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"
#include "hb-shaper-private.hh"
#include "hb-shape-plan-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_func;
  void                      *user_data;
  hb_destroy_func_t          destroy;

  unsigned int index;
  mutable unsigned int upem;
  mutable unsigned int num_glyphs;

  struct hb_shaper_data_t shaper_data;

  struct plan_node_t {
    hb_shape_plan_t *shape_plan;
    plan_node_t *next;
  } *shape_plans;


  inline hb_blob_t *reference_table (hb_tag_t tag) const
  {
    hb_blob_t *blob;

    if (unlikely (!this || !reference_table_func))
      return hb_blob_get_empty ();

    blob = reference_table_func (/*XXX*/const_cast<hb_face_t *> (this), tag, user_data);
    if (unlikely (!blob))
      return hb_blob_get_empty ();

    return blob;
  }

  inline unsigned int get_upem (void) const
  {
    if (unlikely (!upem))
      load_upem ();
    return upem;
  }

  inline unsigned int get_num_glyphs (void) const
  {
    if (unlikely (num_glyphs == (unsigned int) -1))
      load_num_glyphs ();
    return num_glyphs;
  }

  private:
  HB_INTERNAL void load_upem (void) const;
  HB_INTERNAL void load_num_glyphs (void) const;
};

#define HB_SHAPER_DATA_CREATE_FUNC_EXTRA_ARGS
#define HB_SHAPER_IMPLEMENT(shaper) HB_SHAPER_DATA_PROTOTYPE(shaper, face);
#include "hb-shaper-list.hh"
#undef HB_SHAPER_IMPLEMENT
#undef HB_SHAPER_DATA_CREATE_FUNC_EXTRA_ARGS


/*
 * 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;

  struct hb_shaper_data_t shaper_data;


  /* 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);
  }


  /* Public getters */

  inline hb_bool_t get_glyph (hb_codepoint_t unicode, hb_codepoint_t variation_selector,
			      hb_codepoint_t *glyph)
  {
    *glyph = 0;
    return klass->get.glyph (this, user_data,
			     unicode, variation_selector, glyph,
			     klass->user_data.glyph);
  }

  inline hb_position_t get_glyph_h_advance (hb_codepoint_t glyph)
  {
    return klass->get.glyph_h_advance (this, user_data,
				       glyph,
				       klass->user_data.glyph_h_advance);
  }

  inline hb_position_t get_glyph_v_advance (hb_codepoint_t glyph)
  {
    return klass->get.glyph_v_advance (this, user_data,
				       glyph,
				       klass->user_data.glyph_v_advance);
  }

  inline hb_bool_t get_glyph_h_origin (hb_codepoint_t glyph,
				       hb_position_t *x, hb_position_t *y)
  {
    *x = *y = 0;
    return klass->get.glyph_h_origin (this, user_data,
				      glyph, x, y,
				      klass->user_data.glyph_h_origin);
  }

  inline hb_bool_t get_glyph_v_origin (hb_codepoint_t glyph,
				       hb_position_t *x, hb_position_t *y)
  {
    *x = *y = 0;
    return klass->get.glyph_v_origin (this, user_data,
				      glyph, x, y,
				      klass->user_data.glyph_v_origin);
  }

  inline hb_position_t get_glyph_h_kerning (hb_codepoint_t left_glyph, hb_codepoint_t right_glyph)
  {
    return klass->get.glyph_h_kerning (this, user_data,
				       left_glyph, right_glyph,
				       klass->user_data.glyph_h_kerning);
  }

  inline hb_position_t get_glyph_v_kerning (hb_codepoint_t left_glyph, hb_codepoint_t right_glyph)
  {
    return klass->get.glyph_v_kerning (this, user_data,
				       left_glyph, right_glyph,
				       klass->user_data.glyph_v_kerning);
  }

  inline hb_bool_t get_glyph_extents (hb_codepoint_t glyph,
				      hb_glyph_extents_t *extents)
  {
    memset (extents, 0, sizeof (*extents));
    return klass->get.glyph_extents (this, user_data,
				     glyph,
				     extents,
				     klass->user_data.glyph_extents);
  }

  inline hb_bool_t get_glyph_contour_point (hb_codepoint_t glyph, unsigned int point_index,
					    hb_position_t *x, hb_position_t *y)
  {
    *x = *y = 0;
    return klass->get.glyph_contour_point (this, user_data,
					   glyph, point_index,
					   x, y,
					   klass->user_data.glyph_contour_point);
  }

  inline hb_bool_t get_glyph_name (hb_codepoint_t glyph,
				   char *name, unsigned int size)
  {
    if (size) *name = '\0';
    return klass->get.glyph_name (this, user_data,
				  glyph,
				  name, size,
				  klass->user_data.glyph_name);
  }

  inline hb_bool_t get_glyph_from_name (const char *name, int len, /* -1 means nul-terminated */
					hb_codepoint_t *glyph)
  {
    *glyph = 0;
    if (len == -1) len = strlen (name);
    return klass->get.glyph_from_name (this, user_data,
				       name, len,
				       glyph,
				       klass->user_data.glyph_from_name);
  }


  /* A bit higher-level, and with fallback */

  inline void get_glyph_advance_for_direction (hb_codepoint_t glyph,
					       hb_direction_t direction,
					       hb_position_t *x, hb_position_t *y)
  {
    if (likely (HB_DIRECTION_IS_HORIZONTAL (direction))) {
      *x = get_glyph_h_advance (glyph);
      *y = 0;
    } else {
      *x = 0;
      *y = get_glyph_v_advance (glyph);
    }
  }

  /* Internal only */
  inline void guess_v_origin_minus_h_origin (hb_codepoint_t glyph,
					     hb_position_t *x, hb_position_t *y)
  {
    *x = get_glyph_h_advance (glyph) / 2;

    /* TODO use font_metics.ascent */
    *y = y_scale;
  }

  inline void get_glyph_origin_for_direction (hb_codepoint_t glyph,
					      hb_direction_t direction,
					      hb_position_t *x, hb_position_t *y)
  {
    if (likely (HB_DIRECTION_IS_HORIZONTAL (direction))) {
      hb_bool_t ret = get_glyph_h_origin (glyph, x, y);
      if (!ret && (ret = get_glyph_v_origin (glyph, x, y))) {
	hb_position_t dx, dy;
	guess_v_origin_minus_h_origin (glyph, &dx, &dy);
	*x -= dx; *y -= dy;
      }
    } else {
      hb_bool_t ret = get_glyph_v_origin (glyph, x, y);
      if (!ret && (ret = get_glyph_h_origin (glyph, x, y))) {
	hb_position_t dx, dy;
	guess_v_origin_minus_h_origin (glyph, &dx, &dy);
	*x += dx; *y += dy;
      }
    }
  }

  inline void add_glyph_origin_for_direction (hb_codepoint_t glyph,
					      hb_direction_t direction,
					      hb_position_t *x, hb_position_t *y)
  {
    hb_position_t origin_x, origin_y;

    get_glyph_origin_for_direction (glyph, direction, &origin_x, &origin_y);

    *x += origin_x;
    *y += origin_y;
  }

  inline void subtract_glyph_origin_for_direction (hb_codepoint_t glyph,
						   hb_direction_t direction,
						   hb_position_t *x, hb_position_t *y)
  {
    hb_position_t origin_x, origin_y;

    get_glyph_origin_for_direction (glyph, direction, &origin_x, &origin_y);

    *x -= origin_x;
    *y -= origin_y;
  }

  inline void get_glyph_kerning_for_direction (hb_codepoint_t first_glyph, hb_codepoint_t second_glyph,
					       hb_direction_t direction,
					       hb_position_t *x, hb_position_t *y)
  {
    if (likely (HB_DIRECTION_IS_HORIZONTAL (direction))) {
      *x = get_glyph_h_kerning (first_glyph, second_glyph);
      *y = 0;
    } else {
      *x = 0;
      *y = get_glyph_v_kerning (first_glyph, second_glyph);
    }
  }

  inline hb_bool_t get_glyph_extents_for_origin (hb_codepoint_t glyph,
						 hb_direction_t direction,
						 hb_glyph_extents_t *extents)
  {
    hb_bool_t ret = get_glyph_extents (glyph, extents);

    if (ret)
      subtract_glyph_origin_for_direction (glyph, direction, &extents->x_bearing, &extents->y_bearing);

    return ret;
  }

  inline hb_bool_t get_glyph_contour_point_for_origin (hb_codepoint_t glyph, unsigned int point_index,
						       hb_direction_t direction,
						       hb_position_t *x, hb_position_t *y)
  {
    hb_bool_t ret = get_glyph_contour_point (glyph, point_index, x, y);

    if (ret)
      subtract_glyph_origin_for_direction (glyph, direction, x, y);

    return ret;
  }

  /* Generates gidDDD if glyph has no name. */
  inline void
  glyph_to_string (hb_codepoint_t glyph,
		   char *s, unsigned int size)
  {
    if (get_glyph_name (glyph, s, size)) return;

    snprintf (s, size, "gid%u", glyph);
  }

  /* Parses gidDDD and uniUUUU strings automatically. */
  inline hb_bool_t
  glyph_from_string (const char *s, int len, /* -1 means nul-terminated */
		     hb_codepoint_t *glyph)
  {
    if (get_glyph_from_name (s, len, glyph)) return true;

    if (len == -1) len = strlen (s);

    /* Straight glyph index. */
    if (hb_codepoint_parse (s, len, 10, glyph))
      return true;

    if (len > 3)
    {
      /* gidDDD syntax for glyph indices. */
      if (0 == strncmp (s, "gid", 3) &&
	  hb_codepoint_parse (s + 3, len - 3, 10, glyph))
	return true;

      /* uniUUUU and other Unicode character indices. */
      hb_codepoint_t unichar;
      if (0 == strncmp (s, "uni", 3) &&
	  hb_codepoint_parse (s + 3, len - 3, 16, &unichar) &&
	  get_glyph (unichar, 0, glyph))
	return true;
    }

    return false;
  }

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

#define HB_SHAPER_DATA_CREATE_FUNC_EXTRA_ARGS
#define HB_SHAPER_IMPLEMENT(shaper) HB_SHAPER_DATA_PROTOTYPE(shaper, font);
#include "hb-shaper-list.hh"
#undef HB_SHAPER_IMPLEMENT
#undef HB_SHAPER_DATA_CREATE_FUNC_EXTRA_ARGS


#endif /* HB_FONT_PRIVATE_HH */