Basic context menus

Missing a ton of functionality (separators, keyboard accessibility,
submenus), but the basic concept is working.

examples/menu.rs

@@ -0,0 +1,40 @@
+use cushy::widget::MakeWidget;
+use cushy::widgets::layers::{OverlayLayer, Overlayable};
+use cushy::widgets::menu::{Menu, MenuItem};
+use cushy::Run;
+
+#[derive(Clone, Copy, Debug)]
+enum MenuOptions {
+    First,
+    Second,
+    Third,
+}
+
+fn main() -> cushy::Result {
+    let overlay = OverlayLayer::default();
+
+    "Click Me"
+        .into_button()
+        .on_click({
+            let overlay = overlay.clone();
+            move |click| {
+                if let Some(click) = click {
+                    Menu::new()
+                        .with(MenuItem::new(MenuOptions::First, "First"))
+                        .with(MenuItem::new(MenuOptions::Second, "Second"))
+                        .with(MenuItem::new(MenuOptions::Third, "Third"))
+                        .on_selected(|selected| {
+                            println!("Selected item: {selected:?}");
+                        })
+                        .overlay_in(&overlay)
+                        .at(click.window_location)
+                        .show();
+                }
+            }
+        })
+        .centered()
+        .expand()
+        .and(overlay)
+        .into_layers()
+        .run()
+}

examples/overlays.rs

@@ -1,6 +1,6 @@
 use cushy::widget::{MakeWidget, MakeWidgetWithTag, WidgetTag};
 use cushy::widgets::container::ContainerShadow;
-use cushy::widgets::layers::{OverlayBuilder, OverlayLayer};
+use cushy::widgets::layers::{OverlayBuilder, OverlayLayer, Overlayable};
 use cushy::Run;
 use figures::units::Lp;
 use figures::{Point, Zero};

src/styles/components.rs

@@ -220,7 +220,7 @@ define_components! {
         OpaqueWidgetColor(Color, "opaque_color", .surface.opaque_widget)
         /// A set of radius descriptions for how much roundness to apply to the
         /// shapes of widgets.
-        CornerRadius(CornerRadii<Dimension>, "corner_radius", CornerRadii::from(Dimension::Lp(Lp::points(10))))
+        CornerRadius(CornerRadii<Dimension>, "corner_radius", CornerRadii::from(Dimension::Lp(Lp::points(6))))
         /// The font family to render text using.
         FontFamily(FontFamilyList, "font_family", FontFamilyList::from(FamilyOwned::SansSerif))
         /// The font (boldness) weight to apply to text rendering.

src/widgets.rs

@@ -18,6 +18,7 @@ pub mod input;
 pub mod label;
 pub mod layers;
 pub mod list;
+pub mod menu;
 mod mode_switch;
 pub mod progress;
 pub mod radio;

src/widgets/layers.rs

@@ -574,6 +574,48 @@ impl OverlayState {
     }
 }
 
+/// A type that is being prepared to be shown in an [`OverlayLayer`].
+pub trait Overlayable: Sized {
+    /// The resulting handle type when this overlay is shown.
+    type Handle;
+
+    /// Sets this overlay to hide automatically when it or its relative widget
+    /// are no longer hovered by the mouse cursor.
+    #[must_use]
+    fn hide_on_unhover(self) -> Self;
+
+    /// Show this overlay to the left of the specified widget.
+    #[must_use]
+    fn left_of(self, id: WidgetId) -> Self;
+
+    /// Show this overlay to the right of the specified widget.
+    #[must_use]
+    fn right_of(self, id: WidgetId) -> Self;
+
+    /// Show this overlay to show below the specified widget.
+    #[must_use]
+    fn below(self, id: WidgetId) -> Self;
+
+    /// Show this overlay to show above the specified widget.
+    #[must_use]
+    fn above(self, id: WidgetId) -> Self;
+
+    /// Shows this overlay near `id` off to the `direction` side.
+    #[must_use]
+    fn near(self, id: WidgetId, direction: Direction) -> Self;
+
+    /// Shows this overlay at a specified window `location`.
+    #[must_use]
+    fn at(self, location: Point<Px>) -> Self;
+
+    /// Sets `callback` to be invoked once this overlay is dismissed.
+    #[must_use]
+    fn on_dismiss(self, callback: Callback) -> Self;
+
+    /// Shows this overlay, returning a handle that to the displayed overlay.
+    fn show(self) -> Self::Handle;
+}
+
 /// A builder for overlaying a widget on an [`OverlayLayer`].
 #[derive(Debug, Clone)]
 pub struct OverlayBuilder<'a> {
@@ -581,64 +623,47 @@ pub struct OverlayBuilder<'a> {
     layout: OverlayLayout,
 }
 
-impl OverlayBuilder<'_> {
-    /// Sets this overlay to hide automatically when it or its relative widget
-    /// are no longer hovered by the mouse cursor.
-    #[must_use]
-    pub fn hide_on_unhover(mut self) -> Self {
+impl Overlayable for OverlayBuilder<'_> {
+    type Handle = OverlayHandle;
+
+    fn hide_on_unhover(mut self) -> Self {
         self.layout.requires_hover = true;
         self
     }
 
-    /// Show this overlay to the left of the specified widget.
-    #[must_use]
-    pub fn left_of(self, id: WidgetId) -> Self {
+    fn left_of(self, id: WidgetId) -> Self {
         self.near(id, Direction::Left)
     }
 
-    /// Show this overlay to the right of the specified widget.
-    #[must_use]
-    pub fn right_of(self, id: WidgetId) -> Self {
+    fn right_of(self, id: WidgetId) -> Self {
         self.near(id, Direction::Right)
     }
 
-    /// Show this overlay to show below the specified widget.
-    #[must_use]
-    pub fn below(self, id: WidgetId) -> Self {
+    fn below(self, id: WidgetId) -> Self {
         self.near(id, Direction::Down)
     }
 
-    /// Show this overlay to show above the specified widget.
-    #[must_use]
-    pub fn above(self, id: WidgetId) -> Self {
+    fn above(self, id: WidgetId) -> Self {
         self.near(id, Direction::Up)
     }
 
-    /// Shows this overlay near `id` off to the `direction` side.
-    #[must_use]
-    pub fn near(mut self, id: WidgetId, direction: Direction) -> Self {
+    fn near(mut self, id: WidgetId, direction: Direction) -> Self {
         self.layout.relative_to = Some(id);
         self.layout.positioning = Position::Relative(direction);
         self
     }
 
-    /// Shows this overlay at a specified window `location`.
-    #[must_use]
-    pub fn at(mut self, location: Point<Px>) -> Self {
+    fn at(mut self, location: Point<Px>) -> Self {
         self.layout.positioning = Position::At(location);
         self
     }
 
-    /// Sets `callback` to be invoked once this overlay is dismissed.
-    #[must_use]
-    pub fn on_dismiss(mut self, callback: Callback) -> Self {
+    fn on_dismiss(mut self, callback: Callback) -> Self {
         self.layout.on_dismiss = Some(Arc::new(Mutex::new(callback)));
         self
     }
 
-    /// Shows this overlay, returning a handle that to the displayed overlay.
-    #[must_use]
-    pub fn show(self) -> OverlayHandle {
+    fn show(self) -> Self::Handle {
         self.fade_in();
         self.overlay.state.map_mut(|mut state| {
             state.new_overlays += 1;
@@ -649,7 +674,9 @@ impl OverlayBuilder<'_> {
             }
         })
     }
+}
 
+impl OverlayBuilder<'_> {
     fn fade_in(&self) {
         self.layout
             .opacity
@@ -746,6 +773,7 @@ impl Direction {
 
 /// A handle to an overlay that was shown in an [`OverlayLayer`].
 #[derive(PartialEq, Eq)]
+#[must_use = "Overlay handles will dismiss the shown overlay when dropped."]
 pub struct OverlayHandle {
     state: Dynamic<OverlayState>,
     id: LotId,

src/widgets/menu.rs

@@ -0,0 +1,359 @@
+//! Overlay menu widgets.
+
+use std::fmt::Debug;
+use std::sync::Arc;
+
+use figures::units::{Lp, Px, UPx};
+use figures::{IntoSigned, Point, Rect, Size, Zero};
+use parking_lot::Mutex;
+
+use super::button::{ButtonClick, ButtonKind};
+use super::container::ContainerShadow;
+use super::layers::{OverlayBuilder, OverlayHandle, OverlayLayer, Overlayable};
+use crate::context::{GraphicsContext, LayoutContext};
+use crate::value::Dynamic;
+use crate::widget::{Callback, MakeWidget, Widget, WidgetInstance, WidgetRef};
+use crate::ConstraintLimit;
+
+/// An overlayable menu of selectable items.
+///
+/// This widget is designed to implement Cushy's contextual menu system. When
+/// used with an [`OverlayLayer`], this widget can be shown above other widgets
+/// or at a specific location.
+#[derive(Debug, Clone)]
+pub struct Menu<T> {
+    items: Vec<MenuItem<T>>,
+    on_click: Option<Arc<Mutex<Callback<ChosenMenuItem<T>>>>>,
+}
+
+impl<T> Default for Menu<T>
+where
+    T: Debug + Send + Clone + 'static,
+{
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+impl<T> Menu<T>
+where
+    T: Debug + Send + Clone + 'static,
+{
+    /// Returns a new, empty menu.
+    #[must_use]
+    pub const fn new() -> Self {
+        Self {
+            items: Vec::new(),
+            on_click: None,
+        }
+    }
+
+    /// Adds another menu `item` that is displayed using `widget`.
+    #[must_use]
+    pub fn with(mut self, item: impl Into<MenuItem<T>>) -> Self {
+        self.items.push(item.into());
+        self
+    }
+
+    /// Sets the selected handler to `selected`, causing it to be invoked when
+    /// an item is chosen.
+    #[must_use]
+    pub fn on_selected<F>(mut self, selected: F) -> Self
+    where
+        F: FnMut(ChosenMenuItem<T>) + Send + 'static,
+    {
+        self.on_click = Some(Arc::new(Mutex::new(Callback::new(selected))));
+        self
+    }
+
+    /// Presents this menu in `overlay`, returning an [`Overlayable`] that can
+    /// be positioned relative or absolutely within `overlay`.
+    #[must_use]
+    pub fn overlay_in<'overlay>(&self, overlay: &'overlay OverlayLayer) -> MenuOverlay<'overlay> {
+        let Self { items, on_click } = self;
+        let handle = OpenMenuHandle(Dynamic::new(None));
+        let items = items
+            .iter()
+            .map(|item| {
+                let MenuItem { value, widget } = item;
+                let handle = handle.clone();
+                OpenItem {
+                    contents: WidgetRef::new(
+                        widget
+                            .clone()
+                            .into_button()
+                            .kind(ButtonKind::Transparent)
+                            .on_click({
+                                let on_click = on_click.clone();
+                                let value = value.clone();
+                                move |click| {
+                                    if let Some(on_click) = &on_click {
+                                        let mut on_click = on_click.lock();
+                                        on_click.invoke(ChosenMenuItem {
+                                            item: value.clone(),
+                                            click,
+                                        });
+                                    }
+                                    handle.dismiss();
+                                }
+                            }),
+                    ),
+                    height: UPx::ZERO,
+                }
+            })
+            .collect();
+        MenuOverlay(
+            overlay.build_overlay(
+                OpenMenu {
+                    items,
+                    handle: handle.clone(),
+                }
+                .contain()
+                .shadow(ContainerShadow::drop(Lp::mm(1), Lp::mm(2)))
+                .vertical_scroll(),
+            ),
+            handle,
+        )
+    }
+}
+
+/// A [`Menu`] that is preparing to be shown in an [`OverlayLayer`].
+pub struct MenuOverlay<'a>(OverlayBuilder<'a>, OpenMenuHandle);
+
+impl<'a> Overlayable for MenuOverlay<'a> {
+    type Handle = OpenMenuHandle;
+
+    fn hide_on_unhover(self) -> Self {
+        Self(self.0.hide_on_unhover(), self.1)
+    }
+
+    fn left_of(self, id: crate::widget::WidgetId) -> Self {
+        Self(self.0.left_of(id), self.1)
+    }
+
+    fn right_of(self, id: crate::widget::WidgetId) -> Self {
+        Self(self.0.right_of(id), self.1)
+    }
+
+    fn below(self, id: crate::widget::WidgetId) -> Self {
+        Self(self.0.below(id), self.1)
+    }
+
+    fn above(self, id: crate::widget::WidgetId) -> Self {
+        Self(self.0.above(id), self.1)
+    }
+
+    fn near(self, id: crate::widget::WidgetId, direction: super::layers::Direction) -> Self {
+        Self(self.0.near(id, direction), self.1)
+    }
+
+    fn at(self, location: Point<Px>) -> Self {
+        Self(self.0.at(location), self.1)
+    }
+
+    fn on_dismiss(self, callback: Callback) -> Self {
+        Self(self.0.on_dismiss(callback), self.1)
+    }
+
+    fn show(self) -> Self::Handle {
+        let handle = self.0.show();
+        *self.1 .0.lock() = Some(handle);
+        self.1
+    }
+}
+
+/// A handle to a [`Menu`] that was shown.
+#[derive(Clone, Debug)]
+pub struct OpenMenuHandle(Dynamic<Option<OverlayHandle>>);
+
+impl OpenMenuHandle {
+    /// Closes the menu, if it is still shown.
+    pub fn dismiss(&self) {
+        *self.0.lock() = None;
+    }
+}
+
+/// The selected item of a shown [`Menu<T>`].
+#[derive(Debug, Clone, Copy, Eq, PartialEq)]
+pub struct ChosenMenuItem<T> {
+    /// The item that was chosen.
+    pub item: T,
+    /// Information about the button click that caused this item to be chosen,
+    /// if present.
+    pub click: Option<ButtonClick>,
+}
+
+/// A builder of a [`MenuItem<T>`].
+pub struct MenuItemBuilder<T, Contents = ()> {
+    value: T,
+    contents: Contents,
+}
+
+impl<T> MenuItemBuilder<T, ()> {
+    /// Sets the text of this menu item to `text` and returns self.
+    pub fn text(self, text: impl Into<String>) -> MenuItemBuilder<T, String> {
+        let Self {
+            value,
+            contents: (),
+        } = self;
+
+        MenuItemBuilder {
+            value,
+            contents: text.into(),
+        }
+    }
+
+    /// Sets the contents of this menu item to `widget` and returns self.
+    pub fn widget(self, widget: impl MakeWidget) -> MenuItemBuilder<T, WidgetInstance> {
+        let Self {
+            value,
+            contents: (),
+        } = self;
+
+        MenuItemBuilder {
+            value,
+            contents: widget.make_widget(),
+        }
+    }
+}
+
+/// A type that can be used inside of a [`MenuItemBuilder`] as a menu item's
+/// contents.
+pub trait MenuItemContents<T>: sealed::MenuItemContentsSealed<T> {}
+
+mod sealed {
+    pub trait MenuItemContentsSealed<T> {
+        fn make_item(self, value: T) -> super::MenuItem<T>;
+    }
+}
+
+impl<T> MenuItemContents<T> for String {}
+impl<T> MenuItemContents<T> for WidgetInstance {}
+impl<T> sealed::MenuItemContentsSealed<T> for String {
+    fn make_item(self, value: T) -> MenuItem<T> {
+        MenuItem {
+            value,
+            widget: self.make_widget(),
+        }
+    }
+}
+
+impl<T> sealed::MenuItemContentsSealed<T> for WidgetInstance {
+    fn make_item(self, value: T) -> MenuItem<T> {
+        MenuItem {
+            value,
+            widget: self,
+        }
+    }
+}
+
+impl<T, Contents> MenuItemBuilder<T, Contents>
+where
+    Contents: MenuItemContents<T>,
+{
+    /// Returns the finished menu item.
+    pub fn finish(self) -> MenuItem<T> {
+        self.contents.make_item(self.value)
+    }
+}
+
+impl<T, Contents> From<MenuItemBuilder<T, Contents>> for MenuItem<T>
+where
+    Contents: MenuItemContents<T>,
+{
+    fn from(builder: MenuItemBuilder<T, Contents>) -> Self {
+        builder.finish()
+    }
+}
+
+/// An item in a [`Menu<T>`].
+#[derive(Debug, Clone)]
+pub struct MenuItem<T> {
+    value: T,
+    widget: WidgetInstance,
+    // submenu: Option<Menu<T>>,
+}
+
+impl<T> MenuItem<T> {
+    /// Returns a new menu item with the given value and contents.
+    pub fn new(value: T, contents: impl MakeWidget) -> Self {
+        Self::build(value).widget(contents).finish()
+    }
+
+    /// Returns a builder for a menu item with the given value.
+    pub fn build(value: T) -> MenuItemBuilder<T, ()> {
+        MenuItemBuilder {
+            value,
+            contents: (),
+        }
+    }
+}
+
+#[derive(Debug)]
+struct OpenMenu {
+    items: Vec<OpenItem>,
+    handle: OpenMenuHandle,
+}
+
+#[derive(Debug)]
+struct OpenItem {
+    contents: WidgetRef,
+    height: UPx,
+}
+
+impl Widget for OpenMenu {
+    fn redraw(&mut self, context: &mut GraphicsContext<'_, '_, '_, '_>) {
+        for item in &mut self.items {
+            let mounted = item.contents.mounted(context);
+            context.for_other(&mounted).redraw();
+        }
+    }
+
+    fn layout(
+        &mut self,
+        available_space: Size<ConstraintLimit>,
+        context: &mut LayoutContext<'_, '_, '_, '_>,
+    ) -> Size<UPx> {
+        let mut maximum_item_width = UPx::ZERO;
+        let mut remaining_height = available_space.height.max();
+
+        for item in &mut self.items {
+            let mounted = item.contents.mounted(context);
+            let size = context.for_other(&mounted).layout(Size::new(
+                ConstraintLimit::SizeToFit(available_space.width.max()),
+                ConstraintLimit::SizeToFit(remaining_height),
+            ));
+            item.height = size.height;
+
+            remaining_height = remaining_height.saturating_sub(item.height);
+            maximum_item_width = maximum_item_width.max(size.width);
+        }
+
+        let mut y = UPx::ZERO;
+        for item in &mut self.items {
+            let mounted = item.contents.mounted(context);
+            context.set_child_layout(
+                &mounted,
+                Rect::new(
+                    Point::new(Px::ZERO, y.into_signed()),
+                    Size::new(maximum_item_width, item.height).into_signed(),
+                ),
+            );
+            y += item.height;
+        }
+
+        Size::new(maximum_item_width, y)
+    }
+
+    fn accept_focus(&mut self, _context: &mut crate::context::EventContext<'_>) -> bool {
+        true
+    }
+
+    fn mounted(&mut self, context: &mut crate::context::EventContext<'_>) {
+        context.focus();
+    }
+
+    fn blur(&mut self, _context: &mut crate::context::EventContext<'_>) {
+        self.handle.dismiss();
+    }
+}