1 files changed, 53 insertions, 0 deletions
diff --git a/src/layout/pad.rs b/src/layout/pad.rs
new file mode 100644
index 00000000..2e1817b7
--- /dev/null
+++ b/src/layout/pad.rs
@@ -0,0 +1,53 @@
+use super::*;
+use crate::geom::Linear;
+
+/// A node that pads its child at the sides.
+#[derive(Debug, Clone, PartialEq)]
+pub struct Pad {
+    pub padding: Sides<Linear>,
+    pub child: LayoutNode,
+}
+
+#[async_trait(?Send)]
+impl Layout for Pad {
+    async fn layout(
+        &self,
+        ctx: &mut LayoutContext,
+        constraints: LayoutConstraints,
+    ) -> Vec<LayoutItem> {
+        self.child
+            .layout(ctx, LayoutConstraints {
+                spaces: constraints
+                    .spaces
+                    .into_iter()
+                    .map(|space| LayoutSpace {
+                        base: space.base - self.padding.eval(space.base).size(),
+                        size: space.size - self.padding.eval(space.size).size(),
+                    })
+                    .collect(),
+                repeat: constraints.repeat,
+            })
+            .await
+            .into_iter()
+            .map(|item| match item {
+                LayoutItem::Box(boxed, align) => {
+                    let padding = self.padding.eval(boxed.size);
+                    let padded = boxed.size + padding.size();
+
+                    let mut outer = BoxLayout::new(padded);
+                    let start = Point::new(padding.left, padding.top);
+                    outer.push_layout(start, boxed);
+
+                    LayoutItem::Box(outer, align)
+                }
+                item => item,
+            })
+            .collect()
+    }
+}
+
+impl From<Pad> for LayoutNode {
+    fn from(pad: Pad) -> Self {
+        Self::dynamic(pad)
+    }
+}