summaryrefslogtreecommitdiff
path: root/libs/cairo-1.16.0/src/cairo-clip.c
blob: d499bf0adece001705ea02e26ebe2aa9093c856c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
/* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */
/* cairo - a vector graphics library with display and print output
 *
 * Copyright © 2002 University of Southern California
 * Copyright © 2005 Red Hat, Inc.
 * Copyright © 2009 Chris Wilson
 *
 * This library is free software; you can redistribute it and/or
 * modify it either under the terms of the GNU Lesser General Public
 * License version 2.1 as published by the Free Software Foundation
 * (the "LGPL") or, at your option, under the terms of the Mozilla
 * Public License Version 1.1 (the "MPL"). If you do not alter this
 * notice, a recipient may use your version of this file under either
 * the MPL or the LGPL.
 *
 * You should have received a copy of the LGPL along with this library
 * in the file COPYING-LGPL-2.1; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
 * You should have received a copy of the MPL along with this library
 * in the file COPYING-MPL-1.1
 *
 * The contents of this file are subject to the Mozilla Public License
 * Version 1.1 (the "License"); you may not use this file except in
 * compliance with the License. You may obtain a copy of the License at
 * http://www.mozilla.org/MPL/
 *
 * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
 * OF ANY KIND, either express or implied. See the LGPL or the MPL for
 * the specific language governing rights and limitations.
 *
 * The Original Code is the cairo graphics library.
 *
 * The Initial Developer of the Original Code is University of Southern
 * California.
 *
 * Contributor(s):
 *	Carl D. Worth <cworth@cworth.org>
 *	Kristian Høgsberg <krh@redhat.com>
 *	Chris Wilson <chris@chris-wilson.co.uk>
 */

#include "cairoint.h"
#include "cairo-clip-inline.h"
#include "cairo-clip-private.h"
#include "cairo-error-private.h"
#include "cairo-freed-pool-private.h"
#include "cairo-gstate-private.h"
#include "cairo-path-fixed-private.h"
#include "cairo-pattern-private.h"
#include "cairo-composite-rectangles-private.h"
#include "cairo-region-private.h"

static freed_pool_t clip_path_pool;
static freed_pool_t clip_pool;

const cairo_clip_t __cairo_clip_all;

static cairo_clip_path_t *
_cairo_clip_path_create (cairo_clip_t *clip)
{
    cairo_clip_path_t *clip_path;

    clip_path = _freed_pool_get (&clip_path_pool);
    if (unlikely (clip_path == NULL)) {
	clip_path = _cairo_malloc (sizeof (cairo_clip_path_t));
	if (unlikely (clip_path == NULL))
	    return NULL;
    }

    CAIRO_REFERENCE_COUNT_INIT (&clip_path->ref_count, 1);

    clip_path->prev = clip->path;
    clip->path = clip_path;

    return clip_path;
}

cairo_clip_path_t *
_cairo_clip_path_reference (cairo_clip_path_t *clip_path)
{
    assert (CAIRO_REFERENCE_COUNT_HAS_REFERENCE (&clip_path->ref_count));

    _cairo_reference_count_inc (&clip_path->ref_count);

    return clip_path;
}

void
_cairo_clip_path_destroy (cairo_clip_path_t *clip_path)
{
    assert (CAIRO_REFERENCE_COUNT_HAS_REFERENCE (&clip_path->ref_count));

    if (! _cairo_reference_count_dec_and_test (&clip_path->ref_count))
	return;

    _cairo_path_fixed_fini (&clip_path->path);

    if (clip_path->prev != NULL)
	_cairo_clip_path_destroy (clip_path->prev);

    _freed_pool_put (&clip_path_pool, clip_path);
}

cairo_clip_t *
_cairo_clip_create (void)
{
    cairo_clip_t *clip;

    clip = _freed_pool_get (&clip_pool);
    if (unlikely (clip == NULL)) {
	clip = _cairo_malloc (sizeof (cairo_clip_t));
	if (unlikely (clip == NULL))
	    return NULL;
    }

    clip->extents = _cairo_unbounded_rectangle;

    clip->path = NULL;
    clip->boxes = NULL;
    clip->num_boxes = 0;
    clip->region = NULL;
    clip->is_region = FALSE;

    return clip;
}

void
_cairo_clip_destroy (cairo_clip_t *clip)
{
    if (clip == NULL || _cairo_clip_is_all_clipped (clip))
	return;

    if (clip->path != NULL)
	_cairo_clip_path_destroy (clip->path);

    if (clip->boxes != &clip->embedded_box)
	free (clip->boxes);
    cairo_region_destroy (clip->region);

    _freed_pool_put (&clip_pool, clip);
}

cairo_clip_t *
_cairo_clip_copy (const cairo_clip_t *clip)
{
    cairo_clip_t *copy;

    if (clip == NULL || _cairo_clip_is_all_clipped (clip))
	return (cairo_clip_t *) clip;

    copy = _cairo_clip_create ();

    if (clip->path)
	copy->path = _cairo_clip_path_reference (clip->path);

    if (clip->num_boxes) {
	if (clip->num_boxes == 1) {
	    copy->boxes = &copy->embedded_box;
	} else {
	    copy->boxes = _cairo_malloc_ab (clip->num_boxes, sizeof (cairo_box_t));
	    if (unlikely (copy->boxes == NULL))
		return _cairo_clip_set_all_clipped (copy);
	}

	memcpy (copy->boxes, clip->boxes,
		clip->num_boxes * sizeof (cairo_box_t));
	copy->num_boxes = clip->num_boxes;
    }

    copy->extents = clip->extents;
    copy->region = cairo_region_reference (clip->region);
    copy->is_region = clip->is_region;

    return copy;
}

cairo_clip_t *
_cairo_clip_copy_path (const cairo_clip_t *clip)
{
    cairo_clip_t *copy;

    if (clip == NULL || _cairo_clip_is_all_clipped (clip))
	return (cairo_clip_t *) clip;

    assert (clip->num_boxes);

    copy = _cairo_clip_create ();
    copy->extents = clip->extents;
    if (clip->path)
	copy->path = _cairo_clip_path_reference (clip->path);

    return copy;
}

cairo_clip_t *
_cairo_clip_copy_region (const cairo_clip_t *clip)
{
    cairo_clip_t *copy;
    int i;

    if (clip == NULL || _cairo_clip_is_all_clipped (clip))
	return (cairo_clip_t *) clip;

    assert (clip->num_boxes);

    copy = _cairo_clip_create ();
    copy->extents = clip->extents;

    if (clip->num_boxes == 1) {
	copy->boxes = &copy->embedded_box;
    } else {
	copy->boxes = _cairo_malloc_ab (clip->num_boxes, sizeof (cairo_box_t));
	if (unlikely (copy->boxes == NULL))
	    return _cairo_clip_set_all_clipped (copy);
    }

    for (i = 0; i < clip->num_boxes; i++) {
	copy->boxes[i].p1.x = _cairo_fixed_floor (clip->boxes[i].p1.x);
	copy->boxes[i].p1.y = _cairo_fixed_floor (clip->boxes[i].p1.y);
	copy->boxes[i].p2.x = _cairo_fixed_ceil (clip->boxes[i].p2.x);
	copy->boxes[i].p2.y = _cairo_fixed_ceil (clip->boxes[i].p2.y);
    }
    copy->num_boxes = clip->num_boxes;

    copy->region = cairo_region_reference (clip->region);
    copy->is_region = TRUE;

    return copy;
}

cairo_clip_t *
_cairo_clip_intersect_path (cairo_clip_t       *clip,
			    const cairo_path_fixed_t *path,
			    cairo_fill_rule_t   fill_rule,
			    double              tolerance,
			    cairo_antialias_t   antialias)
{
    cairo_clip_path_t *clip_path;
    cairo_status_t status;
    cairo_rectangle_int_t extents;
    cairo_box_t box;

    if (_cairo_clip_is_all_clipped (clip))
	return clip;

    /* catch the empty clip path */
    if (_cairo_path_fixed_fill_is_empty (path))
	return _cairo_clip_set_all_clipped (clip);

    if (_cairo_path_fixed_is_box (path, &box)) {
	if (antialias == CAIRO_ANTIALIAS_NONE) {
	    box.p1.x = _cairo_fixed_round_down (box.p1.x);
	    box.p1.y = _cairo_fixed_round_down (box.p1.y);
	    box.p2.x = _cairo_fixed_round_down (box.p2.x);
	    box.p2.y = _cairo_fixed_round_down (box.p2.y);
	}

	return _cairo_clip_intersect_box (clip, &box);
    }
    if (_cairo_path_fixed_fill_is_rectilinear (path))
	return _cairo_clip_intersect_rectilinear_path (clip, path,
						       fill_rule, antialias);

    _cairo_path_fixed_approximate_clip_extents (path, &extents);
    if (extents.width == 0 || extents.height == 0)
	return _cairo_clip_set_all_clipped (clip);

    clip = _cairo_clip_intersect_rectangle (clip, &extents);
    if (_cairo_clip_is_all_clipped (clip))
	return clip;

    clip_path = _cairo_clip_path_create (clip);
    if (unlikely (clip_path == NULL))
	return _cairo_clip_set_all_clipped (clip);

    status = _cairo_path_fixed_init_copy (&clip_path->path, path);
    if (unlikely (status))
	return _cairo_clip_set_all_clipped (clip);

    clip_path->fill_rule = fill_rule;
    clip_path->tolerance = tolerance;
    clip_path->antialias = antialias;

    if (clip->region) {
	cairo_region_destroy (clip->region);
	clip->region = NULL;
    }

    clip->is_region = FALSE;
    return clip;
}

static cairo_clip_t *
_cairo_clip_intersect_clip_path (cairo_clip_t *clip,
				 const cairo_clip_path_t *clip_path)
{
    if (clip_path->prev)
	clip = _cairo_clip_intersect_clip_path (clip, clip_path->prev);

    return _cairo_clip_intersect_path (clip,
				       &clip_path->path,
				       clip_path->fill_rule,
				       clip_path->tolerance,
				       clip_path->antialias);
}

cairo_clip_t *
_cairo_clip_intersect_clip (cairo_clip_t *clip,
			    const cairo_clip_t *other)
{
    if (_cairo_clip_is_all_clipped (clip))
	return clip;

    if (other == NULL)
	return clip;

    if (clip == NULL)
	return _cairo_clip_copy (other);

    if (_cairo_clip_is_all_clipped (other))
	return _cairo_clip_set_all_clipped (clip);

    if (! _cairo_rectangle_intersect (&clip->extents, &other->extents))
	return _cairo_clip_set_all_clipped (clip);

    if (other->num_boxes) {
	cairo_boxes_t boxes;

	_cairo_boxes_init_for_array (&boxes, other->boxes, other->num_boxes);
	clip = _cairo_clip_intersect_boxes (clip, &boxes);
    }

    if (! _cairo_clip_is_all_clipped (clip)) {
	if (other->path) {
	    if (clip->path == NULL)
		clip->path = _cairo_clip_path_reference (other->path);
	    else
		clip = _cairo_clip_intersect_clip_path (clip, other->path);
	}
    }

    if (clip->region) {
	cairo_region_destroy (clip->region);
	clip->region = NULL;
    }
    clip->is_region = FALSE;

    return clip;
}

cairo_bool_t
_cairo_clip_equal (const cairo_clip_t *clip_a,
		   const cairo_clip_t *clip_b)
{
    const cairo_clip_path_t *cp_a, *cp_b;

    /* are both all-clipped or no-clip? */
    if (clip_a == clip_b)
	return TRUE;

    /* or just one of them? */
    if (clip_a == NULL || clip_b == NULL ||
	_cairo_clip_is_all_clipped (clip_a) ||
	_cairo_clip_is_all_clipped (clip_b))
    {
	return FALSE;
    }

    /* We have a pair of normal clips, check their contents */

    if (clip_a->num_boxes != clip_b->num_boxes)
	return FALSE;

    if (memcmp (clip_a->boxes, clip_b->boxes,
		sizeof (cairo_box_t) * clip_a->num_boxes))
	return FALSE;

    cp_a = clip_a->path;
    cp_b = clip_b->path;
    while (cp_a && cp_b) {
	if (cp_a == cp_b)
	    return TRUE;

	/* XXX compare reduced polygons? */

	if (cp_a->antialias != cp_b->antialias)
	    return FALSE;

	if (cp_a->tolerance != cp_b->tolerance)
	    return FALSE;

	if (cp_a->fill_rule != cp_b->fill_rule)
	    return FALSE;

	if (! _cairo_path_fixed_equal (&cp_a->path,
				       &cp_b->path))
	    return FALSE;

	cp_a = cp_a->prev;
	cp_b = cp_b->prev;
    }

    return cp_a == NULL && cp_b == NULL;
}

static cairo_clip_t *
_cairo_clip_path_copy_with_translation (cairo_clip_t      *clip,
					cairo_clip_path_t *other_path,
					int fx, int fy)
{
    cairo_status_t status;
    cairo_clip_path_t *clip_path;

    if (other_path->prev != NULL)
	clip = _cairo_clip_path_copy_with_translation (clip, other_path->prev,
						       fx, fy);
    if (_cairo_clip_is_all_clipped (clip))
	return clip;

    clip_path = _cairo_clip_path_create (clip);
    if (unlikely (clip_path == NULL))
	return _cairo_clip_set_all_clipped (clip);

    status = _cairo_path_fixed_init_copy (&clip_path->path,
					  &other_path->path);
    if (unlikely (status))
	return _cairo_clip_set_all_clipped (clip);

    _cairo_path_fixed_translate (&clip_path->path, fx, fy);

    clip_path->fill_rule = other_path->fill_rule;
    clip_path->tolerance = other_path->tolerance;
    clip_path->antialias = other_path->antialias;

    return clip;
}

cairo_clip_t *
_cairo_clip_translate (cairo_clip_t *clip, int tx, int ty)
{
    int fx, fy, i;
    cairo_clip_path_t *clip_path;

    if (clip == NULL || _cairo_clip_is_all_clipped (clip))
	return clip;

    if (tx == 0 && ty == 0)
	return clip;

    fx = _cairo_fixed_from_int (tx);
    fy = _cairo_fixed_from_int (ty);

    for (i = 0; i < clip->num_boxes; i++) {
	clip->boxes[i].p1.x += fx;
	clip->boxes[i].p2.x += fx;
	clip->boxes[i].p1.y += fy;
	clip->boxes[i].p2.y += fy;
    }

    clip->extents.x += tx;
    clip->extents.y += ty;

    if (clip->path == NULL)
	return clip;

    clip_path = clip->path;
    clip->path = NULL;
    clip = _cairo_clip_path_copy_with_translation (clip, clip_path, fx, fy);
    _cairo_clip_path_destroy (clip_path);

    return clip;
}

static cairo_status_t
_cairo_path_fixed_add_box (cairo_path_fixed_t *path,
			   const cairo_box_t *box)
{
    cairo_status_t status;

    status = _cairo_path_fixed_move_to (path, box->p1.x, box->p1.y);
    if (unlikely (status))
	return status;

    status = _cairo_path_fixed_line_to (path, box->p2.x, box->p1.y);
    if (unlikely (status))
	return status;

    status = _cairo_path_fixed_line_to (path, box->p2.x, box->p2.y);
    if (unlikely (status))
	return status;

    status = _cairo_path_fixed_line_to (path, box->p1.x, box->p2.y);
    if (unlikely (status))
	return status;

    return _cairo_path_fixed_close_path (path);
}

static cairo_status_t
_cairo_path_fixed_init_from_boxes (cairo_path_fixed_t *path,
				   const cairo_boxes_t *boxes)
{
    cairo_status_t status;
    const struct _cairo_boxes_chunk *chunk;
    int i;

    _cairo_path_fixed_init (path);
    if (boxes->num_boxes == 0)
	return CAIRO_STATUS_SUCCESS;

    for (chunk = &boxes->chunks; chunk; chunk = chunk->next) {
	for (i = 0; i < chunk->count; i++) {
	    status = _cairo_path_fixed_add_box (path, &chunk->base[i]);
	    if (unlikely (status)) {
		_cairo_path_fixed_fini (path);
		return status;
	    }
	}
    }

    return CAIRO_STATUS_SUCCESS;
}

static cairo_clip_t *
_cairo_clip_intersect_clip_path_transformed (cairo_clip_t *clip,
					     const cairo_clip_path_t *clip_path,
					     const cairo_matrix_t *m)
{
    cairo_path_fixed_t path;

    if (clip_path->prev)
	clip = _cairo_clip_intersect_clip_path_transformed (clip,
							    clip_path->prev,
							    m);

    if (_cairo_path_fixed_init_copy (&path, &clip_path->path))
	return _cairo_clip_set_all_clipped (clip);

    _cairo_path_fixed_transform (&path, m);

    clip =  _cairo_clip_intersect_path (clip,
				       &path,
				       clip_path->fill_rule,
				       clip_path->tolerance,
				       clip_path->antialias);
    _cairo_path_fixed_fini (&path);

    return clip;
}

cairo_clip_t *
_cairo_clip_transform (cairo_clip_t *clip, const cairo_matrix_t *m)
{
    cairo_clip_t *copy;

    if (clip == NULL || _cairo_clip_is_all_clipped (clip))
	return clip;

    if (_cairo_matrix_is_translation (m))
	return _cairo_clip_translate (clip, m->x0, m->y0);

    copy = _cairo_clip_create ();

    if (clip->num_boxes) {
	cairo_path_fixed_t path;
	cairo_boxes_t boxes;

	_cairo_boxes_init_for_array (&boxes, clip->boxes, clip->num_boxes);
	_cairo_path_fixed_init_from_boxes (&path, &boxes);
	_cairo_path_fixed_transform (&path, m);

	copy = _cairo_clip_intersect_path (copy, &path,
					   CAIRO_FILL_RULE_WINDING,
					   0.1,
					   CAIRO_ANTIALIAS_DEFAULT);

	_cairo_path_fixed_fini (&path);
    }

    if (clip->path)
	copy = _cairo_clip_intersect_clip_path_transformed (copy, clip->path,m);

    _cairo_clip_destroy (clip);
    return copy;
}

cairo_clip_t *
_cairo_clip_copy_with_translation (const cairo_clip_t *clip, int tx, int ty)
{
    cairo_clip_t *copy;
    int fx, fy, i;

    if (clip == NULL || _cairo_clip_is_all_clipped (clip))
	return (cairo_clip_t *)clip;

    if (tx == 0 && ty == 0)
	return _cairo_clip_copy (clip);

    copy = _cairo_clip_create ();
    if (copy == NULL)
	    return _cairo_clip_set_all_clipped (copy);

    fx = _cairo_fixed_from_int (tx);
    fy = _cairo_fixed_from_int (ty);

    if (clip->num_boxes) {
	if (clip->num_boxes == 1) {
	    copy->boxes = &copy->embedded_box;
	} else {
	    copy->boxes = _cairo_malloc_ab (clip->num_boxes, sizeof (cairo_box_t));
	    if (unlikely (copy->boxes == NULL))
		return _cairo_clip_set_all_clipped (copy);
	}

	for (i = 0; i < clip->num_boxes; i++) {
	    copy->boxes[i].p1.x = clip->boxes[i].p1.x + fx;
	    copy->boxes[i].p2.x = clip->boxes[i].p2.x + fx;
	    copy->boxes[i].p1.y = clip->boxes[i].p1.y + fy;
	    copy->boxes[i].p2.y = clip->boxes[i].p2.y + fy;
	}
	copy->num_boxes = clip->num_boxes;
    }

    copy->extents = clip->extents;
    copy->extents.x += tx;
    copy->extents.y += ty;

    if (clip->path == NULL)
	return copy;

    return _cairo_clip_path_copy_with_translation (copy, clip->path, fx, fy);
}

cairo_bool_t
_cairo_clip_contains_extents (const cairo_clip_t *clip,
			      const cairo_composite_rectangles_t *extents)
{
    const cairo_rectangle_int_t *rect;

    rect = extents->is_bounded ? &extents->bounded : &extents->unbounded;
    return _cairo_clip_contains_rectangle (clip, rect);
}

void
_cairo_debug_print_clip (FILE *stream, const cairo_clip_t *clip)
{
    int i;

    if (clip == NULL) {
	fprintf (stream, "no clip\n");
	return;
    }

    if (_cairo_clip_is_all_clipped (clip)) {
	fprintf (stream, "clip: all-clipped\n");
	return;
    }

    fprintf (stream, "clip:\n");
    fprintf (stream, "  extents: (%d, %d) x (%d, %d), is-region? %d",
	     clip->extents.x, clip->extents.y,
	     clip->extents.width, clip->extents.height,
	     clip->is_region);

    fprintf (stream, "  num_boxes = %d\n", clip->num_boxes);
    for (i = 0; i < clip->num_boxes; i++) {
	fprintf (stream, "  [%d] = (%f, %f), (%f, %f)\n", i,
		 _cairo_fixed_to_double (clip->boxes[i].p1.x),
		 _cairo_fixed_to_double (clip->boxes[i].p1.y),
		 _cairo_fixed_to_double (clip->boxes[i].p2.x),
		 _cairo_fixed_to_double (clip->boxes[i].p2.y));
    }

    if (clip->path) {
	cairo_clip_path_t *clip_path = clip->path;
	do {
	    fprintf (stream, "path: aa=%d, tolerance=%f, rule=%d: ",
		     clip_path->antialias,
		     clip_path->tolerance,
		     clip_path->fill_rule);
	    _cairo_debug_print_path (stream, &clip_path->path);
	    fprintf (stream, "\n");
	} while ((clip_path = clip_path->prev) != NULL);
    }
}

const cairo_rectangle_int_t *
_cairo_clip_get_extents (const cairo_clip_t *clip)
{
    if (clip == NULL)
	return &_cairo_unbounded_rectangle;

    if (_cairo_clip_is_all_clipped (clip))
	return &_cairo_empty_rectangle;

    return &clip->extents;
}

const cairo_rectangle_list_t _cairo_rectangles_nil =
  { CAIRO_STATUS_NO_MEMORY, NULL, 0 };
static const cairo_rectangle_list_t _cairo_rectangles_not_representable =
  { CAIRO_STATUS_CLIP_NOT_REPRESENTABLE, NULL, 0 };

static cairo_bool_t
_cairo_clip_int_rect_to_user (cairo_gstate_t *gstate,
			      cairo_rectangle_int_t *clip_rect,
			      cairo_rectangle_t *user_rect)
{
    cairo_bool_t is_tight;

    double x1 = clip_rect->x;
    double y1 = clip_rect->y;
    double x2 = clip_rect->x + (int) clip_rect->width;
    double y2 = clip_rect->y + (int) clip_rect->height;

    _cairo_gstate_backend_to_user_rectangle (gstate,
					     &x1, &y1, &x2, &y2,
					     &is_tight);

    user_rect->x = x1;
    user_rect->y = y1;
    user_rect->width  = x2 - x1;
    user_rect->height = y2 - y1;

    return is_tight;
}

cairo_rectangle_list_t *
_cairo_rectangle_list_create_in_error (cairo_status_t status)
{
    cairo_rectangle_list_t *list;

    if (status == CAIRO_STATUS_NO_MEMORY)
	return (cairo_rectangle_list_t*) &_cairo_rectangles_nil;
    if (status == CAIRO_STATUS_CLIP_NOT_REPRESENTABLE)
	return (cairo_rectangle_list_t*) &_cairo_rectangles_not_representable;

    list = _cairo_malloc (sizeof (*list));
    if (unlikely (list == NULL)) {
	status = _cairo_error (CAIRO_STATUS_NO_MEMORY);
	return (cairo_rectangle_list_t*) &_cairo_rectangles_nil;
    }

    list->status = status;
    list->rectangles = NULL;
    list->num_rectangles = 0;

    return list;
}

cairo_rectangle_list_t *
_cairo_clip_copy_rectangle_list (cairo_clip_t *clip, cairo_gstate_t *gstate)
{
#define ERROR_LIST(S) _cairo_rectangle_list_create_in_error (_cairo_error (S))

    cairo_rectangle_list_t *list;
    cairo_rectangle_t *rectangles = NULL;
    cairo_region_t *region = NULL;
    int n_rects = 0;
    int i;

    if (clip == NULL)
	return ERROR_LIST (CAIRO_STATUS_CLIP_NOT_REPRESENTABLE);

    if (_cairo_clip_is_all_clipped (clip))
	goto DONE;

    if (! _cairo_clip_is_region (clip))
	return ERROR_LIST (CAIRO_STATUS_CLIP_NOT_REPRESENTABLE);

    region = _cairo_clip_get_region (clip);
    if (region == NULL)
	return ERROR_LIST (CAIRO_STATUS_NO_MEMORY);

    n_rects = cairo_region_num_rectangles (region);
    if (n_rects) {
	rectangles = _cairo_malloc_ab (n_rects, sizeof (cairo_rectangle_t));
	if (unlikely (rectangles == NULL)) {
	    return ERROR_LIST (CAIRO_STATUS_NO_MEMORY);
	}

	for (i = 0; i < n_rects; ++i) {
	    cairo_rectangle_int_t clip_rect;

	    cairo_region_get_rectangle (region, i, &clip_rect);

	    if (! _cairo_clip_int_rect_to_user (gstate,
						&clip_rect,
						&rectangles[i]))
	    {
		free (rectangles);
		return ERROR_LIST (CAIRO_STATUS_CLIP_NOT_REPRESENTABLE);
	    }
	}
    }

 DONE:
    list = _cairo_malloc (sizeof (cairo_rectangle_list_t));
    if (unlikely (list == NULL)) {
        free (rectangles);
	return ERROR_LIST (CAIRO_STATUS_NO_MEMORY);
    }

    list->status = CAIRO_STATUS_SUCCESS;
    list->rectangles = rectangles;
    list->num_rectangles = n_rects;
    return list;

#undef ERROR_LIST
}

/**
 * cairo_rectangle_list_destroy:
 * @rectangle_list: a rectangle list, as obtained from cairo_copy_clip_rectangle_list()
 *
 * Unconditionally frees @rectangle_list and all associated
 * references. After this call, the @rectangle_list pointer must not
 * be dereferenced.
 *
 * Since: 1.4
 **/
void
cairo_rectangle_list_destroy (cairo_rectangle_list_t *rectangle_list)
{
    if (rectangle_list == NULL || rectangle_list == &_cairo_rectangles_nil ||
        rectangle_list == &_cairo_rectangles_not_representable)
        return;

    free (rectangle_list->rectangles);
    free (rectangle_list);
}

void
_cairo_clip_reset_static_data (void)
{
    _freed_pool_reset (&clip_path_pool);
    _freed_pool_reset (&clip_pool);
}