hb-style.h 3.3 KB

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  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. #if !defined(HB_H_IN) && !defined(HB_NO_SINGLE_HEADER_ERROR)
  25. #error "Include <hb.h> instead."
  26. #endif
  27. #ifndef HB_STYLE_H
  28. #define HB_STYLE_H
  29. #include "hb.h"
  30. HB_BEGIN_DECLS
  31. /**
  32. * hb_style_tag_t:
  33. * @HB_STYLE_TAG_ITALIC: Used to vary between non-italic and italic.
  34. * A value of 0 can be interpreted as "Roman" (non-italic); a value of 1 can
  35. * be interpreted as (fully) italic.
  36. * @HB_STYLE_TAG_OPTICAL_SIZE: Used to vary design to suit different text sizes.
  37. * Non-zero. Values can be interpreted as text size, in points.
  38. * @HB_STYLE_TAG_SLANT_ANGLE: Used to vary between upright and slanted text. Values
  39. * must be greater than -90 and less than +90. Values can be interpreted as
  40. * the angle, in counter-clockwise degrees, of oblique slant from whatever the
  41. * designer considers to be upright for that font design. Typical right-leaning
  42. * Italic fonts have a negative slant angle (typically around -12)
  43. * @HB_STYLE_TAG_SLANT_RATIO: same as @HB_STYLE_TAG_SLANT_ANGLE expression as ratio.
  44. * Typical right-leaning Italic fonts have a positive slant ratio (typically around 0.2)
  45. * @HB_STYLE_TAG_WIDTH: Used to vary width of text from narrower to wider.
  46. * Non-zero. Values can be interpreted as a percentage of whatever the font
  47. * designer considers “normal width” for that font design.
  48. * @HB_STYLE_TAG_WEIGHT: Used to vary stroke thicknesses or other design details
  49. * to give variation from lighter to blacker. Values can be interpreted in direct
  50. * comparison to values for usWeightClass in the OS/2 table,
  51. * or the CSS font-weight property.
  52. *
  53. * Defined by [OpenType Design-Variation Axis Tag Registry](https://docs.microsoft.com/en-us/typography/opentype/spec/dvaraxisreg).
  54. *
  55. * Since: 3.0.0
  56. **/
  57. typedef enum
  58. {
  59. HB_STYLE_TAG_ITALIC = HB_TAG ('i','t','a','l'),
  60. HB_STYLE_TAG_OPTICAL_SIZE = HB_TAG ('o','p','s','z'),
  61. HB_STYLE_TAG_SLANT_ANGLE = HB_TAG ('s','l','n','t'),
  62. HB_STYLE_TAG_SLANT_RATIO = HB_TAG ('S','l','n','t'),
  63. HB_STYLE_TAG_WIDTH = HB_TAG ('w','d','t','h'),
  64. HB_STYLE_TAG_WEIGHT = HB_TAG ('w','g','h','t'),
  65. /*< private >*/
  66. _HB_STYLE_TAG_MAX_VALUE = HB_TAG_MAX_SIGNED /*< skip >*/
  67. } hb_style_tag_t;
  68. HB_EXTERN float
  69. hb_style_get_value (hb_font_t *font, hb_style_tag_t style_tag);
  70. HB_END_DECLS
  71. #endif /* HB_STYLE_H */