gimp/plug-ins/sel2path/curve.c

/* curve.c: operations on the lists of pixels and lists of curves.

Copyright (C) 1992 Free Software Foundation, Inc.

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 2, 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, write to the Free Software
Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.  */

#include "config.h"

#include <glib.h>

#include "global.h"
#include "curve.h"


/* Return an entirely empty curve.  */

curve_type
new_curve (void)
{
  curve_type curve = g_new (struct curve, 1);

  curve->point_list = NULL;
  CURVE_LENGTH (curve) = 0;
  CURVE_CYCLIC (curve) = false;
  CURVE_START_TANGENT (curve) = CURVE_END_TANGENT (curve) = NULL;
  PREVIOUS_CURVE (curve) = NEXT_CURVE (curve) = NULL;

  return curve;
}


/* Start the returned curve off with COORD as the first point.  */

curve_type
init_curve (coordinate_type coord)
{
  curve_type curve = new_curve ();

  curve->point_list = g_new (point_type, 1);
  CURVE_LENGTH (curve) = 1;

  CURVE_POINT (curve, 0) = int_to_real_coord (coord);

  return curve;
}


/* Don't copy the points or tangents, but copy everything else.  */

curve_type
copy_most_of_curve (curve_type old_curve)
{
  curve_type curve = new_curve ();

  CURVE_CYCLIC (curve) = CURVE_CYCLIC (old_curve);
  PREVIOUS_CURVE (curve) = PREVIOUS_CURVE (old_curve);
  NEXT_CURVE (curve) = NEXT_CURVE (old_curve);

  return curve;
}


/* The length of CURVE will be zero if we ended up not being able to fit
   it (which in turn implies a problem elsewhere in the program, but at
   any rate, we shouldn't try here to free the nonexistent curve).  */

void
free_curve (curve_type curve)
{
  if (CURVE_LENGTH (curve) > 0)
    safe_free ((address *) &(curve->point_list));
}


void
append_pixel (curve_type curve, coordinate_type coord)
{
  append_point (curve, int_to_real_coord (coord));
}


void
append_point (curve_type curve, real_coordinate_type coord)
{
  CURVE_LENGTH (curve)++;
  curve->point_list = g_realloc (curve->point_list,CURVE_LENGTH (curve) * sizeof(point_type));
  LAST_CURVE_POINT (curve) = coord;
  /* The t value does not need to be set.  */
}

/* Return an initialized but empty curve list.  */

curve_list_type
new_curve_list (void)
{
  curve_list_type curve_list;

  curve_list.length = 0;
  curve_list.data = NULL;

  return curve_list;
}


/* Free a curve list and all the curves it contains.  */

void
free_curve_list (curve_list_type *curve_list)
{
  unsigned this_curve;

  for (this_curve = 0; this_curve < curve_list->length; this_curve++)
    free_curve (curve_list->data[this_curve]);

  /* If the character was empty, it won't have any curves.  */
  if (curve_list->data != NULL)
    safe_free ((address *) &(curve_list->data));
}


/* Add an element to a curve list.  */

void
append_curve (curve_list_type *curve_list, curve_type curve)
{
  curve_list->length++;
  curve_list->data = g_realloc (curve_list->data,curve_list->length*sizeof(curve_type));
  curve_list->data[curve_list->length - 1] = curve;
}


/* Return an initialized but empty curve list array.  */

curve_list_array_type
new_curve_list_array (void)
{
  curve_list_array_type curve_list_array;

  CURVE_LIST_ARRAY_LENGTH (curve_list_array) = 0;
  curve_list_array.data = NULL;

  return curve_list_array;
}


/* Free a curve list array and all the curve lists it contains.  */

void
free_curve_list_array (curve_list_array_type *curve_list_array)
{
  unsigned this_list;

  for (this_list = 0; this_list < CURVE_LIST_ARRAY_LENGTH (*curve_list_array);
       this_list++) 
    free_curve_list (&CURVE_LIST_ARRAY_ELT (*curve_list_array, this_list));

  /* If the character was empty, it won't have any curves.  */
  if (curve_list_array->data != NULL)
    safe_free ((address *) &(curve_list_array->data));
}


/* Add an element to a curve list array.  */

void
append_curve_list (curve_list_array_type *l, curve_list_type curve_list)
{
  CURVE_LIST_ARRAY_LENGTH (*l)++;
  l->data = g_realloc (l->data,( CURVE_LIST_ARRAY_LENGTH (*l))*sizeof(curve_list_type));
  LAST_CURVE_LIST_ARRAY_ELT (*l) = curve_list;
}