PIKApp/plug-ins/selection-to-path/selection-to-path.c

/*
 * Copyright (C) 1995 Spencer Kimball and Peter Mattis
 *
 * This is a plug-in for PIKA.
 *
 * Plugin to convert a selection to a path.
 *
 * Copyright (C) 1999 Andy Thomas  alt@gimp.org
 *
 * 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/>.
 *
 */

/* Change log:-
 * 0.1 First version.
 */

#include "config.h"

#include <string.h>

#include "libpika/pika.h"
#include "libpika/pikaui.h"

#include "libpikamath/pikamath.h"

#include "global.h"
#include "types.h"
#include "pxl-outline.h"
#include "fit.h"
#include "spline.h"
#include "selection-to-path.h"

#include "libpika/stdplugins-intl.h"


#define PLUG_IN_PROC   "plug-in-sel2path"
#define PLUG_IN_BINARY "selection-to-path"
#define PLUG_IN_ROLE   "pika-selection-to-path"

#define RESPONSE_RESET 1
#define MID_POINT      127


typedef struct _Sel2path      Sel2path;
typedef struct _Sel2pathClass Sel2pathClass;

struct _Sel2path
{
  PikaPlugIn parent_instance;
};

struct _Sel2pathClass
{
  PikaPlugInClass parent_class;
};


#define SEL2PATH_TYPE  (sel2path_get_type ())
#define SEL2PATH (obj) (G_TYPE_CHECK_INSTANCE_CAST ((obj), SEL2PATH_TYPE, Sel2path))

GType                   sel2path_get_type         (void) G_GNUC_CONST;

static GList          * sel2path_query_procedures (PikaPlugIn           *plug_in);
static PikaProcedure  * sel2path_create_procedure (PikaPlugIn           *plug_in,
                                                   const gchar          *name);

static PikaValueArray * sel2path_run              (PikaProcedure        *procedure,
                                                   PikaRunMode           run_mode,
                                                   PikaImage            *image,
                                                   gint                  n_drawables,
                                                   PikaDrawable        **drawables,
                                                   PikaProcedureConfig  *config,
                                                   gpointer              run_data);

static gint             sel2path_dialog           (PikaProcedure        *procedure,
                                                   PikaProcedureConfig  *config);
static gboolean         sel2path                  (PikaImage            *image);


G_DEFINE_TYPE (Sel2path, sel2path, PIKA_TYPE_PLUG_IN)

PIKA_MAIN (SEL2PATH_TYPE)
DEFINE_STD_SET_I18N


static gint         sel_x1, sel_y1, sel_x2, sel_y2;
static gint         has_sel, sel_width, sel_height;
static GeglSampler *sel_sampler;


static void
sel2path_class_init (Sel2pathClass *klass)
{
  PikaPlugInClass *plug_in_class = PIKA_PLUG_IN_CLASS (klass);

  plug_in_class->query_procedures = sel2path_query_procedures;
  plug_in_class->create_procedure = sel2path_create_procedure;
  plug_in_class->set_i18n         = STD_SET_I18N;
}

static void
sel2path_init (Sel2path *sel2path)
{
}

static GList *
sel2path_query_procedures (PikaPlugIn *plug_in)
{
  return g_list_append (NULL, g_strdup (PLUG_IN_PROC));
}

static PikaProcedure *
sel2path_create_procedure (PikaPlugIn  *plug_in,
                           const gchar *name)
{
  PikaProcedure *procedure = NULL;

  if (! strcmp (name, PLUG_IN_PROC))
    {
      procedure = pika_image_procedure_new (plug_in, name,
                                            PIKA_PDB_PROC_TYPE_PLUGIN,
                                            sel2path_run, NULL, NULL);

      pika_procedure_set_image_types (procedure, "*");
      pika_procedure_set_sensitivity_mask (procedure,
                                           PIKA_PROCEDURE_SENSITIVE_DRAWABLE  |
                                           PIKA_PROCEDURE_SENSITIVE_DRAWABLES |
                                           PIKA_PROCEDURE_SENSITIVE_NO_DRAWABLES);

      pika_procedure_set_documentation (procedure,
                                        _("Converts a selection to a path"),
                                        _("Converts a selection to a path"),
                                        name);
      pika_procedure_set_attribution (procedure,
                                      "Andy Thomas",
                                      "Andy Thomas",
                                      "1999");

      PIKA_PROC_ARG_DOUBLE (procedure, "align-threshold",
                            _("_Align Threshold"),
                            _("If two endpoints are closer than this, "
                              "they are made to be equal."),
                            0.2, 2.0, 0.5,
                            G_PARAM_READWRITE);

      PIKA_PROC_ARG_DOUBLE (procedure, "corner-always-threshold",
                            _("Corner Al_ways Threshold"),
                            _("If the angle defined by a point and its predecessors "
                              "and successors is smaller than this, it's a corner, "
                              "even if it's within 'corner_surround' pixels of a "
                              "point with a smaller angle."),
                            30, 180, 60.0,
                            G_PARAM_READWRITE);

      PIKA_PROC_ARG_INT (procedure, "corner-surround",
                         _("Corner _Surround"),
                         _("Number of points to consider when determining if a "
                           "point is a corner or not."),
                         3, 8, 4,
                         G_PARAM_READWRITE);

      PIKA_PROC_ARG_DOUBLE (procedure, "corner-threshold",
                            _("Cor_ner Threshold"),
                            _("If a point, its predecessors, and its successors "
                              "define an angle smaller than this, it's a corner."),
                            0, 180, 100.0,
                            G_PARAM_READWRITE);

      PIKA_PROC_ARG_DOUBLE (procedure, "error-threshold",
                            _("Error Thres_hold"),
                            _("Amount of error at which a fitted spline is "
                              "unacceptable. If any pixel is further away "
                              "than this from the fitted curve, we try again."),
                            0.2, 10, 0.4,
                            G_PARAM_READWRITE);

      PIKA_PROC_ARG_INT (procedure, "filter-alternative-surround",
                         _("_Filter Alternative Surround"),
                         _("A second number of adjacent points to consider "
                           "when filtering."),
                         1, 10, 1,
                         G_PARAM_READWRITE);

      PIKA_PROC_ARG_DOUBLE (procedure, "filter-epsilon",
                            _("Filter E_psilon"),
                            _("If the angles between the vectors produced by "
                              "filter_surround and filter_alternative_surround "
                              "points differ by more than this, use the one from "
                              "filter_alternative_surround."),
                            5, 40, 10.0,
                            G_PARAM_READWRITE);

      PIKA_PROC_ARG_INT (procedure, "filter-iteration-count",
                         _("Filter Iteration Co_unt"),
                         _("Number of times to smooth original data points.  "
                           "Increasing this number dramatically --- to 50 or "
                           "so --- can produce vastly better results. But if "
                           "any points that 'should' be corners aren't found, "
                           "the curve goes to hell around that point."),
                         4, 70, 4,
                         G_PARAM_READWRITE);

      PIKA_PROC_ARG_DOUBLE (procedure, "filter-percent",
                            _("Filt_er Percent"),
                            _("To produce the new point, use the old point plus "
                              "this times the neighbors."),
                            0, 1, 0.33,
                            G_PARAM_READWRITE);

      PIKA_PROC_ARG_INT (procedure, "filter-secondary-surround",
                         _("Filter Secondar_y Surround"),
                         _("Number of adjacent points to consider if "
                           "'filter_surround' points defines a straight line."),
                         3, 10, 3,
                         G_PARAM_READWRITE);

      PIKA_PROC_ARG_INT (procedure, "filter-surround",
                         _("Filter Surroun_d"),
                         _("Number of adjacent points to consider when filtering."),
                         2, 10, 2,
                         G_PARAM_READWRITE);

      PIKA_PROC_ARG_BOOLEAN (procedure, "keep-knees",
                             _("_Keep Knees"),
                             _("Says whether or not to remove 'knee' "
                               "points after finding the outline."),
                             FALSE,
                             G_PARAM_READWRITE);

      PIKA_PROC_ARG_DOUBLE (procedure, "line-reversion-threshold",
                            _("_Line Reversion Threshold"),
                            _("If a spline is closer to a straight line than this, "
                              "it remains a straight line, even if it would otherwise "
                              "be changed back to a curve. This is weighted by the "
                              "square of the curve length, to make shorter curves "
                              "more likely to be reverted."),
                            0.01, 0.2, 0.01,
                            G_PARAM_READWRITE);

      PIKA_PROC_ARG_DOUBLE (procedure, "line-threshold",
                            _("L_ine Threshold"),
                            _("How many pixels (on the average) a spline can "
                              "diverge from the line determined by its endpoints "
                              "before it is changed to a straight line."),
                            0.2, 4, 0.5,
                            G_PARAM_READWRITE);

      PIKA_PROC_ARG_DOUBLE (procedure, "reparametrize-improvement",
                            _("Reparametri_ze Improvement"),
                            _("If reparameterization doesn't improve the fit by this "
                              "much percent, stop doing it. ""Amount of error at which "
                              "it is pointless to reparameterize."),
                            0, 1, 0.01,
                            G_PARAM_READWRITE);

      PIKA_PROC_ARG_DOUBLE (procedure, "reparametrize-threshold",
                            _("Repara_metrize Threshold"),
                            _("Amount of error at which it is pointless to reparameterize.  "
                              "This happens, for example, when we are trying to fit the "
                              "outline of the outside of an 'O' with a single spline. "
                              "The initial fit is not good enough for the Newton-Raphson "
                              "iteration to improve it.  It may be that it would be better "
                              "to detect the cases where we didn't find any corners."),
                            1, 50, 1.0,
                            G_PARAM_READWRITE);

      PIKA_PROC_ARG_DOUBLE (procedure, "subdivide-search",
                            _("Subdi_vide Search"),
                            _("Percentage of the curve away from the worst point "
                             "to look for a better place to subdivide."),
                            0.05, 1, 0.1,
                            G_PARAM_READWRITE);

      PIKA_PROC_ARG_INT (procedure, "subdivide-surround",
                         _("Su_bdivide Surround"),
                         _("Number of points to consider when deciding whether "
                           "a given point is a better place to subdivide."),
                         2, 10, 4,
                         G_PARAM_READWRITE);

      PIKA_PROC_ARG_DOUBLE (procedure, "subdivide-threshold",
                            _("Subdivide Th_reshold"),
                            _("How many pixels a point can diverge from a straight "
                              "line and still be considered a better place to "
                              "subdivide."),
                            0.01, 1, 0.03,
                            G_PARAM_READWRITE);

      PIKA_PROC_ARG_INT (procedure, "tangent-surround",
                         _("_Tangent Surround"),
                         _("Number of points to look at on either side of a "
                           "point when computing the approximation to the "
                           "tangent at that point."),
                         2, 10, 3,
                         G_PARAM_READWRITE);
    }

  return procedure;
}

static PikaValueArray *
sel2path_run (PikaProcedure        *procedure,
              PikaRunMode           run_mode,
              PikaImage            *image,
              gint                  n_drawables,
              PikaDrawable        **drawables,
              PikaProcedureConfig  *config,
              gpointer              run_data)
{
  gegl_init (NULL, NULL);

  if (pika_selection_is_empty (image))
    {
      g_message (_("No selection to convert"));

      return pika_procedure_new_return_values (procedure,
                                               PIKA_PDB_SUCCESS,
                                               NULL);
    }

  if (run_mode == PIKA_RUN_INTERACTIVE &&
      ! sel2path_dialog (procedure, config))
    return pika_procedure_new_return_values (procedure,
                                             PIKA_PDB_CANCEL,
                                             NULL);

  fit_set_params (config);

  if (! sel2path (image))
    return pika_procedure_new_return_values (procedure,
                                             PIKA_PDB_EXECUTION_ERROR,
                                             NULL);

  return pika_procedure_new_return_values (procedure, PIKA_PDB_SUCCESS, NULL);
}

/* Build the dialog up. This was the hard part! */
static gint
sel2path_dialog (PikaProcedure       *procedure,
                 PikaProcedureConfig *config)
{
  GtkWidget *dialog;
  GtkWidget *vbox;
  GtkWidget *scrolled_win;
  gboolean   run;

  pika_ui_init (PLUG_IN_BINARY);

  dialog = pika_procedure_dialog_new (procedure,
                                      PIKA_PROCEDURE_CONFIG (config),
                                      _("Selection to Path Advanced Settings"));

  pika_dialog_set_alternative_button_order (GTK_DIALOG (dialog),
                                            RESPONSE_RESET,
                                            GTK_RESPONSE_OK,
                                            GTK_RESPONSE_CANCEL,
                                            -1);

  pika_window_set_transient (GTK_WINDOW (dialog));

  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "align-threshold", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "corner-always-threshold", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "corner-surround", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "corner-threshold", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "error-threshold", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "filter-alternative-surround", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "filter-epsilon", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "filter-iteration-count", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "filter-percent", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "filter-secondary-surround", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "filter-surround", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "line-reversion-threshold", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "line-threshold", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "reparametrize-improvement", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "reparametrize-threshold", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "subdivide-search", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "subdivide-surround", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "subdivide-threshold", 1.0);
  pika_procedure_dialog_get_scale_entry (PIKA_PROCEDURE_DIALOG (dialog),
                                         "tangent-surround", 1.0);

  vbox = pika_procedure_dialog_fill_box (PIKA_PROCEDURE_DIALOG (dialog),
                                         "selection-to-path-box",
                                         "align-threshold",
                                         "corner-always-threshold",
                                         "corner-surround",
                                         "corner-threshold",
                                         "error-threshold",
                                         "filter-alternative-surround",
                                         "filter-epsilon",
                                         "filter-iteration-count",
                                         "filter-percent",
                                         "filter-secondary-surround",
                                         "filter-surround",
                                         "keep-knees",
                                         "line-reversion-threshold",
                                         "line-threshold",
                                         "reparametrize-improvement",
                                         "reparametrize-threshold",
                                         "subdivide-search",
                                         "subdivide-surround",
                                         "subdivide-threshold",
                                         "tangent-surround",
                                          NULL);
  gtk_box_set_spacing (GTK_BOX (vbox), 12);

  scrolled_win = pika_procedure_dialog_fill_scrolled_window (PIKA_PROCEDURE_DIALOG (dialog),
                                                             "scrollwin",
                                                             "selection-to-path-box");
  gtk_widget_set_size_request (scrolled_win, 400, 400);
  gtk_scrolled_window_set_shadow_type (GTK_SCROLLED_WINDOW (scrolled_win),
                                       GTK_SHADOW_NONE);
  gtk_scrolled_window_set_policy (GTK_SCROLLED_WINDOW (scrolled_win),
                                  GTK_POLICY_NEVER,
                                  GTK_POLICY_ALWAYS);
  gtk_scrolled_window_set_overlay_scrolling (GTK_SCROLLED_WINDOW (scrolled_win),
                                             FALSE);

  pika_procedure_dialog_fill (PIKA_PROCEDURE_DIALOG (dialog),
                              "scrollwin",
                              NULL);

  gtk_widget_show (dialog);

  run = pika_procedure_dialog_run (PIKA_PROCEDURE_DIALOG (dialog));

  gtk_widget_destroy (dialog);

  return run;
}

guchar
sel_pixel_value (gint row,
                 gint col)
{
  guchar ret;

  if (col > sel_width || row > sel_height)
    {
      g_warning ("sel_pixel_value [%d,%d] out of bounds", col, row);
      return 0;
    }

  gegl_sampler_get (sel_sampler,
                    col + sel_x1, row + sel_y1, NULL, &ret, GEGL_ABYSS_NONE);

  return ret;
}

gboolean
sel_pixel_is_white (gint row,
                    gint col)
{
  if (sel_pixel_value (row, col) < MID_POINT)
    return TRUE;
  else
    return FALSE;
}

gint
sel_get_width (void)
{
  return sel_width;
}

gint
sel_get_height (void)
{
  return sel_height;
}

gboolean
sel_valid_pixel (gint row,
                 gint col)
{
  return (0 <= (row) && (row) < sel_get_height ()
          && 0 <= (col) && (col) < sel_get_width ());
}


static void
do_points (spline_list_array_type  in_splines,
           PikaImage              *image)
{
  PikaVectors *vectors;
  gint32       stroke;
  gint         i, j;
  gboolean     have_points = FALSE;
  spline_list_type spline_list;

  /* check if there really is something to do... */
  for (i = 0; i < SPLINE_LIST_ARRAY_LENGTH (in_splines); i++)
    {
      spline_list = SPLINE_LIST_ARRAY_ELT (in_splines, i);
      /* Ignore single points that are on their own */
      if (SPLINE_LIST_LENGTH (spline_list) < 2)
        continue;
      have_points = TRUE;
      break;
    }

  if (! have_points)
    return;

  vectors = pika_vectors_new (image, _("Selection"));

  for (j = 0; j < SPLINE_LIST_ARRAY_LENGTH (in_splines); j++)
    {
      spline_type seg;

      spline_list = SPLINE_LIST_ARRAY_ELT (in_splines, j);

      /* Ignore single points that are on their own */
      if (SPLINE_LIST_LENGTH (spline_list) < 2)
        continue;

      /*
       * we're constructing the path backwards
       * to have the result of least surprise for "Text along Path".
       */
      seg = SPLINE_LIST_ELT (spline_list, SPLINE_LIST_LENGTH (spline_list) - 1);
      stroke = pika_vectors_bezier_stroke_new_moveto (vectors,
                                                      END_POINT (seg).x,
                                                      END_POINT (seg).y);

      for (i = SPLINE_LIST_LENGTH (spline_list); i > 0; i--)
        {
          seg = SPLINE_LIST_ELT (spline_list, i-1);

          if (SPLINE_DEGREE (seg) == LINEAR)
            pika_vectors_bezier_stroke_lineto (vectors, stroke,
                                               START_POINT (seg).x,
                                               START_POINT (seg).y);
          else if (SPLINE_DEGREE (seg) == CUBIC)
            pika_vectors_bezier_stroke_cubicto (vectors, stroke,
                                                CONTROL2 (seg).x,
                                                CONTROL2 (seg).y,
                                                CONTROL1 (seg).x,
                                                CONTROL1 (seg).y,
                                                START_POINT (seg).x,
                                                START_POINT (seg).y);
          else
            g_warning ("print_spline: strange degree (%d)",
                       SPLINE_DEGREE (seg));
        }

      pika_vectors_stroke_close (vectors, stroke);

      /* transform to PIKAs coordinate system, taking the selections
       * bounding box into account  */
      pika_vectors_stroke_scale (vectors, stroke, 1.0, -1.0);
      pika_vectors_stroke_translate (vectors, stroke,
                                     sel_x1, sel_y1 + sel_height + 1);
    }

  pika_image_insert_vectors (image, vectors, NULL, -1);
}


static gboolean
sel2path (PikaImage *image)
{
  PikaSelection           *selection;
  GeglBuffer              *sel_buffer;
  pixel_outline_list_type  olt;
  spline_list_array_type   splines;

  pika_selection_bounds (image, &has_sel,
                         &sel_x1, &sel_y1, &sel_x2, &sel_y2);

  sel_width  = sel_x2 - sel_x1;
  sel_height = sel_y2 - sel_y1;

  /* Now get the selection channel */

  selection = pika_image_get_selection (image);

  if (! selection)
    return FALSE;

  sel_buffer  = pika_drawable_get_buffer (PIKA_DRAWABLE (selection));
  sel_sampler = gegl_buffer_sampler_new (sel_buffer,
                                         babl_format ("Y u8"),
                                         GEGL_SAMPLER_NEAREST);

  olt = find_outline_pixels ();

  splines = fitted_splines (olt);

  do_points (splines, image);

  g_object_unref (sel_sampler);
  g_object_unref (sel_buffer);

  pika_displays_flush ();

  return TRUE;
}

void
safe_free (address *item)
{
  g_free (*item);
  *item = NULL;
}