libswfdec/swfdec_rectangle.c

   1 /* Swfdec
   2  * Copyright (C) 2007 Benjamin Otte <otte@gnome.org>
   3  *
   4  * This library is free software; you can redistribute it and/or
   5  * modify it under the terms of the GNU Lesser General Public
   6  * License as published by the Free Software Foundation; either
   7  * version 2.1 of the License, or (at your option) any later version.
   8  *
   9  * This library is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12  * Lesser General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU Lesser General Public
  15  * License along with this library; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Fifth Floor,
  17  * Boston, MA  02110-1301  USA
  18  */
  19
  20 #ifdef HAVE_CONFIG_H
  21 #include "config.h"
  22 #endif
  23
  24 #include "swfdec_rectangle.h"
  25
  26 /**
  27  * SECTION:SwfdecRectangle
  28  * @title: SwfdecRectangle
  29  * @short_description: handling regions on the screen
  30  *
  31  * This section describes how regions are handled in Swfdec. Regions are
  32  * important when tracking which parts of the screen have been invalidated and
  33  * need to be repainted. See SwfdecPlayer::invalidate for an example.
  34  */
  35
  36 /**
  37  * SwfdecRectangle:
  38  * @x: x coordinate of top-left point
  39  * @y: y coordinate of top-left point
  40  * @width: width of rectangle or 0 for empty
  41  * @height: height of rectangle or 0 for empty
  42  *
  43  * This structure represents a rectangular region. It is identical to the
  44  * #GdkRectangle structure, so you can cast freely between them. The only
  45  * difference is that Gdk does not allow empty rectangles, while Swfdec does.
  46  * You can use swfdec_rectangle_is_empty() to check for this.
  47  */
  48
  49 static gpointer
  50 swfdec_rectangle_copy (gpointer src)
  51 {
  52   return g_memdup (src, sizeof (SwfdecRectangle));
  53 }
  54
  55 GType
  56 swfdec_rectangle_get_type (void)
  57 {
  58   static GType type = 0;
  59
  60   if (!type)
  61     type = g_boxed_type_register_static ("SwfdecRectangle",
  62        swfdec_rectangle_copy, g_free);
  63
  64   return type;
  65 }
  66
  67 /**
  68  * swfdec_rectangle_init_empty:
  69  * @rectangle: rectangle to initialize
  70  *
  71  * Initializes the rectangle as empty.
  72  **/
  73 void
  74 swfdec_rectangle_init_empty (SwfdecRectangle *rectangle)
  75 {
  76   rectangle->x = rectangle->y = rectangle->width = rectangle->height = 0;
  77 }
  78
  79 /**
  80  * swfdec_rectangle_is_empty:
  81  * @rectangle: rectangle to check
  82  *
  83  * Checks if the given @rectangle is empty.
  84  *
  85  * Returns: %TRUE if the rectangle is emtpy
  86  **/
  87 gboolean
  88 swfdec_rectangle_is_empty (const SwfdecRectangle *rectangle)
  89 {
  90   g_return_val_if_fail (rectangle != NULL, FALSE);
  91
  92   return rectangle->width <= 0 || rectangle->height <= 0;
  93 }
  94
  95 /**
  96  * swfdec_rectangle_intersect:
  97  * @dest: the rectangle to take the result or %NULL
  98  * @a: first rectangle to intersect
  99  * @b: second rectangle to intersect
 100  *
 101  * Intersects the rectangles @a and @b and puts the result into @dest. It is
 102  * allowed if @dest is the same as @a or @b.
 103  *
 104  * Returns: %TRUE if the intersection is not empty.
 105  **/
 106 gboolean
 107 swfdec_rectangle_intersect (SwfdecRectangle *dest, const SwfdecRectangle *a,
 108     const SwfdecRectangle *b)
 109 {
 110   SwfdecRectangle tmp;
 111
 112   g_return_val_if_fail (a != NULL, FALSE);
 113   g_return_val_if_fail (b != NULL, FALSE);
 114
 115   tmp.x = MAX (a->x, b->x);
 116   tmp.y = MAX (a->y, b->y);
 117   tmp.width = MIN (a->x + a->width, b->x + b->width) - tmp.x;
 118   tmp.height = MIN (a->y + a->height, b->y + b->height) - tmp.y;
 119
 120   if (tmp.width <= 0 && tmp.height <= 0) {
 121     if (dest)
 122       dest->x = dest->y = dest->width = dest->height = 0;
 123     return FALSE;
 124   }
 125
 126   if (dest != NULL)
 127     *dest = tmp;
 128   return TRUE;
 129 }
 130
 131 /**
 132  * swfdec_rectangle_union:
 133  * @dest: destination to take the union
 134  * @a: first rectangle to union
 135  * @b: second rectangle to union
 136  *
 137  * Computes the smallest rectangle that contains both @a and @b and puts it in
 138  * @dest.
 139  **/
 140 void
 141 swfdec_rectangle_union (SwfdecRectangle *dest, const SwfdecRectangle *a,
 142     const SwfdecRectangle *b)
 143 {
 144   int x, y;
 145
 146   g_return_if_fail (dest != NULL);
 147   g_return_if_fail (a != NULL);
 148   g_return_if_fail (b != NULL);
 149
 150   if (swfdec_rectangle_is_empty (a)) {
 151     *dest = *b;
 152     return;
 153   } else if (swfdec_rectangle_is_empty (b)) {
 154     *dest = *a;
 155     return;
 156   }
 157   x = MIN (a->x, b->x);
 158   y = MIN (a->y, b->y);
 159   dest->width = MAX (a->x + a->width, b->x + b->width) - x;
 160   dest->height = MAX (a->y + a->height, b->y + b->height) - y;
 161   dest->x = x;
 162   dest->y = y;
 163 }
 164
 165 /**
 166  * swfdec_rectangle_contains:
 167  * @container: the supposedly bigger rectangle
 168  * @content: the supposedly smaller rectangle
 169  *
 170  * Checks if @container contains the whole rectangle @content.
 171  *
 172  * Returns: %TRUE if @container contains @content.
 173  **/
 174 gboolean
 175 swfdec_rectangle_contains (const SwfdecRectangle *container, const SwfdecRectangle *content)
 176 {
 177   g_return_val_if_fail (container != NULL, FALSE);
 178   g_return_val_if_fail (content != NULL, FALSE);
 179
 180   return container->x <= content->x &&
 181       container->y <= content->y &&
 182       container->x + container->width >= content->x + content->width &&
 183       container->y + container->height >= content->y + content->height;
 184 }
 185
 186 /**
 187  * swfdec_rectangle_contains_point:
 188  * @rectangle: a rectangle
 189  * @x: x coordinate of point to check
 190  * @y: y coordinate of point to check
 191  *
 192  * Checks if the given point is inside the given rectangle.
 193  *
 194  * Returns: %TRUE if the point is inside the rectangle
 195  **/
 196 gboolean
 197 swfdec_rectangle_contains_point (const SwfdecRectangle *rectangle, int x, int y)
 198 {
 199   g_return_val_if_fail (rectangle != NULL, FALSE);
 200
 201   return rectangle->x <= x && rectangle->y <= y &&
 202       rectangle->x + rectangle->width > x && rectangle->y + rectangle->height > y;
 203 }