summaryrefslogtreecommitdiff
path: root/src/cairo-path-fill.c
blob: 50cd2183a83d9c4a3c07c183289dfbf42779ecf3 (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
/* cairo - a vector graphics library with display and print output
 *
 * Copyright © 2002 University of Southern California
 *
 * 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 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>
 */

#include "cairoint.h"
#include "cairo-path-fixed-private.h"
#include "cairo-region-private.h"

typedef struct cairo_filler {
    double tolerance;
    cairo_point_t current_point;
    cairo_polygon_t *polygon;
} cairo_filler_t;

static void
_cairo_filler_init (cairo_filler_t *filler,
		    double tolerance,
		    cairo_polygon_t *polygon)
{
    filler->tolerance = tolerance;
    filler->polygon = polygon;

    filler->current_point.x = 0;
    filler->current_point.y = 0;
}

static void
_cairo_filler_fini (cairo_filler_t *filler)
{
}

static cairo_status_t
_cairo_filler_move_to (void *closure,
		       const cairo_point_t *point)
{
    cairo_filler_t *filler = closure;
    cairo_polygon_t *polygon = filler->polygon;

    _cairo_polygon_close (polygon);
    _cairo_polygon_move_to (polygon, point);

    filler->current_point = *point;

    return _cairo_polygon_status (filler->polygon);
}

static cairo_status_t
_cairo_filler_line_to (void *closure,
		       const cairo_point_t *point)
{
    cairo_filler_t *filler = closure;
    cairo_polygon_t *polygon = filler->polygon;

    _cairo_polygon_line_to (polygon, point);

    filler->current_point = *point;

    return _cairo_polygon_status (filler->polygon);
}

static cairo_status_t
_cairo_filler_curve_to (void *closure,
			const cairo_point_t *b,
			const cairo_point_t *c,
			const cairo_point_t *d)
{
    cairo_filler_t *filler = closure;
    cairo_spline_t spline;

    if (! _cairo_spline_init (&spline,
			      _cairo_filler_line_to, filler,
			      &filler->current_point, b, c, d))
    {
	return _cairo_filler_line_to (closure, d);
    }

    return _cairo_spline_decompose (&spline, filler->tolerance);
}

static cairo_status_t
_cairo_filler_close_path (void *closure)
{
    cairo_filler_t *filler = closure;
    cairo_polygon_t *polygon = filler->polygon;

    _cairo_polygon_close (polygon);

    return _cairo_polygon_status (polygon);
}

cairo_status_t
_cairo_path_fixed_fill_to_polygon (const cairo_path_fixed_t *path,
				   double tolerance,
				   cairo_polygon_t *polygon)
{
    cairo_filler_t filler;
    cairo_status_t status;

    _cairo_filler_init (&filler, tolerance, polygon);

    status = _cairo_path_fixed_interpret (path,
					  CAIRO_DIRECTION_FORWARD,
					  _cairo_filler_move_to,
					  _cairo_filler_line_to,
					  _cairo_filler_curve_to,
					  _cairo_filler_close_path,
					  &filler);
    if (unlikely (status))
	return status;

    _cairo_polygon_close (polygon);
    status = _cairo_polygon_status (polygon);
    _cairo_filler_fini (&filler);

    return status;
}

cairo_status_t
_cairo_path_fixed_fill_to_traps (const cairo_path_fixed_t *path,
				 cairo_fill_rule_t fill_rule,
				 double tolerance,
				 cairo_traps_t *traps)
{
    cairo_polygon_t polygon;
    cairo_status_t status;

    _cairo_polygon_init (&polygon);
    if (traps->has_limits)
	_cairo_polygon_limit (&polygon, &traps->limits);

    status = _cairo_path_fixed_fill_to_polygon (path,
						tolerance,
						&polygon);
    if (unlikely (status))
	goto CLEANUP;

    if (path->is_rectilinear) {
	status = _cairo_bentley_ottmann_tessellate_rectilinear_polygon (traps,
									&polygon,
									fill_rule);
    } else {
	status = _cairo_bentley_ottmann_tessellate_polygon (traps,
							    &polygon,
							    fill_rule);
    }

  CLEANUP:
    _cairo_polygon_fini (&polygon);
    return status;
}

static cairo_region_t *
_cairo_path_fixed_fill_rectilinear_tessellate_to_region (const cairo_path_fixed_t	*path,
							 cairo_fill_rule_t	 fill_rule,
							 const cairo_rectangle_int_t *extents)
{
    cairo_polygon_t polygon;
    cairo_traps_t traps;
    cairo_status_t status;
    cairo_region_t *region;

    _cairo_polygon_init (&polygon);
    if (extents != NULL) {
	cairo_box_t box;

	_cairo_box_from_rectangle (&box, extents);
	_cairo_polygon_limit (&polygon, &box);
    }

    /* tolerance will be ignored as the path is rectilinear */
    status = _cairo_path_fixed_fill_to_polygon (path, 0., &polygon);
    if (unlikely (status))
	goto CLEANUP_POLYGON;

    if (polygon.num_edges == 0) {
	region = cairo_region_create ();
    } else {
	_cairo_traps_init (&traps);

	status = _cairo_bentley_ottmann_tessellate_rectilinear_polygon (&traps,
									&polygon,
									fill_rule);
	if (likely (status == CAIRO_STATUS_SUCCESS))
	    status = _cairo_traps_extract_region (&traps, &region);

	_cairo_traps_fini (&traps);
    }

  CLEANUP_POLYGON:
    _cairo_polygon_fini (&polygon);

    if (unlikely (status)) { /* XXX _cairo_region_create_in_error() */
	region = cairo_region_create ();
	if (likely (region->status) == CAIRO_STATUS_SUCCESS)
	    region->status = status;
    }

    return region;
}

/* This special-case filler supports only a path that describes a
 * device-axis aligned rectangle. It exists to avoid the overhead of
 * the general tessellator when drawing very common rectangles.
 *
 * If the path described anything but a device-axis aligned rectangle,
 * this function will abort.
 */
cairo_region_t *
_cairo_path_fixed_fill_rectilinear_to_region (const cairo_path_fixed_t	*path,
					      cairo_fill_rule_t	 fill_rule,
					      const cairo_rectangle_int_t *extents)
{
    cairo_rectangle_int_t rectangle_stack[CAIRO_STACK_ARRAY_LENGTH (cairo_rectangle_int_t)];
    cairo_box_t box;
    cairo_region_t *region = NULL;

    assert (path->maybe_fill_region);

    if (_cairo_path_fixed_is_box (path, &box)) {
	if (box.p1.x > box.p2.x) {
	    cairo_fixed_t t;

	    t = box.p1.x;
	    box.p1.x = box.p2.x;
	    box.p2.x = t;
	}

	if (box.p1.y > box.p2.y) {
	    cairo_fixed_t t;

	    t = box.p1.y;
	    box.p1.y = box.p2.y;
	    box.p2.y = t;
	}

	rectangle_stack[0].x = _cairo_fixed_integer_part (box.p1.x);
	rectangle_stack[0].y = _cairo_fixed_integer_part (box.p1.y);
	rectangle_stack[0].width = _cairo_fixed_integer_part (box.p2.x) -
	                            rectangle_stack[0].x;
	rectangle_stack[0].height = _cairo_fixed_integer_part (box.p2.y) -
	                            rectangle_stack[0].y;
	if (! _cairo_rectangle_intersect (&rectangle_stack[0], extents))
	    region = cairo_region_create ();
	else
	    region = cairo_region_create_rectangle (&rectangle_stack[0]);
    } else if (fill_rule == CAIRO_FILL_RULE_WINDING) {
	cairo_rectangle_int_t *rects = rectangle_stack;
	cairo_path_fixed_iter_t iter;
	int last_cw = -1;
	int size = ARRAY_LENGTH (rectangle_stack);
	int count = 0;

	/* Support a series of rectangles as can be expected to describe a
	 * GdkRegion clip region during exposes.
	 */
	_cairo_path_fixed_iter_init (&iter, path);
	while (_cairo_path_fixed_iter_is_fill_box (&iter, &box)) {
	    int cw = 0;

	    if (box.p1.x > box.p2.x) {
		cairo_fixed_t t;

		t = box.p1.x;
		box.p1.x = box.p2.x;
		box.p2.x = t;

		cw = ! cw;
	    }

	    if (box.p1.y > box.p2.y) {
		cairo_fixed_t t;

		t = box.p1.y;
		box.p1.y = box.p2.y;
		box.p2.y = t;

		cw = ! cw;
	    }

	    if (last_cw < 0)
		last_cw = cw;
	    else if (last_cw != cw)
		goto TESSELLATE;

	    if (count == size) {
		cairo_rectangle_int_t *new_rects;

		size *= 4;
		if (rects == rectangle_stack) {
		    new_rects = _cairo_malloc_ab (size,
						  sizeof (cairo_rectangle_int_t));
		    if (unlikely (new_rects == NULL)) {
			/* XXX _cairo_region_nil */
			break;
		    }
		    memcpy (new_rects, rects, sizeof (rectangle_stack));
		} else {
		    new_rects = _cairo_realloc_ab (rects, size,
						   sizeof (cairo_rectangle_int_t));
		    if (unlikely (new_rects == NULL)) {
			/* XXX _cairo_region_nil */
			break;
		    }
		}
		rects = new_rects;
	    }

	    rects[count].x = _cairo_fixed_integer_part (box.p1.x);
	    rects[count].y = _cairo_fixed_integer_part (box.p1.y);
	    rects[count].width = _cairo_fixed_integer_part (box.p2.x) - rects[count].x;
	    rects[count].height = _cairo_fixed_integer_part (box.p2.y) - rects[count].y;
	    if (_cairo_rectangle_intersect (&rects[count], extents))
		count++;
	}

	if (_cairo_path_fixed_iter_at_end (&iter))
	    region = cairo_region_create_rectangles (rects, count);

TESSELLATE:
	if (rects != rectangle_stack)
	    free (rects);
    }

    if (region == NULL) {
	/* Hmm, complex polygon */
	region = _cairo_path_fixed_fill_rectilinear_tessellate_to_region (path,
									  fill_rule,
									  extents);


    }

    return region;
}