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/* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */

/* cairo - a vector graphics library with display and print output

 *

 * Copyright © 2002 University of Southern California

 * Copyright © 2005 Red Hat, Inc.

 * Copyright © 2006 Red Hat, Inc.

 *

 * 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 University of Southern

 * California.

 *

 * Contributor(s):

 *	Carl D. Worth 

 */

#include "cairoint.h"

#include "cairo-box-inline.h"

const cairo_rectangle_int_t _cairo_empty_rectangle = { 0, 0, 0, 0 };

const cairo_rectangle_int_t _cairo_unbounded_rectangle = {

     CAIRO_RECT_INT_MIN, CAIRO_RECT_INT_MIN,

     CAIRO_RECT_INT_MAX - CAIRO_RECT_INT_MIN,

     CAIRO_RECT_INT_MAX - CAIRO_RECT_INT_MIN,

};

cairo_private void

_cairo_box_from_doubles (cairo_box_t *box,

			 double *x1, double *y1,

			 double *x2, double *y2)

{

    box->p1.x = _cairo_fixed_from_double (*x1);

    box->p1.y = _cairo_fixed_from_double (*y1);

    box->p2.x = _cairo_fixed_from_double (*x2);

    box->p2.y = _cairo_fixed_from_double (*y2);

}

cairo_private void

_cairo_box_to_doubles (const cairo_box_t *box,

		       double *x1, double *y1,

		       double *x2, double *y2)

{

    *x1 = _cairo_fixed_to_double (box->p1.x);

    *y1 = _cairo_fixed_to_double (box->p1.y);

    *x2 = _cairo_fixed_to_double (box->p2.x);

    *y2 = _cairo_fixed_to_double (box->p2.y);

}

void

_cairo_box_from_rectangle (cairo_box_t                 *box,

			   const cairo_rectangle_int_t *rect)

{

    box->p1.x = _cairo_fixed_from_int (rect->x);

    box->p1.y = _cairo_fixed_from_int (rect->y);

    box->p2.x = _cairo_fixed_from_int (rect->x + rect->width);

    box->p2.y = _cairo_fixed_from_int (rect->y + rect->height);

}

void

_cairo_boxes_get_extents (const cairo_box_t *boxes,

			  int num_boxes,

			  cairo_box_t *extents)

{

    assert (num_boxes > 0);

    *extents = *boxes;

    while (--num_boxes)

	_cairo_box_add_box (extents, ++boxes);

}

/* XXX We currently have a confusing mix of boxes and rectangles as

 * exemplified by this function.  A #cairo_box_t is a rectangular area

 * represented by the coordinates of the upper left and lower right

 * corners, expressed in fixed point numbers.  A #cairo_rectangle_int_t is

 * also a rectangular area, but represented by the upper left corner

 * and the width and the height, as integer numbers.

 *

 * This function converts a #cairo_box_t to a #cairo_rectangle_int_t by

 * increasing the area to the nearest integer coordinates.  We should

 * standardize on #cairo_rectangle_fixed_t and #cairo_rectangle_int_t, and

 * this function could be renamed to the more reasonable

 * _cairo_rectangle_fixed_round.

 */

void

_cairo_box_round_to_rectangle (const cairo_box_t     *box,

			       cairo_rectangle_int_t *rectangle)

{

    rectangle->x = _cairo_fixed_integer_floor (box->p1.x);

    rectangle->y = _cairo_fixed_integer_floor (box->p1.y);

    rectangle->width = _cairo_fixed_integer_ceil (box->p2.x) - rectangle->x;

    rectangle->height = _cairo_fixed_integer_ceil (box->p2.y) - rectangle->y;

}

cairo_bool_t

_cairo_rectangle_intersect (cairo_rectangle_int_t *dst,

			    const cairo_rectangle_int_t *src)

{

    int x1, y1, x2, y2;

    x1 = MAX (dst->x, src->x);

    y1 = MAX (dst->y, src->y);

    /* Beware the unsigned promotion, fortunately we have bits to spare

     * as (CAIRO_RECT_INT_MAX - CAIRO_RECT_INT_MIN) < UINT_MAX

     */

    x2 = MIN (dst->x + (int) dst->width,  src->x + (int) src->width);

    y2 = MIN (dst->y + (int) dst->height, src->y + (int) src->height);

    if (x1 >= x2 || y1 >= y2) {

	dst->x = 0;

	dst->y = 0;

	dst->width  = 0;

	dst->height = 0;

	return FALSE;

    } else {

	dst->x = x1;

	dst->y = y1;

	dst->width  = x2 - x1;

	dst->height = y2 - y1;

	return TRUE;

    }

}

/* Extends the dst rectangle to also contain src.

 * If one of the rectangles is empty, the result is undefined

 */

void

_cairo_rectangle_union (cairo_rectangle_int_t *dst,

			const cairo_rectangle_int_t *src)

{

    int x1, y1, x2, y2;

    x1 = MIN (dst->x, src->x);

    y1 = MIN (dst->y, src->y);

    /* Beware the unsigned promotion, fortunately we have bits to spare

     * as (CAIRO_RECT_INT_MAX - CAIRO_RECT_INT_MIN) < UINT_MAX

     */

    x2 = MAX (dst->x + (int) dst->width,  src->x + (int) src->width);

    y2 = MAX (dst->y + (int) dst->height, src->y + (int) src->height);

    dst->x = x1;

    dst->y = y1;

    dst->width  = x2 - x1;

    dst->height = y2 - y1;

}

#define P1x (line->p1.x)

#define P1y (line->p1.y)

#define P2x (line->p2.x)

#define P2y (line->p2.y)

#define B1x (box->p1.x)

#define B1y (box->p1.y)

#define B2x (box->p2.x)

#define B2y (box->p2.y)

/*

 * Check whether any part of line intersects box.  This function essentially

 * computes whether the ray starting at line->p1 in the direction of line->p2

 * intersects the box before it reaches p2.  Normally, this is done

 * by dividing by the lengths of the line projected onto each axis.  Because

 * we're in fixed point, this function does a bit more work to avoid having to

 * do the division -- we don't care about the actual intersection point, so

 * it's of no interest to us.

 */

cairo_bool_t

_cairo_box_intersects_line_segment (const cairo_box_t *box, cairo_line_t *line)

{

    cairo_fixed_t t1=0, t2=0, t3=0, t4=0;

    cairo_int64_t t1y, t2y, t3x, t4x;

    cairo_fixed_t xlen, ylen;

    if (_cairo_box_contains_point (box, &line->p1) ||

	_cairo_box_contains_point (box, &line->p2))

	return TRUE;

    xlen = P2x - P1x;

    ylen = P2y - P1y;

    if (xlen) {

	if (xlen > 0) {

	    t1 = B1x - P1x;

	    t2 = B2x - P1x;

	} else {

	    t1 = P1x - B2x;

	    t2 = P1x - B1x;

	    xlen = - xlen;

	}

	if ((t1 < 0 || t1 > xlen) &&

	    (t2 < 0 || t2 > xlen))

	    return FALSE;

    } else {

	/* Fully vertical line -- check that X is in bounds */

	if (P1x < B1x || P1x > B2x)

	    return FALSE;

    }

    if (ylen) {

	if (ylen > 0) {

	    t3 = B1y - P1y;

	    t4 = B2y - P1y;

	} else {

	    t3 = P1y - B2y;

	    t4 = P1y - B1y;

	    ylen = - ylen;

	}

	if ((t3 < 0 || t3 > ylen) &&

	    (t4 < 0 || t4 > ylen))

	    return FALSE;

    } else {

	/* Fully horizontal line -- check Y */

	if (P1y < B1y || P1y > B2y)

	    return FALSE;

    }

    /* If we had a horizontal or vertical line, then it's already been checked */

    if (P1x == P2x || P1y == P2y)

	return TRUE;

    /* Check overlap.  Note that t1 < t2 and t3 < t4 here. */

    t1y = _cairo_int32x32_64_mul (t1, ylen);

    t2y = _cairo_int32x32_64_mul (t2, ylen);

    t3x = _cairo_int32x32_64_mul (t3, xlen);

    t4x = _cairo_int32x32_64_mul (t4, xlen);

    if (_cairo_int64_lt(t1y, t4x) &&

	_cairo_int64_lt(t3x, t2y))

	return TRUE;

    return FALSE;

}

static cairo_status_t

_cairo_box_add_spline_point (void *closure,

			     const cairo_point_t *point,

			     const cairo_slope_t *tangent)

{

    _cairo_box_add_point (closure, point);

    return CAIRO_STATUS_SUCCESS;

}

/* assumes a has been previously added */

void

_cairo_box_add_curve_to (cairo_box_t *extents,

			 const cairo_point_t *a,

			 const cairo_point_t *b,

			 const cairo_point_t *c,

			 const cairo_point_t *d)

{

    _cairo_box_add_point (extents, d);

    if (!_cairo_box_contains_point (extents, b) ||

	!_cairo_box_contains_point (extents, c))

    {

	cairo_status_t status;

	status = _cairo_spline_bound (_cairo_box_add_spline_point,

				      extents, a, b, c, d);

	assert (status == CAIRO_STATUS_SUCCESS);

    }

}

void

_cairo_rectangle_int_from_double (cairo_rectangle_int_t *recti,

				  const cairo_rectangle_t *rectf)

{

	recti->x = floor (rectf->x);

	recti->y = floor (rectf->y);

	recti->width  = ceil (rectf->x + rectf->width) - floor (rectf->x);

	recti->height = ceil (rectf->y + rectf->height) - floor (rectf->y);

}