1/* GDK - The GIMP Drawing Kit
2 * Copyright (C) 1995-1997 Peter Mattis, Spencer Kimball and Josh MacDonald
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 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, see <http://www.gnu.org/licenses/>.
16 */
17
18/*
19 * Modified by the GTK+ Team and others 1997-2000. See the AUTHORS
20 * file for a list of people on the GTK+ Team. See the ChangeLog
21 * files for a list of changes. These files are distributed with
22 * GTK+ at ftp://ftp.gtk.org/pub/gtk/.
23 */
24
25#include "config.h"
26
27#include "gdkrectangle.h"
28#include <cairo-gobject.h>
29
30
31/**
32 * SECTION:regions
33 * @Short_description: Simple graphical data types
34 * @Title: Points and Rectangles
35 *
36 * GDK provides the #GdkPoint and #GdkRectangle data types for representing pixels
37 * and sets of pixels on the screen. Together with Cairo’s #cairo_region_t data
38 * type, they make up the central types for representing graphical data.
39 *
40 * A #GdkPoint represents an x and y coordinate of a point.
41 *
42 * A #GdkRectangle represents the position and size of a rectangle.
43 * The intersection of two rectangles can be computed with
44 * gdk_rectangle_intersect(). To find the union of two rectangles use
45 * gdk_rectangle_union().
46 *
47 * #cairo_region_t is usually used for managing clipping of graphical operations.
48 */
49
50
51/**
52 * gdk_rectangle_union:
53 * @src1: a #GdkRectangle
54 * @src2: a #GdkRectangle
55 * @dest: (out): return location for the union of @src1 and @src2
56 *
57 * Calculates the union of two rectangles.
58 * The union of rectangles @src1 and @src2 is the smallest rectangle which
59 * includes both @src1 and @src2 within it.
60 * It is allowed for @dest to be the same as either @src1 or @src2.
61 *
62 * Note that this function does not ignore 'empty' rectangles (ie. with
63 * zero width or height).
64 */
65void
66gdk_rectangle_union (const GdkRectangle *src1,
67 const GdkRectangle *src2,
68 GdkRectangle *dest)
69{
70 gint dest_x, dest_y;
71
72 g_return_if_fail (src1 != NULL);
73 g_return_if_fail (src2 != NULL);
74 g_return_if_fail (dest != NULL);
75
76 dest_x = MIN (src1->x, src2->x);
77 dest_y = MIN (src1->y, src2->y);
78 dest->width = MAX (src1->x + src1->width, src2->x + src2->width) - dest_x;
79 dest->height = MAX (src1->y + src1->height, src2->y + src2->height) - dest_y;
80 dest->x = dest_x;
81 dest->y = dest_y;
82}
83
84/**
85 * gdk_rectangle_intersect:
86 * @src1: a #GdkRectangle
87 * @src2: a #GdkRectangle
88 * @dest: (out caller-allocates) (allow-none): return location for the
89 * intersection of @src1 and @src2, or %NULL
90 *
91 * Calculates the intersection of two rectangles. It is allowed for
92 * @dest to be the same as either @src1 or @src2. If the rectangles
93 * do not intersect, @dest’s width and height is set to 0 and its x
94 * and y values are undefined. If you are only interested in whether
95 * the rectangles intersect, but not in the intersecting area itself,
96 * pass %NULL for @dest.
97 *
98 * Returns: %TRUE if the rectangles intersect.
99 */
100gboolean
101gdk_rectangle_intersect (const GdkRectangle *src1,
102 const GdkRectangle *src2,
103 GdkRectangle *dest)
104{
105 gint dest_x, dest_y;
106 gint dest_x2, dest_y2;
107 gint return_val;
108
109 g_return_val_if_fail (src1 != NULL, FALSE);
110 g_return_val_if_fail (src2 != NULL, FALSE);
111
112 return_val = FALSE;
113
114 dest_x = MAX (src1->x, src2->x);
115 dest_y = MAX (src1->y, src2->y);
116 dest_x2 = MIN (src1->x + src1->width, src2->x + src2->width);
117 dest_y2 = MIN (src1->y + src1->height, src2->y + src2->height);
118
119 if (dest_x2 > dest_x && dest_y2 > dest_y)
120 {
121 if (dest)
122 {
123 dest->x = dest_x;
124 dest->y = dest_y;
125 dest->width = dest_x2 - dest_x;
126 dest->height = dest_y2 - dest_y;
127 }
128 return_val = TRUE;
129 }
130 else if (dest)
131 {
132 dest->width = 0;
133 dest->height = 0;
134 }
135
136 return return_val;
137}
138
139/**
140 * gdk_rectangle_equal:
141 * @rect1: a #GdkRectangle
142 * @rect2: a #GdkRectangle
143 *
144 * Checks if the two given rectangles are equal.
145 *
146 * Returns: %TRUE if the rectangles are equal.
147 *
148 * Since: 3.20
149 */
150gboolean
151gdk_rectangle_equal (const GdkRectangle *rect1,
152 const GdkRectangle *rect2)
153{
154 return rect1->x == rect2->x
155 && rect1->y == rect2->y
156 && rect1->width == rect2->width
157 && rect1->height == rect2->height;
158}
159
160static GdkRectangle *
161gdk_rectangle_copy (const GdkRectangle *rectangle)
162{
163 GdkRectangle *result = g_new (GdkRectangle, 1);
164 *result = *rectangle;
165
166 return result;
167}
168
169/* Transforms between identical boxed types.
170 */
171static void
172gdk_rectangle_value_transform_rect (const GValue *src_value, GValue *dest_value)
173{
174 g_value_set_boxed (dest_value, g_value_get_boxed (src_value));
175}
176
177/* Allow GValue transformation between the identical structs
178 * cairo_rectangle_int_t and GdkRectangle.
179 */
180static void
181gdk_rectangle_register_value_transform_funcs (GType gtype_gdk_rectangle)
182{
183 /* This function is called from the first call to gdk_rectangle_get_type(),
184 * before g_once_init_leave() has been called.
185 * If gdk_rectangle_get_type() is called from here (e.g. via
186 * GDK_TYPE_RECTANGLE), the program will wait indefinitely at
187 * g_once_init_enter() in gdk_rectangle_get_type().
188 */
189 g_value_register_transform_func (CAIRO_GOBJECT_TYPE_RECTANGLE_INT,
190 gtype_gdk_rectangle,
191 gdk_rectangle_value_transform_rect);
192 g_value_register_transform_func (gtype_gdk_rectangle,
193 CAIRO_GOBJECT_TYPE_RECTANGLE_INT,
194 gdk_rectangle_value_transform_rect);
195}
196
197G_DEFINE_BOXED_TYPE_WITH_CODE (GdkRectangle, gdk_rectangle,
198 gdk_rectangle_copy,
199 g_free,
200 gdk_rectangle_register_value_transform_funcs (g_define_type_id))
201
202