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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
*
* 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);
}