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  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. }
  197.