/*

 * 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 * -HB_PI / 180.f);

}

static inline float

_hb_ratio_to_angle (float r)

{

  return atanf (r) * -180.f / HB_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, first tries to get default style values in `STAT` table

 * then tries to polyfill 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