Strong delta

library/src/text/misc.rs

@@ -40,12 +40,15 @@ impl Behave for LinebreakNode {
     }
 }
 
-/// Strong content, rendered in boldface by default.
+/// Strongly emphasizes content by increasing the font weight.
 #[derive(Debug, Hash)]
 pub struct StrongNode(pub Content);
 
 #[node(Show)]
 impl StrongNode {
+    /// The delta to apply on the font weight.
+    pub const DELTA: i64 = 300;
+
     fn construct(_: &Vm, args: &mut Args) -> SourceResult<Content> {
         Ok(Self(args.expect("body")?).pack())
     }
@@ -59,12 +62,30 @@ impl StrongNode {
 }
 
 impl Show for StrongNode {
-    fn show(&self, _: Tracked<dyn World>, _: StyleChain) -> Content {
-        self.0.clone().styled(TextNode::BOLD, Toggle)
+    fn show(&self, _: Tracked<dyn World>, styles: StyleChain) -> Content {
+        self.0.clone().styled(TextNode::DELTA, Delta(styles.get(Self::DELTA)))
     }
 }
 
-/// Emphasized content, rendered with an italic font by default.
+/// A delta that is summed up when folded.
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
+pub struct Delta(pub i64);
+
+castable! {
+    Delta,
+    Expected: "integer",
+    Value::Int(delta) => Self(delta),
+}
+
+impl Fold for Delta {
+    type Output = i64;
+
+    fn fold(self, outer: Self::Output) -> Self::Output {
+        outer + self.0
+    }
+}
+
+/// Emphasizes content by flipping the italicness.
 #[derive(Debug, Hash)]
 pub struct EmphNode(pub Content);
 
@@ -84,7 +105,7 @@ impl EmphNode {
 
 impl Show for EmphNode {
     fn show(&self, _: Tracked<dyn World>, _: StyleChain) -> Content {
-        self.0.clone().styled(TextNode::ITALIC, Toggle)
+        self.0.clone().styled(TextNode::EMPH, Toggle)
     }
 }
 

library/src/text/mod.rs

@@ -111,12 +111,12 @@ impl TextNode {
     #[property(fold)]
     pub const FEATURES: FontFeatures = FontFeatures(vec![]);
 
-    /// Whether the font weight should be increased by 300.
+    /// A delta to apply on the font weight.
     #[property(skip, fold)]
-    pub const BOLD: Toggle = false;
+    pub const DELTA: Delta = 0;
     /// Whether the font style should be inverted.
     #[property(skip, fold)]
-    pub const ITALIC: Toggle = false;
+    pub const EMPH: Toggle = false;
     /// A case transformation that should be applied to the text.
     #[property(skip)]
     pub const CASE: Option<Case> = None;

library/src/text/shaping.rs

@@ -537,11 +537,12 @@ pub fn variant(styles: StyleChain) -> FontVariant {
         styles.get(TextNode::STRETCH),
     );
 
-    if styles.get(TextNode::BOLD) {
-        variant.weight = variant.weight.thicken(300);
-    }
+    let delta = styles.get(TextNode::DELTA);
+    variant.weight = variant
+        .weight
+        .thicken(delta.clamp(i16::MIN as i64, i16::MAX as i64) as i16);
 
-    if styles.get(TextNode::ITALIC) {
+    if styles.get(TextNode::EMPH) {
         variant.style = match variant.style {
             FontStyle::Normal => FontStyle::Italic,
             FontStyle::Italic => FontStyle::Normal,

src/model/cast.rs

@@ -280,10 +280,7 @@ castable! {
 castable! {
     FontWeight,
     Expected: "integer or string",
-    Value::Int(v) => Value::Int(v)
-        .cast::<usize>()?
-        .try_into()
-        .map_or(Self::BLACK, Self::from_number),
+    Value::Int(v) => Self::from_number(v.clamp(0, u16::MAX as i64) as u16),
     Value::Str(string) => match string.as_str() {
         "thin" => Self::THIN,
         "extralight" => Self::EXTRALIGHT,

tests/typ/text/emphasis.typ

@@ -16,6 +16,16 @@ _Still [
 // Inside of words can still use the functions.
 P#strong[art]ly em#emph[phas]ized.
 
+---
+// Adjusting the delta that strong applies on the weight.
+Normal
+
+#set strong(delta: 300)
+*Bold*
+
+#set strong(delta: 150)
+*Medium* and *[*Bold*]*
+
 ---
 // Error: 13 expected underscore
 #box[_Scoped] to body.