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| 4349 | Serge | 1 | /* -*- Mode: c; tab-width: 8; c-basic-offset: 4; indent-tabs-mode: t; -*- */ |
| 2 | /* cairo - a vector graphics library with display and print output |
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| 3 | * |
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| 4 | * Copyright © 2002 University of Southern California |
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| 5 | * |
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| 6 | * This library is free software; you can redistribute it and/or |
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| 7 | * modify it either under the terms of the GNU Lesser General Public |
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| 8 | * License version 2.1 as published by the Free Software Foundation |
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| 9 | * (the "LGPL") or, at your option, under the terms of the Mozilla |
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| 10 | * Public License Version 1.1 (the "MPL"). If you do not alter this |
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| 11 | * notice, a recipient may use your version of this file under either |
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| 12 | * the MPL or the LGPL. |
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| 13 | * |
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| 14 | * You should have received a copy of the LGPL along with this library |
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| 15 | * in the file COPYING-LGPL-2.1; if not, write to the Free Software |
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| 16 | * Foundation, Inc., 51 Franklin Street, Suite 500, Boston, MA 02110-1335, USA |
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| 17 | * You should have received a copy of the MPL along with this library |
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| 18 | * in the file COPYING-MPL-1.1 |
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| 19 | * |
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| 20 | * The contents of this file are subject to the Mozilla Public License |
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| 21 | * Version 1.1 (the "License"); you may not use this file except in |
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| 22 | * compliance with the License. You may obtain a copy of the License at |
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| 23 | * http://www.mozilla.org/MPL/ |
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| 24 | * |
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| 25 | * This software is distributed on an "AS IS" basis, WITHOUT WARRANTY |
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| 26 | * OF ANY KIND, either express or implied. See the LGPL or the MPL for |
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| 27 | * the specific language governing rights and limitations. |
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| 28 | * |
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| 29 | * The Original Code is the cairo graphics library. |
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| 30 | * |
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| 31 | * The Initial Developer of the Original Code is University of Southern |
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| 32 | * California. |
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| 33 | * |
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| 34 | * Contributor(s): |
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| 35 | * Carl D. Worth |
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| 36 | * Chris Wilson |
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| 37 | */ |
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| 38 | |||
| 39 | #include "cairoint.h" |
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| 40 | |||
| 41 | #include "cairo-stroke-dash-private.h" |
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| 42 | |||
| 43 | void |
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| 44 | _cairo_stroker_dash_start (cairo_stroker_dash_t *dash) |
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| 45 | { |
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| 46 | double offset; |
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| 47 | cairo_bool_t on = TRUE; |
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| 48 | unsigned int i = 0; |
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| 49 | |||
| 50 | if (! dash->dashed) |
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| 51 | return; |
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| 52 | |||
| 53 | offset = dash->dash_offset; |
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| 54 | |||
| 55 | /* We stop searching for a starting point as soon as the |
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| 56 | offset reaches zero. Otherwise when an initial dash |
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| 57 | segment shrinks to zero it will be skipped over. */ |
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| 58 | while (offset > 0.0 && offset >= dash->dashes[i]) { |
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| 59 | offset -= dash->dashes[i]; |
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| 60 | on = !on; |
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| 61 | if (++i == dash->num_dashes) |
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| 62 | i = 0; |
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| 63 | } |
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| 64 | |||
| 65 | dash->dash_index = i; |
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| 66 | dash->dash_on = dash->dash_starts_on = on; |
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| 67 | dash->dash_remain = dash->dashes[i] - offset; |
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| 68 | } |
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| 69 | |||
| 70 | void |
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| 71 | _cairo_stroker_dash_step (cairo_stroker_dash_t *dash, double step) |
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| 72 | { |
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| 73 | dash->dash_remain -= step; |
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| 74 | if (dash->dash_remain < CAIRO_FIXED_ERROR_DOUBLE) { |
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| 75 | if (++dash->dash_index == dash->num_dashes) |
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| 76 | dash->dash_index = 0; |
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| 77 | |||
| 78 | dash->dash_on = ! dash->dash_on; |
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| 79 | dash->dash_remain += dash->dashes[dash->dash_index]; |
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| 80 | } |
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| 81 | } |
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| 82 | |||
| 83 | void |
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| 84 | _cairo_stroker_dash_init (cairo_stroker_dash_t *dash, |
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| 85 | const cairo_stroke_style_t *style) |
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| 86 | { |
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| 87 | dash->dashed = style->dash != NULL; |
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| 88 | if (! dash->dashed) |
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| 89 | return; |
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| 90 | |||
| 91 | dash->dashes = style->dash; |
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| 92 | dash->num_dashes = style->num_dashes; |
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| 93 | dash->dash_offset = style->dash_offset; |
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| 94 | |||
| 95 | _cairo_stroker_dash_start (dash); |
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| 96 | } |