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 * GdkRectangle:
33 * @x: the x coordinate of the top left corner
34 * @y: the y coordinate of the top left corner
35 * @width: the width of the rectangle
36 * @height: the height of the rectangle
37 *
38 * A `GdkRectangle` data type for representing rectangles.
39 *
40 * `GdkRectangle` is identical to `cairo_rectangle_t`. Together with Cairo’s
41 * `cairo_region_t` data type, these are the central types for representing
42 * sets of pixels.
43 *
44 * The intersection of two rectangles can be computed with
45 * [method@Gdk.Rectangle.intersect]; to find the union of two rectangles use
46 * [method@Gdk.Rectangle.union].
47 *
48 * The `cairo_region_t` type provided by Cairo is usually used for managing
49 * non-rectangular clipping of graphical operations.
50 *
51 * The Graphene library has a number of other data types for regions and
52 * volumes in 2D and 3D.
53 */
54
55
56/**
57 * gdk_rectangle_union:
58 * @src1: a `GdkRectangle`
59 * @src2: a `GdkRectangle`
60 * @dest: (out): return location for the union of @src1 and @src2
61 *
62 * Calculates the union of two rectangles.
63 *
64 * The union of rectangles @src1 and @src2 is the smallest rectangle which
65 * includes both @src1 and @src2 within it. It is allowed for @dest to be
66 * the same as either @src1 or @src2.
67 *
68 * Note that this function does not ignore 'empty' rectangles (ie. with
69 * zero width or height).
70 */
71void
72gdk_rectangle_union (const GdkRectangle *src1,
73 const GdkRectangle *src2,
74 GdkRectangle *dest)
75{
76 int dest_x, dest_y;
77
78 g_return_if_fail (src1 != NULL);
79 g_return_if_fail (src2 != NULL);
80 g_return_if_fail (dest != NULL);
81
82 dest_x = MIN (src1->x, src2->x);
83 dest_y = MIN (src1->y, src2->y);
84 dest->width = MAX (src1->x + src1->width, src2->x + src2->width) - dest_x;
85 dest->height = MAX (src1->y + src1->height, src2->y + src2->height) - dest_y;
86 dest->x = dest_x;
87 dest->y = dest_y;
88}
89
90/**
91 * gdk_rectangle_intersect:
92 * @src1: a `GdkRectangle`
93 * @src2: a `GdkRectangle`
94 * @dest: (out caller-allocates) (optional): return location for the
95 * intersection of @src1 and @src2
96 *
97 * Calculates the intersection of two rectangles.
98 *
99 * It is allowed for @dest to be the same as either @src1 or @src2.
100 * If the rectangles do not intersect, @dest’s width and height is set
101 * to 0 and its x and y values are undefined. If you are only interested
102 * in whether the rectangles intersect, but not in the intersecting area
103 * itself, pass %NULL for @dest.
104 *
105 * Returns: %TRUE if the rectangles intersect.
106 */
107gboolean
108gdk_rectangle_intersect (const GdkRectangle *src1,
109 const GdkRectangle *src2,
110 GdkRectangle *dest)
111{
112 int dest_x, dest_y;
113 int dest_x2, dest_y2;
114 int return_val;
115
116 g_return_val_if_fail (src1 != NULL, FALSE);
117 g_return_val_if_fail (src2 != NULL, FALSE);
118
119 return_val = FALSE;
120
121 dest_x = MAX (src1->x, src2->x);
122 dest_y = MAX (src1->y, src2->y);
123 dest_x2 = MIN (src1->x + src1->width, src2->x + src2->width);
124 dest_y2 = MIN (src1->y + src1->height, src2->y + src2->height);
125
126 if (dest_x2 > dest_x && dest_y2 > dest_y)
127 {
128 if (dest)
129 {
130 dest->x = dest_x;
131 dest->y = dest_y;
132 dest->width = dest_x2 - dest_x;
133 dest->height = dest_y2 - dest_y;
134 }
135 return_val = TRUE;
136 }
137 else if (dest)
138 {
139 dest->width = 0;
140 dest->height = 0;
141 }
142
143 return return_val;
144}
145
146/**
147 * gdk_rectangle_contains_point:
148 * @rect: a `GdkRectangle`
149 * @x: X coordinate
150 * @y: Y coordinate
151 *
152 * Returns %TRUE if @rect contains the point described by @x and @y.
153 *
154 * Returns: %TRUE if @rect contains the point
155 **/
156gboolean
157gdk_rectangle_contains_point (const GdkRectangle *rect,
158 int x,
159 int y)
160{
161 g_return_val_if_fail (rect != NULL, FALSE);
162
163 return x >= rect->x &&
164 x < rect->x + rect->width &&
165 y >= rect->y &&
166 y < rect->y + rect->height;
167}
168
169/**
170 * gdk_rectangle_equal:
171 * @rect1: a `GdkRectangle`
172 * @rect2: a `GdkRectangle`
173 *
174 * Checks if the two given rectangles are equal.
175 *
176 * Returns: %TRUE if the rectangles are equal.
177 */
178gboolean
179gdk_rectangle_equal (const GdkRectangle *rect1,
180 const GdkRectangle *rect2)
181{
182 return rect1->x == rect2->x
183 && rect1->y == rect2->y
184 && rect1->width == rect2->width
185 && rect1->height == rect2->height;
186}
187
188static GdkRectangle *
189gdk_rectangle_copy (const GdkRectangle *rectangle)
190{
191 GdkRectangle *result = g_new (GdkRectangle, 1);
192 *result = *rectangle;
193
194 return result;
195}
196
197/* Transforms between identical boxed types.
198 */
199static void
200gdk_rectangle_value_transform_rect (const GValue *src_value, GValue *dest_value)
201{
202 g_value_set_boxed (value: dest_value, v_boxed: g_value_get_boxed (value: src_value));
203}
204
205/* Allow GValue transformation between the identical structs
206 * cairo_rectangle_int_t and GdkRectangle.
207 */
208static void
209gdk_rectangle_register_value_transform_funcs (GType gtype_gdk_rectangle)
210{
211 /* This function is called from the first call to gdk_rectangle_get_type(),
212 * before g_once_init_leave() has been called.
213 * If gdk_rectangle_get_type() is called from here (e.g. via
214 * GDK_TYPE_RECTANGLE), the program will wait indefinitely at
215 * g_once_init_enter() in gdk_rectangle_get_type().
216 */
217 g_value_register_transform_func (CAIRO_GOBJECT_TYPE_RECTANGLE_INT,
218 dest_type: gtype_gdk_rectangle,
219 transform_func: gdk_rectangle_value_transform_rect);
220 g_value_register_transform_func (src_type: gtype_gdk_rectangle,
221 CAIRO_GOBJECT_TYPE_RECTANGLE_INT,
222 transform_func: gdk_rectangle_value_transform_rect);
223}
224
225G_DEFINE_BOXED_TYPE_WITH_CODE (GdkRectangle, gdk_rectangle,
226 gdk_rectangle_copy,
227 g_free,
228 gdk_rectangle_register_value_transform_funcs (g_define_type_id))
229
230

source code of gtk/gdk/gdkrectangle.c