From 5a59bb48216352d04f78c9a9392ca7cef280d7b2 Mon Sep 17 00:00:00 2001
From: Laurenz <laurmaedje@gmail.com>
Date: Thu, 18 Nov 2021 12:50:28 +0100
Subject: Page fill

---
 src/eval/template.rs |  9 ++++++---
 src/library/page.rs  | 26 +++++++++++++++++++++++---
 src/library/shape.rs |  1 +
 src/style/mod.rs     |  3 +++
 4 files changed, 33 insertions(+), 6 deletions(-)

(limited to 'src')

diff --git a/src/eval/template.rs b/src/eval/template.rs
index 7801dc79..307bff2a 100644
--- a/src/eval/template.rs
+++ b/src/eval/template.rs
@@ -6,7 +6,7 @@ use std::ops::{Add, AddAssign};
 use std::rc::Rc;
 
 use crate::diag::StrResult;
-use crate::geom::{Align, Dir, GenAxis, Length, Linear, Sides, Size};
+use crate::geom::{Align, Dir, GenAxis, Length, Linear, Paint, Sides, Size};
 use crate::layout::{Layout, PackedNode};
 use crate::library::{
     Decoration, DocumentNode, FlowChild, FlowNode, PageNode, ParChild, ParNode,
@@ -384,6 +384,7 @@ impl Builder {
 struct PageBuilder {
     size: Size,
     padding: Sides<Linear>,
+    fill: Option<Paint>,
     hard: bool,
 }
 
@@ -392,15 +393,17 @@ impl PageBuilder {
         Self {
             size: style.page.size,
             padding: style.page.margins(),
+            fill: style.page.fill,
             hard,
         }
     }
 
     fn build(self, child: FlowNode, keep: bool) -> Option<PageNode> {
-        let Self { size, padding, hard } = self;
+        let Self { size, padding, fill, hard } = self;
         (!child.children.is_empty() || (keep && hard)).then(|| PageNode {
-            size,
             child: child.pack().padded(padding),
+            size,
+            fill,
         })
     }
 }
diff --git a/src/library/page.rs b/src/library/page.rs
index a5935002..6642de16 100644
--- a/src/library/page.rs
+++ b/src/library/page.rs
@@ -18,6 +18,7 @@ pub fn page(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
     let right = args.named("right")?;
     let bottom = args.named("bottom")?;
     let flip = args.named("flip")?;
+    let fill = args.named("fill")?;
 
     ctx.template.modify(move |style| {
         let page = style.page_mut();
@@ -60,6 +61,10 @@ pub fn page(ctx: &mut EvalContext, args: &mut Args) -> TypResult<Value> {
         if flip.unwrap_or(false) {
             std::mem::swap(&mut page.size.w, &mut page.size.h);
         }
+
+        if let Some(fill) = fill {
+            page.fill = Some(Paint::Color(fill));
+        }
     });
 
     ctx.template.pagebreak(false);
@@ -77,10 +82,12 @@ pub fn pagebreak(_: &mut EvalContext, _: &mut Args) -> TypResult<Value> {
 /// Layouts its children onto one or multiple pages.
 #[derive(Debug, Hash)]
 pub struct PageNode {
-    /// The size of the page.
-    pub size: Size,
     /// The node that produces the actual pages.
     pub child: PackedNode,
+    /// The size of the page.
+    pub size: Size,
+    /// The background fill.
+    pub fill: Option<Paint>,
 }
 
 impl PageNode {
@@ -90,6 +97,19 @@ impl PageNode {
         // that axis.
         let expand = self.size.to_spec().map(Length::is_finite);
         let regions = Regions::repeat(self.size, self.size, expand);
-        self.child.layout(ctx, &regions).into_iter().map(|c| c.item).collect()
+
+        // Layout the child.
+        let mut frames: Vec<_> =
+            self.child.layout(ctx, &regions).into_iter().map(|c| c.item).collect();
+
+        // Add background fill if requested.
+        if let Some(fill) = self.fill {
+            for frame in &mut frames {
+                let element = Element::Geometry(Geometry::Rect(frame.size), fill);
+                Rc::make_mut(frame).prepend(Point::zero(), element)
+            }
+        }
+
+        frames
     }
 }
diff --git a/src/library/shape.rs b/src/library/shape.rs
index 7c543958..d0df5f48 100644
--- a/src/library/shape.rs
+++ b/src/library/shape.rs
@@ -131,6 +131,7 @@ impl Layout for ShapeNode {
                 frames = node.layout(ctx, &pod);
             }
 
+            // TODO: What if there are multiple or no frames?
             // Extract the frame.
             Rc::take(frames.into_iter().next().unwrap().item)
         } else {
diff --git a/src/style/mod.rs b/src/style/mod.rs
index 9cf2de07..4588163b 100644
--- a/src/style/mod.rs
+++ b/src/style/mod.rs
@@ -71,6 +71,8 @@ pub struct PageStyle {
     /// 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>>,
+    /// The background fill of the page.
+    pub fill: Option<Paint>,
 }
 
 impl PageStyle {
@@ -93,6 +95,7 @@ impl Default for PageStyle {
             class: paper.class(),
             size: paper.size(),
             margins: Sides::splat(None),
+            fill: None,
         }
     }
 }
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