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#ifndef OT_LAYOUT_GPOS_GPOS_HH
#define OT_LAYOUT_GPOS_GPOS_HH
#include "../../../hb-ot-layout-common.hh"
#include "../../../hb-ot-layout-gsubgpos.hh"
#include "Common.hh"
#include "PosLookup.hh"
namespace OT {
using Layout::GPOS_impl::PosLookup;
namespace Layout {
static void
propagate_attachment_offsets (hb_glyph_position_t *pos,
unsigned int len,
unsigned int i,
hb_direction_t direction,
unsigned nesting_level = HB_MAX_NESTING_LEVEL);
/*
* GPOS -- Glyph Positioning
* https://docs.microsoft.com/en-us/typography/opentype/spec/gpos
*/
struct GPOS : GSUBGPOS
{
static constexpr hb_tag_t tableTag = HB_OT_TAG_GPOS;
using Lookup = PosLookup;
const PosLookup& get_lookup (unsigned int i) const
{ return static_cast<const PosLookup &> (GSUBGPOS::get_lookup (i)); }
static inline void position_start (hb_font_t *font, hb_buffer_t *buffer);
static inline void position_finish_advances (hb_font_t *font, hb_buffer_t *buffer);
static inline void position_finish_offsets (hb_font_t *font, hb_buffer_t *buffer);
bool subset (hb_subset_context_t *c) const
{
hb_subset_layout_context_t l (c, tableTag);
return GSUBGPOS::subset<PosLookup> (&l);
}
bool sanitize (hb_sanitize_context_t *c) const
{
TRACE_SANITIZE (this);
return_trace (GSUBGPOS::sanitize<PosLookup> (c));
}
HB_INTERNAL bool is_blocklisted (hb_blob_t *blob,
hb_face_t *face) const;
void collect_variation_indices (hb_collect_variation_indices_context_t *c) const
{
for (unsigned i = 0; i < GSUBGPOS::get_lookup_count (); i++)
{
if (!c->gpos_lookups->has (i)) continue;
const PosLookup &l = get_lookup (i);
l.dispatch (c);
}
}
void closure_lookups (hb_face_t *face,
const hb_set_t *glyphs,
hb_set_t *lookup_indexes /* IN/OUT */) const
{ GSUBGPOS::closure_lookups<PosLookup> (face, glyphs, lookup_indexes); }
typedef GSUBGPOS::accelerator_t<GPOS> accelerator_t;
};
static void
propagate_attachment_offsets (hb_glyph_position_t *pos,
unsigned int len,
unsigned int i,
hb_direction_t direction,
unsigned nesting_level)
{
/* Adjusts offsets of attached glyphs (both cursive and mark) to accumulate
* offset of glyph they are attached to. */
int chain = pos[i].attach_chain(), type = pos[i].attach_type();
if (likely (!chain))
return;
pos[i].attach_chain() = 0;
unsigned int j = (int) i + chain;
if (unlikely (j >= len))
return;
if (unlikely (!nesting_level))
return;
propagate_attachment_offsets (pos, len, j, direction, nesting_level - 1);
assert (!!(type & GPOS_impl::ATTACH_TYPE_MARK) ^ !!(type & GPOS_impl::ATTACH_TYPE_CURSIVE));
if (type & GPOS_impl::ATTACH_TYPE_CURSIVE)
{
if (HB_DIRECTION_IS_HORIZONTAL (direction))
pos[i].y_offset += pos[j].y_offset;
else
pos[i].x_offset += pos[j].x_offset;
}
else /*if (type & GPOS_impl::ATTACH_TYPE_MARK)*/
{
pos[i].x_offset += pos[j].x_offset;
pos[i].y_offset += pos[j].y_offset;
assert (j < i);
if (HB_DIRECTION_IS_FORWARD (direction))
for (unsigned int k = j; k < i; k++) {
pos[i].x_offset -= pos[k].x_advance;
pos[i].y_offset -= pos[k].y_advance;
}
else
for (unsigned int k = j + 1; k < i + 1; k++) {
pos[i].x_offset += pos[k].x_advance;
pos[i].y_offset += pos[k].y_advance;
}
}
}
void
GPOS::position_start (hb_font_t *font HB_UNUSED, hb_buffer_t *buffer)
{
unsigned int count = buffer->len;
for (unsigned int i = 0; i < count; i++)
buffer->pos[i].attach_chain() = buffer->pos[i].attach_type() = 0;
}
void
GPOS::position_finish_advances (hb_font_t *font HB_UNUSED, hb_buffer_t *buffer HB_UNUSED)
{
//_hb_buffer_assert_gsubgpos_vars (buffer);
}
void
GPOS::position_finish_offsets (hb_font_t *font, hb_buffer_t *buffer)
{
_hb_buffer_assert_gsubgpos_vars (buffer);
unsigned int len;
hb_glyph_position_t *pos = hb_buffer_get_glyph_positions (buffer, &len);
hb_direction_t direction = buffer->props.direction;
/* Handle attachments */
if (buffer->scratch_flags & HB_BUFFER_SCRATCH_FLAG_HAS_GPOS_ATTACHMENT)
for (unsigned i = 0; i < len; i++)
propagate_attachment_offsets (pos, len, i, direction);
if (unlikely (font->slant))
{
for (unsigned i = 0; i < len; i++)
if (unlikely (pos[i].y_offset))
pos[i].x_offset += _hb_roundf (font->slant_xy * pos[i].y_offset);
}
}
}
struct GPOS_accelerator_t : Layout::GPOS::accelerator_t {
GPOS_accelerator_t (hb_face_t *face) : Layout::GPOS::accelerator_t (face) {}
};
}
#endif /* OT_LAYOUT_GPOS_GPOS_HH */
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