55 lines
1.8 KiB
Rust
55 lines
1.8 KiB
Rust
// https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-13-many-to-one-range-mappings
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use core::convert::TryFrom;
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use super::format12::SequentialMapGroup;
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use crate::parser::{LazyArray32, Stream};
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use crate::GlyphId;
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/// A [format 13](https://docs.microsoft.com/en-us/typography/opentype/spec/cmap#format-13-segmented-coverage)
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/// subtable.
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#[derive(Clone, Copy)]
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pub struct Subtable13<'a> {
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groups: LazyArray32<'a, SequentialMapGroup>,
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}
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impl<'a> Subtable13<'a> {
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/// Parses a subtable from raw data.
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pub fn parse(data: &'a [u8]) -> Option<Self> {
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let mut s = Stream::new(data);
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s.skip::<u16>(); // format
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s.skip::<u16>(); // reserved
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s.skip::<u32>(); // length
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s.skip::<u32>(); // language
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let count = s.read::<u32>()?;
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let groups = s.read_array32::<super::format12::SequentialMapGroup>(count)?;
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Some(Self { groups })
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}
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/// Returns a glyph index for a code point.
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pub fn glyph_index(&self, code_point: u32) -> Option<GlyphId> {
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for group in self.groups {
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let start_char_code = group.start_char_code;
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if code_point >= start_char_code && code_point <= group.end_char_code {
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return u16::try_from(group.start_glyph_id).ok().map(GlyphId);
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}
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}
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None
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}
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/// Calls `f` for each codepoint defined in this table.
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pub fn codepoints(&self, mut f: impl FnMut(u32)) {
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for group in self.groups {
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for code_point in group.start_char_code..=group.end_char_code {
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f(code_point);
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}
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}
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}
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}
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impl core::fmt::Debug for Subtable13<'_> {
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fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
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write!(f, "Subtable13 {{ ... }}")
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}
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}
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