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/* 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;
}