Updating changelog + API cleanup

While updating the changelog I noticed that size now returned a layout,
and it seemed more appropriate to rename the function even though it's a
larger breaking change

Author: ecton

CHANGELOG.md

@@ -127,6 +127,22 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
   value containers.
 - `cushy::value::CallbackDisconnected` and `cushy::value::CallbackHandle` are
   now exported from `cushy::reactive`.
+- Cushy now generically supports `HorizontalAlignment` and `VerticalAlignment`
+  of widgets contained within other widgets. Additionally, baseline vertical
+  alignment support has been added to make it simple to align widgets vertically
+  based on the content of the widget. To support this, many APIs have required
+  changes:
+
+  - `Widget::layout()` and `LayoutContext::layout()` now returns `WidgetLayout`.
+  - `IndicatorBehavior::size()` has been renamed to
+    `IndicatorBehavior::layout()` and now returns `WidgetLayout`.
+  - `WrappedLayout` now has the field `baseline: Baseline`.
+  - `WrappedLayout::aligned` now accepts `Into<WidgetLayout>` for its first
+    parameter. This should be mostly compatible with existing code.
+  - `WrapperWidget::position_child` now accepts a `WidgetLayout` instead of a
+    `Size<UPx>` as its first parameter.
+  - `Button`'s label is automatically centered horizontally using a new style
+    component: `ButtonLabelAlignment`.
 
 ### Changed
 

src/widgets/checkbox.rs

@@ -214,7 +214,7 @@ fn indicator_layout(context: &mut GraphicsContext<'_, '_, '_, '_>) -> WidgetLayo
 impl IndicatorBehavior for CheckboxIndicator {
     type Colors = CheckboxColors;
 
-    fn size(&self, context: &mut GraphicsContext<'_, '_, '_, '_>) -> WidgetLayout {
+    fn layout(&self, context: &mut GraphicsContext<'_, '_, '_, '_>) -> WidgetLayout {
         indicator_layout(context)
     }
 

src/widgets/grid.rs

@@ -684,7 +684,6 @@ impl GridLayout {
         row_index: usize,
         vertical_alignment: VerticalAlign,
     ) -> Rect<Px> {
-        // TODO We need to honor expanding the child if we are supposed to expand it.
         let mut position = Rect::new(
             self.orientation
                 .make_point(layout.offset, other_offset)

src/widgets/indicator.rs

@@ -59,8 +59,8 @@ pub trait IndicatorBehavior: Send + Debug + 'static {
         region: Rect<Px>,
         context: &mut GraphicsContext<'_, '_, '_, '_>,
     );
-    /// Returns the size of this indicator.
-    fn size(&self, context: &mut GraphicsContext<'_, '_, '_, '_>) -> WidgetLayout;
+    /// Returns the size and basline of this indicator.
+    fn layout(&self, context: &mut GraphicsContext<'_, '_, '_, '_>) -> WidgetLayout;
 }
 
 /// The current state of an [`Indicator`] widget.
@@ -252,7 +252,7 @@ where
         context: &mut LayoutContext<'_, '_, '_, '_>,
     ) -> WidgetLayout {
         let window_local = self.per_window.entry(context).or_default();
-        let indicator_layout = self.behavior.size(context);
+        let indicator_layout = self.behavior.layout(context);
         window_local.size = indicator_layout.size.ceil();
         window_local.checkbox_region.size = window_local.size.into_signed();
 

src/widgets/menu.rs

@@ -24,8 +24,8 @@ use crate::styles::components::{
 };
 use crate::styles::Styles;
 use crate::widget::{
-    Callback, EventHandling, MakeWidget, MakeWidgetWithTag, SharedNotify, Widget, WidgetId,
-    WidgetInstance, WidgetLayout, WidgetRef, WidgetTag, HANDLED,
+    Baseline, Callback, EventHandling, MakeWidget, MakeWidgetWithTag, SharedNotify, Widget,
+    WidgetId, WidgetInstance, WidgetLayout, WidgetRef, WidgetTag, HANDLED,
 };
 use crate::ConstraintLimit;
 
@@ -664,20 +664,21 @@ where
         let available_width = available_space.width.max() - double_padding;
 
         let mut y = self.padding;
-        for rendered in &mut self.items {
+        let mut first_baseline = Baseline::NONE;
+        for (index, rendered) in self.items.iter_mut().enumerate() {
             let (height, full_height) = match &mut rendered.item {
                 ItemKind::Item(item) => {
                     let mounted = item.contents.mounted(context);
                     let available_width = available_width - submenu_space;
-                    let size = context
-                        .for_other(&mounted)
-                        .layout(Size::new(
-                            ConstraintLimit::SizeToFit(available_width),
-                            ConstraintLimit::SizeToFit(remaining_height),
-                        ))
-                        .size;
-                    maximum_item_width = maximum_item_width.max(size.width);
-                    (size.height, size.height + double_padding)
+                    let layout = context.for_other(&mounted).layout(Size::new(
+                        ConstraintLimit::SizeToFit(available_width),
+                        ConstraintLimit::SizeToFit(remaining_height),
+                    ));
+                    maximum_item_width = maximum_item_width.max(layout.size.width);
+                    if index == 0 {
+                        first_baseline = layout.baseline;
+                    }
+                    (layout.size.height, layout.size.height + double_padding)
                 }
                 ItemKind::Separator => (UPx::ZERO, self.padding),
             };
@@ -704,8 +705,10 @@ where
             );
         }
 
-        // TODO should a Menu report its baseline?
-        Size::new(maximum_item_width + double_padding * 2 + submenu_space, y).into()
+        WidgetLayout {
+            size: Size::new(maximum_item_width + double_padding * 2 + submenu_space, y),
+            baseline: first_baseline,
+        }
     }
 
     fn hit_test(

src/widgets/radio.rs

@@ -165,7 +165,7 @@ where
 {
     type Colors = RadioColors;
 
-    fn size(&self, context: &mut GraphicsContext<'_, '_, '_, '_>) -> WidgetLayout {
+    fn layout(&self, context: &mut GraphicsContext<'_, '_, '_, '_>) -> WidgetLayout {
         let size = Size::squared(context.get(&RadioSize).into_upx(context.gfx.scale()).ceil());
         let outline_width = context
             .get(&OutlineWidth)