src/cairo-surface-clipper.c

   1 /* cairo - a vector graphics library with display and print output
   2  *
   3  * Copyright © 2009 Chris Wilson
   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., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, 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 Red Hat, Inc.
  31  *
  32  * Contributor(s):
  33  *      Chris Wilson <chris@chris-wilson.co.uk>
  34  */
  35
  36 #include "cairoint.h"
  37
  38 #include "cairo-clip-inline.h"
  39 #include "cairo-surface-clipper-private.h"
  40
  41 /* A collection of routines to facilitate vector surface clipping */
  42
  43 /* XXX Eliminate repeated paths and nested clips */
  44
  45 static cairo_status_t
  46 _cairo_path_fixed_add_box (cairo_path_fixed_t *path,
  47                            const cairo_box_t *box)
  48 {
  49     cairo_status_t status;
  50
  51     status = _cairo_path_fixed_move_to (path, box->p1.x, box->p1.y);
  52     if (unlikely (status))
  53         return status;
  54
  55     status = _cairo_path_fixed_line_to (path, box->p2.x, box->p1.y);
  56     if (unlikely (status))
  57         return status;
  58
  59     status = _cairo_path_fixed_line_to (path, box->p2.x, box->p2.y);
  60     if (unlikely (status))
  61         return status;
  62
  63     status = _cairo_path_fixed_line_to (path, box->p1.x, box->p2.y);
  64     if (unlikely (status))
  65         return status;
  66
  67     return _cairo_path_fixed_close_path (path);
  68 }
  69
  70 static cairo_status_t
  71 _cairo_surface_clipper_intersect_clip_boxes (cairo_surface_clipper_t *clipper,
  72                                              const cairo_clip_t *clip)
  73 {
  74     cairo_path_fixed_t path;
  75     cairo_status_t status;
  76     int i;
  77
  78     if (clip->num_boxes == 0)
  79         return CAIRO_STATUS_SUCCESS;
  80
  81     /* Reconstruct the path for the clip boxes.
  82      * XXX maybe a new clipper callback?
  83      */
  84
  85     _cairo_path_fixed_init (&path);
  86     for (i = 0; i < clip->num_boxes; i++) {
  87         status = _cairo_path_fixed_add_box (&path, &clip->boxes[i]);
  88         if (unlikely (status)) {
  89             _cairo_path_fixed_fini (&path);
  90             return status;
  91         }
  92     }
  93
  94     status = clipper->intersect_clip_path (clipper, &path,
  95                                            CAIRO_FILL_RULE_WINDING,
  96                                            0.,
  97                                            CAIRO_ANTIALIAS_DEFAULT);
  98     _cairo_path_fixed_fini (&path);
  99
 100     return status;
 101 }
 102
 103 static cairo_status_t
 104 _cairo_surface_clipper_intersect_clip_path_recursive (cairo_surface_clipper_t *clipper,
 105                                                       cairo_clip_path_t *clip_path,
 106                                                       cairo_clip_path_t *end)
 107 {
 108     cairo_status_t status;
 109
 110     if (clip_path->prev != end) {
 111         status =
 112             _cairo_surface_clipper_intersect_clip_path_recursive (clipper,
 113                                                                   clip_path->prev,
 114                                                                   end);
 115         if (unlikely (status))
 116             return status;
 117     }
 118
 119     return clipper->intersect_clip_path (clipper,
 120                                          &clip_path->path,
 121                                          clip_path->fill_rule,
 122                                          clip_path->tolerance,
 123                                          clip_path->antialias);
 124 }
 125
 126 cairo_status_t
 127 _cairo_surface_clipper_set_clip (cairo_surface_clipper_t *clipper,
 128                                  const cairo_clip_t *clip)
 129 {
 130     cairo_status_t status;
 131     cairo_bool_t incremental = FALSE;
 132
 133     if (_cairo_clip_equal (clip, clipper->clip))
 134         return CAIRO_STATUS_SUCCESS;
 135
 136     /* all clipped out state should never propagate this far */
 137     assert (!_cairo_clip_is_all_clipped (clip));
 138
 139     /* XXX Is this an incremental clip? */
 140     if (clipper->clip && clip &&
 141         clip->num_boxes == clipper->clip->num_boxes &&
 142         memcmp (clip->boxes, clipper->clip->boxes,
 143                 sizeof (cairo_box_t) * clip->num_boxes) == 0)
 144     {
 145         cairo_clip_path_t *clip_path = clip->path;
 146         while (clip_path != NULL && clip_path != clipper->clip->path)
 147             clip_path = clip_path->prev;
 148
 149         if (clip_path) {
 150             incremental = TRUE;
 151             status = _cairo_surface_clipper_intersect_clip_path_recursive (clipper,
 152                                                                            clip->path,
 153                                                                            clipper->clip->path);
 154         }
 155     }
 156
 157     _cairo_clip_destroy (clipper->clip);
 158     clipper->clip = _cairo_clip_copy (clip);
 159
 160     if (incremental)
 161         return status;
 162
 163     status = clipper->intersect_clip_path (clipper, NULL, 0, 0, 0);
 164     if (unlikely (status))
 165         return status;
 166
 167     if (clip == NULL)
 168         return CAIRO_STATUS_SUCCESS;
 169
 170     status = _cairo_surface_clipper_intersect_clip_boxes (clipper, clip);
 171     if (unlikely (status))
 172         return status;
 173
 174     if (clip->path != NULL) {
 175             status = _cairo_surface_clipper_intersect_clip_path_recursive (clipper,
 176                                                                            clip->path,
 177                                                                            NULL);
 178     }
 179
 180     return status;
 181 }
 182
 183 void
 184 _cairo_surface_clipper_init (cairo_surface_clipper_t *clipper,
 185                              cairo_surface_clipper_intersect_clip_path_func_t func)
 186 {
 187     clipper->clip = NULL;
 188     clipper->intersect_clip_path = func;
 189 }
 190
 191 void
 192 _cairo_surface_clipper_reset (cairo_surface_clipper_t *clipper)
 193 {
 194     _cairo_clip_destroy (clipper->clip);
 195     clipper->clip = NULL;
 196 }