Better expansion behaviour 🐪

This makes expansion behaviour inheritable by placing it into the area and passing it down during layouting instead of computing some approximation of what we want during execution.

3 files changed, 18 insertions, 27 deletions

diff --git a/src/exec/context.rs b/src/exec/context.rs
index d491a251..4d2047a6 100644
--- a/src/exec/context.rs
+++ b/src/exec/context.rs
@@ -7,7 +7,7 @@ use super::*;
 use crate::diag::{Diag, DiagSet};
 use crate::geom::{ChildAlign, Dir, Gen, LayoutDirs, Length, Linear, Sides, Size};
 use crate::layout::{
-    Expansion, Node, NodePad, NodePages, NodePar, NodeSpacing, NodeStack, NodeText, Tree,
+    Node, NodePad, NodePages, NodePar, NodeSpacing, NodeStack, NodeText, Tree,
 };
 use crate::parse::is_newline;
 
@@ -105,18 +105,18 @@ impl<'a> ExecContext<'a> {
         }
     }
 
-    /// Execute the body of a function and return the result as a stack node.
-    pub fn exec_body(&mut self, body: &ValueTemplate, expand: Spec<Expansion>) -> Node {
+    /// Execute a template and return the result as a stack node.
+    pub fn exec(&mut self, template: &ValueTemplate) -> Node {
         let dirs = self.state.dirs;
         let align = self.state.align;
 
         self.start_group(ContentGroup);
         self.start_par_group();
-        body.exec(self);
+        template.exec(self);
         self.end_par_group();
         let children = self.end_group::<ContentGroup>().1;
 
-        NodeStack { dirs, align, expand, children }.into()
+        NodeStack { dirs, align, children }.into()
     }
 
     /// Start a page group based on the active page state.
@@ -128,7 +128,6 @@ impl<'a> ExecContext<'a> {
     pub fn start_page_group(&mut self, softness: Softness) {
         self.start_group(PageGroup {
             size: self.state.page.size,
-            expand: self.state.page.expand,
             padding: self.state.page.margins(),
             dirs: self.state.dirs,
             align: self.state.align,
@@ -158,7 +157,6 @@ impl<'a> ExecContext<'a> {
                     child: NodeStack {
                         dirs: group.dirs,
                         align: group.align,
-                        expand: group.expand,
                         children,
                     }
                     .into(),
@@ -186,13 +184,6 @@ impl<'a> ExecContext<'a> {
             self.push(NodePar {
                 dirs: group.dirs,
                 align: group.align,
-                // FIXME: This is a hack and should be superseded by something
-                //        better.
-                cross_expansion: if self.groups.len() <= 1 {
-                    Expansion::Fill
-                } else {
-                    Expansion::Fit
-                },
                 line_spacing: group.line_spacing,
                 children,
             });
@@ -306,7 +297,6 @@ pub enum Softness {
 #[derive(Debug)]
 struct PageGroup {
     size: Size,
-    expand: Spec<Expansion>,
     padding: Sides<Linear>,
     dirs: LayoutDirs,
     align: ChildAlign,
diff --git a/src/exec/mod.rs b/src/exec/mod.rs
index ea2c90f4..79ad81e7 100644
--- a/src/exec/mod.rs
+++ b/src/exec/mod.rs
@@ -11,8 +11,7 @@ use std::rc::Rc;
 use crate::diag::Pass;
 use crate::env::Env;
 use crate::eval::{ExprMap, TemplateFunc, TemplateNode, Value, ValueTemplate};
-use crate::geom::Spec;
-use crate::layout::{self, Expansion, NodeSpacing, NodeStack};
+use crate::layout::{self, NodeFixed, NodeSpacing, NodeStack};
 use crate::pretty::pretty;
 use crate::syntax::*;
 
@@ -120,11 +119,17 @@ impl Exec for NodeRaw {
             ctx.apply_parbreak();
         }
 
-        ctx.push(NodeStack {
-            dirs: ctx.state.dirs,
-            align: ctx.state.align,
-            expand: Spec::uniform(Expansion::Fit),
-            children,
+        // This is wrapped in a fixed node to make sure the stack fits to its
+        // content instead of filling the available area.
+        ctx.push(NodeFixed {
+            width: None,
+            height: None,
+            child: NodeStack {
+                dirs: ctx.state.dirs,
+                align: ctx.state.align,
+                children,
+            }
+            .into(),
         });
 
         if self.block {
diff --git a/src/exec/state.rs b/src/exec/state.rs
index 416b5d08..3293662a 100644
--- a/src/exec/state.rs
+++ b/src/exec/state.rs
@@ -3,9 +3,8 @@ use std::rc::Rc;
 use fontdock::{fallback, FallbackTree, FontStretch, FontStyle, FontVariant, FontWeight};
 
 use crate::geom::{
-    Align, ChildAlign, Dir, LayoutDirs, Length, Linear, Relative, Sides, Size, Spec,
+    Align, ChildAlign, Dir, LayoutDirs, Length, Linear, Relative, Sides, Size,
 };
-use crate::layout::Expansion;
 use crate::paper::{Paper, PaperClass, PAPER_A4};
 
 /// The evaluation state.
@@ -42,8 +41,6 @@ pub struct PageState {
     pub class: PaperClass,
     /// The width and height of the page.
     pub size: Size,
-    /// Whether the expand the pages to the `size` or to fit the content.
-    pub expand: Spec<Expansion>,
     /// The amount of white space on each side of the page. If a side is set to
     /// `None`, the default for the paper class is used.
     pub margins: Sides<Option<Linear>>,
@@ -55,7 +52,6 @@ impl PageState {
         Self {
             class: paper.class,
             size: paper.size(),
-            expand: Spec::uniform(Expansion::Fill),
             margins: Sides::uniform(None),
         }
     }