Improve alignment of text inside raw blocks (#1034)

library/src/text/raw.rs

@@ -102,6 +102,27 @@ pub struct RawElem {
     /// ```
     /// ````
     pub lang: Option<EcoString>,
+
+    /// The horizontal alignment that each line in a raw block should have.
+    /// This option is ignored if this is not a raw block (if specified
+    /// `block: false` or single backticks were used in markup mode).
+    ///
+    /// By default, this is set to `{start}`, meaning that raw text is
+    /// aligned towards the start of the text direction inside the block
+    /// by default, regardless of the current context's alignment (allowing
+    /// you to center the raw block itself without centering the text inside
+    /// it, for example).
+    ///
+    /// ````example
+    /// #set raw(align: center)
+    ///
+    /// ```typc
+    /// let f(x) = x
+    /// code = "centered"
+    /// ```
+    /// ````
+    #[default(HorizontalAlign(GenAlign::Start))]
+    pub align: HorizontalAlign,
 }
 
 impl RawElem {
@@ -180,6 +201,8 @@ impl Show for RawElem {
         };
 
         if self.block(styles) {
+            // Align the text before inserting it into the block.
+            realized = realized.aligned(Axes::with_x(Some(self.align(styles).into())));
             realized = BlockElem::new().with_body(Some(realized)).pack();
         }
 

src/geom/align.rs

@@ -106,6 +106,18 @@ impl From<Align> for GenAlign {
     }
 }
 
+impl From<HorizontalAlign> for GenAlign {
+    fn from(align: HorizontalAlign) -> Self {
+        align.0
+    }
+}
+
+impl From<VerticalAlign> for GenAlign {
+    fn from(align: VerticalAlign) -> Self {
+        align.0
+    }
+}
+
 impl Debug for GenAlign {
     fn fmt(&self, f: &mut Formatter) -> fmt::Result {
         match self {
@@ -184,7 +196,45 @@ impl Fold for GenAlign {
     }
 }
 
-#[derive(Copy, Clone, Eq, PartialEq, Debug)]
+/// Utility struct to restrict a passed alignment value to the horizontal axis
+/// on cast.
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
+pub struct HorizontalAlign(pub GenAlign);
+
+cast_from_value! {
+    HorizontalAlign,
+    align: GenAlign => {
+        if align.axis() != Axis::X {
+            Err("alignment must be horizontal")?;
+        }
+        Self(align)
+    },
+}
+
+cast_to_value! {
+    v: HorizontalAlign => v.0.into()
+}
+
+/// Utility struct to restrict a passed alignment value to the vertical axis on
+/// cast.
+#[derive(Debug, Copy, Clone, Eq, PartialEq, Hash)]
+pub struct VerticalAlign(pub GenAlign);
+
+cast_from_value! {
+    VerticalAlign,
+    align: GenAlign => {
+        if align.axis() != Axis::Y {
+            Err("alignment must be vertical")?;
+        }
+        Self(align)
+    },
+}
+
+cast_to_value! {
+    v: VerticalAlign => v.0.into()
+}
+
+#[derive(Debug, Copy, Clone, Eq, PartialEq)]
 pub enum LeftRightAlternator {
     Left,
     Right,

tests/typ/text/raw-align.typ

@@ -0,0 +1,37 @@
+// Test the alignment of text inside of raw blocks.
+
+---
+// Text inside raw block should be unaffected by outer alignment by default.
+#set align(center)
+#set page(width: 180pt)
+#set text(6pt)
+
+#lorem(20)
+
+```py
+def something(x):
+  return x
+
+a = 342395823859823958329
+b = 324923
+```
+
+#lorem(20)
+
+---
+// Text inside raw block should follow the specified alignment.
+#set page(width: 180pt)
+#set text(6pt)
+
+#lorem(20)
+#align(center, raw(
+  lang: "typ",
+  block: true,
+  align: right,
+  "#let f(x) = x\n#align(center, line(length: 1em))",
+))
+#lorem(20)
+
+---
+// Error: 17-20 alignment must be horizontal
+#set raw(align: top)