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