harfbuzz/src/hb-font-private.hh

/*
 * Copyright © 2009  Red Hat, Inc.
 * Copyright © 2011  Google, Inc.
 *
 *  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.
 *
 * Red Hat Author(s): Behdad Esfahbod
 * Google Author(s): Behdad Esfahbod
 */

#ifndef HB_FONT_PRIVATE_HH
#define HB_FONT_PRIVATE_HH

#include "hb-private.hh"

#include "hb-font.h"
#include "hb-object-private.hh"



/*
 * hb_font_funcs_t
 */

#define HB_FONT_FUNCS_IMPLEMENT_CALLBACKS \
  HB_FONT_FUNC_IMPLEMENT (glyph) \
  HB_FONT_FUNC_IMPLEMENT (glyph_h_advance) \
  HB_FONT_FUNC_IMPLEMENT (glyph_v_advance) \
  HB_FONT_FUNC_IMPLEMENT (glyph_h_origin) \
  HB_FONT_FUNC_IMPLEMENT (glyph_v_origin) \
  HB_FONT_FUNC_IMPLEMENT (glyph_h_kerning) \
  HB_FONT_FUNC_IMPLEMENT (glyph_v_kerning) \
  HB_FONT_FUNC_IMPLEMENT (glyph_extents) \
  HB_FONT_FUNC_IMPLEMENT (glyph_contour_point) \
  HB_FONT_FUNC_IMPLEMENT (glyph_name) \
  HB_FONT_FUNC_IMPLEMENT (glyph_from_name) \
  /* ^--- Add new callbacks here */

struct _hb_font_funcs_t {
  hb_object_header_t header;
  ASSERT_POD ();

  hb_bool_t immutable;

  /* Don't access these directly.  Call hb_font_get_*() instead. */

  struct {
#define HB_FONT_FUNC_IMPLEMENT(name) hb_font_get_##name##_func_t name;
    HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
#undef HB_FONT_FUNC_IMPLEMENT
  } get;

  struct {
#define HB_FONT_FUNC_IMPLEMENT(name) void *name;
    HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
#undef HB_FONT_FUNC_IMPLEMENT
  } user_data;

  struct {
#define HB_FONT_FUNC_IMPLEMENT(name) hb_destroy_func_t name;
    HB_FONT_FUNCS_IMPLEMENT_CALLBACKS
#undef HB_FONT_FUNC_IMPLEMENT
  } destroy;
};


/*
 * hb_face_t
 */

struct _hb_face_t {
  hb_object_header_t header;
  ASSERT_POD ();

  hb_bool_t immutable;

  hb_reference_table_func_t  reference_table;
  void                      *user_data;
  hb_destroy_func_t          destroy;

  struct hb_ot_layout_t *ot_layout;

  unsigned int index;
  unsigned int upem;
};


/*
 * hb_font_t
 */

struct _hb_font_t {
  hb_object_header_t header;
  ASSERT_POD ();

  hb_bool_t immutable;

  hb_font_t *parent;
  hb_face_t *face;

  int x_scale;
  int y_scale;

  unsigned int x_ppem;
  unsigned int y_ppem;

  hb_font_funcs_t   *klass;
  void              *user_data;
  hb_destroy_func_t  destroy;


  /* Convert from font-space to user-space */
  inline hb_position_t em_scale_x (int16_t v) { return em_scale (v, this->x_scale); }
  inline hb_position_t em_scale_y (int16_t v) { return em_scale (v, this->y_scale); }

  /* Convert from parent-font user-space to our user-space */
  inline hb_position_t parent_scale_x_distance (hb_position_t v) {
    if (unlikely (parent && parent->x_scale != x_scale))
      return v * (int64_t) this->x_scale / this->parent->x_scale;
    return v;
  }
  inline hb_position_t parent_scale_y_distance (hb_position_t v) {
    if (unlikely (parent && parent->y_scale != y_scale))
      return v * (int64_t) this->y_scale / this->parent->y_scale;
    return v;
  }
  inline hb_position_t parent_scale_x_position (hb_position_t v) {
    return parent_scale_x_distance (v);
  }
  inline hb_position_t parent_scale_y_position (hb_position_t v) {
    return parent_scale_y_distance (v);
  }

  inline void parent_scale_distance (hb_position_t *x, hb_position_t *y) {
    *x = parent_scale_x_distance (*x);
    *y = parent_scale_y_distance (*y);
  }
  inline void parent_scale_position (hb_position_t *x, hb_position_t *y) {
    *x = parent_scale_x_position (*x);
    *y = parent_scale_y_position (*y);
  }


  private:
  inline hb_position_t em_scale (int16_t v, int scale) { return v * (int64_t) scale / hb_face_get_upem (this->face); }
};



#endif /* HB_FONT_PRIVATE_HH */