gdkrectangle.c 4.49 KB
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/* GDK - The GIMP Drawing Kit
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 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
 *
 * This library is free software; you can redistribute it and/or
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 * modify it under the terms of the GNU Lesser General Public
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 * License as published by the Free Software Foundation; either
 * version 2 of the License, or (at your option) any later version.
 *
 * This library 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
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 * Lesser General Public License for more details.
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 *
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 * You should have received a copy of the GNU Lesser General Public
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 * License along with this library; if not, write to the
 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
 * Boston, MA 02111-1307, USA.
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 */
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/*
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 * Modified by the GTK+ Team and others 1997-2000.  See the AUTHORS
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 * file for a list of people on the GTK+ Team.  See the ChangeLog
 * files for a list of changes.  These files are distributed with
 * GTK+ at ftp://ftp.gtk.org/pub/gtk/. 
 */

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#include "config.h"
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#include "gdkrectangle.h"
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/**
 * SECTION:regions
 * @Short_description: Simple graphical data types
 * @Title: Points and Rectangles
 *
 * GDK provides the #GdkPoint and #GdkRectangle data types for representing pixels
 * and sets of pixels on the screen. Together with Cairo's #cairo_region_t data
 * type, they make up the central types for representing graphical data.
 *
 * #GdkPoint is a simple structure containing an x and y coordinate of a point.
 *
 * #GdkRectangle is a structure holding the position and size of a rectangle.
 * The intersection of two rectangles can be computed with
 * gdk_rectangle_intersect(). To find the union of two rectangles use
 * gdk_rectangle_union().
 *
 * #cairo_region_t is usually used for managing clipping of graphical operations.
 */


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/**
 * gdk_rectangle_union:
 * @src1: a #GdkRectangle
 * @src2: a #GdkRectangle
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 * @dest: (out): return location for the union of @src1 and @src2
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 *
 * Calculates the union of two rectangles.
 * The union of rectangles @src1 and @src2 is the smallest rectangle which
 * includes both @src1 and @src2 within it.
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 * It is allowed for @dest to be the same as either @src1 or @src2.
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 */
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void
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gdk_rectangle_union (const GdkRectangle *src1,
		     const GdkRectangle *src2,
		     GdkRectangle       *dest)
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{
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  gint dest_x, dest_y;
  
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  g_return_if_fail (src1 != NULL);
  g_return_if_fail (src2 != NULL);
  g_return_if_fail (dest != NULL);

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  dest_x = MIN (src1->x, src2->x);
  dest_y = MIN (src1->y, src2->y);
  dest->width = MAX (src1->x + src1->width, src2->x + src2->width) - dest_x;
  dest->height = MAX (src1->y + src1->height, src2->y + src2->height) - dest_y;
  dest->x = dest_x;
  dest->y = dest_y;
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}

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/**
 * gdk_rectangle_intersect:
 * @src1: a #GdkRectangle
 * @src2: a #GdkRectangle
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 * @dest: (out caller-allocates) (allow-none): return location for the
 * intersection of @src1 and @src2, or %NULL
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 *
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 * Calculates the intersection of two rectangles. It is allowed for
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 * @dest to be the same as either @src1 or @src2. If the rectangles 
 * do not intersect, @dest's width and height is set to 0 and its x 
 * and y values are undefined. If you are only interested in whether
 * the rectangles intersect, but not in the intersecting area itself,
 * pass %NULL for @dest.
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 *
 * Returns: %TRUE if the rectangles intersect.
 */
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gboolean
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gdk_rectangle_intersect (const GdkRectangle *src1,
			 const GdkRectangle *src2,
			 GdkRectangle       *dest)
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{
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  gint dest_x, dest_y;
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  gint dest_x2, dest_y2;
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  gint return_val;

  g_return_val_if_fail (src1 != NULL, FALSE);
  g_return_val_if_fail (src2 != NULL, FALSE);

  return_val = FALSE;

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  dest_x = MAX (src1->x, src2->x);
  dest_y = MAX (src1->y, src2->y);
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  dest_x2 = MIN (src1->x + src1->width, src2->x + src2->width);
  dest_y2 = MIN (src1->y + src1->height, src2->y + src2->height);
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  if (dest_x2 > dest_x && dest_y2 > dest_y)
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    {
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      if (dest)
        {
          dest->x = dest_x;
          dest->y = dest_y;
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          dest->width = dest_x2 - dest_x;
          dest->height = dest_y2 - dest_y;
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        }
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      return_val = TRUE;
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    }
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  else if (dest)
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    {
      dest->width = 0;
      dest->height = 0;
    }

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  return return_val;
}
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static GdkRectangle *
gdk_rectangle_copy (const GdkRectangle *rectangle)
{
  GdkRectangle *result = g_new (GdkRectangle, 1);
  *result = *rectangle;

  return result;
}

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G_DEFINE_BOXED_TYPE (GdkRectangle, gdk_rectangle,
                     gdk_rectangle_copy,
                     g_free)