gimp/app/display/gimpdisplay-area.c

106 lines
2.5 KiB
C

/* The GIMP -- an image manipulation program
* Copyright (C) 1995 Spencer Kimball and Peter Mattis
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 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, write to the Free Software
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "config.h"
#include <gtk/gtk.h>
#include "display-types.h"
#include "gimpdisplay-area.h"
#define OVERHEAD 25 /* in units of pixel area */
GimpArea *
gimp_area_new (gint x1,
gint y1,
gint x2,
gint y2)
{
GimpArea *area;
area = g_new (GimpArea, 1);
area->x1 = x1;
area->y1 = y1;
area->x2 = x2;
area->y2 = y2;
return area;
}
/*
* As far as I can tell, this function takes a GimpArea and unifies it with
* an existing list of GimpAreas, trying to avoid overdraw. [adam]
*/
GSList *
gimp_display_area_list_process (GSList *list,
GimpArea *area)
{
GSList *new_list;
GSList *l;
gint area1, area2, area3;
GimpArea *ga2;
/* start new list off */
new_list = g_slist_prepend (NULL, area);
for (l = list; l; l = g_slist_next (l))
{
ga2 = (GimpArea *) l->data;
area1 = (area->x2 - area->x1) * (area->y2 - area->y1) + OVERHEAD;
area2 = (ga2->x2 - ga2->x1) * (ga2->y2 - ga2->y1) + OVERHEAD;
area3 = (MAX (ga2->x2, area->x2) - MIN (ga2->x1, area->x1)) *
(MAX (ga2->y2, area->y2) - MIN (ga2->y1, area->y1)) + OVERHEAD;
if ((area1 + area2) < area3)
{
new_list = g_slist_prepend (new_list, ga2);
}
else
{
area->x1 = MIN (area->x1, ga2->x1);
area->y1 = MIN (area->y1, ga2->y1);
area->x2 = MAX (area->x2, ga2->x2);
area->y2 = MAX (area->y2, ga2->y2);
g_free (ga2);
}
}
if (list)
g_slist_free (list);
return new_list;
}
GSList *
gimp_display_area_list_free (GSList *list)
{
if (list)
{
g_slist_foreach (list, (GFunc) g_free, NULL);
g_slist_free (list);
}
return NULL;
}