State-based monospace handling

4 files changed, 72 insertions, 53 deletions

diff --git a/src/exec/context.rs b/src/exec/context.rs
index 925fd7de..13e53b09 100644
--- a/src/exec/context.rs
+++ b/src/exec/context.rs
@@ -1,7 +1,7 @@
 use std::mem;
 use std::rc::Rc;
 
-use super::{Exec, ExecWithMap, FontFamily, State};
+use super::{Exec, ExecWithMap, State};
 use crate::diag::{Diag, DiagSet, Pass};
 use crate::eco::EcoString;
 use crate::eval::{ExprMap, Template};
@@ -44,15 +44,6 @@ impl ExecContext {
         self.diags.insert(diag);
     }
 
-    /// Set the font to monospace.
-    pub fn set_monospace(&mut self) {
-        self.state
-            .font_mut()
-            .families_mut()
-            .list
-            .insert(0, FontFamily::Monospace);
-    }
-
     /// Execute a template and return the result as a stack node.
     pub fn exec_template_stack(&mut self, template: &Template) -> StackNode {
         self.exec_stack(|ctx| template.exec(ctx))
@@ -83,6 +74,14 @@ impl ExecContext {
         self.stack.par.push(self.make_text_node(text));
     }
 
+    /// Push text, but in monospace.
+    pub fn push_monospace_text(&mut self, text: impl Into<EcoString>) {
+        let prev = Rc::clone(&self.state.font);
+        self.state.font_mut().monospace = true;
+        self.push_text(text);
+        self.state.font = prev;
+    }
+
     /// Push a word space into the active paragraph.
     pub fn push_word_space(&mut self) {
         self.stack.par.push_soft(self.make_text_node(" "));
diff --git a/src/exec/mod.rs b/src/exec/mod.rs
index d61e0793..76857b44 100644
--- a/src/exec/mod.rs
+++ b/src/exec/mod.rs
@@ -7,7 +7,6 @@ pub use context::*;
 pub use state::*;
 
 use std::fmt::Write;
-use std::rc::Rc;
 
 use crate::diag::Pass;
 use crate::eco::EcoString;
@@ -75,10 +74,7 @@ impl Exec for RawNode {
             ctx.parbreak();
         }
 
-        let snapshot = Rc::clone(&ctx.state.font);
-        ctx.set_monospace();
-        ctx.push_text(&self.text);
-        ctx.state.font = snapshot;
+        ctx.push_monospace_text(&self.text);
 
         if self.block {
             ctx.parbreak();
@@ -143,14 +139,9 @@ impl Exec for Value {
             Value::Str(v) => ctx.push_text(v),
             Value::Template(v) => v.exec(ctx),
             Value::Error => {}
-            other => {
-                // For values which can't be shown "naturally", we print
-                // the representation in monospace.
-                let prev = Rc::clone(&ctx.state.font.families);
-                ctx.set_monospace();
-                ctx.push_text(pretty(other));
-                ctx.state.font_mut().families = prev;
-            }
+            // For values which can't be shown "naturally", we print the
+            // representation in monospace.
+            other => ctx.push_monospace_text(pretty(other)),
         }
     }
 }
diff --git a/src/exec/state.rs b/src/exec/state.rs
index f99a8901..624394ba 100644
--- a/src/exec/state.rs
+++ b/src/exec/state.rs
@@ -111,6 +111,14 @@ pub struct FontState {
     pub families: Rc<FamilyList>,
     /// The selected font variant.
     pub variant: FontVariant,
+    /// Whether the strong toggle is active or inactive. This determines
+    /// whether the next `*` adds or removes font weight.
+    pub strong: bool,
+    /// Whether the emphasis toggle is active or inactive. This determines
+    /// whether the next `_` makes italic or non-italic.
+    pub emph: bool,
+    /// Whether the monospace toggle is active or inactive.
+    pub monospace: bool,
     /// The font size.
     pub size: Length,
     /// The top end of the text bounding box.
@@ -119,12 +127,6 @@ pub struct FontState {
     pub bottom_edge: VerticalFontMetric,
     /// Glyph color.
     pub fill: Paint,
-    /// Whether the strong toggle is active or inactive. This determines
-    /// whether the next `*` adds or removes font weight.
-    pub strong: bool,
-    /// Whether the emphasis toggle is active or inactive. This determines
-    /// whether the next `_` makes italic or non-italic.
-    pub emph: bool,
     /// The specifications for a strikethrough line, if any.
     pub strikethrough: Option<Rc<LineState>>,
     /// The specifications for a underline, if any.
@@ -138,6 +140,35 @@ impl FontState {
     pub fn families_mut(&mut self) -> &mut FamilyList {
         Rc::make_mut(&mut self.families)
     }
+
+    /// The canonical family iterator.
+    pub fn families(&self) -> impl Iterator<Item = &str> + Clone {
+        let head = if self.monospace {
+            self.families.monospace.as_slice()
+        } else {
+            &[]
+        };
+        head.iter().map(String::as_str).chain(self.families.iter())
+    }
+
+    /// The canonical variant with `strong` and `emph` factored in.
+    pub fn variant(&self) -> FontVariant {
+        let mut variant = self.variant;
+
+        if self.strong {
+            variant.weight = variant.weight.thicken(300);
+        }
+
+        if self.emph {
+            variant.style = match variant.style {
+                FontStyle::Normal => FontStyle::Italic,
+                FontStyle::Italic => FontStyle::Normal,
+                FontStyle::Oblique => FontStyle::Normal,
+            }
+        }
+
+        variant
+    }
 }
 
 impl Default for FontState {
@@ -149,12 +180,13 @@ impl Default for FontState {
                 weight: FontWeight::REGULAR,
                 stretch: FontStretch::NORMAL,
             },
+            strong: false,
+            emph: false,
+            monospace: false,
             size: Length::pt(11.0),
             top_edge: VerticalFontMetric::CapHeight,
             bottom_edge: VerticalFontMetric::Baseline,
             fill: Paint::Color(Color::Rgba(RgbaColor::BLACK)),
-            strong: false,
-            emph: false,
             strikethrough: None,
             underline: None,
             overline: None,
diff --git a/src/layout/shaping.rs b/src/layout/shaping.rs
index 5e1bc327..3ede5122 100644
--- a/src/layout/shaping.rs
+++ b/src/layout/shaping.rs
@@ -6,7 +6,7 @@ use rustybuzz::UnicodeBuffer;
 
 use super::{Element, Frame, Glyph, LayoutContext, Text};
 use crate::exec::{FontState, LineState};
-use crate::font::{Face, FaceId, FontStyle, LineMetrics};
+use crate::font::{Face, FaceId, FontVariant, LineMetrics};
 use crate::geom::{Dir, Length, Point, Size};
 use crate::layout::Geometry;
 use crate::util::SliceExt;
@@ -188,9 +188,18 @@ pub fn shape<'a>(
     state: &'a FontState,
 ) -> ShapedText<'a> {
     let mut glyphs = vec![];
-    let families = state.families.iter();
     if !text.is_empty() {
-        shape_segment(ctx, &mut glyphs, 0, text, dir, state, families, None);
+        shape_segment(
+            ctx,
+            &mut glyphs,
+            0,
+            text,
+            dir,
+            state.size,
+            state.variant(),
+            state.families(),
+            None,
+        );
     }
 
     let (size, baseline) = measure(ctx, &glyphs, state);
@@ -212,7 +221,8 @@ fn shape_segment<'a>(
     base: usize,
     text: &str,
     dir: Dir,
-    state: &FontState,
+    size: Length,
+    variant: FontVariant,
     mut families: impl Iterator<Item = &'a str> + Clone,
     mut first_face: Option<FaceId>,
 ) {
@@ -221,20 +231,6 @@ fn shape_segment<'a>(
         // Try to load the next available font family.
         match families.next() {
             Some(family) => {
-                let mut variant = state.variant;
-
-                if state.strong {
-                    variant.weight = variant.weight.thicken(300);
-                }
-
-                if state.emph {
-                    variant.style = match variant.style {
-                        FontStyle::Normal => FontStyle::Italic,
-                        FontStyle::Italic => FontStyle::Normal,
-                        FontStyle::Oblique => FontStyle::Normal,
-                    }
-                }
-
                 if let Some(id) = ctx.fonts.select(family, variant) {
                     break (id, true);
                 }
@@ -280,8 +276,8 @@ fn shape_segment<'a>(
             glyphs.push(ShapedGlyph {
                 face_id,
                 glyph_id: info.glyph_id as u16,
-                x_advance: face.to_em(pos[i].x_advance).to_length(state.size),
-                x_offset: face.to_em(pos[i].x_offset).to_length(state.size),
+                x_advance: face.to_em(pos[i].x_advance).to_length(size),
+                x_offset: face.to_em(pos[i].x_offset).to_length(size),
                 text_index: base + cluster,
                 safe_to_break: !info.unsafe_to_break(),
             });
@@ -332,7 +328,8 @@ fn shape_segment<'a>(
                 base + range.start,
                 &text[range],
                 dir,
-                state,
+                size,
+                variant,
                 families.clone(),
                 first_face,
             );
@@ -362,7 +359,7 @@ fn measure(
     if glyphs.is_empty() {
         // When there are no glyphs, we just use the vertical metrics of the
         // first available font.
-        for family in state.families.iter() {
+        for family in state.families() {
             if let Some(face_id) = ctx.fonts.select(family, state.variant) {
                 expand_vertical(ctx.fonts.get(face_id));
                 break;