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-rw-r--r--src/cairo-stroke-dash.c96
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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);
+}