Merge pull request #17 from typst/rects

Add rectangle function 🎛

3 files changed, 95 insertions, 12 deletions

diff --git a/src/layout/background.rs b/src/layout/background.rs
new file mode 100644
index 00000000..07248e02
--- /dev/null
+++ b/src/layout/background.rs
@@ -0,0 +1,37 @@
+use super::*;
+
+/// A node that represents a rectangular box.
+#[derive(Debug, Clone, PartialEq)]
+pub struct NodeBackground {
+    /// The background fill.
+    pub fill: Fill,
+    /// The child node to be filled in.
+    pub child: Node,
+}
+
+impl Layout for NodeBackground {
+    fn layout(&self, ctx: &mut LayoutContext, areas: &Areas) -> Layouted {
+        let mut layouted = self.child.layout(ctx, areas);
+
+        if let Some(first) = layouted.frames_mut().first_mut() {
+            first.elements.insert(
+                0,
+                (
+                    Point::ZERO,
+                    Element::Geometry(Geometry {
+                        shape: Shape::Rect(first.size),
+                        fill: self.fill.clone(),
+                    }),
+                ),
+            )
+        }
+
+        layouted
+    }
+}
+
+impl From<NodeBackground> for NodeAny {
+    fn from(background: NodeBackground) -> Self {
+        Self::new(background)
+    }
+}
diff --git a/src/layout/mod.rs b/src/layout/mod.rs
index 44960de7..30295841 100644
--- a/src/layout/mod.rs
+++ b/src/layout/mod.rs
@@ -1,5 +1,6 @@
 //! Layouting.
 
+mod background;
 mod fixed;
 mod node;
 mod pad;
@@ -8,10 +9,12 @@ mod spacing;
 mod stack;
 mod text;
 
+use crate::color::Color;
 use crate::env::{Env, ResourceId};
 use crate::geom::*;
 use crate::shaping::Shaped;
 
+pub use background::*;
 pub use fixed::*;
 pub use node::*;
 pub use pad::*;
@@ -54,7 +57,7 @@ impl NodePages {
     pub fn layout(&self, ctx: &mut LayoutContext) -> Vec<Frame> {
         let areas = Areas::repeat(self.size);
         let layouted = self.child.layout(ctx, &areas);
-        layouted.frames()
+        layouted.into_frames()
     }
 }
 
@@ -157,9 +160,27 @@ pub enum Layouted {
 }
 
 impl Layouted {
-    /// Return all frames contained in this variant (zero, one or arbitrarily
-    /// many).
-    pub fn frames(self) -> Vec<Frame> {
+    /// Return a reference to all frames contained in this variant (zero, one or
+    /// arbitrarily many).
+    pub fn frames(&self) -> &[Frame] {
+        match self {
+            Self::Spacing(_) => &[],
+            Self::Frame(frame, _) => std::slice::from_ref(frame),
+            Self::Frames(frames, _) => frames,
+        }
+    }
+
+    /// Return a mutable reference to all frames contained in this variant.
+    pub fn frames_mut(&mut self) -> &mut [Frame] {
+        match self {
+            Self::Spacing(_) => &mut [],
+            Self::Frame(frame, _) => std::slice::from_mut(frame),
+            Self::Frames(frames, _) => frames,
+        }
+    }
+
+    /// Return all frames contained in this varian.
+    pub fn into_frames(self) -> Vec<Frame> {
         match self {
             Self::Spacing(_) => vec![],
             Self::Frame(frame, _) => vec![frame],
@@ -204,6 +225,37 @@ pub enum Element {
     Text(Shaped),
     /// An image.
     Image(Image),
+    /// Some shape that could hold another frame.
+    Geometry(Geometry),
+}
+
+/// The kind of graphic fill to be applied to a [`Shape`].
+#[derive(Debug, Clone, PartialEq)]
+pub enum Fill {
+    /// The fill is a color.
+    Color(Color),
+    /// The fill is an image.
+    Image(Image),
+}
+
+/// A shape with some kind of fill.
+#[derive(Debug, Clone, PartialEq)]
+pub struct Geometry {
+    /// The shape to draw.
+    pub shape: Shape,
+    /// How the shape looks on the inside.
+    //
+    //  TODO: This could be made into a Vec<Fill> or something such that
+    //        the user can compose multiple fills with alpha values less
+    //        than one to achieve cool effects.
+    pub fill: Fill,
+}
+
+/// Some shape.
+#[derive(Debug, Clone, PartialEq)]
+pub enum Shape {
+    /// A rectangle.
+    Rect(Size),
 }
 
 /// An image element.
diff --git a/src/layout/pad.rs b/src/layout/pad.rs
index f8a623e3..425fa41b 100644
--- a/src/layout/pad.rs
+++ b/src/layout/pad.rs
@@ -15,14 +15,8 @@ impl Layout for NodePad {
         let areas = shrink(areas, self.padding);
 
         let mut layouted = self.child.layout(ctx, &areas);
-        match &mut layouted {
-            Layouted::Spacing(_) => {}
-            Layouted::Frame(frame, _) => pad(frame, self.padding),
-            Layouted::Frames(frames, _) => {
-                for frame in frames {
-                    pad(frame, self.padding);
-                }
-            }
+        for frame in layouted.frames_mut() {
+            pad(frame, self.padding);
         }
 
         layouted