source/libs/cairo/cairo-src/src/cairo-clip-polygon.c

   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
   3  *
   4  * Copyright © 2011 Intel Corporation
   5  *
   6  * This library is free software; you can redistribute it and/or
   7  * modify it either under the terms of the GNU Lesser General Public
   8  * License version 2.1 as published by the Free Software Foundation
   9  * (the "LGPL") or, at your option, under the terms of the Mozilla
  10  * Public License Version 1.1 (the "MPL"). If you do not alter this
  11  * notice, a recipient may use your version of this file under either
  12  * the MPL or the LGPL.
  13  *
  14  * You should have received a copy of the LGPL along with this library
  15  * in the file COPYING-LGPL-2.1; if not, write to the Free Software
  16  * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
  17  * You should have received a copy of the MPL along with this library
  18  * in the file COPYING-MPL-1.1
  19  *
  20  * The contents of this file are subject to the Mozilla Public License
  21  * Version 1.1 (the "License"); you may not use this file except in
  22  * compliance with the License. You may obtain a copy of the License at
  23  * http://www.mozilla.org/MPL/
  24  *
  25  * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
  26  * OF ANY KIND, either express or implied. See the LGPL or the MPL for
  27  * the specific language governing rights and limitations.
  28  *
  29  * The Original Code is the cairo graphics library.
  30  *
  31  * The Initial Developer of the Original Code is University of Southern
  32  * California.
  33  *
  34  * Contributor(s):
  35  *      Chris Wilson <chris@chris-wilson.co.uk>
  36  */
  37
  38 #include "cairoint.h"
  39 #include "cairo-clip-inline.h"
  40 #include "cairo-clip-private.h"
  41 #include "cairo-error-private.h"
  42 #include "cairo-freed-pool-private.h"
  43 #include "cairo-gstate-private.h"
  44 #include "cairo-path-fixed-private.h"
  45 #include "cairo-pattern-private.h"
  46 #include "cairo-composite-rectangles-private.h"
  47 #include "cairo-region-private.h"
  48
  49 static cairo_bool_t
  50 can_convert_to_polygon (const cairo_clip_t *clip)
  51 {
  52     cairo_clip_path_t *clip_path = clip->path;
  53     cairo_antialias_t antialias = clip_path->antialias;
  54
  55     while ((clip_path = clip_path->prev) != NULL) {
  56         if (clip_path->antialias != antialias)
  57             return FALSE;
  58     }
  59
  60     return TRUE;
  61 }
  62
  63 cairo_int_status_t
  64 _cairo_clip_get_polygon (const cairo_clip_t *clip,
  65                          cairo_polygon_t *polygon,
  66                          cairo_fill_rule_t *fill_rule,
  67                          cairo_antialias_t *antialias)
  68 {
  69     cairo_status_t status;
  70     cairo_clip_path_t *clip_path;
  71
  72     if (_cairo_clip_is_all_clipped (clip)) {
  73         _cairo_polygon_init (polygon, NULL, 0);
  74         return CAIRO_INT_STATUS_SUCCESS;
  75     }
  76
  77     /* If there is no clip, we need an infinite polygon */
  78     assert (clip && (clip->path || clip->num_boxes));
  79
  80     if (clip->path == NULL) {
  81         *fill_rule = CAIRO_FILL_RULE_WINDING;
  82         *antialias = CAIRO_ANTIALIAS_DEFAULT;
  83         return _cairo_polygon_init_box_array (polygon,
  84                                               clip->boxes,
  85                                               clip->num_boxes);
  86     }
  87
  88     /* check that residual is all of the same type/tolerance */
  89     if (! can_convert_to_polygon (clip))
  90         return CAIRO_INT_STATUS_UNSUPPORTED;
  91
  92     if (clip->num_boxes < 2)
  93         _cairo_polygon_init_with_clip (polygon, clip);
  94     else
  95         _cairo_polygon_init_with_clip (polygon, NULL);
  96
  97     clip_path = clip->path;
  98     *fill_rule = clip_path->fill_rule;
  99     *antialias = clip_path->antialias;
 100
 101     status = _cairo_path_fixed_fill_to_polygon (&clip_path->path,
 102                                                 clip_path->tolerance,
 103                                                 polygon);
 104     if (unlikely (status))
 105         goto err;
 106
 107     if (clip->num_boxes > 1) {
 108         status = _cairo_polygon_intersect_with_boxes (polygon, fill_rule,
 109                                                       clip->boxes, clip->num_boxes);
 110         if (unlikely (status))
 111             goto err;
 112     }
 113
 114     polygon->limits = NULL;
 115     polygon->num_limits = 0;
 116
 117     while ((clip_path = clip_path->prev) != NULL) {
 118         cairo_polygon_t next;
 119
 120         _cairo_polygon_init (&next, NULL, 0);
 121         status = _cairo_path_fixed_fill_to_polygon (&clip_path->path,
 122                                                     clip_path->tolerance,
 123                                                     &next);
 124         if (likely (status == CAIRO_STATUS_SUCCESS))
 125                 status = _cairo_polygon_intersect (polygon, *fill_rule,
 126                                                    &next, clip_path->fill_rule);
 127         _cairo_polygon_fini (&next);
 128         if (unlikely (status))
 129             goto err;
 130
 131         *fill_rule = CAIRO_FILL_RULE_WINDING;
 132     }
 133
 134     return CAIRO_STATUS_SUCCESS;
 135
 136 err:
 137     _cairo_polygon_fini (polygon);
 138     return status;
 139 }
 140
 141 cairo_bool_t
 142 _cairo_clip_is_polygon (const cairo_clip_t *clip)
 143 {
 144     if (_cairo_clip_is_all_clipped (clip))
 145         return TRUE;
 146
 147     /* If there is no clip, we need an infinite polygon */
 148     if (clip == NULL)
 149         return FALSE;
 150
 151     if (clip->path == NULL)
 152         return TRUE;
 153
 154     /* check that residual is all of the same type/tolerance */
 155     return can_convert_to_polygon (clip);
 156 }