1use crate::hb::ot::layout::GPOS::mark_array::MarkArrayExt;
2use crate::hb::ot_layout::{_hb_glyph_info_get_lig_comp, _hb_glyph_info_get_lig_id};
3use crate::hb::ot_layout_common::lookup_flags;
4use crate::hb::ot_layout_gsubgpos::OT::hb_ot_apply_context_t;
5use crate::hb::ot_layout_gsubgpos::{match_t, skipping_iterator_t, Apply};
6use ttf_parser::gpos::MarkToLigatureAdjustment;
7
8impl Apply for MarkToLigatureAdjustment<'_> {
9 fn apply(&self, ctx: &mut hb_ot_apply_context_t) -> Option<()> {
10 let buffer = &ctx.buffer;
11 let mark_glyph = ctx.buffer.cur(0).as_glyph();
12 let mark_index = self.mark_coverage.get(mark_glyph)?;
13
14 // Due to borrowing rules, we have this piece of code before creating the
15 // iterator, unlike in harfbuzz.
16 if ctx.last_base_until > buffer.idx as u32 {
17 ctx.last_base_until = 0;
18 ctx.last_base = -1;
19 }
20
21 // Now we search backwards for a non-mark glyph
22 let mut iter = skipping_iterator_t::new(ctx, 0, false);
23 iter.set_lookup_props(u32::from(lookup_flags::IGNORE_MARKS));
24
25 let mut j = buffer.idx;
26 while j > ctx.last_base_until as usize {
27 let mut _match = iter.match_(&buffer.info[j - 1]);
28 if _match == match_t::MATCH {
29 ctx.last_base = j as i32 - 1;
30 break;
31 }
32 j -= 1;
33 }
34
35 ctx.last_base_until = buffer.idx as u32;
36
37 if ctx.last_base == -1 {
38 ctx.buffer
39 .unsafe_to_concat_from_outbuffer(Some(0), Some(buffer.idx + 1));
40 return None;
41 }
42
43 let idx = ctx.last_base as usize;
44
45 // Checking that matched glyph is actually a ligature by GDEF is too strong; disabled
46
47 let lig_glyph = buffer.info[idx].as_glyph();
48 let Some(lig_index) = self.ligature_coverage.get(lig_glyph) else {
49 ctx.buffer
50 .unsafe_to_concat_from_outbuffer(Some(idx), Some(buffer.idx + 1));
51 return None;
52 };
53 let lig_attach = self.ligature_array.get(lig_index)?;
54
55 // Find component to attach to
56 let comp_count = lig_attach.rows;
57 if comp_count == 0 {
58 ctx.buffer
59 .unsafe_to_concat_from_outbuffer(Some(idx), Some(buffer.idx + 1));
60 return None;
61 }
62
63 // We must now check whether the ligature ID of the current mark glyph
64 // is identical to the ligature ID of the found ligature. If yes, we
65 // can directly use the component index. If not, we attach the mark
66 // glyph to the last component of the ligature.
67 let lig_id = _hb_glyph_info_get_lig_id(&buffer.info[idx]);
68 let mark_id = _hb_glyph_info_get_lig_id(buffer.cur(0));
69 let mark_comp = u16::from(_hb_glyph_info_get_lig_comp(buffer.cur(0)));
70 let matches = lig_id != 0 && lig_id == mark_id && mark_comp > 0;
71 let comp_index = if matches {
72 mark_comp.min(comp_count)
73 } else {
74 comp_count
75 } - 1;
76
77 self.marks
78 .apply(ctx, lig_attach, mark_index, comp_index, idx)
79 }
80}
81