Subversion Repositories Kolibri OS

/* 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 

 */

#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;

}