Extract regions into separate module

2 files changed, 125 insertions, 121 deletions

diff --git a/library/src/layout/mod.rs b/library/src/layout/mod.rs
index 6c01759c..f603ef6c 100644
--- a/library/src/layout/mod.rs
+++ b/library/src/layout/mod.rs
@@ -14,6 +14,7 @@ mod pad;
 mod page;
 mod par;
 mod place;
+mod regions;
 mod repeat;
 mod spacing;
 mod stack;
@@ -34,6 +35,7 @@ pub use self::pad::*;
 pub use self::page::*;
 pub use self::par::*;
 pub use self::place::*;
+pub use self::regions::*;
 pub use self::repeat::*;
 pub use self::spacing::*;
 pub use self::stack::*;
@@ -45,7 +47,6 @@ use std::mem;
 
 use typed_arena::Arena;
 use typst::diag::SourceResult;
-use typst::geom::*;
 use typst::model::{
     applicable, capability, realize, Content, Node, SequenceNode, Style, StyleChain,
     StyleVecBuilder, StyledNode,
@@ -147,126 +148,6 @@ impl Layout for Content {
 #[capability]
 pub trait Inline: Layout {}
 
-/// A sequence of regions to layout into.
-#[derive(Copy, Clone, Hash)]
-pub struct Regions<'a> {
-    /// The (remaining) size of the first region.
-    pub first: Size,
-    /// The base size for relative sizing.
-    pub base: Size,
-    /// The height of followup regions. The width is the same for all regions.
-    pub backlog: &'a [Abs],
-    /// The height of the final region that is repeated once the backlog is
-    /// drained. The width is the same for all regions.
-    pub last: Option<Abs>,
-    /// Whether nodes should expand to fill the regions instead of shrinking to
-    /// fit the content.
-    pub expand: Axes<bool>,
-}
-
-impl<'a> Regions<'a> {
-    /// Create a new region sequence with exactly one region.
-    pub fn one(size: Size, base: Size, expand: Axes<bool>) -> Self {
-        Self {
-            first: size,
-            base,
-            backlog: &[],
-            last: None,
-            expand,
-        }
-    }
-
-    /// Create a new sequence of same-size regions that repeats indefinitely.
-    pub fn repeat(size: Size, base: Size, expand: Axes<bool>) -> Self {
-        Self {
-            first: size,
-            base,
-            backlog: &[],
-            last: Some(size.y),
-            expand,
-        }
-    }
-
-    /// Create new regions where all sizes are mapped with `f`.
-    ///
-    /// Note that since all regions must have the same width, the width returned
-    /// by `f` is ignored for the backlog and the final region.
-    pub fn map<'v, F>(&self, backlog: &'v mut Vec<Abs>, mut f: F) -> Regions<'v>
-    where
-        F: FnMut(Size) -> Size,
-    {
-        let x = self.first.x;
-        backlog.clear();
-        backlog.extend(self.backlog.iter().map(|&y| f(Size::new(x, y)).y));
-        Regions {
-            first: f(self.first),
-            base: f(self.base),
-            backlog,
-            last: self.last.map(|y| f(Size::new(x, y)).y),
-            expand: self.expand,
-        }
-    }
-
-    /// Whether the first region is full and a region break is called for.
-    pub fn is_full(&self) -> bool {
-        Abs::zero().fits(self.first.y) && !self.in_last()
-    }
-
-    /// Whether the first region is the last usable region.
-    ///
-    /// If this is true, calling `next()` will have no effect.
-    pub fn in_last(&self) -> bool {
-        self.backlog.is_empty() && self.last.map_or(true, |height| self.first.y == height)
-    }
-
-    /// Advance to the next region if there is any.
-    pub fn next(&mut self) {
-        if let Some(height) = self
-            .backlog
-            .split_first()
-            .map(|(first, tail)| {
-                self.backlog = tail;
-                *first
-            })
-            .or(self.last)
-        {
-            self.first.y = height;
-            self.base.y = height;
-        }
-    }
-
-    /// An iterator that returns the sizes of the first and all following
-    /// regions, equivalently to what would be produced by calling
-    /// [`next()`](Self::next) repeatedly until all regions are exhausted.
-    /// This iterator may be infinite.
-    pub fn iter(&self) -> impl Iterator<Item = Size> + '_ {
-        let first = std::iter::once(self.first);
-        let backlog = self.backlog.iter();
-        let last = self.last.iter().cycle();
-        first.chain(backlog.chain(last).map(|&h| Size::new(self.first.x, h)))
-    }
-}
-
-impl Debug for Regions<'_> {
-    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
-        f.write_str("Regions ")?;
-        let mut list = f.debug_list();
-        let mut prev = self.first.y;
-        list.entry(&self.first);
-        for &height in self.backlog {
-            list.entry(&Size::new(self.first.x, height));
-            prev = height;
-        }
-        if let Some(last) = self.last {
-            if last != prev {
-                list.entry(&Size::new(self.first.x, last));
-            }
-            list.entry(&(..));
-        }
-        list.finish()
-    }
-}
-
 /// Realize into a node that is capable of root-level layout.
 fn realize_root<'a>(
     vt: &mut Vt,
diff --git a/library/src/layout/regions.rs b/library/src/layout/regions.rs
new file mode 100644
index 00000000..2592210b
--- /dev/null
+++ b/library/src/layout/regions.rs
@@ -0,0 +1,123 @@
+use std::fmt::{self, Debug, Formatter};
+
+use typst::geom::{Abs, Axes, Size};
+
+/// A sequence of regions to layout into.
+#[derive(Copy, Clone, Hash)]
+pub struct Regions<'a> {
+    /// The (remaining) size of the first region.
+    pub first: Size,
+    /// The base size for relative sizing.
+    pub base: Size,
+    /// The height of followup regions. The width is the same for all regions.
+    pub backlog: &'a [Abs],
+    /// The height of the final region that is repeated once the backlog is
+    /// drained. The width is the same for all regions.
+    pub last: Option<Abs>,
+    /// Whether nodes should expand to fill the regions instead of shrinking to
+    /// fit the content.
+    pub expand: Axes<bool>,
+}
+
+impl<'a> Regions<'a> {
+    /// Create a new region sequence with exactly one region.
+    pub fn one(size: Size, base: Size, expand: Axes<bool>) -> Self {
+        Self {
+            first: size,
+            base,
+            backlog: &[],
+            last: None,
+            expand,
+        }
+    }
+
+    /// Create a new sequence of same-size regions that repeats indefinitely.
+    pub fn repeat(size: Size, base: Size, expand: Axes<bool>) -> Self {
+        Self {
+            first: size,
+            base,
+            backlog: &[],
+            last: Some(size.y),
+            expand,
+        }
+    }
+
+    /// Create new regions where all sizes are mapped with `f`.
+    ///
+    /// Note that since all regions must have the same width, the width returned
+    /// by `f` is ignored for the backlog and the final region.
+    pub fn map<'v, F>(&self, backlog: &'v mut Vec<Abs>, mut f: F) -> Regions<'v>
+    where
+        F: FnMut(Size) -> Size,
+    {
+        let x = self.first.x;
+        backlog.clear();
+        backlog.extend(self.backlog.iter().map(|&y| f(Size::new(x, y)).y));
+        Regions {
+            first: f(self.first),
+            base: f(self.base),
+            backlog,
+            last: self.last.map(|y| f(Size::new(x, y)).y),
+            expand: self.expand,
+        }
+    }
+
+    /// Whether the first region is full and a region break is called for.
+    pub fn is_full(&self) -> bool {
+        Abs::zero().fits(self.first.y) && !self.in_last()
+    }
+
+    /// Whether the first region is the last usable region.
+    ///
+    /// If this is true, calling `next()` will have no effect.
+    pub fn in_last(&self) -> bool {
+        self.backlog.is_empty() && self.last.map_or(true, |height| self.first.y == height)
+    }
+
+    /// Advance to the next region if there is any.
+    pub fn next(&mut self) {
+        if let Some(height) = self
+            .backlog
+            .split_first()
+            .map(|(first, tail)| {
+                self.backlog = tail;
+                *first
+            })
+            .or(self.last)
+        {
+            self.first.y = height;
+            self.base.y = height;
+        }
+    }
+
+    /// An iterator that returns the sizes of the first and all following
+    /// regions, equivalently to what would be produced by calling
+    /// [`next()`](Self::next) repeatedly until all regions are exhausted.
+    /// This iterator may be infinite.
+    pub fn iter(&self) -> impl Iterator<Item = Size> + '_ {
+        let first = std::iter::once(self.first);
+        let backlog = self.backlog.iter();
+        let last = self.last.iter().cycle();
+        first.chain(backlog.chain(last).map(|&h| Size::new(self.first.x, h)))
+    }
+}
+
+impl Debug for Regions<'_> {
+    fn fmt(&self, f: &mut Formatter<'_>) -> fmt::Result {
+        f.write_str("Regions ")?;
+        let mut list = f.debug_list();
+        let mut prev = self.first.y;
+        list.entry(&self.first);
+        for &height in self.backlog {
+            list.entry(&Size::new(self.first.x, height));
+            prev = height;
+        }
+        if let Some(last) = self.last {
+            if last != prev {
+                list.entry(&Size::new(self.first.x, last));
+            }
+            list.entry(&(..));
+        }
+        list.finish()
+    }
+}