292 lines
7.1 KiB
C
292 lines
7.1 KiB
C
/* cairo - a vector graphics library with display and print output
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*
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* Copyright © 2008 Chris Wilson
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*
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* This library is free software; you can redistribute it and/or
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* modify it either under the terms of the GNU Lesser General Public
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* License version 2.1 as published by the Free Software Foundation
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* (the "LGPL") or, at your option, under the terms of the Mozilla
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* Public License Version 1.1 (the "MPL"). If you do not alter this
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* notice, a recipient may use your version of this file under either
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* the MPL or the LGPL.
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*
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* You should have received a copy of the LGPL along with this library
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* in the file COPYING-LGPL-2.1; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA
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* You should have received a copy of the MPL along with this library
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* in the file COPYING-MPL-1.1
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*
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* The contents of this file are subject to the Mozilla Public License
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* Version 1.1 (the "License"); you may not use this file except in
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* compliance with the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* This software is distributed on an "AS IS" basis, WITHOUT WARRANTY
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* OF ANY KIND, either express or implied. See the LGPL or the MPL for
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* the specific language governing rights and limitations.
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*
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* The Original Code is the cairo graphics library.
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*
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* The Initial Developer of the Original Code is Chris Wilson.
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*
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* Contributor(s):
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* Chris Wilson <chris@chris-wilson.co.uk>
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*/
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#include "cairoint.h"
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#include "cairo-path-fixed-private.h"
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typedef struct cairo_in_fill {
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double tolerance;
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cairo_bool_t on_edge;
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int winding;
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cairo_fixed_t x, y;
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cairo_bool_t has_current_point;
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cairo_point_t current_point;
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cairo_point_t first_point;
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} cairo_in_fill_t;
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static void
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_cairo_in_fill_init (cairo_in_fill_t *in_fill,
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double tolerance,
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double x,
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double y)
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{
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in_fill->on_edge = FALSE;
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in_fill->winding = 0;
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in_fill->tolerance = tolerance;
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in_fill->x = _cairo_fixed_from_double (x);
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in_fill->y = _cairo_fixed_from_double (y);
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in_fill->has_current_point = FALSE;
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in_fill->current_point.x = 0;
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in_fill->current_point.y = 0;
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}
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static void
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_cairo_in_fill_fini (cairo_in_fill_t *in_fill)
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{
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}
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static int
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edge_compare_for_y_against_x (const cairo_point_t *p1,
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const cairo_point_t *p2,
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cairo_fixed_t y,
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cairo_fixed_t x)
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{
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cairo_fixed_t adx, ady;
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cairo_fixed_t dx, dy;
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cairo_int64_t L, R;
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adx = p2->x - p1->x;
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dx = x - p1->x;
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if (adx == 0)
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return -dx;
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if ((adx ^ dx) < 0)
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return adx;
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dy = y - p1->y;
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ady = p2->y - p1->y;
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L = _cairo_int32x32_64_mul (dy, adx);
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R = _cairo_int32x32_64_mul (dx, ady);
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return _cairo_int64_cmp (L, R);
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}
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static void
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_cairo_in_fill_add_edge (cairo_in_fill_t *in_fill,
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const cairo_point_t *p1,
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const cairo_point_t *p2)
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{
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int dir;
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if (in_fill->on_edge)
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return;
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/* count the number of edge crossing to -∞ */
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dir = 1;
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if (p2->y < p1->y) {
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const cairo_point_t *tmp;
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tmp = p1;
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p1 = p2;
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p2 = tmp;
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dir = -1;
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}
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/* First check whether the query is on an edge */
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if ((p1->x == in_fill->x && p1->y == in_fill->y) ||
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(p2->x == in_fill->x && p2->y == in_fill->y) ||
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(! (p2->y < in_fill->y || p1->y > in_fill->y ||
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(p1->x > in_fill->x && p2->x > in_fill->x) ||
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(p1->x < in_fill->x && p2->x < in_fill->x)) &&
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edge_compare_for_y_against_x (p1, p2, in_fill->y, in_fill->x) == 0))
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{
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in_fill->on_edge = TRUE;
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return;
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}
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/* edge is entirely above or below, note the shortening rule */
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if (p2->y <= in_fill->y || p1->y > in_fill->y)
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return;
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/* edge lies wholly to the right */
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if (p1->x >= in_fill->x && p2->x >= in_fill->x)
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return;
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if ((p1->x <= in_fill->x && p2->x <= in_fill->x) ||
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edge_compare_for_y_against_x (p1, p2, in_fill->y, in_fill->x) < 0)
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{
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in_fill->winding += dir;
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}
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}
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static cairo_status_t
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_cairo_in_fill_move_to (void *closure,
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const cairo_point_t *point)
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{
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cairo_in_fill_t *in_fill = closure;
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/* implicit close path */
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if (in_fill->has_current_point) {
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_cairo_in_fill_add_edge (in_fill,
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&in_fill->current_point,
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&in_fill->first_point);
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}
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in_fill->first_point = *point;
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in_fill->current_point = *point;
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in_fill->has_current_point = TRUE;
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return CAIRO_STATUS_SUCCESS;
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}
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static cairo_status_t
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_cairo_in_fill_line_to (void *closure,
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const cairo_point_t *point)
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{
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cairo_in_fill_t *in_fill = closure;
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if (in_fill->has_current_point)
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_cairo_in_fill_add_edge (in_fill, &in_fill->current_point, point);
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in_fill->current_point = *point;
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in_fill->has_current_point = TRUE;
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return CAIRO_STATUS_SUCCESS;
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}
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static cairo_status_t
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_cairo_in_fill_curve_to (void *closure,
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const cairo_point_t *b,
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const cairo_point_t *c,
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const cairo_point_t *d)
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{
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cairo_in_fill_t *in_fill = closure;
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cairo_spline_t spline;
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cairo_fixed_t top, bot, left;
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/* first reject based on bbox */
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bot = top = in_fill->current_point.y;
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if (b->y < top) top = b->y;
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if (b->y > bot) bot = b->y;
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if (c->y < top) top = c->y;
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if (c->y > bot) bot = c->y;
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if (d->y < top) top = d->y;
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if (d->y > bot) bot = d->y;
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if (bot < in_fill->y || top > in_fill->y) {
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in_fill->current_point = *d;
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return CAIRO_STATUS_SUCCESS;
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}
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left = in_fill->current_point.x;
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if (b->x < left) left = b->x;
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if (c->x < left) left = c->x;
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if (d->x < left) left = d->x;
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if (left > in_fill->x) {
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in_fill->current_point = *d;
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return CAIRO_STATUS_SUCCESS;
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}
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/* XXX Investigate direct inspection of the inflections? */
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if (! _cairo_spline_init (&spline,
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_cairo_in_fill_line_to,
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in_fill,
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&in_fill->current_point, b, c, d))
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{
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return CAIRO_STATUS_SUCCESS;
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}
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return _cairo_spline_decompose (&spline, in_fill->tolerance);
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}
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static cairo_status_t
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_cairo_in_fill_close_path (void *closure)
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{
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cairo_in_fill_t *in_fill = closure;
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if (in_fill->has_current_point) {
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_cairo_in_fill_add_edge (in_fill,
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&in_fill->current_point,
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&in_fill->first_point);
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in_fill->has_current_point = FALSE;
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}
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return CAIRO_STATUS_SUCCESS;
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}
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cairo_bool_t
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_cairo_path_fixed_in_fill (const cairo_path_fixed_t *path,
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cairo_fill_rule_t fill_rule,
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double tolerance,
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double x,
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double y)
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{
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cairo_in_fill_t in_fill;
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cairo_status_t status;
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cairo_bool_t is_inside;
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if (path->is_empty_fill)
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return FALSE;
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_cairo_in_fill_init (&in_fill, tolerance, x, y);
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status = _cairo_path_fixed_interpret (path,
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CAIRO_DIRECTION_FORWARD,
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_cairo_in_fill_move_to,
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_cairo_in_fill_line_to,
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_cairo_in_fill_curve_to,
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_cairo_in_fill_close_path,
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&in_fill);
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assert (status == CAIRO_STATUS_SUCCESS);
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_cairo_in_fill_close_path (&in_fill);
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if (in_fill.on_edge) {
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is_inside = TRUE;
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} else switch (fill_rule) {
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case CAIRO_FILL_RULE_EVEN_ODD:
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is_inside = in_fill.winding & 1;
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break;
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case CAIRO_FILL_RULE_WINDING:
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is_inside = in_fill.winding != 0;
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break;
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default:
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ASSERT_NOT_REACHED;
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is_inside = FALSE;
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break;
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}
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_cairo_in_fill_fini (&in_fill);
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return is_inside;
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}
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