1/*
2 * Copyright © 2019 Ebrahim Byagowi
3 *
4 * This is part of HarfBuzz, a text shaping library.
5 *
6 * Permission is hereby granted, without written agreement and without
7 * license or royalty fees, to use, copy, modify, and distribute this
8 * software and its documentation for any purpose, provided that the
9 * above copyright notice and the following two paragraphs appear in
10 * all copies of this software.
11 *
12 * IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
13 * DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
14 * ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
15 * IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
16 * DAMAGE.
17 *
18 * THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
19 * BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
20 * FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
21 * ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
22 * PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
23 */
24
25#if !defined(HB_H_IN) && !defined(HB_NO_SINGLE_HEADER_ERROR)
26#error "Include <hb.h> instead."
27#endif
28
29#ifndef HB_STYLE_H
30#define HB_STYLE_H
31
32#include "hb.h"
33
34HB_BEGIN_DECLS
35
36/**
37 * hb_style_tag_t:
38 * @HB_STYLE_TAG_ITALIC: Used to vary between non-italic and italic.
39 * A value of 0 can be interpreted as "Roman" (non-italic); a value of 1 can
40 * be interpreted as (fully) italic.
41 * @HB_STYLE_TAG_OPTICAL_SIZE: Used to vary design to suit different text sizes.
42 * Non-zero. Values can be interpreted as text size, in points.
43 * @HB_STYLE_TAG_SLANT_ANGLE: Used to vary between upright and slanted text. Values
44 * must be greater than -90 and less than +90. Values can be interpreted as
45 * the angle, in counter-clockwise degrees, of oblique slant from whatever the
46 * designer considers to be upright for that font design. Typical right-leaning
47 * Italic fonts have a negative slant angle (typically around -12)
48 * @HB_STYLE_TAG_SLANT_RATIO: same as @HB_STYLE_TAG_SLANT_ANGLE expression as ratio.
49 * Typical right-leaning Italic fonts have a positive slant ratio (typically around 0.2)
50 * @HB_STYLE_TAG_WIDTH: Used to vary width of text from narrower to wider.
51 * Non-zero. Values can be interpreted as a percentage of whatever the font
52 * designer considers “normal width” for that font design.
53 * @HB_STYLE_TAG_WEIGHT: Used to vary stroke thicknesses or other design details
54 * to give variation from lighter to blacker. Values can be interpreted in direct
55 * comparison to values for usWeightClass in the OS/2 table,
56 * or the CSS font-weight property.
57 *
58 * Defined by [OpenType Design-Variation Axis Tag Registry](https://docs.microsoft.com/en-us/typography/opentype/spec/dvaraxisreg).
59 *
60 * Since: 3.0.0
61 **/
62typedef enum
63{
64 HB_STYLE_TAG_ITALIC = HB_TAG ('i','t','a','l'),
65 HB_STYLE_TAG_OPTICAL_SIZE = HB_TAG ('o','p','s','z'),
66 HB_STYLE_TAG_SLANT_ANGLE = HB_TAG ('s','l','n','t'),
67 HB_STYLE_TAG_SLANT_RATIO = HB_TAG ('S','l','n','t'),
68 HB_STYLE_TAG_WIDTH = HB_TAG ('w','d','t','h'),
69 HB_STYLE_TAG_WEIGHT = HB_TAG ('w','g','h','t'),
70
71 /*< private >*/
72 _HB_STYLE_TAG_MAX_VALUE = HB_TAG_MAX_SIGNED /*< skip >*/
73} hb_style_tag_t;
74
75
76HB_EXTERN float
77hb_style_get_value (hb_font_t *font, hb_style_tag_t style_tag);
78
79HB_END_DECLS
80
81#endif /* HB_STYLE_H */
82