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Diffstat (limited to 'library/src/math/accent.rs')
| -rw-r--r-- | library/src/math/accent.rs | 139 |
1 files changed, 0 insertions, 139 deletions
diff --git a/library/src/math/accent.rs b/library/src/math/accent.rs deleted file mode 100644 index d1bee198..00000000 --- a/library/src/math/accent.rs +++ /dev/null @@ -1,139 +0,0 @@ -use super::*; - -/// How much the accent can be shorter than the base. -const ACCENT_SHORT_FALL: Em = Em::new(0.5); - -/// Attaches an accent to a base. -/// -/// ## Example { #example } -/// ```example -/// $grave(a) = accent(a, `)$ \ -/// $arrow(a) = accent(a, arrow)$ \ -/// $tilde(a) = accent(a, \u{0303})$ -/// ``` -/// -/// Display: Accent -/// Category: math -#[element(LayoutMath)] -pub struct AccentElem { - /// The base to which the accent is applied. - /// May consist of multiple letters. - /// - /// ```example - /// $arrow(A B C)$ - /// ``` - #[required] - pub base: Content, - - /// The accent to apply to the base. - /// - /// Supported accents include: - /// - /// | Accent | Name | Codepoint | - /// | ------------- | --------------- | --------- | - /// | Grave | `grave` | <code>`</code> | - /// | Acute | `acute` | `´` | - /// | Circumflex | `hat` | `^` | - /// | Tilde | `tilde` | `~` | - /// | Macron | `macron` | `¯` | - /// | Breve | `breve` | `˘` | - /// | Dot | `dot` | `.` | - /// | Double dot | `dot.double` | `¨` | - /// | Triple dot | `dot.triple` | <code>⃛</code> | - /// | Quadruple dot | `dot.quad` | <code>⃜</code> | - /// | Diaeresis | `diaer` | `¨` | - /// | Circle | `circle` | `∘` | - /// | Double acute | `acute.double` | `˝` | - /// | Caron | `caron` | `ˇ` | - /// | Right arrow | `arrow`, `->` | `→` | - /// | Left arrow | `arrow.l`, `<-` | `←` | - #[required] - pub accent: Accent, -} - -impl LayoutMath for AccentElem { - #[tracing::instrument(skip(ctx))] - fn layout_math(&self, ctx: &mut MathContext) -> SourceResult<()> { - ctx.style(ctx.style.with_cramped(true)); - let base = ctx.layout_fragment(&self.base())?; - ctx.unstyle(); - - // Preserve class to preserve automatic spacing. - let base_class = base.class().unwrap_or(MathClass::Normal); - let base_attach = match &base { - MathFragment::Glyph(base) => { - attachment(ctx, base.id, base.italics_correction) - } - _ => (base.width() + base.italics_correction()) / 2.0, - }; - - // Forcing the accent to be at least as large as the base makes it too - // wide in many case. - let Accent(c) = self.accent(); - let glyph = GlyphFragment::new(ctx, c, self.span()); - let short_fall = ACCENT_SHORT_FALL.scaled(ctx); - let variant = glyph.stretch_horizontal(ctx, base.width(), short_fall); - let accent = variant.frame; - let accent_attach = match variant.id { - Some(id) => attachment(ctx, id, variant.italics_correction), - None => accent.width() / 2.0, - }; - - // Descent is negative because the accent's ink bottom is above the - // baseline. Therefore, the default gap is the accent's negated descent - // minus the accent base height. Only if the base is very small, we need - // a larger gap so that the accent doesn't move too low. - let accent_base_height = scaled!(ctx, accent_base_height); - let gap = -accent.descent() - base.height().min(accent_base_height); - let size = Size::new(base.width(), accent.height() + gap + base.height()); - let accent_pos = Point::with_x(base_attach - accent_attach); - let base_pos = Point::with_y(accent.height() + gap); - let base_ascent = base.ascent(); - let baseline = base_pos.y + base.ascent(); - - let mut frame = Frame::new(size); - frame.set_baseline(baseline); - frame.push_frame(accent_pos, accent); - frame.push_frame(base_pos, base.into_frame()); - ctx.push( - FrameFragment::new(ctx, frame) - .with_class(base_class) - .with_base_ascent(base_ascent), - ); - - Ok(()) - } -} - -/// The horizontal attachment position for the given glyph. -fn attachment(ctx: &MathContext, id: GlyphId, italics_correction: Abs) -> Abs { - ctx.table - .glyph_info - .and_then(|info| info.top_accent_attachments) - .and_then(|attachments| attachments.get(id)) - .map(|record| record.value.scaled(ctx)) - .unwrap_or_else(|| { - let advance = ctx.ttf.glyph_hor_advance(id).unwrap_or_default(); - (advance.scaled(ctx) + italics_correction) / 2.0 - }) -} - -/// An accent character. -pub struct Accent(char); - -impl Accent { - /// Normalize a character into an accent. - pub fn new(c: char) -> Self { - Self(Symbol::combining_accent(c).unwrap_or(c)) - } -} - -cast! { - Accent, - self => self.0.into_value(), - v: char => Self::new(v), - v: Content => match v.to::<TextElem>() { - Some(elem) => Value::Str(elem.text().into()).cast()?, - None => bail!("expected text"), - }, -} |