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/*
* Copyright © 2007,2008,2009 Red Hat, Inc.
* Copyright © 2012 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_OT_LAYOUT_PRIVATE_HH
#define HB_OT_LAYOUT_PRIVATE_HH
#include "hb-private.hh"
#include "hb-ot-layout.h"
#include "hb-font-private.hh"
#include "hb-buffer-private.hh"
#include "hb-set-private.hh"
/* buffer var allocations, used during the GSUB/GPOS processing */
#define glyph_props() var1.u16[0] /* GDEF glyph properties */
#define syllable() var1.u8[2] /* GSUB/GPOS shaping boundaries */
#define lig_props() var1.u8[3] /* GSUB/GPOS ligature tracking */
#define hb_ot_layout_from_face(face) ((hb_ot_layout_t *) face->shaper_data.ot)
/*
* GDEF
*/
typedef enum {
HB_OT_LAYOUT_GLYPH_PROPS_UNCLASSIFIED = 0x0001,
HB_OT_LAYOUT_GLYPH_PROPS_BASE_GLYPH = 0x0002,
HB_OT_LAYOUT_GLYPH_PROPS_LIGATURE = 0x0004,
HB_OT_LAYOUT_GLYPH_PROPS_MARK = 0x0008,
HB_OT_LAYOUT_GLYPH_PROPS_COMPONENT = 0x0010
} hb_ot_layout_glyph_class_mask_t;
/*
* GSUB/GPOS
*/
/* lig_id / lig_comp
*
* When a ligature is formed:
*
* - The ligature glyph and any marks in between all the same newly allocated
* lig_id,
* - The ligature glyph will get lig_num_comps set to the number of components
* - The marks get lig_comp > 0, reflecting which component of the ligature
* they were applied to.
* - This is used in GPOS to attach marks to the right component of a ligature
* in MarkLigPos.
*
* When a multiple-substitution is done:
*
* - All resulting glyphs will have lig_id = 0,
* - The resulting glyphs will have lig_comp = 0, 1, 2, ... respectively.
* - This is used in GPOS to attach marks to the first component of a
* multiple substitution in MarkBasePos.
*
* The numbers are also used in GPOS to do mark-to-mark positioning only
* to marks that belong to the same component of a ligature in MarkMarPos.
*/
#define IS_LIG_BASE 0x10
static inline void
set_lig_props_for_ligature (hb_glyph_info_t &info, unsigned int lig_id, unsigned int lig_num_comps)
{
info.lig_props() = (lig_id << 5) | IS_LIG_BASE | (lig_num_comps & 0x0F);
}
static inline void
set_lig_props_for_mark (hb_glyph_info_t &info, unsigned int lig_id, unsigned int lig_comp)
{
info.lig_props() = (lig_id << 5) | (lig_comp & 0x0F);
}
static inline void
set_lig_props_for_component (hb_glyph_info_t &info, unsigned int comp)
{
set_lig_props_for_mark (info, 0, comp);
}
static inline unsigned int
get_lig_id (const hb_glyph_info_t &info)
{
return info.lig_props() >> 5;
}
static inline bool
is_a_ligature (const hb_glyph_info_t &info)
{
return !!(info.lig_props() & IS_LIG_BASE);
}
static inline unsigned int
get_lig_comp (const hb_glyph_info_t &info)
{
if (is_a_ligature (info))
return 0;
else
return info.lig_props() & 0x0F;
}
static inline unsigned int
get_lig_num_comps (const hb_glyph_info_t &info)
{
if ((info.glyph_props() & HB_OT_LAYOUT_GLYPH_PROPS_LIGATURE) && is_a_ligature (info))
return info.lig_props() & 0x0F;
else
return 1;
}
static inline uint8_t allocate_lig_id (hb_buffer_t *buffer) {
uint8_t lig_id = buffer->next_serial () & 0x07;
if (unlikely (!lig_id))
lig_id = allocate_lig_id (buffer); /* in case of overflow */
return lig_id;
}
HB_INTERNAL hb_bool_t
hb_ot_layout_lookup_would_substitute_fast (hb_face_t *face,
unsigned int lookup_index,
const hb_codepoint_t *glyphs,
unsigned int glyphs_length,
hb_bool_t zero_context);
/* Should be called before all the substitute_lookup's are done. */
HB_INTERNAL void
hb_ot_layout_substitute_start (hb_font_t *font,
hb_buffer_t *buffer);
HB_INTERNAL hb_bool_t
hb_ot_layout_substitute_lookup (hb_font_t *font,
hb_buffer_t *buffer,
unsigned int lookup_index,
hb_mask_t mask);
/* Should be called after all the substitute_lookup's are done */
HB_INTERNAL void
hb_ot_layout_substitute_finish (hb_font_t *font,
hb_buffer_t *buffer);
/* Should be called before all the position_lookup's are done. Resets positions to zero. */
HB_INTERNAL void
hb_ot_layout_position_start (hb_font_t *font,
hb_buffer_t *buffer);
HB_INTERNAL hb_bool_t
hb_ot_layout_position_lookup (hb_font_t *font,
hb_buffer_t *buffer,
unsigned int lookup_index,
hb_mask_t mask);
/* Should be called after all the position_lookup's are done */
HB_INTERNAL void
hb_ot_layout_position_finish (hb_font_t *font,
hb_buffer_t *buffer,
hb_bool_t zero_width_attached_marks);
/*
* hb_ot_layout_t
*/
namespace OT {
struct GDEF;
struct GSUB;
struct GPOS;
}
struct hb_ot_layout_t
{
hb_blob_t *gdef_blob;
hb_blob_t *gsub_blob;
hb_blob_t *gpos_blob;
const struct OT::GDEF *gdef;
const struct OT::GSUB *gsub;
const struct OT::GPOS *gpos;
unsigned int gsub_lookup_count;
unsigned int gpos_lookup_count;
hb_set_digest_t *gsub_digests;
hb_set_digest_t *gpos_digests;
};
HB_INTERNAL hb_ot_layout_t *
_hb_ot_layout_create (hb_face_t *face);
HB_INTERNAL void
_hb_ot_layout_destroy (hb_ot_layout_t *layout);
#endif /* HB_OT_LAYOUT_PRIVATE_HH */
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