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ChainedSequenceContexts support, otf_metrics tweaks
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@archaephyrryx
archaephyrryx committed Nov 27, 2024
1 parent b2db848 commit 8e5585d
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Showing 3 changed files with 1,118 additions and 194 deletions.
169 changes: 158 additions & 11 deletions doodle-formats/src/format/opentype.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -384,9 +384,8 @@ pub fn main(module: &mut FormatModule, base: &BaseModule) -> FormatRef {
const SHORT_OFFSET16: u16 = 0;
const LONG_OFFSET32: u16 = 1;

let table_record = module.define_format_args(
let table_record = module.define_format(
"opentype.table_record",
vec![START_ARG],
record([
("table_id", tag.call()), // should be ascending within the repetition "table_records" field in table_directory
("checksum", base.u32be()),
Expand Down Expand Up @@ -2528,9 +2527,21 @@ pub fn main(module: &mut FormatModule, base: &BaseModule) -> FormatRef {
match_variant(
var("format"),
[
(Pattern::U16(1), "Format1", sequence_context_format1(var("table_start"))),
(Pattern::U16(2), "Format2", sequence_context_format2(var("table_start"))),
(Pattern::U16(3), "Format3", sequence_context_format3(var("table_start"))),
(
Pattern::U16(1),
"Format1",
sequence_context_format1(var("table_start")),
),
(
Pattern::U16(2),
"Format2",
sequence_context_format2(var("table_start")),
),
(
Pattern::U16(3),
"Format3",
sequence_context_format3(var("table_start")),
),
(Pattern::Wildcard, "BadFormat", Format::Fail),
],
),
Expand All @@ -2539,8 +2550,147 @@ pub fn main(module: &mut FormatModule, base: &BaseModule) -> FormatRef {
)
};
let chained_sequence_context = {
/* STUB */
module.define_format("opentype.common.chained_sequence_context", Format::EMPTY)
let rule_set = {
let chained_sequence_rule = record([
("backtrack_glyph_count", base.u16be()),
(
"backtrack_sequence",
repeat_count(var("backtrack_glyph_count"), base.u16be()),
),
("input_glyph_count", base.u16be()),
(
"input_sequence",
repeat_count(sub(var("input_glyph_count"), Expr::U16(1)), base.u16be()),
),
("lookahead_glyph_count", base.u16be()),
(
"lookahead_sequence",
repeat_count(var("lookahead_glyph_count"), base.u16be()),
),
("seq_lookup_count", base.u16be()),
(
"seq_lookup_records",
repeat_count(var("seq_lookup_count"), sequence_lookup_record.call()),
),
]);
record([
("table_start", pos32()),
("chained_seq_rule_count", base.u16be()),
(
"chained_seq_rules",
repeat_count(var("chained_seq_rule_count"), chained_sequence_rule),
),
])
};
let chained_sequence_context_format1 = |table_start: Expr| {
record([
(
"coverage",
offset16(table_start.clone(), coverage_table.call(), base),
),
("chained_seq_rule_set_count", base.u16be()),
(
"chained_seq_rule_sets",
repeat_count(
var("chained_seq_rule_set_count"),
offset16(table_start, rule_set.clone(), base),
),
),
])
};
let chained_sequence_context_format2 = |table_start: Expr| {
record([
(
"coverage",
offset16(table_start.clone(), coverage_table.call(), base),
),
(
"backtrack_class_def",
offset16(table_start.clone(), class_def.call(), base),
),
(
"input_class_def",
offset16(table_start.clone(), class_def.call(), base),
),
(
"lookahead_class_def",
offset16(table_start.clone(), class_def.call(), base),
),
("chained_class_seq_rule_set_count", base.u16be()),
(
"chained_class_seq_rule_sets",
repeat_count(
var("chained_class_seq_rule_set_count"),
offset16(table_start, rule_set.clone(), base),
),
),
])
};
let chained_sequence_context_format3 = |table_start: Expr| {
record([
("backtrack_glyph_count", base.u16be()),
(
"backtrack_coverages",
repeat_count(
var("backtrack_glyph_count"),
offset16(table_start.clone(), coverage_table.call(), base),
),
),
("input_glyph_count", base.u16be()),
(
"input_coverages",
repeat_count(
var("input_glyph_count"),
offset16(table_start.clone(), coverage_table.call(), base),
),
),
("lookahead_glyph_count", base.u16be()),
(
"lookahead_coverages",
repeat_count(
var("lookahead_glyph_count"),
offset16(table_start, coverage_table.call(), base),
),
),
("seq_lookup_count", base.u16be()),
(
"seq_lookup_records",
repeat_count(var("seq_lookup_count"), sequence_lookup_record.call()),
),
])
};
module.define_format(
"opentype.common.chained_sequence_context",
record([
("table_start", pos32()),
("format", base.u16be()),
// REVIEW - this is a GSUB-biased field-name, do we have a better field-name for this?
(
"subst",
match_variant(
var("format"),
[
(
Pattern::U16(1),
"Format1",
chained_sequence_context_format1(var("table_start")),
),
(
Pattern::U16(2),
"Format2",
chained_sequence_context_format2(var("table_start")),
),
(
Pattern::U16(3),
"Format3",
chained_sequence_context_format3(var("table_start")),
),
(Pattern::Wildcard, "BadFormat", Format::Fail),
],
),
),
]),
)
};

let layout_table = |tag: u32| {
Expand Down Expand Up @@ -3108,10 +3258,7 @@ pub fn main(module: &mut FormatModule, base: &BaseModule) -> FormatRef {
("range_shift", base.u16be()), // TODO[validation] - should be (NumTables x 16) - searchRange
(
"table_records",
repeat_count(
var("num_tables"),
table_record.call_args(vec![var("start")]),
),
repeat_count(var("num_tables"), table_record.call()),
),
(
"table_links",
Expand Down
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