cairo/src/cairo-path-bounds.c

   1 /* cairo - a vector graphics library with display and print output
   2  *
   3  * Copyright © 2003 University of Southern California
   4  *
   5  * This library is free software; you can redistribute it and/or
   6  * modify it either under the terms of the GNU Lesser General Public
   7  * License version 2.1 as published by the Free Software Foundation
   8  * (the "LGPL") or, at your option, under the terms of the Mozilla
   9  * Public License Version 1.1 (the "MPL"). If you do not alter this
  10  * notice, a recipient may use your version of this file under either
  11  * the MPL or the LGPL.
  12  *
  13  * You should have received a copy of the LGPL along with this library
  14  * in the file COPYING-LGPL-2.1; if not, write to the Free Software
  15  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  16  * You should have received a copy of the MPL along with this library
  17  * in the file COPYING-MPL-1.1
  18  *
  19  * The contents of this file are subject to the Mozilla Public License
  20  * Version 1.1 (the "License"); you may not use this file except in
  21  * compliance with the License. You may obtain a copy of the License at
  22  * http://www.mozilla.org/MPL/
  23  *
  24  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
  25  * OF ANY KIND, either express or implied. See the LGPL or the MPL for
  26  * the specific language governing rights and limitations.
  27  *
  28  * The Original Code is the cairo graphics library.
  29  *
  30  * The Initial Developer of the Original Code is University of Southern
  31  * California.
  32  *
  33  * Contributor(s):
  34  *      Carl D. Worth <cworth@cworth.org>
  35  */
  36
  37 #include "cairoint.h"
  38
  39 typedef struct cairo_path_bounder {
  40     cairo_point_t move_to_point;
  41     cairo_bool_t has_move_to_point;
  42     cairo_bool_t has_point;
  43
  44     cairo_fixed_t min_x;
  45     cairo_fixed_t min_y;
  46     cairo_fixed_t max_x;
  47     cairo_fixed_t max_y;
  48 } cairo_path_bounder_t;
  49
  50 static void
  51 _cairo_path_bounder_init (cairo_path_bounder_t *bounder);
  52
  53 static void
  54 _cairo_path_bounder_fini (cairo_path_bounder_t *bounder);
  55
  56 static void
  57 _cairo_path_bounder_add_point (cairo_path_bounder_t *bounder, cairo_point_t *point);
  58
  59 static cairo_status_t
  60 _cairo_path_bounder_move_to (void *closure, cairo_point_t *point);
  61
  62 static cairo_status_t
  63 _cairo_path_bounder_line_to (void *closure, cairo_point_t *point);
  64
  65 static cairo_status_t
  66 _cairo_path_bounder_close_path (void *closure);
  67
  68 static void
  69 _cairo_path_bounder_init (cairo_path_bounder_t *bounder)
  70 {
  71     bounder->has_move_to_point = FALSE;
  72     bounder->has_point = FALSE;
  73 }
  74
  75 static void
  76 _cairo_path_bounder_fini (cairo_path_bounder_t *bounder)
  77 {
  78     bounder->has_move_to_point = FALSE;
  79     bounder->has_point = FALSE;
  80 }
  81
  82 static void
  83 _cairo_path_bounder_add_point (cairo_path_bounder_t *bounder, cairo_point_t *point)
  84 {
  85     if (bounder->has_point) {
  86         if (point->x < bounder->min_x)
  87             bounder->min_x = point->x;
  88
  89         if (point->y < bounder->min_y)
  90             bounder->min_y = point->y;
  91
  92         if (point->x > bounder->max_x)
  93             bounder->max_x = point->x;
  94
  95         if (point->y > bounder->max_y)
  96             bounder->max_y = point->y;
  97     } else {
  98         bounder->min_x = point->x;
  99         bounder->min_y = point->y;
 100         bounder->max_x = point->x;
 101         bounder->max_y = point->y;
 102
 103         bounder->has_point = TRUE;
 104     }
 105 }
 106
 107 static cairo_status_t
 108 _cairo_path_bounder_move_to (void *closure, cairo_point_t *point)
 109 {
 110     cairo_path_bounder_t *bounder = closure;
 111
 112     bounder->move_to_point = *point;
 113     bounder->has_move_to_point = TRUE;
 114
 115     return CAIRO_STATUS_SUCCESS;
 116 }
 117
 118 static cairo_status_t
 119 _cairo_path_bounder_line_to (void *closure, cairo_point_t *point)
 120 {
 121     cairo_path_bounder_t *bounder = closure;
 122
 123     if (bounder->has_move_to_point) {
 124         _cairo_path_bounder_add_point (bounder,
 125                                        &bounder->move_to_point);
 126         bounder->has_move_to_point = FALSE;
 127     }
 128
 129     _cairo_path_bounder_add_point (bounder, point);
 130
 131     return CAIRO_STATUS_SUCCESS;
 132 }
 133
 134 static cairo_status_t
 135 _cairo_path_bounder_close_path (void *closure)
 136 {
 137     return CAIRO_STATUS_SUCCESS;
 138 }
 139
 140 /* XXX: Perhaps this should compute a PixRegion rather than 4 doubles */
 141 cairo_status_t
 142 _cairo_path_fixed_bounds (cairo_path_fixed_t *path,
 143                           double *x1, double *y1,
 144                           double *x2, double *y2,
 145                           double tolerance)
 146 {
 147     cairo_path_bounder_t bounder;
 148     cairo_status_t status;
 149
 150     _cairo_path_bounder_init (&bounder);
 151
 152     status = _cairo_path_fixed_interpret_flat (path, CAIRO_DIRECTION_FORWARD,
 153                                                _cairo_path_bounder_move_to,
 154                                                _cairo_path_bounder_line_to,
 155                                                _cairo_path_bounder_close_path,
 156                                                &bounder,
 157                                                tolerance);
 158
 159     if (status == CAIRO_STATUS_SUCCESS && bounder.has_point) {
 160         *x1 = _cairo_fixed_to_double (bounder.min_x);
 161         *y1 = _cairo_fixed_to_double (bounder.min_y);
 162         *x2 = _cairo_fixed_to_double (bounder.max_x);
 163         *y2 = _cairo_fixed_to_double (bounder.max_y);
 164     } else {
 165         *x1 = 0.0;
 166         *y1 = 0.0;
 167         *x2 = 0.0;
 168         *y2 = 0.0;
 169     }
 170
 171     _cairo_path_bounder_fini (&bounder);
 172
 173     return status;
 174 }