summaryrefslogtreecommitdiff
path: root/Build/source/libs/cairo/cairo-src/src/cairo-path-in-fill.c
blob: 1787fb1a3bab05807e6c74ed063a8469c669ad74 (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
/* cairo - a vector graphics library with display and print output
 *
 * Copyright © 2008 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 Chris Wilson.
 *
 * Contributor(s):
 *	Chris Wilson <chris@chris-wilson.co.uk>
 */

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

typedef struct cairo_in_fill {
    double tolerance;
    cairo_bool_t on_edge;
    int winding;

    cairo_fixed_t x, y;

    cairo_bool_t has_current_point;
    cairo_point_t current_point;
    cairo_point_t first_point;
} cairo_in_fill_t;

static void
_cairo_in_fill_init (cairo_in_fill_t	*in_fill,
		     double		 tolerance,
		     double		 x,
		     double		 y)
{
    in_fill->on_edge = FALSE;
    in_fill->winding = 0;
    in_fill->tolerance = tolerance;

    in_fill->x = _cairo_fixed_from_double (x);
    in_fill->y = _cairo_fixed_from_double (y);

    in_fill->has_current_point = FALSE;
    in_fill->current_point.x = 0;
    in_fill->current_point.y = 0;
}

static void
_cairo_in_fill_fini (cairo_in_fill_t *in_fill)
{
}

static int
edge_compare_for_y_against_x (const cairo_point_t *p1,
			      const cairo_point_t *p2,
			      cairo_fixed_t y,
			      cairo_fixed_t x)
{
    cairo_fixed_t adx, ady;
    cairo_fixed_t dx, dy;
    cairo_int64_t L, R;

    adx = p2->x - p1->x;
    dx = x - p1->x;

    if (adx == 0)
	return -dx;
    if ((adx ^ dx) < 0)
	return adx;

    dy = y - p1->y;
    ady = p2->y - p1->y;

    L = _cairo_int32x32_64_mul (dy, adx);
    R = _cairo_int32x32_64_mul (dx, ady);

    return _cairo_int64_cmp (L, R);
}

static void
_cairo_in_fill_add_edge (cairo_in_fill_t *in_fill,
			 const cairo_point_t *p1,
			 const cairo_point_t *p2)
{
    int dir;

    if (in_fill->on_edge)
	return;

    /* count the number of edge crossing to -∞ */

    dir = 1;
    if (p2->y < p1->y) {
	const cairo_point_t *tmp;

	tmp = p1;
	p1 = p2;
	p2 = tmp;

	dir = -1;
    }

    /* First check whether the query is on an edge */
    if ((p1->x == in_fill->x && p1->y == in_fill->y) ||
	(p2->x == in_fill->x && p2->y == in_fill->y) ||
	(! (p2->y < in_fill->y || p1->y > in_fill->y ||
	   (p1->x > in_fill->x && p2->x > in_fill->x) ||
	   (p1->x < in_fill->x && p2->x < in_fill->x)) &&
	 edge_compare_for_y_against_x (p1, p2, in_fill->y, in_fill->x) == 0))
    {
	in_fill->on_edge = TRUE;
	return;
    }

    /* edge is entirely above or below, note the shortening rule */
    if (p2->y <= in_fill->y || p1->y > in_fill->y)
	return;

    /* edge lies wholly to the right */
    if (p1->x >= in_fill->x && p2->x >= in_fill->x)
	return;

    if ((p1->x <= in_fill->x && p2->x <= in_fill->x) ||
	edge_compare_for_y_against_x (p1, p2, in_fill->y, in_fill->x) < 0)
    {
	in_fill->winding += dir;
    }
}

static cairo_status_t
_cairo_in_fill_move_to (void *closure,
			const cairo_point_t *point)
{
    cairo_in_fill_t *in_fill = closure;

    /* implicit close path */
    if (in_fill->has_current_point) {
	_cairo_in_fill_add_edge (in_fill,
				 &in_fill->current_point,
				 &in_fill->first_point);
    }

    in_fill->first_point = *point;
    in_fill->current_point = *point;
    in_fill->has_current_point = TRUE;

    return CAIRO_STATUS_SUCCESS;
}

static cairo_status_t
_cairo_in_fill_line_to (void *closure,
			const cairo_point_t *point)
{
    cairo_in_fill_t *in_fill = closure;

    if (in_fill->has_current_point)
	_cairo_in_fill_add_edge (in_fill, &in_fill->current_point, point);

    in_fill->current_point = *point;
    in_fill->has_current_point = TRUE;

    return CAIRO_STATUS_SUCCESS;
}

static cairo_status_t
_cairo_in_fill_curve_to (void *closure,
			 const cairo_point_t *b,
			 const cairo_point_t *c,
			 const cairo_point_t *d)
{
    cairo_in_fill_t *in_fill = closure;
    cairo_spline_t spline;
    cairo_fixed_t top, bot, left;

    /* first reject based on bbox */
    bot = top = in_fill->current_point.y;
    if (b->y < top) top = b->y;
    if (b->y > bot) bot = b->y;
    if (c->y < top) top = c->y;
    if (c->y > bot) bot = c->y;
    if (d->y < top) top = d->y;
    if (d->y > bot) bot = d->y;
    if (bot < in_fill->y || top > in_fill->y) {
	in_fill->current_point = *d;
	return CAIRO_STATUS_SUCCESS;
    }

    left = in_fill->current_point.x;
    if (b->x < left) left = b->x;
    if (c->x < left) left = c->x;
    if (d->x < left) left = d->x;
    if (left > in_fill->x) {
	in_fill->current_point = *d;
	return CAIRO_STATUS_SUCCESS;
    }

    /* XXX Investigate direct inspection of the inflections? */
    if (! _cairo_spline_init (&spline,
			      (cairo_spline_add_point_func_t)_cairo_in_fill_line_to,
			      in_fill,
			      &in_fill->current_point, b, c, d))
    {
	return CAIRO_STATUS_SUCCESS;
    }

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

static cairo_status_t
_cairo_in_fill_close_path (void *closure)
{
    cairo_in_fill_t *in_fill = closure;

    if (in_fill->has_current_point) {
	_cairo_in_fill_add_edge (in_fill,
				 &in_fill->current_point,
				 &in_fill->first_point);

	in_fill->has_current_point = FALSE;
    }

    return CAIRO_STATUS_SUCCESS;
}

cairo_bool_t
_cairo_path_fixed_in_fill (const cairo_path_fixed_t	*path,
			   cairo_fill_rule_t	 fill_rule,
			   double		 tolerance,
			   double		 x,
			   double		 y)
{
    cairo_in_fill_t in_fill;
    cairo_status_t status;
    cairo_bool_t is_inside;

    if (_cairo_path_fixed_fill_is_empty (path))
	return FALSE;

    _cairo_in_fill_init (&in_fill, tolerance, x, y);

    status = _cairo_path_fixed_interpret (path,
					  _cairo_in_fill_move_to,
					  _cairo_in_fill_line_to,
					  _cairo_in_fill_curve_to,
					  _cairo_in_fill_close_path,
					  &in_fill);
    assert (status == CAIRO_STATUS_SUCCESS);

    _cairo_in_fill_close_path (&in_fill);

    if (in_fill.on_edge) {
	is_inside = TRUE;
    } else switch (fill_rule) {
    case CAIRO_FILL_RULE_EVEN_ODD:
	is_inside = in_fill.winding & 1;
	break;
    case CAIRO_FILL_RULE_WINDING:
	is_inside = in_fill.winding != 0;
	break;
    default:
	ASSERT_NOT_REACHED;
	is_inside = FALSE;
	break;
    }

    _cairo_in_fill_fini (&in_fill);

    return is_inside;
}