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| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,115 @@ | ||
| //! A [Vertical Metrics Variations Table]( | ||
| //! https://docs.microsoft.com/en-us/typography/opentype/spec/hvar) implementation. | ||
|
|
||
| use crate::delta_set::DeltaSetIndexMap; | ||
| use crate::parser::{Offset, Offset32, Stream}; | ||
| use crate::var_store::ItemVariationStore; | ||
| use crate::{GlyphId, NormalizedCoordinate}; | ||
|
|
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| /// A [Vertical Metrics Variations Table]( | ||
| /// https://docs.microsoft.com/en-us/typography/opentype/spec/hvar). | ||
| #[derive(Clone, Copy)] | ||
| pub struct Table<'a> { | ||
| data: &'a [u8], | ||
| variation_store: ItemVariationStore<'a>, | ||
| advance_height_mapping_offset: Option<Offset32>, | ||
| tsb_mapping_offset: Option<Offset32>, | ||
| bsb_mapping_offset: Option<Offset32>, | ||
| vorg_mapping_offset: Option<Offset32>, | ||
| } | ||
|
|
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| impl<'a> Table<'a> { | ||
| /// Parses a table from raw data. | ||
| pub fn parse(data: &'a [u8]) -> Option<Self> { | ||
| let mut s = Stream::new(data); | ||
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|
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| let version = s.read::<u32>()?; | ||
| if version != 0x00010000 { | ||
| return None; | ||
| } | ||
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|
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| let variation_store_offset = s.read::<Offset32>()?; | ||
| let var_store_s = Stream::new_at(data, variation_store_offset.to_usize())?; | ||
| let variation_store = ItemVariationStore::parse(var_store_s)?; | ||
|
|
||
| Some(Table { | ||
| data, | ||
| variation_store, | ||
| advance_height_mapping_offset: s.read::<Option<Offset32>>()?, | ||
| tsb_mapping_offset: s.read::<Option<Offset32>>()?, | ||
| bsb_mapping_offset: s.read::<Option<Offset32>>()?, | ||
| vorg_mapping_offset: s.read::<Option<Offset32>>()?, | ||
| }) | ||
| } | ||
|
|
||
| /// Returns the advance height offset for a glyph. | ||
| #[inline] | ||
| pub fn advance_offset( | ||
| &self, | ||
| glyph_id: GlyphId, | ||
| coordinates: &[NormalizedCoordinate], | ||
| ) -> Option<f32> { | ||
| let (outer_idx, inner_idx) = if let Some(offset) = self.advance_height_mapping_offset { | ||
| DeltaSetIndexMap::new(self.data.get(offset.to_usize()..)?).map(glyph_id.0 as u32)? | ||
| } else { | ||
| // 'If there is no delta-set index mapping table for advance widths, | ||
| // then glyph IDs implicitly provide the indices: | ||
| // for a given glyph ID, the delta-set outer-level index is zero, | ||
| // and the glyph ID is the delta-set inner-level index.' | ||
| (0, glyph_id.0) | ||
| }; | ||
|
|
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| self.variation_store | ||
| .parse_delta(outer_idx, inner_idx, coordinates) | ||
| } | ||
|
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| /// Returns the top side bearing offset for a glyph. | ||
| #[inline] | ||
| pub fn top_side_bearing_offset( | ||
| &self, | ||
| glyph_id: GlyphId, | ||
| coordinates: &[NormalizedCoordinate], | ||
| ) -> Option<f32> { | ||
| let set_data = self.data.get(self.tsb_mapping_offset?.to_usize()..)?; | ||
| self.side_bearing_offset(glyph_id, coordinates, set_data) | ||
| } | ||
|
|
||
| /// Returns the bottom side bearing offset for a glyph. | ||
| #[inline] | ||
| pub fn bottom_side_bearing_offset( | ||
| &self, | ||
| glyph_id: GlyphId, | ||
| coordinates: &[NormalizedCoordinate], | ||
| ) -> Option<f32> { | ||
| let set_data = self.data.get(self.bsb_mapping_offset?.to_usize()..)?; | ||
| self.side_bearing_offset(glyph_id, coordinates, set_data) | ||
| } | ||
|
|
||
| /// Returns the vertical origin offset for a glyph. | ||
| #[inline] | ||
| pub fn vertical_origin_offset( | ||
| &self, | ||
| glyph_id: GlyphId, | ||
| coordinates: &[NormalizedCoordinate], | ||
| ) -> Option<f32> { | ||
| let set_data = self.data.get(self.vorg_mapping_offset?.to_usize()..)?; | ||
| self.side_bearing_offset(glyph_id, coordinates, set_data) | ||
| } | ||
|
|
||
| fn side_bearing_offset( | ||
| &self, | ||
| glyph_id: GlyphId, | ||
| coordinates: &[NormalizedCoordinate], | ||
| set_data: &[u8], | ||
| ) -> Option<f32> { | ||
| let (outer_idx, inner_idx) = DeltaSetIndexMap::new(set_data).map(glyph_id.0 as u32)?; | ||
| self.variation_store | ||
| .parse_delta(outer_idx, inner_idx, coordinates) | ||
| } | ||
| } | ||
|
|
||
| impl core::fmt::Debug for Table<'_> { | ||
| fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { | ||
| write!(f, "Table {{ ... }}") | ||
| } | ||
| } |