harfbuzz/src/hb-style.cc

135 lines
3.8 KiB
C++

/*
* 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
#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"
/**
* SECTION:hb-style
* @title: hb-style
* @short_description: Font Styles
* @include: hb.h
*
* Functions for fetching style information from fonts.
**/
static inline float
_hb_angle_to_ratio (float a)
{
return tanf (a * float (-M_PI / 180.));
}
static inline float
_hb_ratio_to_angle (float r)
{
return atanf (r) * float (-180. / M_PI);
}
/**
* 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: 3.0.0
**/
float
hb_style_get_value (hb_font_t *font, hb_style_tag_t style_tag)
{
if (unlikely (style_tag == HB_STYLE_TAG_SLANT_RATIO))
return _hb_angle_to_ratio (hb_style_get_value (font, HB_STYLE_TAG_SLANT_ANGLE));
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, design, upper;
return face->table.OS2->v5 ().get_optical_size (&lower, &upper)
? (float) (lower + upper) / 2.f
: hb_ot_layout_get_size_params (face, &design, nullptr, nullptr, nullptr, nullptr)
? design / 10.f
: 12.f;
}
case HB_STYLE_TAG_SLANT_ANGLE:
{
float angle = face->table.post->table->italicAngle.to_float ();
if (font->slant)
angle = _hb_ratio_to_angle (font->slant + _hb_angle_to_ratio (angle));
return angle;
}
case HB_STYLE_TAG_WIDTH:
return face->table.OS2->has_data ()
? face->table.OS2->get_width ()
: (face->table.head->is_condensed () ? 75 :
face->table.head->is_expanded () ? 125 :
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