/* -*- 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

 *

 * 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 <cworth@cworth.org>

 *  Chris Wilson <chris@chris-wilson.co.uk>

 */

#include "cairoint.h"

#include "cairo-stroke-dash-private.h"

void

_cairo_stroker_dash_start (cairo_stroker_dash_t *dash)

{

    double offset;

    cairo_bool_t on = TRUE;

    unsigned int i = 0;

    if (! dash->dashed)

  return;

    offset = dash->dash_offset;

    /* We stop searching for a starting point as soon as the

       offset reaches zero.  Otherwise when an initial dash

       segment shrinks to zero it will be skipped over. */

    while (offset > 0.0 && offset >= dash->dashes[i]) {

  offset -= dash->dashes[i];

  on = !on;

  if (++i == dash->num_dashes)

      i = 0;

    }

    dash->dash_index = i;

    dash->dash_on = dash->dash_starts_on = on;

    dash->dash_remain = dash->dashes[i] - offset;

}

void

_cairo_stroker_dash_step (cairo_stroker_dash_t *dash, double step)

{

    dash->dash_remain -= step;

    if (dash->dash_remain < CAIRO_FIXED_ERROR_DOUBLE) {

  if (++dash->dash_index == dash->num_dashes)

      dash->dash_index = 0;

  dash->dash_on = ! dash->dash_on;

  dash->dash_remain += dash->dashes[dash->dash_index];

    }

}

void

_cairo_stroker_dash_init (cairo_stroker_dash_t *dash,

        const cairo_stroke_style_t *style)

{

    dash->dashed = style->dash != NULL;

    if (! dash->dashed)

  return;

    dash->dashes = style->dash;

    dash->num_dashes = style->num_dashes;

    dash->dash_offset = style->dash_offset;

    _cairo_stroker_dash_start (dash);

}