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/*
* Copyright © 2019 Ebrahim Byagowi
*
* This is part of HarfBuzz, a text shaping library.
*
* Permission is hereby granted, without written agreement and without
* license or royalty fees, to use, copy, modify, and distribute this
* software and its documentation for any purpose, provided that the
* above copyright notice and the following two paragraphs appear in
* all copies of this software.
*
* IN NO EVENT SHALL THE COPYRIGHT HOLDER BE LIABLE TO ANY PARTY FOR
* DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
* ARISING OUT OF THE USE OF THIS SOFTWARE AND ITS DOCUMENTATION, EVEN
* IF THE COPYRIGHT HOLDER HAS BEEN ADVISED OF THE POSSIBILITY OF SUCH
* DAMAGE.
*
* THE COPYRIGHT HOLDER SPECIFICALLY DISCLAIMS ANY WARRANTIES, INCLUDING,
* BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND
* FITNESS FOR A PARTICULAR PURPOSE. THE SOFTWARE PROVIDED HEREUNDER IS
* ON AN "AS IS" BASIS, AND THE COPYRIGHT HOLDER HAS NO OBLIGATION TO
* PROVIDE MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
*/
#include "hb.hh"
#ifndef HB_NO_STYLE
#ifdef HB_EXPERIMENTAL_API
#include "hb-ot-var-avar-table.hh"
#include "hb-ot-var-fvar-table.hh"
#include "hb-ot-stat-table.hh"
#include "hb-ot-os2-table.hh"
#include "hb-ot-head-table.hh"
#include "hb-ot-post-table.hh"
#include "hb-ot-face.hh"
/**
* hb_style_tag_t:
* @HB_STYLE_TAG_ITALIC: Used to vary between non-italic and italic.
* A value of 0 can be interpreted as "Roman" (non-italic); a value of 1 can
* be interpreted as (fully) italic.
* @HB_STYLE_TAG_OPTICAL_SIZE: Used to vary design to suit different text sizes.
* Non-zero. Values can be interpreted as text size, in points.
* @HB_STYLE_TAG_SLANT: Used to vary between upright and slanted text. Values
* must be greater than -90 and less than +90. Values can be interpreted as
* the angle, in counter-clockwise degrees, of oblique slant from whatever the
* designer considers to be upright for that font design.
* @HB_STYLE_TAG_WIDTH: Used to vary width of text from narrower to wider.
* Non-zero. Values can be interpreted as a percentage of whatever the font
* designer considers “normal width” for that font design.
* @HB_STYLE_TAG_WEIGHT: Used to vary stroke thicknesses or other design details
* to give variation from lighter to blacker. Values can be interpreted in direct
* comparison to values for usWeightClass in the OS/2 table,
* or the CSS font-weight property.
*
* Defined by https://docs.microsoft.com/en-us/typography/opentype/spec/dvaraxisreg
*
* Since: EXPERIMENTAL
**/
typedef enum {
HB_STYLE_TAG_ITALIC = HB_TAG ('i','t','a','l'),
HB_STYLE_TAG_OPTICAL_SIZE = HB_TAG ('o','p','s','z'),
HB_STYLE_TAG_SLANT = HB_TAG ('s','l','n','t'),
HB_STYLE_TAG_WIDTH = HB_TAG ('w','d','t','h'),
HB_STYLE_TAG_WEIGHT = HB_TAG ('w','g','h','t'),
_HB_STYLE_TAG_MAX_VALUE = HB_TAG_MAX_SIGNED /*< skip >*/
} hb_style_tag_t;
/**
* hb_style_get_value:
* @font: a #hb_font_t object.
* @style_tag: a style tag.
*
* Searches variation axes of a hb_font_t object for a specific axis first,
* if not set, then tries to get default style values from different
* tables of the font.
*
* Returns: Corresponding axis or default value to a style tag.
*
* Since: EXPERIMENTAL
**/
float
hb_style_get_value (hb_font_t *font, hb_tag_t tag)
{
hb_style_tag_t style_tag = (hb_style_tag_t) tag;
hb_face_t *face = font->face;
#ifndef HB_NO_VAR
hb_ot_var_axis_info_t axis;
if (hb_ot_var_find_axis_info (face, style_tag, &axis))
{
if (axis.axis_index < font->num_coords) return font->design_coords[axis.axis_index];
/* If a face is variable, fvar's default_value is better than STAT records */
return axis.default_value;
}
#endif
if (style_tag == HB_STYLE_TAG_OPTICAL_SIZE && font->ptem)
return font->ptem;
/* STAT */
float value;
if (face->table.STAT->get_value (style_tag, &value))
return value;
switch ((unsigned) style_tag)
{
case HB_STYLE_TAG_ITALIC:
return face->table.OS2->is_italic () || face->table.head->is_italic () ? 1 : 0;
case HB_STYLE_TAG_OPTICAL_SIZE:
{
unsigned int lower, upper;
return face->table.OS2->v5 ().get_optical_size (&lower, &upper)
? (float) (lower + upper) / 2.f
: 12.f;
}
case HB_STYLE_TAG_SLANT:
return face->table.post->table->italicAngle.to_float ();
case HB_STYLE_TAG_WIDTH:
return face->table.OS2->has_data ()
? face->table.OS2->get_width ()
: (face->table.head->is_condensed () ? 75 : 100);
case HB_STYLE_TAG_WEIGHT:
return face->table.OS2->has_data ()
? face->table.OS2->usWeightClass
: (face->table.head->is_bold () ? 700 : 400);
default:
return 0;
}
}
#endif
#endif
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