1 /* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */
2 /* cairo - a vector graphics library with display and print output
4 * Copyright © 2002 University of Southern California
5 * Copyright © 2005 Red Hat, Inc.
6 * Copyright © 2006 Red Hat, Inc.
8 * This library is free software; you can redistribute it and/or
9 * modify it either under the terms of the GNU Lesser General Public
10 * License version 2.1 as published by the Free Software Foundation
11 * (the "LGPL") or, at your option, under the terms of the Mozilla
12 * Public License Version 1.1 (the "MPL"). If you do not alter this
13 * notice, a recipient may use your version of this file under either
14 * the MPL or the LGPL.
16 * You should have received a copy of the LGPL along with this library
17 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
19 * You should have received a copy of the MPL along with this library
20 * in the file COPYING-MPL-1.1
22 * The contents of this file are subject to the Mozilla Public License
23 * Version 1.1 (the "License"); you may not use this file except in
24 * compliance with the License. You may obtain a copy of the License at
25 * http://www.mozilla.org/MPL/
27 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
28 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
29 * the specific language governing rights and limitations.
31 * The Original Code is the cairo graphics library.
33 * The Initial Developer of the Original Code is University of Southern
37 * Carl D. Worth <cworth@cworth.org>
42 #include "cairo-box-inline.h"
44 const cairo_rectangle_int_t _cairo_empty_rectangle = { 0, 0, 0, 0 };
45 const cairo_rectangle_int_t _cairo_unbounded_rectangle = {
46 CAIRO_RECT_INT_MIN, CAIRO_RECT_INT_MIN,
47 CAIRO_RECT_INT_MAX - CAIRO_RECT_INT_MIN,
48 CAIRO_RECT_INT_MAX - CAIRO_RECT_INT_MIN,
52 _cairo_box_from_doubles (cairo_box_t *box,
53 double *x1, double *y1,
54 double *x2, double *y2)
56 box->p1.x = _cairo_fixed_from_double (*x1);
57 box->p1.y = _cairo_fixed_from_double (*y1);
58 box->p2.x = _cairo_fixed_from_double (*x2);
59 box->p2.y = _cairo_fixed_from_double (*y2);
63 _cairo_box_to_doubles (const cairo_box_t *box,
64 double *x1, double *y1,
65 double *x2, double *y2)
67 *x1 = _cairo_fixed_to_double (box->p1.x);
68 *y1 = _cairo_fixed_to_double (box->p1.y);
69 *x2 = _cairo_fixed_to_double (box->p2.x);
70 *y2 = _cairo_fixed_to_double (box->p2.y);
74 _cairo_box_from_rectangle (cairo_box_t *box,
75 const cairo_rectangle_int_t *rect)
77 box->p1.x = _cairo_fixed_from_int (rect->x);
78 box->p1.y = _cairo_fixed_from_int (rect->y);
79 box->p2.x = _cairo_fixed_from_int (rect->x + rect->width);
80 box->p2.y = _cairo_fixed_from_int (rect->y + rect->height);
84 _cairo_boxes_get_extents (const cairo_box_t *boxes,
90 assert (num_boxes > 0);
93 for (n = 1; n < num_boxes; n++) {
94 if (boxes[n].p1.x < extents->p1.x)
95 extents->p1.x = boxes[n].p1.x;
96 if (boxes[n].p2.x > extents->p2.x)
97 extents->p2.x = boxes[n].p2.x;
99 if (boxes[n].p1.y < extents->p1.y)
100 extents->p1.y = boxes[n].p1.y;
101 if (boxes[n].p2.y > extents->p2.y)
102 extents->p2.y = boxes[n].p2.y;
106 /* XXX We currently have a confusing mix of boxes and rectangles as
107 * exemplified by this function. A #cairo_box_t is a rectangular area
108 * represented by the coordinates of the upper left and lower right
109 * corners, expressed in fixed point numbers. A #cairo_rectangle_int_t is
110 * also a rectangular area, but represented by the upper left corner
111 * and the width and the height, as integer numbers.
113 * This function converts a #cairo_box_t to a #cairo_rectangle_int_t by
114 * increasing the area to the nearest integer coordinates. We should
115 * standardize on #cairo_rectangle_fixed_t and #cairo_rectangle_int_t, and
116 * this function could be renamed to the more reasonable
117 * _cairo_rectangle_fixed_round.
121 _cairo_box_round_to_rectangle (const cairo_box_t *box,
122 cairo_rectangle_int_t *rectangle)
124 rectangle->x = _cairo_fixed_integer_floor (box->p1.x);
125 rectangle->y = _cairo_fixed_integer_floor (box->p1.y);
126 rectangle->width = _cairo_fixed_integer_ceil (box->p2.x) - rectangle->x;
127 rectangle->height = _cairo_fixed_integer_ceil (box->p2.y) - rectangle->y;
131 _cairo_rectangle_intersect (cairo_rectangle_int_t *dst,
132 const cairo_rectangle_int_t *src)
136 x1 = MAX (dst->x, src->x);
137 y1 = MAX (dst->y, src->y);
138 /* Beware the unsigned promotion, fortunately we have bits to spare
139 * as (CAIRO_RECT_INT_MAX - CAIRO_RECT_INT_MIN) < UINT_MAX
141 x2 = MIN (dst->x + (int) dst->width, src->x + (int) src->width);
142 y2 = MIN (dst->y + (int) dst->height, src->y + (int) src->height);
144 if (x1 >= x2 || y1 >= y2) {
154 dst->width = x2 - x1;
155 dst->height = y2 - y1;
161 /* Extends the dst rectangle to also contain src.
162 * If one of the rectangles is empty, the result is undefined
165 _cairo_rectangle_union (cairo_rectangle_int_t *dst,
166 const cairo_rectangle_int_t *src)
170 x1 = MIN (dst->x, src->x);
171 y1 = MIN (dst->y, src->y);
172 /* Beware the unsigned promotion, fortunately we have bits to spare
173 * as (CAIRO_RECT_INT_MAX - CAIRO_RECT_INT_MIN) < UINT_MAX
175 x2 = MAX (dst->x + (int) dst->width, src->x + (int) src->width);
176 y2 = MAX (dst->y + (int) dst->height, src->y + (int) src->height);
180 dst->width = x2 - x1;
181 dst->height = y2 - y1;
184 #define P1x (line->p1.x)
185 #define P1y (line->p1.y)
186 #define P2x (line->p2.x)
187 #define P2y (line->p2.y)
188 #define B1x (box->p1.x)
189 #define B1y (box->p1.y)
190 #define B2x (box->p2.x)
191 #define B2y (box->p2.y)
194 * Check whether any part of line intersects box. This function essentially
195 * computes whether the ray starting at line->p1 in the direction of line->p2
196 * intersects the box before it reaches p2. Normally, this is done
197 * by dividing by the lengths of the line projected onto each axis. Because
198 * we're in fixed point, this function does a bit more work to avoid having to
199 * do the division -- we don't care about the actual intersection point, so
200 * it's of no interest to us.
204 _cairo_box_intersects_line_segment (cairo_box_t *box, cairo_line_t *line)
206 cairo_fixed_t t1=0, t2=0, t3=0, t4=0;
207 cairo_int64_t t1y, t2y, t3x, t4x;
209 cairo_fixed_t xlen, ylen;
211 if (_cairo_box_contains_point (box, &line->p1) ||
212 _cairo_box_contains_point (box, &line->p2))
228 if ((t1 < 0 || t1 > xlen) &&
229 (t2 < 0 || t2 > xlen))
232 /* Fully vertical line -- check that X is in bounds */
233 if (P1x < B1x || P1x > B2x)
247 if ((t3 < 0 || t3 > ylen) &&
248 (t4 < 0 || t4 > ylen))
251 /* Fully horizontal line -- check Y */
252 if (P1y < B1y || P1y > B2y)
256 /* If we had a horizontal or vertical line, then it's already been checked */
257 if (P1x == P2x || P1y == P2y)
260 /* Check overlap. Note that t1 < t2 and t3 < t4 here. */
261 t1y = _cairo_int32x32_64_mul (t1, ylen);
262 t2y = _cairo_int32x32_64_mul (t2, ylen);
263 t3x = _cairo_int32x32_64_mul (t3, xlen);
264 t4x = _cairo_int32x32_64_mul (t4, xlen);
266 if (_cairo_int64_lt(t1y, t4x) &&
267 _cairo_int64_lt(t3x, t2y))
273 static cairo_status_t
274 _cairo_box_add_spline_point (void *closure,
275 const cairo_point_t *point,
276 const cairo_slope_t *tangent)
278 _cairo_box_add_point (closure, point);
280 return CAIRO_STATUS_SUCCESS;
283 /* assumes a has been previously added */
285 _cairo_box_add_curve_to (cairo_box_t *extents,
286 const cairo_point_t *a,
287 const cairo_point_t *b,
288 const cairo_point_t *c,
289 const cairo_point_t *d)
291 _cairo_box_add_point (extents, d);
292 if (!_cairo_box_contains_point (extents, b) ||
293 !_cairo_box_contains_point (extents, c))
295 cairo_status_t status;
297 status = _cairo_spline_bound (_cairo_box_add_spline_point,
298 extents, a, b, c, d);
299 assert (status == CAIRO_STATUS_SUCCESS);
304 _cairo_rectangle_int_from_double (cairo_rectangle_int_t *recti,
305 const cairo_rectangle_t *rectf)
307 recti->x = floor (rectf->x);
308 recti->y = floor (rectf->y);
309 recti->width = ceil (rectf->x + rectf->width) - floor (rectf->x);
310 recti->height = ceil (rectf->y + rectf->height) - floor (rectf->y);