Introduce useful helpers in layout module

core/src/layout.rs

@@ -7,7 +7,7 @@ pub mod flex;
 pub use limits::Limits;
 pub use node::Node;
 
-use crate::{Point, Rectangle, Size, Vector};
+use crate::{Length, Padding, Point, Rectangle, Size, Vector};
 
 /// The bounds of a [`Node`] and its children, using absolute coordinates.
 #[derive(Debug, Clone, Copy)]
@@ -96,3 +96,95 @@ pub fn next_to_each_other(
         ],
     )
 }
+
+/// Computes the resulting [`Node`] that fits the [`Limits`] given
+/// some width and height requirements and no intrinsic size.
+pub fn atomic(
+    limits: &Limits,
+    width: impl Into<Length>,
+    height: impl Into<Length>,
+) -> Node {
+    let width = width.into();
+    let height = height.into();
+
+    Node::new(limits.resolve(width, height, Size::ZERO))
+}
+
+/// Computes the resulting [`Node`] that fits the [`Limits`] given
+/// some width and height requirements and a closure that produces
+/// the intrinsic [`Size`] inside the given [`Limits`].
+pub fn sized(
+    limits: &Limits,
+    width: impl Into<Length>,
+    height: impl Into<Length>,
+    f: impl FnOnce(&Limits) -> Size,
+) -> Node {
+    let width = width.into();
+    let height = height.into();
+
+    let limits = limits.width(width).height(height);
+    let intrinsic_size = f(&limits);
+
+    Node::new(limits.resolve(width, height, intrinsic_size))
+}
+
+/// Computes the resulting [`Node`] that fits the [`Limits`] given
+/// some width and height requirements and a closure that produces
+/// the content [`Node`] inside the given [`Limits`].
+pub fn contained(
+    limits: &Limits,
+    width: impl Into<Length>,
+    height: impl Into<Length>,
+    f: impl FnOnce(&Limits) -> Node,
+) -> Node {
+    let width = width.into();
+    let height = height.into();
+
+    let limits = limits.width(width).height(height);
+    let content = f(&limits);
+
+    Node::with_children(
+        limits.resolve(width, height, content.size()),
+        vec![content],
+    )
+}
+
+/// Computes the [`Node`] that fits the [`Limits`] given some width, height, and
+/// [`Padding`] requirements and a closure that produces the content [`Node`]
+/// inside the given [`Limits`].
+pub fn padded(
+    limits: &Limits,
+    width: impl Into<Length>,
+    height: impl Into<Length>,
+    padding: impl Into<Padding>,
+    layout: impl FnOnce(&Limits) -> Node,
+) -> Node {
+    positioned(limits, width, height, padding, layout, |content, _| content)
+}
+
+/// Computes a [`padded`] [`Node`] with a positioning step.
+pub fn positioned(
+    limits: &Limits,
+    width: impl Into<Length>,
+    height: impl Into<Length>,
+    padding: impl Into<Padding>,
+    layout: impl FnOnce(&Limits) -> Node,
+    position: impl FnOnce(Node, Size) -> Node,
+) -> Node {
+    let width = width.into();
+    let height = height.into();
+    let padding = padding.into();
+
+    let limits = limits.width(width).height(height);
+    let content = layout(&limits.shrink(padding));
+    let padding = padding.fit(content.size(), limits.max());
+
+    let size = limits
+        .shrink(padding)
+        .resolve(width, height, content.size());
+
+    Node::with_children(
+        size.expand(padding),
+        vec![position(content.move_to((padding.left, padding.top)), size)],
+    )
+}

core/src/layout/flex.rs

@@ -239,9 +239,9 @@ where
 
     let (intrinsic_width, intrinsic_height) = axis.pack(main - pad.0, cross);
     let size = limits.resolve(
-        Size::new(intrinsic_width, intrinsic_height),
         width,
         height,
+        Size::new(intrinsic_width, intrinsic_height),
     );
 
     Node::with_children(size.expand(padding), nodes)

core/src/layout/limits.rs

@@ -114,13 +114,14 @@ impl Limits {
         }
     }
 
-    /// Computes the resulting [`Size`] that fits the [`Limits`] given the
-    /// intrinsic size of some content.
+    /// Computes the resulting [`Size`] that fits the [`Limits`] given
+    /// some width and height requirements and the intrinsic size of
+    /// some content.
     pub fn resolve(
         &self,
-        intrinsic_size: Size,
         width: impl Into<Length>,
         height: impl Into<Length>,
+        intrinsic_size: Size,
     ) -> Size {
         let width = match width.into() {
             Length::Fill | Length::FillPortion(_) => self.max.width,

core/src/layout/node.rs

@@ -89,19 +89,23 @@ impl Node {
     }
 
     /// Moves the [`Node`] to the given position.
-    pub fn move_to(mut self, position: Point) -> Self {
+    pub fn move_to(mut self, position: impl Into<Point>) -> Self {
         self.move_to_mut(position);
         self
     }
 
     /// Mutable reference version of [`move_to`].
-    pub fn move_to_mut(&mut self, position: Point) {
+    pub fn move_to_mut(&mut self, position: impl Into<Point>) {
+        let position = position.into();
+
         self.bounds.x = position.x;
         self.bounds.y = position.y;
     }
 
     /// Translates the [`Node`] by the given translation.
-    pub fn translate(self, translation: Vector) -> Self {
+    pub fn translate(self, translation: impl Into<Vector>) -> Self {
+        let translation = translation.into();
+
         Self {
             bounds: self.bounds + translation,
             ..self

core/src/point.rs

@@ -36,20 +36,26 @@ impl<T: Num> Point<T> {
     }
 }
 
-impl From<[f32; 2]> for Point {
-    fn from([x, y]: [f32; 2]) -> Self {
+impl<T> From<[T; 2]> for Point<T>
+where
+    T: Num,
+{
+    fn from([x, y]: [T; 2]) -> Self {
         Point { x, y }
     }
 }
 
-impl From<[u16; 2]> for Point<u16> {
-    fn from([x, y]: [u16; 2]) -> Self {
-        Point::new(x, y)
+impl<T> From<(T, T)> for Point<T>
+where
+    T: Num,
+{
+    fn from((x, y): (T, T)) -> Self {
+        Self { x, y }
     }
 }
 
-impl From<Point> for [f32; 2] {
-    fn from(point: Point) -> [f32; 2] {
+impl<T> From<Point<T>> for [T; 2] {
+    fn from(point: Point<T>) -> [T; 2] {
         [point.x, point.y]
     }
 }

core/src/widget/text.rs

@@ -206,28 +206,27 @@ pub fn layout<Renderer>(
 where
     Renderer: text::Renderer,
 {
-    let limits = limits.width(width).height(height);
-    let bounds = limits.max();
+    layout::sized(limits, width, height, |limits| {
+        let bounds = limits.max();
 
-    let size = size.unwrap_or_else(|| renderer.default_size());
-    let font = font.unwrap_or_else(|| renderer.default_font());
+        let size = size.unwrap_or_else(|| renderer.default_size());
+        let font = font.unwrap_or_else(|| renderer.default_font());
 
-    let State(ref mut paragraph) = state;
+        let State(ref mut paragraph) = state;
 
-    paragraph.update(text::Text {
-        content,
-        bounds,
-        size,
-        line_height,
-        font,
-        horizontal_alignment,
-        vertical_alignment,
-        shaping,
-    });
+        paragraph.update(text::Text {
+            content,
+            bounds,
+            size,
+            line_height,
+            font,
+            horizontal_alignment,
+            vertical_alignment,
+            shaping,
+        });
 
-    let size = limits.resolve(paragraph.min_bounds(), width, height);
-
-    layout::Node::new(size)
+        paragraph.min_bounds()
+    })
 }
 
 /// Draws text using the same logic as the [`Text`] widget.