Move math styling to codex and add math.scr (#6309)

Cargo.lock

@@ -413,7 +413,7 @@ dependencies = [
 [[package]]
 name = "codex"
 version = "0.1.1"
-source = "git+https://github.com/typst/codex?rev=a5428cb#a5428cb9c81a41354d44b44dbd5a16a710bbd928"
+source = "git+https://github.com/typst/codex?rev=9ac86f9#9ac86f96af5b89fce555e6bba8b6d1ac7b44ef00"
 
 [[package]]
 name = "color-print"
@@ -2861,7 +2861,7 @@ dependencies = [
 [[package]]
 name = "typst-assets"
 version = "0.13.1"
-source = "git+https://github.com/typst/typst-assets?rev=c1089b4#c1089b46c461bdde579c55caa941a3cc7dec3e8a"
+source = "git+https://github.com/typst/typst-assets?rev=edf0d64#edf0d648376e29738a05a933af9ea99bb81557b1"
 
 [[package]]
 name = "typst-cli"
@@ -3032,6 +3032,7 @@ version = "0.13.1"
 dependencies = [
  "az",
  "bumpalo",
+ "codex",
  "comemo",
  "ecow",
  "hypher",

Cargo.toml

@@ -32,7 +32,7 @@ typst-svg = { path = "crates/typst-svg", version = "0.13.1" }
 typst-syntax = { path = "crates/typst-syntax", version = "0.13.1" }
 typst-timing = { path = "crates/typst-timing", version = "0.13.1" }
 typst-utils = { path = "crates/typst-utils", version = "0.13.1" }
-typst-assets = { git = "https://github.com/typst/typst-assets", rev = "c1089b4" }
+typst-assets = { git = "https://github.com/typst/typst-assets", rev = "edf0d64" }
 typst-dev-assets = { git = "https://github.com/typst/typst-dev-assets", rev = "bfa947f" }
 arrayvec = "0.7.4"
 az = "1.2"
@@ -47,7 +47,7 @@ clap = { version = "4.4", features = ["derive", "env", "wrap_help"] }
 clap_complete = "4.2.1"
 clap_mangen = "0.2.10"
 codespan-reporting = "0.11"
-codex = { git = "https://github.com/typst/codex", rev = "a5428cb" }
+codex = { git = "https://github.com/typst/codex", rev = "9ac86f9" }
 color-print = "0.3.6"
 comemo = "0.4"
 csv = "1"

crates/typst-layout/Cargo.toml

@@ -21,6 +21,7 @@ typst-timing = { workspace = true }
 typst-utils = { workspace = true }
 az = { workspace = true }
 bumpalo = { workspace = true }
+codex = { workspace = true }
 comemo = { workspace = true }
 ecow = { workspace = true }
 hypher = { workspace = true }

crates/typst-layout/src/math/text.rs

@@ -1,10 +1,11 @@
 use std::f64::consts::SQRT_2;
 
+use codex::styling::{to_style, MathStyle};
 use ecow::EcoString;
 use typst_library::diag::SourceResult;
 use typst_library::foundations::{Packed, StyleChain, SymbolElem};
 use typst_library::layout::{Abs, Size};
-use typst_library::math::{EquationElem, MathSize, MathVariant};
+use typst_library::math::{EquationElem, MathSize};
 use typst_library::text::{
     BottomEdge, BottomEdgeMetric, TextElem, TopEdge, TopEdgeMetric,
 };
@@ -64,12 +65,21 @@ fn layout_inline_text(
     ctx: &mut MathContext,
     styles: StyleChain,
 ) -> SourceResult<FrameFragment> {
+    let variant = styles.get(EquationElem::variant);
+    let bold = styles.get(EquationElem::bold);
+    // Disable auto-italic.
+    let italic = styles.get(EquationElem::italic).or(Some(false));
+
     if text.chars().all(|c| c.is_ascii_digit() || c == '.') {
         // Small optimization for numbers. Note that this lays out slightly
         // differently to normal text and is worth re-evaluating in the future.
         let mut fragments = vec![];
         for unstyled_c in text.chars() {
-            let c = styled_char(styles, unstyled_c, false);
+            // This is fine as ascii digits and '.' can never end up as more
+            // than a single char after styling.
+            let style = MathStyle::select(unstyled_c, variant, bold, italic);
+            let c = to_style(unstyled_c, style).next().unwrap();
+
             let glyph = GlyphFragment::new_char(ctx.font, styles, c, span)?;
             fragments.push(glyph.into());
         }
@@ -83,8 +93,10 @@ fn layout_inline_text(
         .map(|p| p.wrap());
 
         let styles = styles.chain(&local);
-        let styled_text: EcoString =
-            text.chars().map(|c| styled_char(styles, c, false)).collect();
+        let styled_text: EcoString = text
+            .chars()
+            .flat_map(|c| to_style(c, MathStyle::select(c, variant, bold, italic)))
+            .collect();
 
         let spaced = styled_text.graphemes(true).nth(1).is_some();
         let elem = TextElem::packed(styled_text).spanned(span);
@@ -124,9 +136,16 @@ pub fn layout_symbol(
         Some(c) if has_dtls_feat(ctx.font) => (c, styles.chain(&dtls)),
         _ => (elem.text, styles),
     };
-    let c = styled_char(styles, unstyled_c, true);
+
+    let variant = styles.get(EquationElem::variant);
+    let bold = styles.get(EquationElem::bold);
+    let italic = styles.get(EquationElem::italic);
+
+    let style = MathStyle::select(unstyled_c, variant, bold, italic);
+    let text: EcoString = to_style(unstyled_c, style).collect();
+
     let fragment: MathFragment =
-        match GlyphFragment::new_char(ctx.font, symbol_styles, c, elem.span()) {
+        match GlyphFragment::new(ctx.font, symbol_styles, &text, elem.span()) {
             Ok(mut glyph) => {
                 adjust_glyph_layout(&mut glyph, ctx, styles);
                 glyph.into()
@@ -134,8 +153,7 @@ pub fn layout_symbol(
             Err(_) => {
                 // Not in the math font, fallback to normal inline text layout.
                 // TODO: Should replace this with proper fallback in [`GlyphFragment::new`].
-                layout_inline_text(c.encode_utf8(&mut [0; 4]), elem.span(), ctx, styles)?
-                    .into()
+                layout_inline_text(&text, elem.span(), ctx, styles)?.into()
             }
         };
     ctx.push(fragment);
@@ -161,226 +179,6 @@ fn adjust_glyph_layout(
     }
 }
 
-/// Style the character by selecting the unicode codepoint for italic, bold,
-/// caligraphic, etc.
-///
-/// <https://www.w3.org/TR/mathml-core/#new-text-transform-mappings>
-/// <https://en.wikipedia.org/wiki/Mathematical_Alphanumeric_Symbols>
-fn styled_char(styles: StyleChain, c: char, auto_italic: bool) -> char {
-    use MathVariant::*;
-
-    let variant = styles.get(EquationElem::variant);
-    let bold = styles.get(EquationElem::bold);
-    let italic = styles.get(EquationElem::italic).unwrap_or(
-        auto_italic
-            && matches!(
-                c,
-                'a'..='z' | 'ħ' | 'ı' | 'ȷ' | 'A'..='Z' |
-                'α'..='ω' | '∂' | 'ϵ' | 'ϑ' | 'ϰ' | 'ϕ' | 'ϱ' | 'ϖ'
-            )
-            && matches!(variant, Sans | Serif),
-    );
-
-    if let Some(c) = basic_exception(c) {
-        return c;
-    }
-
-    if let Some(c) = latin_exception(c, variant, bold, italic) {
-        return c;
-    }
-
-    if let Some(c) = greek_exception(c, variant, bold, italic) {
-        return c;
-    }
-
-    let base = match c {
-        'A'..='Z' => 'A',
-        'a'..='z' => 'a',
-        'Α'..='Ω' => 'Α',
-        'α'..='ω' => 'α',
-        '0'..='9' => '0',
-        // Hebrew Alef -> Dalet.
-        '\u{05D0}'..='\u{05D3}' => '\u{05D0}',
-        _ => return c,
-    };
-
-    let tuple = (variant, bold, italic);
-    let start = match c {
-        // Latin upper.
-        'A'..='Z' => match tuple {
-            (Serif, false, false) => 0x0041,
-            (Serif, true, false) => 0x1D400,
-            (Serif, false, true) => 0x1D434,
-            (Serif, true, true) => 0x1D468,
-            (Sans, false, false) => 0x1D5A0,
-            (Sans, true, false) => 0x1D5D4,
-            (Sans, false, true) => 0x1D608,
-            (Sans, true, true) => 0x1D63C,
-            (Cal, false, _) => 0x1D49C,
-            (Cal, true, _) => 0x1D4D0,
-            (Frak, false, _) => 0x1D504,
-            (Frak, true, _) => 0x1D56C,
-            (Mono, _, _) => 0x1D670,
-            (Bb, _, _) => 0x1D538,
-        },
-
-        // Latin lower.
-        'a'..='z' => match tuple {
-            (Serif, false, false) => 0x0061,
-            (Serif, true, false) => 0x1D41A,
-            (Serif, false, true) => 0x1D44E,
-            (Serif, true, true) => 0x1D482,
-            (Sans, false, false) => 0x1D5BA,
-            (Sans, true, false) => 0x1D5EE,
-            (Sans, false, true) => 0x1D622,
-            (Sans, true, true) => 0x1D656,
-            (Cal, false, _) => 0x1D4B6,
-            (Cal, true, _) => 0x1D4EA,
-            (Frak, false, _) => 0x1D51E,
-            (Frak, true, _) => 0x1D586,
-            (Mono, _, _) => 0x1D68A,
-            (Bb, _, _) => 0x1D552,
-        },
-
-        // Greek upper.
-        'Α'..='Ω' => match tuple {
-            (Serif, false, false) => 0x0391,
-            (Serif, true, false) => 0x1D6A8,
-            (Serif, false, true) => 0x1D6E2,
-            (Serif, true, true) => 0x1D71C,
-            (Sans, _, false) => 0x1D756,
-            (Sans, _, true) => 0x1D790,
-            (Cal | Frak | Mono | Bb, _, _) => return c,
-        },
-
-        // Greek lower.
-        'α'..='ω' => match tuple {
-            (Serif, false, false) => 0x03B1,
-            (Serif, true, false) => 0x1D6C2,
-            (Serif, false, true) => 0x1D6FC,
-            (Serif, true, true) => 0x1D736,
-            (Sans, _, false) => 0x1D770,
-            (Sans, _, true) => 0x1D7AA,
-            (Cal | Frak | Mono | Bb, _, _) => return c,
-        },
-
-        // Hebrew Alef -> Dalet.
-        '\u{05D0}'..='\u{05D3}' => 0x2135,
-
-        // Numbers.
-        '0'..='9' => match tuple {
-            (Serif, false, _) => 0x0030,
-            (Serif, true, _) => 0x1D7CE,
-            (Bb, _, _) => 0x1D7D8,
-            (Sans, false, _) => 0x1D7E2,
-            (Sans, true, _) => 0x1D7EC,
-            (Mono, _, _) => 0x1D7F6,
-            (Cal | Frak, _, _) => return c,
-        },
-
-        _ => unreachable!(),
-    };
-
-    std::char::from_u32(start + (c as u32 - base as u32)).unwrap()
-}
-
-fn basic_exception(c: char) -> Option<char> {
-    Some(match c {
-        '〈' => '⟨',
-        '〉' => '⟩',
-        '《' => '⟪',
-        '》' => '⟫',
-        _ => return None,
-    })
-}
-
-fn latin_exception(
-    c: char,
-    variant: MathVariant,
-    bold: bool,
-    italic: bool,
-) -> Option<char> {
-    use MathVariant::*;
-    Some(match (c, variant, bold, italic) {
-        ('B', Cal, false, _) => 'ℬ',
-        ('E', Cal, false, _) => 'ℰ',
-        ('F', Cal, false, _) => 'ℱ',
-        ('H', Cal, false, _) => 'ℋ',
-        ('I', Cal, false, _) => 'ℐ',
-        ('L', Cal, false, _) => 'ℒ',
-        ('M', Cal, false, _) => 'ℳ',
-        ('R', Cal, false, _) => 'ℛ',
-        ('C', Frak, false, _) => 'ℭ',
-        ('H', Frak, false, _) => 'ℌ',
-        ('I', Frak, false, _) => 'ℑ',
-        ('R', Frak, false, _) => 'ℜ',
-        ('Z', Frak, false, _) => 'ℨ',
-        ('C', Bb, ..) => 'ℂ',
-        ('H', Bb, ..) => 'ℍ',
-        ('N', Bb, ..) => 'ℕ',
-        ('P', Bb, ..) => 'ℙ',
-        ('Q', Bb, ..) => 'ℚ',
-        ('R', Bb, ..) => 'ℝ',
-        ('Z', Bb, ..) => 'ℤ',
-        ('D', Bb, _, true) => 'ⅅ',
-        ('d', Bb, _, true) => 'ⅆ',
-        ('e', Bb, _, true) => 'ⅇ',
-        ('i', Bb, _, true) => 'ⅈ',
-        ('j', Bb, _, true) => 'ⅉ',
-        ('h', Serif, false, true) => 'ℎ',
-        ('e', Cal, false, _) => 'ℯ',
-        ('g', Cal, false, _) => 'ℊ',
-        ('o', Cal, false, _) => 'ℴ',
-        ('ħ', Serif, .., true) => 'ℏ',
-        ('ı', Serif, .., true) => '𝚤',
-        ('ȷ', Serif, .., true) => '𝚥',
-        _ => return None,
-    })
-}
-
-fn greek_exception(
-    c: char,
-    variant: MathVariant,
-    bold: bool,
-    italic: bool,
-) -> Option<char> {
-    use MathVariant::*;
-    if c == 'Ϝ' && variant == Serif && bold {
-        return Some('𝟊');
-    }
-    if c == 'ϝ' && variant == Serif && bold {
-        return Some('𝟋');
-    }
-
-    let list = match c {
-        'ϴ' => ['𝚹', '𝛳', '𝜭', '𝝧', '𝞡', 'ϴ'],
-        '∇' => ['𝛁', '𝛻', '𝜵', '𝝯', '𝞩', '∇'],
-        '∂' => ['𝛛', '𝜕', '𝝏', '𝞉', '𝟃', '∂'],
-        'ϵ' => ['𝛜', '𝜖', '𝝐', '𝞊', '𝟄', 'ϵ'],
-        'ϑ' => ['𝛝', '𝜗', '𝝑', '𝞋', '𝟅', 'ϑ'],
-        'ϰ' => ['𝛞', '𝜘', '𝝒', '𝞌', '𝟆', 'ϰ'],
-        'ϕ' => ['𝛟', '𝜙', '𝝓', '𝞍', '𝟇', 'ϕ'],
-        'ϱ' => ['𝛠', '𝜚', '𝝔', '𝞎', '𝟈', 'ϱ'],
-        'ϖ' => ['𝛡', '𝜛', '𝝕', '𝞏', '𝟉', 'ϖ'],
-        'Γ' => ['𝚪', '𝛤', '𝜞', '𝝘', '𝞒', 'ℾ'],
-        'γ' => ['𝛄', '𝛾', '𝜸', '𝝲', '𝞬', 'ℽ'],
-        'Π' => ['𝚷', '𝛱', '𝜫', '𝝥', '𝞟', 'ℿ'],
-        'π' => ['𝛑', '𝜋', '𝝅', '𝝿', '𝞹', 'ℼ'],
-        '∑' => ['∑', '∑', '∑', '∑', '∑', '⅀'],
-        _ => return None,
-    };
-
-    Some(match (variant, bold, italic) {
-        (Serif, true, false) => list[0],
-        (Serif, false, true) => list[1],
-        (Serif, true, true) => list[2],
-        (Sans, _, false) => list[3],
-        (Sans, _, true) => list[4],
-        (Bb, ..) => list[5],
-        _ => return None,
-    })
-}
-
 /// The non-dotless version of a dotless character that can be used with the
 /// `dtls` OpenType feature.
 pub fn try_dotless(c: char) -> Option<char> {

crates/typst-library/src/math/equation.rs

@@ -1,5 +1,6 @@
 use std::num::NonZeroUsize;
 
+use codex::styling::MathVariant;
 use typst_utils::NonZeroExt;
 use unicode_math_class::MathClass;
 
@@ -12,7 +13,7 @@ use crate::introspection::{Count, Counter, CounterUpdate, Locatable};
 use crate::layout::{
     AlignElem, Alignment, BlockElem, OuterHAlignment, SpecificAlignment, VAlignment,
 };
-use crate::math::{MathSize, MathVariant};
+use crate::math::MathSize;
 use crate::model::{Numbering, Outlinable, ParLine, Refable, Supplement};
 use crate::text::{FontFamily, FontList, FontWeight, LocalName, TextElem};
 
@@ -111,7 +112,7 @@ pub struct EquationElem {
     /// The style variant to select.
     #[internal]
     #[ghost]
-    pub variant: MathVariant,
+    pub variant: Option<MathVariant>,
 
     /// Affects the height of exponents.
     #[internal]
@@ -128,7 +129,7 @@ pub struct EquationElem {
     /// Whether to use italic glyphs.
     #[internal]
     #[ghost]
-    pub italic: Smart<bool>,
+    pub italic: Option<bool>,
 
     /// A forced class to use for all fragment.
     #[internal]

crates/typst-library/src/math/mod.rs

@@ -80,6 +80,7 @@ pub fn module() -> Module {
     math.define_func::<italic>();
     math.define_func::<serif>();
     math.define_func::<sans>();
+    math.define_func::<scr>();
     math.define_func::<cal>();
     math.define_func::<frak>();
     math.define_func::<mono>();

crates/typst-library/src/math/style.rs

@@ -1,4 +1,6 @@
-use crate::foundations::{func, Cast, Content, Smart};
+use codex::styling::MathVariant;
+
+use crate::foundations::{func, Cast, Content};
 use crate::math::EquationElem;
 
 /// Bold font style in math.
@@ -24,7 +26,7 @@ pub fn upright(
     /// The content to style.
     body: Content,
 ) -> Content {
-    body.set(EquationElem::italic, Smart::Custom(false))
+    body.set(EquationElem::italic, Some(false))
 }
 
 /// Italic font style in math.
@@ -35,7 +37,7 @@ pub fn italic(
     /// The content to style.
     body: Content,
 ) -> Content {
-    body.set(EquationElem::italic, Smart::Custom(true))
+    body.set(EquationElem::italic, Some(true))
 }
 
 /// Serif (roman) font style in math.
@@ -46,7 +48,7 @@ pub fn serif(
     /// The content to style.
     body: Content,
 ) -> Content {
-    body.set(EquationElem::variant, MathVariant::Serif)
+    body.set(EquationElem::variant, Some(MathVariant::Plain))
 }
 
 /// Sans-serif font style in math.
@@ -59,23 +61,39 @@ pub fn sans(
     /// The content to style.
     body: Content,
 ) -> Content {
-    body.set(EquationElem::variant, MathVariant::Sans)
+    body.set(EquationElem::variant, Some(MathVariant::SansSerif))
 }
 
-/// Calligraphic font style in math.
+/// Calligraphic (chancery) font style in math.
 ///
 /// ```example
 /// Let $cal(P)$ be the set of ...
 /// ```
 ///
-/// This corresponds both to LaTeX's `\mathcal` and `\mathscr` as both of these
-/// styles share the same Unicode codepoints. Switching between the styles is
-/// thus only possible if supported by the font via
-/// [font features]($text.features).
+/// This is the default calligraphic/script style for most math fonts. See
+/// [`scr`]($math.scr) for more on how to get the other style (roundhand).
+#[func(title = "Calligraphic", keywords = ["mathcal", "chancery"])]
+pub fn cal(
+    /// The content to style.
+    body: Content,
+) -> Content {
+    body.set(EquationElem::variant, Some(MathVariant::Chancery))
+}
+
+/// Script (roundhand) font style in math.
 ///
-/// For the default math font, the roundhand style is available through the
-/// `ss01` feature. Therefore, you could define your own version of `\mathscr`
-/// like this:
+/// ```example
+/// $ scr(S) $
+/// ```
+///
+/// There are two ways that fonts can support differentiating `cal` and `scr`.
+/// The first is using Unicode variation sequences. This works out of the box
+/// in Typst, however only a few math fonts currently support this.
+///
+/// The other way is using [font features]($text.features). For example, the
+/// roundhand style might be available in a font through the `ss01` feature.
+/// To use it in Typst, you could then define your own version of `scr` like
+/// this:
 ///
 /// ```example
 /// #let scr(it) = text(
@@ -88,12 +106,12 @@ pub fn sans(
 ///
 /// (The box is not conceptually necessary, but unfortunately currently needed
 /// due to limitations in Typst's text style handling in math.)
-#[func(title = "Calligraphic", keywords = ["mathcal", "mathscr"])]
-pub fn cal(
+#[func(title = "Script Style", keywords = ["mathscr", "roundhand"])]
+pub fn scr(
     /// The content to style.
     body: Content,
 ) -> Content {
-    body.set(EquationElem::variant, MathVariant::Cal)
+    body.set(EquationElem::variant, Some(MathVariant::Roundhand))
 }
 
 /// Fraktur font style in math.
@@ -106,7 +124,7 @@ pub fn frak(
     /// The content to style.
     body: Content,
 ) -> Content {
-    body.set(EquationElem::variant, MathVariant::Frak)
+    body.set(EquationElem::variant, Some(MathVariant::Fraktur))
 }
 
 /// Monospace font style in math.
@@ -119,7 +137,7 @@ pub fn mono(
     /// The content to style.
     body: Content,
 ) -> Content {
-    body.set(EquationElem::variant, MathVariant::Mono)
+    body.set(EquationElem::variant, Some(MathVariant::Monospace))
 }
 
 /// Blackboard bold (double-struck) font style in math.
@@ -137,7 +155,7 @@ pub fn bb(
     /// The content to style.
     body: Content,
 ) -> Content {
-    body.set(EquationElem::variant, MathVariant::Bb)
+    body.set(EquationElem::variant, Some(MathVariant::DoubleStruck))
 }
 
 /// Forced display style in math.
@@ -240,15 +258,3 @@ pub enum MathSize {
     /// Math on its own line.
     Display,
 }
-
-/// A mathematical style variant, as defined by Unicode.
-#[derive(Debug, Default, Copy, Clone, Eq, PartialEq, Cast, Hash)]
-pub enum MathVariant {
-    #[default]
-    Serif,
-    Sans,
-    Cal,
-    Frak,
-    Mono,
-    Bb,
-}

docs/reference/groups.yml

@@ -5,7 +5,7 @@
   title: Variants
   category: math
   path: ["math"]
-  filter: ["serif", "sans", "frak", "mono", "bb", "cal"]
+  filter: ["serif", "sans", "frak", "mono", "bb", "cal", "scr"]
   details: |
     Alternate typefaces within formulas.
 

tests/suite/math/style.typ

@@ -12,6 +12,15 @@ $A, italic(A), upright(A), bold(A), bold(upright(A)), \
  bb("hello") + bold(cal("world")), \
  mono("SQRT")(x) wreath mono(123 + 456)$
 
+--- math-style-fallback ---
+// Test how math styles fallback.
+$upright(frak(bold(alpha))) = upright(bold(alpha)) \
+bold(mono(ϝ)) = bold(ϝ) \
+sans(Theta) = bold(sans(Theta)) \
+bold(upright(planck)) != planck \
+bb(e) != italic(bb(e)) \
+serif(sans(A)) != serif(A)$
+
 --- math-style-dotless ---
 // Test styling dotless i and j.
 $ dotless.i dotless.j,
@@ -38,7 +47,15 @@ $bb(Gamma) , bb(gamma), bb(Pi), bb(pi), bb(sum)$
 
 --- math-style-hebrew-exceptions ---
 // Test hebrew exceptions.
-$aleph, beth, gimel, daleth$
+$aleph, beth, gimel, daleth$ \
+$upright(aleph), upright(beth), upright(gimel), upright(daleth)$
+
+--- math-style-script ---
+// Test variation selectors for scr and cal.
+$cal(A) scr(A) bold(cal(O)) scr(bold(O))$
+
+#show math.equation: set text(font: "Noto Sans Math")
+$scr(E) cal(E) bold(scr(Y)) cal(bold(Y))$
 
 --- issue-3650-italic-equation ---
 _abc $sin(x) "abc"$_ \