Vendor things

third-party/vendor/ttf-parser-0.15.2/src/tables/os2.rs

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+//! A [OS/2 and Windows Metrics Table](https://docs.microsoft.com/en-us/typography/opentype/spec/os2)
+//! implementation.
+
+use crate::LineMetrics;
+use crate::parser::Stream;
+
+const WEIGHT_CLASS_OFFSET: usize = 4;
+const WIDTH_CLASS_OFFSET: usize = 6;
+const Y_SUBSCRIPT_X_SIZE_OFFSET: usize = 10;
+const Y_SUPERSCRIPT_X_SIZE_OFFSET: usize = 18;
+const Y_STRIKEOUT_SIZE_OFFSET: usize = 26;
+const Y_STRIKEOUT_POSITION_OFFSET: usize = 28;
+const FS_SELECTION_OFFSET: usize = 62;
+const TYPO_ASCENDER_OFFSET: usize = 68;
+const TYPO_DESCENDER_OFFSET: usize = 70;
+const TYPO_LINE_GAP_OFFSET: usize = 72;
+const WIN_ASCENT: usize = 74;
+const WIN_DESCENT: usize = 76;
+const X_HEIGHT_OFFSET: usize = 86;
+const CAP_HEIGHT_OFFSET: usize = 88;
+
+/// A face [weight](https://docs.microsoft.com/en-us/typography/opentype/spec/os2#usweightclass).
+#[allow(missing_docs)]
+#[derive(Clone, Copy, Eq, PartialEq, Debug, Hash)]
+pub enum Weight {
+    Thin,
+    ExtraLight,
+    Light,
+    Normal,
+    Medium,
+    SemiBold,
+    Bold,
+    ExtraBold,
+    Black,
+    Other(u16),
+}
+
+impl Weight {
+    /// Returns a numeric representation of a weight.
+    #[inline]
+    pub fn to_number(self) -> u16 {
+        match self {
+            Weight::Thin        => 100,
+            Weight::ExtraLight  => 200,
+            Weight::Light       => 300,
+            Weight::Normal      => 400,
+            Weight::Medium      => 500,
+            Weight::SemiBold    => 600,
+            Weight::Bold        => 700,
+            Weight::ExtraBold   => 800,
+            Weight::Black       => 900,
+            Weight::Other(n)    => n,
+        }
+    }
+}
+
+impl From<u16> for Weight {
+    #[inline]
+    fn from(value: u16) -> Self {
+        match value {
+            100 => Weight::Thin,
+            200 => Weight::ExtraLight,
+            300 => Weight::Light,
+            400 => Weight::Normal,
+            500 => Weight::Medium,
+            600 => Weight::SemiBold,
+            700 => Weight::Bold,
+            800 => Weight::ExtraBold,
+            900 => Weight::Black,
+            _   => Weight::Other(value),
+        }
+    }
+}
+
+impl Default for Weight {
+    #[inline]
+    fn default() -> Self {
+        Weight::Normal
+    }
+}
+
+
+/// A face [width](https://docs.microsoft.com/en-us/typography/opentype/spec/os2#uswidthclass).
+#[allow(missing_docs)]
+#[derive(Clone, Copy, Eq, PartialEq, Ord, PartialOrd, Debug, Hash)]
+pub enum Width {
+    UltraCondensed,
+    ExtraCondensed,
+    Condensed,
+    SemiCondensed,
+    Normal,
+    SemiExpanded,
+    Expanded,
+    ExtraExpanded,
+    UltraExpanded,
+}
+
+impl Width {
+    /// Returns a numeric representation of a width.
+    #[inline]
+    pub fn to_number(self) -> u16 {
+        match self {
+            Width::UltraCondensed   => 1,
+            Width::ExtraCondensed   => 2,
+            Width::Condensed        => 3,
+            Width::SemiCondensed    => 4,
+            Width::Normal           => 5,
+            Width::SemiExpanded     => 6,
+            Width::Expanded         => 7,
+            Width::ExtraExpanded    => 8,
+            Width::UltraExpanded    => 9,
+        }
+    }
+}
+
+impl Default for Width {
+    #[inline]
+    fn default() -> Self {
+        Width::Normal
+    }
+}
+
+
+/// A face style.
+#[derive(Clone, Copy, PartialEq, Eq, Debug, Hash)]
+pub enum Style {
+    /// A face that is neither italic not obliqued.
+    Normal,
+    /// A form that is generally cursive in nature.
+    Italic,
+    /// A typically-sloped version of the regular face.
+    Oblique,
+}
+
+impl Default for Style {
+    #[inline]
+    fn default() -> Style {
+        Style::Normal
+    }
+}
+
+
+/// A script metrics used by subscript and superscript.
+#[repr(C)]
+#[derive(Clone, Copy, Eq, PartialEq, Debug, Hash)]
+pub struct ScriptMetrics {
+    /// Horizontal face size.
+    pub x_size: i16,
+
+    /// Vertical face size.
+    pub y_size: i16,
+
+    /// X offset.
+    pub x_offset: i16,
+
+    /// Y offset.
+    pub y_offset: i16,
+}
+
+
+// https://docs.microsoft.com/en-us/typography/opentype/spec/os2#fsselection
+#[derive(Clone, Copy)]
+struct SelectionFlags(u16);
+
+impl SelectionFlags {
+    #[inline] fn italic(self) -> bool { self.0 & (1 << 0) != 0 }
+    #[inline] fn bold(self) -> bool { self.0 & (1 << 5) != 0 }
+    // #[inline] fn regular(self) -> bool { self.0 & (1 << 6) != 0 }
+    #[inline] fn use_typo_metrics(self) -> bool { self.0 & (1 << 7) != 0 }
+    #[inline] fn oblique(self) -> bool { self.0 & (1 << 9) != 0 }
+}
+
+
+/// A [OS/2 and Windows Metrics Table](https://docs.microsoft.com/en-us/typography/opentype/spec/os2).
+#[derive(Clone, Copy)]
+pub struct Table<'a> {
+    /// Table version.
+    pub version: u8,
+    data: &'a [u8],
+}
+
+impl<'a> Table<'a> {
+    /// Parses a table from raw data.
+    pub fn parse(data: &'a [u8]) -> Option<Self> {
+        let mut s = Stream::new(data);
+        let version = s.read::<u16>()?;
+
+        let table_len = match version {
+            0 => 78,
+            1 => 86,
+            2 => 96,
+            3 => 96,
+            4 => 96,
+            5 => 100,
+            _ => return None,
+        };
+
+        if data.len() != table_len {
+            return None;
+        }
+
+        Some(Table {
+            version: version as u8,
+            data,
+        })
+    }
+
+    /// Returns weight class.
+    #[inline]
+    pub fn weight(&self) -> Weight {
+        Weight::from(Stream::read_at::<u16>(self.data, WEIGHT_CLASS_OFFSET).unwrap_or(0))
+    }
+
+    /// Returns face width.
+    #[inline]
+    pub fn width(&self) -> Width {
+        match Stream::read_at::<u16>(self.data, WIDTH_CLASS_OFFSET).unwrap_or(0) {
+            1 => Width::UltraCondensed,
+            2 => Width::ExtraCondensed,
+            3 => Width::Condensed,
+            4 => Width::SemiCondensed,
+            5 => Width::Normal,
+            6 => Width::SemiExpanded,
+            7 => Width::Expanded,
+            8 => Width::ExtraExpanded,
+            9 => Width::UltraExpanded,
+            _ => Width::Normal,
+        }
+    }
+
+    /// Returns subscript metrics.
+    #[inline]
+    pub fn subscript_metrics(&self) -> ScriptMetrics {
+        let mut s = Stream::new_at(self.data, Y_SUBSCRIPT_X_SIZE_OFFSET).unwrap_or_default();
+        ScriptMetrics {
+            x_size: s.read::<i16>().unwrap_or(0),
+            y_size: s.read::<i16>().unwrap_or(0),
+            x_offset: s.read::<i16>().unwrap_or(0),
+            y_offset: s.read::<i16>().unwrap_or(0),
+        }
+    }
+
+    /// Returns superscript metrics.
+    #[inline]
+    pub fn superscript_metrics(&self) -> ScriptMetrics {
+        let mut s = Stream::new_at(self.data, Y_SUPERSCRIPT_X_SIZE_OFFSET).unwrap_or_default();
+        ScriptMetrics {
+            x_size: s.read::<i16>().unwrap_or(0),
+            y_size: s.read::<i16>().unwrap_or(0),
+            x_offset: s.read::<i16>().unwrap_or(0),
+            y_offset: s.read::<i16>().unwrap_or(0),
+        }
+    }
+
+    /// Returns strikeout metrics.
+    #[inline]
+    pub fn strikeout_metrics(&self) -> LineMetrics {
+        LineMetrics {
+            thickness: Stream::read_at::<i16>(self.data, Y_STRIKEOUT_SIZE_OFFSET).unwrap_or(0),
+            position: Stream::read_at::<i16>(self.data, Y_STRIKEOUT_POSITION_OFFSET).unwrap_or(0),
+        }
+    }
+
+    #[inline]
+    fn fs_selection(&self) -> u16 {
+        Stream::read_at::<u16>(self.data, FS_SELECTION_OFFSET).unwrap_or(0)
+    }
+
+    /// Returns style.
+    pub fn style(&self) -> Style {
+        let flags = SelectionFlags(self.fs_selection());
+        if flags.italic() {
+            Style::Italic
+        } else if self.version >= 4 && flags.oblique() {
+            Style::Oblique
+        } else {
+            Style::Normal
+        }
+    }
+
+    /// Checks if face is bold.
+    ///
+    /// Do not confuse with [`Weight::Bold`].
+    #[inline]
+    pub fn is_bold(&self) -> bool {
+        SelectionFlags(self.fs_selection()).bold()
+    }
+
+    /// Checks if typographic metrics should be used.
+    #[inline]
+    pub fn use_typographic_metrics(&self) -> bool {
+        if self.version < 4 {
+            false
+        } else {
+            SelectionFlags(self.fs_selection()).use_typo_metrics()
+        }
+    }
+
+    /// Returns typographic ascender.
+    #[inline]
+    pub fn typographic_ascender(&self) -> i16 {
+        Stream::read_at::<i16>(self.data, TYPO_ASCENDER_OFFSET).unwrap_or(0)
+    }
+
+    /// Returns typographic descender.
+    #[inline]
+    pub fn typographic_descender(&self) -> i16 {
+        Stream::read_at::<i16>(self.data, TYPO_DESCENDER_OFFSET).unwrap_or(0)
+    }
+
+    /// Returns typographic line gap.
+    #[inline]
+    pub fn typographic_line_gap(&self) -> i16 {
+        Stream::read_at::<i16>(self.data, TYPO_LINE_GAP_OFFSET).unwrap_or(0)
+    }
+
+    /// Returns Windows ascender.
+    #[inline]
+    pub fn windows_ascender(&self) -> i16 {
+        Stream::read_at::<i16>(self.data, WIN_ASCENT).unwrap_or(0)
+    }
+
+    /// Returns Windows descender.
+    #[inline]
+    pub fn windows_descender(&self) -> i16 {
+        // Should be negated.
+        -Stream::read_at::<i16>(self.data, WIN_DESCENT).unwrap_or(0)
+    }
+
+    /// Returns x height.
+    ///
+    /// Returns `None` version is < 2.
+    #[inline]
+    pub fn x_height(&self) -> Option<i16> {
+        if self.version < 2 {
+            None
+        } else {
+            Stream::read_at::<i16>(self.data, X_HEIGHT_OFFSET)
+        }
+    }
+
+    /// Returns capital height.
+    ///
+    /// Returns `None` version is < 2.
+    #[inline]
+    pub fn capital_height(&self) -> Option<i16> {
+        if self.version < 2 {
+            None
+        } else {
+            Stream::read_at::<i16>(self.data, CAP_HEIGHT_OFFSET)
+        }
+    }
+}
+
+impl core::fmt::Debug for Table<'_> {
+    fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result {
+        write!(f, "Table {{ ... }}")
+    }
+}