin, 0.75 / MAX (dx, dy));
}
if (g_array_index (points, Pixel, points->len - 1).x != p1.x ||
g_array_index (points, Pixel, points->len - 1).y != p1.y)
{
g_array_append_val (points, p1);
}
return points;
}
static gint
pika_number_of_transitions (GArray *pixels,
GeglBuffer *buffer)
{
int result = 0;
if (pixels->len > 0)
{
Pixel it = g_array_index (pixels, Pixel, 0);
guchar value;
gboolean previous;
gint i;
gegl_buffer_sample (buffer, (gint) it.x, (gint) it.y, NULL, &value, NULL,
GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
previous = (gboolean) value;
/* Starts at the second element. */
for (i = 1; i < pixels->len; i++)
{
it = g_array_index (pixels, Pixel, i);
gegl_buffer_sample (buffer, (gint) it.x, (gint) it.y, NULL, &value, NULL,
GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
result += ((gboolean) value != previous);
previous = (gboolean) value;
}
}
return result;
}
/**
* pika_line_art_allow_closure:
* @mask: the current state of line art closure.
* @pixels: the pixels of a candidate closure (spline or segment).
* @fill_pixels: #GList of insignificant pixels to bucket fill.
* @significant_size: number of pixels for area to be considered
* "significant".
* @minimum_size: number of pixels for area to be allowed.
*
* Checks whether adding the set of points @pixels to @mask will create
* 4-connected background regions whose size (i.e. number of pixels)
* will be below @minimum_size. If it creates such small areas, the
* function will refuse this candidate spline/segment, with the
* exception of very small areas under @significant_size. These
* micro-area are considered "insignificant" and accepted (because they
* can be created in some conditions, for instance when created curves
* cross or start from a same endpoint), and one pixel for each
* micro-area will be added to @fill_pixels to be later filled along
* with the candidate pixels.
*
* Returns: %TRUE if @pixels should be added to @mask, %FALSE otherwise.
*/
static gboolean
pika_line_art_allow_closure (GeglBuffer *mask,
GArray *pixels,
GList **fill_pixels,
int significant_size,
int minimum_size)
{
/* A theorem from the paper is that a zone with more than
* `2 * (@minimum_size - 1)` edgels (border pixels) will have more
* than @minimum_size pixels.
* Since we are following the edges of the area, we can therefore stop
* earlier if we reach this number of edgels.
*/
const glong max_edgel_count = 2 * minimum_size;
Pixel *p = (Pixel*) pixels->data;
GList *fp = NULL;
gint i;
/* Mark pixels */
for (i = 0; i < pixels->len; i++)
{
if (p->x >= 0 && p->x < gegl_buffer_get_width (mask) &&
p->y >= 0 && p->y < gegl_buffer_get_height (mask))
{
guchar val;
gegl_buffer_sample (mask, (gint) p->x, (gint) p->y, NULL, &val,
NULL, GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
val = val ? 3 : 2;
gegl_buffer_set (mask, GEGL_RECTANGLE ((gint) p->x, (gint) p->y, 1, 1), 0,
NULL, &val, GEGL_AUTO_ROWSTRIDE);
}
p++;
}
for (i = 0; i < pixels->len; i++)
{
Pixel p = g_array_index (pixels, Pixel, i);
for (int direction = 0; direction < 4; ++direction)
{
if (p.x >= 0 && p.x < gegl_buffer_get_width (mask) &&
p.y >= 0 && p.y < gegl_buffer_get_height (mask) &&
border_in_direction (mask, p, direction))
{
Edgel e;
guchar val;
glong count;
glong area;
gegl_buffer_sample (mask, (gint) p.x, (gint) p.y, NULL, &val,
NULL, GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
if ((gboolean) (val & (4 << direction)))
continue;
pika_edgel_init (&e);
e.x = p.x;
e.y = p.y;
e.direction = direction;
count = pika_edgel_track_mark (mask, e, max_edgel_count);
if ((count != -1) && (count <= max_edgel_count))
{
area = pika_edgel_region_area (mask, e);
if (area >= significant_size && area < minimum_size)
{
gint j;
/* Remove marks */
for (j = 0; j < pixels->len; j++)
{
Pixel p2 = g_array_index (pixels, Pixel, j);
if (p2.x >= 0 && p2.x < gegl_buffer_get_width (mask) &&
p2.y >= 0 && p2.y < gegl_buffer_get_height (mask))
{
guchar val;
gegl_buffer_sample (mask, (gint) p2.x, (gint) p2.y, NULL, &val,
NULL, GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
val &= 1;
gegl_buffer_set (mask, GEGL_RECTANGLE ((gint) p2.x, (gint) p2.y, 1, 1), 0,
NULL, &val, GEGL_AUTO_ROWSTRIDE);
}
}
g_list_free_full (fp, g_free);
return FALSE;
}
else if (area > 0 && area < significant_size)
{
Pixel *np = g_new (Pixel, 1);
np->x = direction == XPlusDirection ? p.x + 1 : (direction == XMinusDirection ? p.x - 1 : p.x);
np->y = direction == YPlusDirection ? p.y + 1 : (direction == YMinusDirection ? p.y - 1 : p.y);
if (np->x >= 0 && np->x < gegl_buffer_get_width (mask) &&
np->y >= 0 && np->y < gegl_buffer_get_height (mask))
fp = g_list_prepend (fp, np);
else
g_free (np);
}
}
}
}
}
*fill_pixels = g_list_concat (*fill_pixels, fp);
/* Remove marks */
for (i = 0; i < pixels->len; i++)
{
Pixel p = g_array_index (pixels, Pixel, i);
if (p.x >= 0 && p.x < gegl_buffer_get_width (mask) &&
p.y >= 0 && p.y < gegl_buffer_get_height (mask))
{
guchar val;
gegl_buffer_sample (mask, (gint) p.x, (gint) p.y, NULL, &val,
NULL, GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
val &= 1;
gegl_buffer_set (mask, GEGL_RECTANGLE ((gint) p.x, (gint) p.y, 1, 1), 0,
NULL, &val, GEGL_AUTO_ROWSTRIDE);
}
}
return TRUE;
}
static GArray *
pika_lineart_line_segment_until_hit (const GeglBuffer *mask,
Pixel start,
PikaVector2 direction,
int size)
{
GeglBuffer *buffer = (GeglBuffer *) mask;
gboolean out = FALSE;
GArray *points = g_array_new (FALSE, TRUE, sizeof (Pixel));
int tmax;
PikaVector2 p0 = pika_vector2_new (start.x, start.y);
pika_vector2_mul (&direction, (gdouble) size);
direction.x = round (direction.x);
direction.y = round (direction.y);
tmax = MAX (abs ((int) direction.x), abs ((int) direction.y));
for (int t = 0; t <= tmax; ++t)
{
PikaVector2 v = pika_vector2_add_val (p0, pika_vector2_mul_val (direction, (float)t / tmax));
Pixel p;
p.x = (gint) round (v.x);
p.y = (gint) round (v.y);
if (p.x >= 0 && p.x < gegl_buffer_get_width (buffer) &&
p.y >= 0 && p.y < gegl_buffer_get_height (buffer))
{
guchar val;
gegl_buffer_sample (buffer, p.x, p.y, NULL, &val,
NULL, GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
if (out && val)
{
return points;
}
out = ! val;
}
else if (out)
{
return points;
}
else
{
g_array_free (points, TRUE);
return g_array_new (FALSE, TRUE, sizeof (Pixel));
}
g_array_append_val (points, p);
}
g_array_free (points, TRUE);
return g_array_new (FALSE, TRUE, sizeof (Pixel));
}
static gfloat *
pika_lineart_estimate_strokes_radii (GeglBuffer *mask,
PikaAsync *async)
{
GeglBufferIterator *gi;
gfloat *dist;
gfloat *thickness;
GeglNode *graph;
GeglNode *input;
GeglNode *op;
gint width = gegl_buffer_get_width (mask);
gint height = gegl_buffer_get_height (mask);
/* Compute a distance map for the line art. */
dist = g_new (gfloat, width * height);
graph = gegl_node_new ();
input = gegl_node_new_child (graph,
"operation", "gegl:buffer-source",
"buffer", mask,
NULL);
op = gegl_node_new_child (graph,
"operation", "gegl:distance-transform",
"metric", GEGL_DISTANCE_METRIC_EUCLIDEAN,
"normalize", FALSE,
NULL);
gegl_node_link (input, op);
gegl_node_blit (op, 1.0, gegl_buffer_get_extent (mask),
NULL, dist, GEGL_AUTO_ROWSTRIDE, GEGL_BLIT_DEFAULT);
g_object_unref (graph);
thickness = g_new0 (gfloat, width * height);
gi = gegl_buffer_iterator_new (mask, NULL, 0, NULL,
GEGL_ACCESS_READ, GEGL_ABYSS_NONE, 1);
while (gegl_buffer_iterator_next (gi))
{
guint8 *m = (guint8*) gi->items[0].data;
gint startx = gi->items[0].roi.x;
gint starty = gi->items[0].roi.y;
gint endy = starty + gi->items[0].roi.height;
gint endx = startx + gi->items[0].roi.width;
gint x;
gint y;
if (pika_async_is_canceled (async))
{
gegl_buffer_iterator_stop (gi);
pika_async_abort (async);
goto end;
}
for (y = starty; y < endy; y++)
for (x = startx; x < endx; x++)
{
if (*m && dist[x + y * width] == 1.0)
{
gint dx = x;
gint dy = y;
gfloat d = 1.0;
gfloat nd;
gboolean neighbour_thicker = TRUE;
while (neighbour_thicker)
{
gint px = dx - 1;
gint py = dy - 1;
gint nx = dx + 1;
gint ny = dy + 1;
neighbour_thicker = FALSE;
if (px >= 0)
{
if ((nd = dist[px + dy * width]) > d)
{
d = nd;
dx = px;
neighbour_thicker = TRUE;
continue;
}
if (py >= 0 && (nd = dist[px + py * width]) > d)
{
d = nd;
dx = px;
dy = py;
neighbour_thicker = TRUE;
continue;
}
if (ny < height && (nd = dist[px + ny * width]) > d)
{
d = nd;
dx = px;
dy = ny;
neighbour_thicker = TRUE;
continue;
}
}
if (nx < width)
{
if ((nd = dist[nx + dy * width]) > d)
{
d = nd;
dx = nx;
neighbour_thicker = TRUE;
continue;
}
if (py >= 0 && (nd = dist[nx + py * width]) > d)
{
d = nd;
dx = nx;
dy = py;
neighbour_thicker = TRUE;
continue;
}
if (ny < height && (nd = dist[nx + ny * width]) > d)
{
d = nd;
dx = nx;
dy = ny;
neighbour_thicker = TRUE;
continue;
}
}
if (py > 0 && (nd = dist[dx + py * width]) > d)
{
d = nd;
dy = py;
neighbour_thicker = TRUE;
continue;
}
if (ny < height && (nd = dist[dx + ny * width]) > d)
{
d = nd;
dy = ny;
neighbour_thicker = TRUE;
continue;
}
}
thickness[(gint) x + (gint) y * width] = d;
}
m++;
}
}
end:
g_free (dist);
if (pika_async_is_stopped (async))
g_clear_pointer (&thickness, g_free);
return thickness;
}
static void
pika_line_art_simple_fill (GeglBuffer *buffer,
gint x,
gint y,
gint *counter)
{
guchar val;
if (x < 0 || x >= gegl_buffer_get_width (buffer) ||
y < 0 || y >= gegl_buffer_get_height (buffer) ||
*counter <= 0)
return;
gegl_buffer_sample (buffer, x, y, NULL, &val,
NULL, GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
if (! val)
{
val = 1;
gegl_buffer_set (buffer, GEGL_RECTANGLE (x, y, 1, 1), 0,
NULL, &val, GEGL_AUTO_ROWSTRIDE);
(*counter)--;
pika_line_art_simple_fill (buffer, x + 1, y, counter);
pika_line_art_simple_fill (buffer, x - 1, y, counter);
pika_line_art_simple_fill (buffer, x, y + 1, counter);
pika_line_art_simple_fill (buffer, x, y - 1, counter);
}
}
static guint
visited_hash_fun (Pixel *key)
{
/* Cantor pairing function. */
return (key->x + key->y) * (key->x + key->y + 1) / 2 + key->y;
}
static gboolean
visited_equal_fun (Pixel *e1,
Pixel *e2)
{
return (e1->x == e2->x && e1->y == e2->y);
}
static inline gboolean
border_in_direction (GeglBuffer *mask,
Pixel p,
int direction)
{
gint px = (gint) p.x + DeltaX[direction];
gint py = (gint) p.y + DeltaY[direction];
if (px >= 0 && px < gegl_buffer_get_width (mask) &&
py >= 0 && py < gegl_buffer_get_height (mask))
{
guchar val;
gegl_buffer_sample (mask, px, py, NULL, &val,
NULL, GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
return ! ((gboolean) val);
}
return TRUE;
}
static inline PikaVector2
pair2normal (Pixel p,
gfloat *normals,
gint width)
{
return pika_vector2_new (normals[((gint) p.x + (gint) p.y * width) * 2],
normals[((gint) p.x + (gint) p.y * width) * 2 + 1]);
}
/* Edgel functions */
static Edgel *
pika_edgel_new (int x,
int y,
Direction direction)
{
Edgel *edgel = g_new (Edgel, 1);
edgel->x = x;
edgel->y = y;
edgel->direction = direction;
pika_edgel_init (edgel);
return edgel;
}
static void
pika_edgel_init (Edgel *edgel)
{
edgel->x_normal = 0;
edgel->y_normal = 0;
edgel->curvature = 0;
edgel->next = edgel->previous = G_MAXUINT;
}
static void
pika_edgel_clear (Edgel **edgel)
{
g_clear_pointer (edgel, g_free);
}
static int
pika_edgel_cmp (const Edgel* e1,
const Edgel* e2)
{
pika_assert (e1 && e2);
if ((e1->x == e2->x) && (e1->y == e2->y) &&
(e1->direction == e2->direction))
return 0;
else if ((e1->y < e2->y) || (e1->y == e2->y && e1->x < e2->x) ||
(e1->y == e2->y && e1->x == e2->x && e1->direction < e2->direction))
return -1;
else
return 1;
}
static guint
edgel2index_hash_fun (Edgel *key)
{
/* Cantor pairing function.
* Was not sure how to use the direction though. :-/
*/
return (key->x + key->y) * (key->x + key->y + 1) / 2 + key->y * key->direction;
}
static gboolean
edgel2index_equal_fun (Edgel *e1,
Edgel *e2)
{
return (e1->x == e2->x && e1->y == e2->y &&
e1->direction == e2->direction);
}
/**
* @mask;
* @edgel:
* @size_limit:
*
* Track a border, marking inner pixels with a bit corresponding to the
* edgel traversed (4 << direction) for direction in {0,1,2,3}.
* Stop tracking after @size_limit edgels have been visited.
*
* Returns: Number of visited edgels, or -1 if an already visited edgel
* has been encountered.
*/
static glong
pika_edgel_track_mark (GeglBuffer *mask,
Edgel edgel,
long size_limit)
{
Edgel start = edgel;
long count = 1;
do
{
guchar val;
pika_edgelset_next8 (mask, &edgel, &edgel);
gegl_buffer_sample (mask, edgel.x, edgel.y, NULL, &val,
NULL, GEGL_SAMPLER_NEAREST, GEGL_ABYSS_NONE);
if (val & 2)
{
/* Only mark pixels of the spline/segment */
if (val & (4 << edgel.direction))
return -1;
/* Mark edgel in pixel (1 == In Mask, 2 == Spline/Segment) */
val |= (4 << edgel.direction);
gegl_buffer_set (mask, GEGL_RECTANGLE (edgel.x, edgel.y, 1, 1), 0,
NULL, &val, GEGL_AUTO_ROWSTRIDE);
}
if (pika_edgel_cmp (&edgel, &start) != 0)
++count;
}
while (pika_edgel_cmp (&edgel, &start) != 0 && count <= size_limit);
return count;
}
/**
* pika_edgel_region_area:
* @mask: current state of closed line art buffer.
* @start_edgel: edgel to follow.
*
* Follows a line border, starting from @start_edgel to compute the area
* enclosed by this border.
* Unfortunately this may return a negative area when the line does not
* close a zone. In this case, there is an uncertainty on the size of
* the created zone, and we should consider it a big size.
*
* Returns: the area enclosed by the followed line, or a negative value
* if the zone is not closed (hence actual area unknown).
*/
static glong
pika_edgel_region_area (const GeglBuffer *mask,
Edgel start_edgel)
{
Edgel edgel = start_edgel;
glong area = 0;
do
{
if (edgel.direction == XPlusDirection)
area -= edgel.x;
else if (edgel.direction == XMinusDirection)
area += edgel.x - 1;
pika_edgelset_next8 (mask, &edgel, &edgel);
}
while (pika_edgel_cmp (&edgel, &start_edgel) != 0);
return area;
}
/* Edgel sets */
static GArray *
pika_edgelset_new (GeglBuffer *buffer,
PikaAsync *async)
{
GeglBufferIterator *gi;
GArray *set;
GHashTable *edgel2index;
gint width = gegl_buffer_get_width (buffer);
gint height = gegl_buffer_get_height (buffer);
set = g_array_new (TRUE, TRUE, sizeof (Edgel *));
g_array_set_clear_func (set, (GDestroyNotify) pika_edgel_clear);
if (width <= 1 || height <= 1)
return set;
edgel2index = g_hash_table_new ((GHashFunc) edgel2index_hash_fun,
(GEqualFunc) edgel2index_equal_fun);
gi = gegl_buffer_iterator_new (buffer, GEGL_RECTANGLE (0, 0, width, height),
0, NULL, GEGL_ACCESS_READ, GEGL_ABYSS_NONE, 5);
gegl_buffer_iterator_add (gi, buffer, GEGL_RECTANGLE (0, -1, width, height),
0, NULL, GEGL_ACCESS_READ, GEGL_ABYSS_NONE);
gegl_buffer_iterator_add (gi, buffer, GEGL_RECTANGLE (0, 1, width, height),
0, NULL, GEGL_ACCESS_READ, GEGL_ABYSS_NONE);
gegl_buffer_iterator_add (gi, buffer, GEGL_RECTANGLE (-1, 0, width, height),
0, NULL, GEGL_ACCESS_READ, GEGL_ABYSS_NONE);
gegl_buffer_iterator_add (gi, buffer, GEGL_RECTANGLE (1, 0, width, height),
0, NULL, GEGL_ACCESS_READ, GEGL_ABYSS_NONE);
while (gegl_buffer_iterator_next (gi))
{
guint8 *p = (guint8*) gi->items[0].data;
guint8 *prevy = (guint8*) gi->items[1].data;
guint8 *nexty = (guint8*) gi->items[2].data;
guint8 *prevx = (guint8*) gi->items[3].data;
guint8 *nextx = (guint8*) gi->items[4].data;
gint startx = gi->items[0].roi.x;
gint starty = gi->items[0].roi.y;
gint endy = starty + gi->items[0].roi.height;
gint endx = startx + gi->items[0].roi.width;
gint x;
gint y;
if (pika_async_is_canceled (async))
{
gegl_buffer_iterator_stop (gi);
pika_async_abort (async);
goto end;
}
for (y = starty; y < endy; y++)
for (x = startx; x < endx; x++)
{
if (*(p++))
{
if (! *prevy)
pika_edgelset_add (set, x, y, YMinusDirection, edgel2index);
if (! *nexty)
pika_edgelset_add (set, x, y, YPlusDirection, edgel2index);
if (! *prevx)
pika_edgelset_add (set, x, y, XMinusDirection, edgel2index);
if (! *nextx)
pika_edgelset_add (set, x, y, XPlusDirection, edgel2index);
}
prevy++;
nexty++;
prevx++;
nextx++;
}
}
pika_edgelset_build_graph (set, buffer, edgel2index, async);
if (pika_async_is_stopped (async))
goto end;
pika_edgelset_init_normals (set);
end:
g_hash_table_destroy (edgel2index);
if (pika_async_is_stopped (async))
{
g_array_free (set, TRUE);
set = NULL;
}
return set;
}
static void
pika_edgelset_add (GArray *set,
int x,
int y,
Direction direction,
GHashTable *edgel2index)
{
Edgel *edgel = pika_edgel_new (x, y, direction);
unsigned long position = set->len;
g_array_append_val (set, edgel);
g_hash_table_insert (edgel2index, edgel, GUINT_TO_POINTER (position));
}
static void
pika_edgelset_init_normals (GArray *set)
{
Edgel **e = (Edgel**) set->data;
while (*e)
{
PikaVector2 n = Direction2Normal[(*e)->direction];
(*e)->x_normal = n.x;
(*e)->y_normal = n.y;
e++;
}
}
static void
pika_edgelset_smooth_normals (GArray *set,
int mask_size,
PikaAsync *async)
{
const gfloat sigma = mask_size * 0.775;
const gfloat den = 2 * sigma * sigma;
gfloat weights[65];
PikaVector2 smoothed_normal;
gint i;
pika_assert (mask_size <= 65);
weights[0] = 1.0f;
for (int i = 1; i <= mask_size; ++i)
weights[i] = expf (-(i * i) / den);
for (i = 0; i < set->len; i++)
{
Edgel *it = g_array_index (set, Edgel*, i);
Edgel *edgel_before = g_array_index (set, Edgel*, it->previous);
Edgel *edgel_after = g_array_index (set, Edgel*, it->next);
int n = mask_size;
int i = 1;
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
return;
}
smoothed_normal = Direction2Normal[it->direction];
while (n-- && (edgel_after != edgel_before))
{
smoothed_normal = pika_vector2_add_val (smoothed_normal,
pika_vector2_mul_val (Direction2Normal[edgel_before->direction], weights[i]));
smoothed_normal = pika_vector2_add_val (smoothed_normal,
pika_vector2_mul_val (Direction2Normal[edgel_after->direction], weights[i]));
edgel_before = g_array_index (set, Edgel *, edgel_before->previous);
edgel_after = g_array_index (set, Edgel *, edgel_after->next);
++i;
}
pika_vector2_normalize (&smoothed_normal);
it->x_normal = smoothed_normal.x;
it->y_normal = smoothed_normal.y;
}
}
static void
pika_edgelset_compute_curvature (GArray *set,
PikaAsync *async)
{
gint i;
for (i = 0; i < set->len; i++)
{
Edgel *it = g_array_index (set, Edgel*, i);
Edgel *previous = g_array_index (set, Edgel *, it->previous);
Edgel *next = g_array_index (set, Edgel *, it->next);
PikaVector2 n_prev = pika_vector2_new (previous->x_normal, previous->y_normal);
PikaVector2 n_next = pika_vector2_new (next->x_normal, next->y_normal);
PikaVector2 diff = pika_vector2_mul_val (pika_vector2_sub_val (n_next, n_prev),
0.5);
const float c = pika_vector2_length_val (diff);
const float crossp = n_prev.x * n_next.y - n_prev.y * n_next.x;
it->curvature = (crossp > 0.0f) ? c : -c;
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
return;
}
}
}
static void
pika_edgelset_build_graph (GArray *set,
GeglBuffer *buffer,
GHashTable *edgel2index,
PikaAsync *async)
{
Edgel edgel;
gint i;
for (i = 0; i < set->len; i++)
{
Edgel *neighbor;
Edgel *it = g_array_index (set, Edgel *, i);
guint neighbor_pos;
if (pika_async_is_canceled (async))
{
pika_async_abort (async);
return;
}
pika_edgelset_next8 (buffer, it, &edgel);
pika_assert (g_hash_table_contains (edgel2index, &edgel));
neighbor_pos = GPOINTER_TO_UINT (g_hash_table_lookup (edgel2index, &edgel));
it->next = neighbor_pos;
neighbor = g_array_index (set, Edgel *, neighbor_pos);
neighbor->previous = i;
}
}
static void
pika_edgelset_next8 (const GeglBuffer *buffer,
Edgel *it,
Edgel *n)
{
guint8 pixels[9];
n->x = it->x;
n->y = it->y;
n->direction = it->direction;
gegl_buffer_get ((GeglBuffer *) buffer,
GEGL_RECTANGLE (n->x - 1, n->y - 1, 3, 3),
1.0, NULL, pixels, GEGL_AUTO_ROWSTRIDE,
GEGL_ABYSS_NONE);
switch (n->direction)
{
case XPlusDirection:
if (pixels[8])
{
++(n->y);
++(n->x);
n->direction = YMinusDirection;
}
else if (pixels[7])
{
++(n->y);
}
else
{
n->direction = YPlusDirection;
}
break;
case YMinusDirection:
if (pixels[2])
{
++(n->x);
--(n->y);
n->direction = XMinusDirection;
}
else if (pixels[5])
{
++(n->x);
}
else
{
n->direction = XPlusDirection;
}
break;
case XMinusDirection:
if (pixels[0])
{
--(n->x);
--(n->y);
n->direction = YPlusDirection;
}
else if (pixels[1])
{
--(n->y);
}
else
{
n->direction = YMinusDirection;
}
break;
case YPlusDirection:
if (pixels[6])
{
--(n->x);
++(n->y);
n->direction = XPlusDirection;
}
else if (pixels[3])
{
--(n->x);
}
else
{
n->direction = XMinusDirection;
}
break;
default:
g_return_if_reached ();
break;
}
}