Introduce useful helpers in `layout` module

26 files changed, 193 insertions, 131 deletions

diff --git a/core/src/layout.rs b/core/src/layout.rs
index 277473fe..95720aba 100644
--- a/core/src/layout.rs
+++ b/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)],
+    )
+}
diff --git a/core/src/layout/flex.rs b/core/src/layout/flex.rs
index 2a12d57f..cf3e1340 100644
--- a/core/src/layout/flex.rs
+++ b/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)
diff --git a/core/src/layout/limits.rs b/core/src/layout/limits.rs
index eef4c4c9..7fbc7b9d 100644
--- a/core/src/layout/limits.rs
+++ b/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,
diff --git a/core/src/layout/node.rs b/core/src/layout/node.rs
index 00087431..40c71436 100644
--- a/core/src/layout/node.rs
+++ b/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
diff --git a/core/src/point.rs b/core/src/point.rs
index ef42852f..cea57518 100644
--- a/core/src/point.rs
+++ b/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]
     }
 }
diff --git a/core/src/widget/text.rs b/core/src/widget/text.rs
index fe3b77d3..4cabc7ce 100644
--- a/core/src/widget/text.rs
+++ b/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();
-
-    let size = size.unwrap_or_else(|| renderer.default_size());
-    let font = font.unwrap_or_else(|| renderer.default_font());
-
-    let State(ref mut paragraph) = state;
-
-    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)
+    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 State(ref mut paragraph) = state;
+
+        paragraph.update(text::Text {
+            content,
+            bounds,
+            size,
+            line_height,
+            font,
+            horizontal_alignment,
+            vertical_alignment,
+            shaping,
+        });
+
+        paragraph.min_bounds()
+    })
 }
 
 /// Draws text using the same logic as the [`Text`] widget.
diff --git a/examples/geometry/src/main.rs b/examples/geometry/src/main.rs
index d6a4c702..5cf9963d 100644
--- a/examples/geometry/src/main.rs
+++ b/examples/geometry/src/main.rs
@@ -29,9 +29,9 @@ mod rainbow {
             _renderer: &Renderer,
             limits: &layout::Limits,
         ) -> layout::Node {
-            let size = limits.resolve(Size::ZERO, Length::Fill, Length::Shrink);
+            let width = limits.max().width;
 
-            layout::Node::new(Size::new(size.width, size.width))
+            layout::Node::new(Size::new(width, width))
         }
 
         fn draw(
diff --git a/examples/loading_spinners/src/circular.rs b/examples/loading_spinners/src/circular.rs
index e80617d0..1b163585 100644
--- a/examples/loading_spinners/src/circular.rs
+++ b/examples/loading_spinners/src/circular.rs
@@ -257,10 +257,7 @@ where
         _renderer: &iced::Renderer<Theme>,
         limits: &layout::Limits,
     ) -> layout::Node {
-        let limits = limits.width(self.size).height(self.size);
-        let size = limits.resolve(Size::ZERO, self.size, self.size);
-
-        layout::Node::new(size)
+        layout::atomic(limits, self.size, self.size)
     }
 
     fn on_event(
diff --git a/examples/loading_spinners/src/linear.rs b/examples/loading_spinners/src/linear.rs
index d205d3f1..d245575c 100644
--- a/examples/loading_spinners/src/linear.rs
+++ b/examples/loading_spinners/src/linear.rs
@@ -178,10 +178,7 @@ where
         _renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
-        let limits = limits.width(self.width).height(self.height);
-        let size = limits.resolve(Size::ZERO, self.width, self.height);
-
-        layout::Node::new(size)
+        layout::atomic(limits, self.width, self.height)
     }
 
     fn on_event(
diff --git a/widget/src/button.rs b/widget/src/button.rs
index 1ce4f662..86abee77 100644
--- a/widget/src/button.rs
+++ b/widget/src/button.rs
@@ -10,8 +10,8 @@ use crate::core::touch;
 use crate::core::widget::tree::{self, Tree};
 use crate::core::widget::Operation;
 use crate::core::{
-    Background, Clipboard, Color, Element, Layout, Length, Padding, Point,
-    Rectangle, Shell, Size, Vector, Widget,
+    Background, Clipboard, Color, Element, Layout, Length, Padding, Rectangle,
+    Shell, Size, Vector, Widget,
 };
 
 pub use iced_style::button::{Appearance, StyleSheet};
@@ -430,20 +430,7 @@ pub fn layout(
     padding: Padding,
     layout_content: impl FnOnce(&layout::Limits) -> layout::Node,
 ) -> layout::Node {
-    let limits = limits.width(width).height(height);
-
-    let content = layout_content(&limits.shrink(padding));
-    let padding = padding.fit(content.size(), limits.max());
-
-    let size = limits
-        .shrink(padding)
-        .resolve(content.size(), width, height)
-        .expand(padding);
-
-    layout::Node::with_children(
-        size,
-        vec![content.move_to(Point::new(padding.left, padding.top))],
-    )
+    layout::padded(limits, width, height, padding, layout_content)
 }
 
 /// Returns the [`mouse::Interaction`] of a [`Button`].
diff --git a/widget/src/canvas.rs b/widget/src/canvas.rs
index 2bf09eec..4e42a671 100644
--- a/widget/src/canvas.rs
+++ b/widget/src/canvas.rs
@@ -133,9 +133,7 @@ where
         _renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
-        let size = limits.resolve(Size::ZERO, self.width, self.height);
-
-        layout::Node::new(size)
+        layout::atomic(limits, self.width, self.height)
     }
 
     fn on_event(
diff --git a/widget/src/container.rs b/widget/src/container.rs
index 93d8daba..c98de41c 100644
--- a/widget/src/container.rs
+++ b/widget/src/container.rs
@@ -321,27 +321,19 @@ pub fn layout(
     vertical_alignment: alignment::Vertical,
     layout_content: impl FnOnce(&layout::Limits) -> layout::Node,
 ) -> layout::Node {
-    let limits = limits
-        .width(width)
-        .height(height)
-        .max_width(max_width)
-        .max_height(max_height);
-
-    let content = layout_content(&limits.shrink(padding).loose());
-    let padding = padding.fit(content.size(), limits.max());
-    let size = limits
-        .shrink(padding)
-        .resolve(content.size(), width, height);
-
-    layout::Node::with_children(
-        size.expand(padding),
-        vec![content
-            .move_to(Point::new(padding.left, padding.top))
-            .align(
+    layout::positioned(
+        &limits.max_width(max_width).max_height(max_height),
+        width,
+        height,
+        padding,
+        |limits| layout_content(&limits.loose()),
+        |content, size| {
+            content.align(
                 Alignment::from(horizontal_alignment),
                 Alignment::from(vertical_alignment),
                 size,
-            )],
+            )
+        },
     )
 }
 
diff --git a/widget/src/image.rs b/widget/src/image.rs
index 6750c1b3..e906ac13 100644
--- a/widget/src/image.rs
+++ b/widget/src/image.rs
@@ -99,7 +99,7 @@ where
     };
 
     // The size to be available to the widget prior to `Shrink`ing
-    let raw_size = limits.resolve(image_size, width, height);
+    let raw_size = limits.resolve(width, height, image_size);
 
     // The uncropped size of the image when fit to the bounds above
     let full_size = content_fit.fit(image_size, raw_size);
diff --git a/widget/src/image/viewer.rs b/widget/src/image/viewer.rs
index dc910f1f..98080577 100644
--- a/widget/src/image/viewer.rs
+++ b/widget/src/image/viewer.rs
@@ -113,9 +113,9 @@ where
         let Size { width, height } = renderer.dimensions(&self.handle);
 
         let mut size = limits.resolve(
-            Size::new(width as f32, height as f32),
             self.width,
             self.height,
+            Size::new(width as f32, height as f32),
         );
 
         let expansion_size = if height > width {
diff --git a/widget/src/overlay/menu.rs b/widget/src/overlay/menu.rs
index b9e06de8..f83eebea 100644
--- a/widget/src/overlay/menu.rs
+++ b/widget/src/overlay/menu.rs
@@ -369,7 +369,7 @@ where
                     * self.options.len() as f32,
             );
 
-            limits.resolve(intrinsic, Length::Fill, Length::Shrink)
+            limits.resolve(Length::Fill, Length::Shrink, intrinsic)
         };
 
         layout::Node::new(size)
diff --git a/widget/src/pane_grid.rs b/widget/src/pane_grid.rs
index 36c785b7..cf1f0455 100644
--- a/widget/src/pane_grid.rs
+++ b/widget/src/pane_grid.rs
@@ -489,7 +489,7 @@ pub fn layout<Renderer, T>(
         &layout::Limits,
     ) -> layout::Node,
 ) -> layout::Node {
-    let size = limits.resolve(Size::ZERO, width, height);
+    let size = limits.resolve(width, height, Size::ZERO);
 
     let regions = node.pane_regions(spacing, size);
     let children = contents
diff --git a/widget/src/pick_list.rs b/widget/src/pick_list.rs
index d83b0624..2576a1e8 100644
--- a/widget/src/pick_list.rs
+++ b/widget/src/pick_list.rs
@@ -392,7 +392,6 @@ where
 {
     use std::f32;
 
-    let limits = limits.width(width).height(Length::Shrink);
     let font = font.unwrap_or_else(|| renderer.default_font());
     let text_size = text_size.unwrap_or_else(|| renderer.default_size());
 
@@ -451,8 +450,10 @@ where
         );
 
         limits
+            .width(width)
+            .height(Length::Shrink)
             .shrink(padding)
-            .resolve(intrinsic, width, Length::Shrink)
+            .resolve(width, Length::Shrink, intrinsic)
             .expand(padding)
     };
 
diff --git a/widget/src/progress_bar.rs b/widget/src/progress_bar.rs
index a05923a2..15f1277b 100644
--- a/widget/src/progress_bar.rs
+++ b/widget/src/progress_bar.rs
@@ -98,13 +98,11 @@ where
         _renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
-        let size = limits.resolve(
-            Size::ZERO,
+        layout::atomic(
+            limits,
             self.width,
             self.height.unwrap_or(Length::Fixed(Self::DEFAULT_HEIGHT)),
-        );
-
-        layout::Node::new(size)
+        )
     }
 
     fn draw(
diff --git a/widget/src/rule.rs b/widget/src/rule.rs
index 4ab16c40..cded9cb1 100644
--- a/widget/src/rule.rs
+++ b/widget/src/rule.rs
@@ -75,7 +75,7 @@ where
         _renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
-        layout::Node::new(limits.resolve(Size::ZERO, self.width, self.height))
+        layout::atomic(limits, self.width, self.height)
     }
 
     fn draw(
diff --git a/widget/src/scrollable.rs b/widget/src/scrollable.rs
index 5197afde..70db490a 100644
--- a/widget/src/scrollable.rs
+++ b/widget/src/scrollable.rs
@@ -469,28 +469,25 @@ pub fn layout<Renderer>(
     direction: &Direction,
     layout_content: impl FnOnce(&Renderer, &layout::Limits) -> layout::Node,
 ) -> layout::Node {
-    let limits = limits.width(width).height(height);
-
-    let child_limits = layout::Limits::new(
-        Size::new(limits.min().width, limits.min().height),
-        Size::new(
-            if direction.horizontal().is_some() {
-                f32::INFINITY
-            } else {
-                limits.max().width
-            },
-            if direction.vertical().is_some() {
-                f32::MAX
-            } else {
-                limits.max().height
-            },
-        ),
-    );
-
-    let content = layout_content(renderer, &child_limits);
-    let size = limits.resolve(content.size(), width, height);
+    layout::contained(limits, width, height, |limits| {
+        let child_limits = layout::Limits::new(
+            Size::new(limits.min().width, limits.min().height),
+            Size::new(
+                if direction.horizontal().is_some() {
+                    f32::INFINITY
+                } else {
+                    limits.max().width
+                },
+                if direction.vertical().is_some() {
+                    f32::MAX
+                } else {
+                    limits.max().height
+                },
+            ),
+        );
 
-    layout::Node::with_children(size, vec![content])
+        layout_content(renderer, &child_limits)
+    })
 }
 
 /// Processes an [`Event`] and updates the [`State`] of a [`Scrollable`]
diff --git a/widget/src/shader.rs b/widget/src/shader.rs
index 82432c6c..16b68c55 100644
--- a/widget/src/shader.rs
+++ b/widget/src/shader.rs
@@ -83,10 +83,7 @@ where
         _renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
-        let limits = limits.width(self.width).height(self.height);
-        let size = limits.resolve(Size::ZERO, self.width, self.height);
-
-        layout::Node::new(size)
+        layout::atomic(limits, self.width, self.height)
     }
 
     fn on_event(
diff --git a/widget/src/slider.rs b/widget/src/slider.rs
index 27588852..1bc94661 100644
--- a/widget/src/slider.rs
+++ b/widget/src/slider.rs
@@ -172,9 +172,7 @@ where
         _renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
-        let size = limits.resolve(Size::ZERO, self.width, self.height);
-
-        layout::Node::new(size)
+        layout::atomic(limits, self.width, self.height)
     }
 
     fn on_event(
diff --git a/widget/src/space.rs b/widget/src/space.rs
index 9fd4dcb9..eef990d1 100644
--- a/widget/src/space.rs
+++ b/widget/src/space.rs
@@ -58,7 +58,7 @@ where
         _renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
-        layout::Node::new(limits.resolve(Size::ZERO, self.width, self.height))
+        layout::atomic(limits, self.width, self.height)
     }
 
     fn draw(
diff --git a/widget/src/svg.rs b/widget/src/svg.rs
index 75ab238a..830abb0f 100644
--- a/widget/src/svg.rs
+++ b/widget/src/svg.rs
@@ -114,7 +114,7 @@ where
         let image_size = Size::new(width as f32, height as f32);
 
         // The size to be available to the widget prior to `Shrink`ing
-        let raw_size = limits.resolve(image_size, self.width, self.height);
+        let raw_size = limits.resolve(self.width, self.height, image_size);
 
         // The uncropped size of the image when fit to the bounds above
         let full_size = self.content_fit.fit(image_size, raw_size);
diff --git a/widget/src/text_input.rs b/widget/src/text_input.rs
index 7e91105c..d8540658 100644
--- a/widget/src/text_input.rs
+++ b/widget/src/text_input.rs
@@ -508,8 +508,8 @@ where
     let padding = padding.fit(Size::ZERO, limits.max());
     let height = line_height.to_absolute(text_size);
 
-    let limits = limits.width(width).shrink(padding).height(height);
-    let text_bounds = limits.resolve(Size::ZERO, width, height);
+    let limits = limits.width(width).shrink(padding);
+    let text_bounds = limits.resolve(width, height, Size::ZERO);
 
     let placeholder_text = Text {
         font,
diff --git a/widget/src/vertical_slider.rs b/widget/src/vertical_slider.rs
index 35bc2fe2..a3029d76 100644
--- a/widget/src/vertical_slider.rs
+++ b/widget/src/vertical_slider.rs
@@ -169,9 +169,7 @@ where
         _renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
-        let size = limits.resolve(Size::ZERO, self.width, self.height);
-
-        layout::Node::new(size)
+        layout::atomic(limits, self.width, self.height)
     }
 
     fn on_event(