Merge pull request #1719 from tarkah/feat/nested-overlay

Nested overlays

5 files changed, 121 insertions, 92 deletions

diff --git a/widget/src/lazy.rs b/widget/src/lazy.rs
index 92a611c3..4903d0ed 100644
--- a/widget/src/lazy.rs
+++ b/widget/src/lazy.rs
@@ -20,6 +20,7 @@ use crate::core::Element;
 use crate::core::{
     self, Clipboard, Hasher, Length, Point, Rectangle, Shell, Size,
 };
+use crate::runtime::overlay::Nested;
 
 use ouroboros::self_referencing;
 use std::cell::RefCell;
@@ -260,14 +261,17 @@ where
                     .unwrap(),
                 tree: &mut tree.children[0],
                 overlay_builder: |element, tree| {
-                    element.as_widget_mut().overlay(tree, layout, renderer)
+                    element
+                        .as_widget_mut()
+                        .overlay(tree, layout, renderer)
+                        .map(|overlay| RefCell::new(Nested::new(overlay)))
                 },
             }
             .build(),
         ));
 
-        let has_overlay = overlay
-            .with_overlay_maybe(|overlay| overlay::Element::position(overlay));
+        let has_overlay =
+            overlay.with_overlay_maybe(|overlay| overlay.position());
 
         has_overlay
             .map(|position| overlay::Element::new(position, Box::new(overlay)))
@@ -285,8 +289,8 @@ where
     tree: &'a mut Tree,
 
     #[borrows(mut element, mut tree)]
-    #[covariant]
-    overlay: Option<overlay::Element<'this, Message, Renderer>>,
+    #[not_covariant]
+    overlay: Option<RefCell<Nested<'this, Message, Renderer>>>,
 }
 
 struct Overlay<'a, Message, Renderer>(Option<Inner<'a, Message, Renderer>>);
@@ -301,19 +305,20 @@ impl<'a, Message, Renderer> Drop for Overlay<'a, Message, Renderer> {
 impl<'a, Message, Renderer> Overlay<'a, Message, Renderer> {
     fn with_overlay_maybe<T>(
         &self,
-        f: impl FnOnce(&overlay::Element<'_, Message, Renderer>) -> T,
+        f: impl FnOnce(&mut Nested<'_, Message, Renderer>) -> T,
     ) -> Option<T> {
-        self.0.as_ref().unwrap().borrow_overlay().as_ref().map(f)
+        self.0.as_ref().unwrap().with_overlay(|overlay| {
+            overlay.as_ref().map(|nested| (f)(&mut nested.borrow_mut()))
+        })
     }
 
     fn with_overlay_mut_maybe<T>(
         &mut self,
-        f: impl FnOnce(&mut overlay::Element<'_, Message, Renderer>) -> T,
+        f: impl FnOnce(&mut Nested<'_, Message, Renderer>) -> T,
     ) -> Option<T> {
-        self.0
-            .as_mut()
-            .unwrap()
-            .with_overlay_mut(|overlay| overlay.as_mut().map(f))
+        self.0.as_mut().unwrap().with_overlay_mut(|overlay| {
+            overlay.as_mut().map(|nested| (f)(nested.get_mut()))
+        })
     }
 }
 
@@ -329,9 +334,7 @@ where
         position: Point,
     ) -> layout::Node {
         self.with_overlay_maybe(|overlay| {
-            let translation = position - overlay.position();
-
-            overlay.layout(renderer, bounds, translation)
+            overlay.layout(renderer, bounds, position)
         })
         .unwrap_or_default()
     }
@@ -377,9 +380,14 @@ where
         .unwrap_or(event::Status::Ignored)
     }
 
-    fn is_over(&self, layout: Layout<'_>, cursor_position: Point) -> bool {
+    fn is_over(
+        &self,
+        layout: Layout<'_>,
+        renderer: &Renderer,
+        cursor_position: Point,
+    ) -> bool {
         self.with_overlay_maybe(|overlay| {
-            overlay.is_over(layout, cursor_position)
+            overlay.is_over(layout, renderer, cursor_position)
         })
         .unwrap_or_default()
     }
diff --git a/widget/src/lazy/component.rs b/widget/src/lazy/component.rs
index f462c8cf..f955d9dd 100644
--- a/widget/src/lazy/component.rs
+++ b/widget/src/lazy/component.rs
@@ -9,6 +9,7 @@ use crate::core::widget::tree::{self, Tree};
 use crate::core::{
     self, Clipboard, Element, Length, Point, Rectangle, Shell, Size, Widget,
 };
+use crate::runtime::overlay::Nested;
 
 use ouroboros::self_referencing;
 use std::cell::RefCell;
@@ -455,11 +456,18 @@ where
                 overlay_builder: |instance, tree| {
                     instance.state.get_mut().as_mut().unwrap().with_element_mut(
                         move |element| {
-                            element.as_mut().unwrap().as_widget_mut().overlay(
-                                &mut tree.children[0],
-                                layout,
-                                renderer,
-                            )
+                            element
+                                .as_mut()
+                                .unwrap()
+                                .as_widget_mut()
+                                .overlay(
+                                    &mut tree.children[0],
+                                    layout,
+                                    renderer,
+                                )
+                                .map(|overlay| {
+                                    RefCell::new(Nested::new(overlay))
+                                })
                         },
                     )
                 },
@@ -468,7 +476,7 @@ where
         ));
 
         let has_overlay = overlay.0.as_ref().unwrap().with_overlay(|overlay| {
-            overlay.as_ref().map(overlay::Element::position)
+            overlay.as_ref().map(|nested| nested.borrow().position())
         });
 
         has_overlay.map(|position| {
@@ -503,8 +511,8 @@ struct Inner<'a, 'b, Message, Renderer, Event, S> {
     types: PhantomData<(Message, Event, S)>,
 
     #[borrows(mut instance, mut tree)]
-    #[covariant]
-    overlay: Option<overlay::Element<'this, Event, Renderer>>,
+    #[not_covariant]
+    overlay: Option<RefCell<Nested<'this, Event, Renderer>>>,
 }
 
 struct OverlayInstance<'a, 'b, Message, Renderer, Event, S> {
@@ -516,7 +524,7 @@ impl<'a, 'b, Message, Renderer, Event, S>
 {
     fn with_overlay_maybe<T>(
         &self,
-        f: impl FnOnce(&overlay::Element<'_, Event, Renderer>) -> T,
+        f: impl FnOnce(&mut Nested<'_, Event, Renderer>) -> T,
     ) -> Option<T> {
         self.overlay
             .as_ref()
@@ -524,14 +532,14 @@ impl<'a, 'b, Message, Renderer, Event, S>
             .0
             .as_ref()
             .unwrap()
-            .borrow_overlay()
-            .as_ref()
-            .map(f)
+            .with_overlay(|overlay| {
+                overlay.as_ref().map(|nested| (f)(&mut nested.borrow_mut()))
+            })
     }
 
     fn with_overlay_mut_maybe<T>(
         &mut self,
-        f: impl FnOnce(&mut overlay::Element<'_, Event, Renderer>) -> T,
+        f: impl FnOnce(&mut Nested<'_, Event, Renderer>) -> T,
     ) -> Option<T> {
         self.overlay
             .as_mut()
@@ -539,7 +547,9 @@ impl<'a, 'b, Message, Renderer, Event, S>
             .0
             .as_mut()
             .unwrap()
-            .with_overlay_mut(|overlay| overlay.as_mut().map(f))
+            .with_overlay_mut(|overlay| {
+                overlay.as_mut().map(|nested| (f)(nested.get_mut()))
+            })
     }
 }
 
@@ -556,9 +566,7 @@ where
         position: Point,
     ) -> layout::Node {
         self.with_overlay_maybe(|overlay| {
-            let translation = position - overlay.position();
-
-            overlay.layout(renderer, bounds, translation)
+            overlay.layout(renderer, bounds, position)
         })
         .unwrap_or_default()
     }
@@ -655,9 +663,14 @@ where
         event_status
     }
 
-    fn is_over(&self, layout: Layout<'_>, cursor_position: Point) -> bool {
+    fn is_over(
+        &self,
+        layout: Layout<'_>,
+        renderer: &Renderer,
+        cursor_position: Point,
+    ) -> bool {
         self.with_overlay_maybe(|overlay| {
-            overlay.is_over(layout, cursor_position)
+            overlay.is_over(layout, renderer, cursor_position)
         })
         .unwrap_or_default()
     }
diff --git a/widget/src/lazy/responsive.rs b/widget/src/lazy/responsive.rs
index bd6385bc..07300857 100644
--- a/widget/src/lazy/responsive.rs
+++ b/widget/src/lazy/responsive.rs
@@ -9,6 +9,7 @@ use crate::core::{
     self, Clipboard, Element, Length, Point, Rectangle, Shell, Size, Widget,
 };
 use crate::horizontal_space;
+use crate::runtime::overlay::Nested;
 
 use ouroboros::self_referencing;
 use std::cell::{RefCell, RefMut};
@@ -298,13 +299,13 @@ where
                 element
                     .as_widget_mut()
                     .overlay(tree, content_layout, renderer)
+                    .map(|overlay| RefCell::new(Nested::new(overlay)))
             },
         }
         .build();
 
-        let has_overlay = overlay.with_overlay(|overlay| {
-            overlay.as_ref().map(overlay::Element::position)
-        });
+        let has_overlay =
+            overlay.with_overlay_maybe(|overlay| overlay.position());
 
         has_overlay
             .map(|position| overlay::Element::new(position, Box::new(overlay)))
@@ -329,23 +330,27 @@ struct Overlay<'a, 'b, Message, Renderer> {
     types: PhantomData<Message>,
 
     #[borrows(mut content, mut tree)]
-    #[covariant]
-    overlay: Option<overlay::Element<'this, Message, Renderer>>,
+    #[not_covariant]
+    overlay: Option<RefCell<Nested<'this, Message, Renderer>>>,
 }
 
 impl<'a, 'b, Message, Renderer> Overlay<'a, 'b, Message, Renderer> {
     fn with_overlay_maybe<T>(
         &self,
-        f: impl FnOnce(&overlay::Element<'_, Message, Renderer>) -> T,
+        f: impl FnOnce(&mut Nested<'_, Message, Renderer>) -> T,
     ) -> Option<T> {
-        self.borrow_overlay().as_ref().map(f)
+        self.with_overlay(|overlay| {
+            overlay.as_ref().map(|nested| (f)(&mut nested.borrow_mut()))
+        })
     }
 
     fn with_overlay_mut_maybe<T>(
         &mut self,
-        f: impl FnOnce(&mut overlay::Element<'_, Message, Renderer>) -> T,
+        f: impl FnOnce(&mut Nested<'_, Message, Renderer>) -> T,
     ) -> Option<T> {
-        self.with_overlay_mut(|overlay| overlay.as_mut().map(f))
+        self.with_overlay_mut(|overlay| {
+            overlay.as_mut().map(|nested| (f)(nested.get_mut()))
+        })
     }
 }
 
@@ -361,9 +366,7 @@ where
         position: Point,
     ) -> layout::Node {
         self.with_overlay_maybe(|overlay| {
-            let translation = position - overlay.position();
-
-            overlay.layout(renderer, bounds, translation)
+            overlay.layout(renderer, bounds, position)
         })
         .unwrap_or_default()
     }
@@ -409,9 +412,14 @@ where
         .unwrap_or(event::Status::Ignored)
     }
 
-    fn is_over(&self, layout: Layout<'_>, cursor_position: Point) -> bool {
+    fn is_over(
+        &self,
+        layout: Layout<'_>,
+        renderer: &Renderer,
+        cursor_position: Point,
+    ) -> bool {
         self.with_overlay_maybe(|overlay| {
-            overlay.is_over(layout, cursor_position)
+            overlay.is_over(layout, renderer, cursor_position)
         })
         .unwrap_or_default()
     }
diff --git a/widget/src/overlay/menu.rs b/widget/src/overlay/menu.rs
index b699def0..ccf4dfb5 100644
--- a/widget/src/overlay/menu.rs
+++ b/widget/src/overlay/menu.rs
@@ -19,7 +19,7 @@ pub use iced_style::menu::{Appearance, StyleSheet};
 
 /// A list of selectable options.
 #[allow(missing_debug_implementations)]
-pub struct Menu<'a, T, Renderer = crate::Renderer>
+pub struct Menu<'a, T, Message, Renderer = crate::Renderer>
 where
     Renderer: text::Renderer,
     Renderer::Theme: StyleSheet,
@@ -27,7 +27,7 @@ where
     state: &'a mut State,
     options: &'a [T],
     hovered_option: &'a mut Option<usize>,
-    last_selection: &'a mut Option<T>,
+    on_selected: Box<dyn FnMut(T) -> Message + 'a>,
     width: f32,
     padding: Padding,
     text_size: Option<f32>,
@@ -37,9 +37,10 @@ where
     style: <Renderer::Theme as StyleSheet>::Style,
 }
 
-impl<'a, T, Renderer> Menu<'a, T, Renderer>
+impl<'a, T, Message, Renderer> Menu<'a, T, Message, Renderer>
 where
     T: ToString + Clone,
+    Message: 'a,
     Renderer: text::Renderer + 'a,
     Renderer::Theme:
         StyleSheet + container::StyleSheet + scrollable::StyleSheet,
@@ -50,13 +51,13 @@ where
         state: &'a mut State,
         options: &'a [T],
         hovered_option: &'a mut Option<usize>,
-        last_selection: &'a mut Option<T>,
+        on_selected: impl FnMut(T) -> Message + 'a,
     ) -> Self {
         Menu {
             state,
             options,
             hovered_option,
-            last_selection,
+            on_selected: Box::new(on_selected),
             width: 0.0,
             padding: Padding::ZERO,
             text_size: None,
@@ -121,7 +122,7 @@ where
     /// The `target_height` will be used to display the menu either on top
     /// of the target or under it, depending on the screen position and the
     /// dimensions of the [`Menu`].
-    pub fn overlay<Message: 'a>(
+    pub fn overlay(
         self,
         position: Point,
         target_height: f32,
@@ -174,7 +175,10 @@ where
     Renderer::Theme:
         StyleSheet + container::StyleSheet + scrollable::StyleSheet,
 {
-    pub fn new<T>(menu: Menu<'a, T, Renderer>, target_height: f32) -> Self
+    pub fn new<T>(
+        menu: Menu<'a, T, Message, Renderer>,
+        target_height: f32,
+    ) -> Self
     where
         T: Clone + ToString,
     {
@@ -182,7 +186,7 @@ where
             state,
             options,
             hovered_option,
-            last_selection,
+            on_selected,
             width,
             padding,
             font,
@@ -195,7 +199,7 @@ where
         let container = Container::new(Scrollable::new(List {
             options,
             hovered_option,
-            last_selection,
+            on_selected,
             font,
             text_size,
             text_line_height,
@@ -306,14 +310,14 @@ where
     }
 }
 
-struct List<'a, T, Renderer>
+struct List<'a, T, Message, Renderer>
 where
     Renderer: text::Renderer,
     Renderer::Theme: StyleSheet,
 {
     options: &'a [T],
     hovered_option: &'a mut Option<usize>,
-    last_selection: &'a mut Option<T>,
+    on_selected: Box<dyn FnMut(T) -> Message + 'a>,
     padding: Padding,
     text_size: Option<f32>,
     text_line_height: text::LineHeight,
@@ -323,7 +327,7 @@ where
 }
 
 impl<'a, T, Message, Renderer> Widget<Message, Renderer>
-    for List<'a, T, Renderer>
+    for List<'a, T, Message, Renderer>
 where
     T: Clone + ToString,
     Renderer: text::Renderer,
@@ -372,14 +376,15 @@ where
         cursor: mouse::Cursor,
         renderer: &Renderer,
         _clipboard: &mut dyn Clipboard,
-        _shell: &mut Shell<'_, Message>,
+        shell: &mut Shell<'_, Message>,
     ) -> event::Status {
         match event {
             Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left)) => {
                 if cursor.is_over(layout.bounds()) {
                     if let Some(index) = *self.hovered_option {
                         if let Some(option) = self.options.get(index) {
-                            *self.last_selection = Some(option.clone());
+                            shell.publish((self.on_selected)(option.clone()));
+                            return event::Status::Captured;
                         }
                     }
                 }
@@ -417,7 +422,8 @@ where
 
                     if let Some(index) = *self.hovered_option {
                         if let Some(option) = self.options.get(index) {
-                            *self.last_selection = Some(option.clone());
+                            shell.publish((self.on_selected)(option.clone()));
+                            return event::Status::Captured;
                         }
                     }
                 }
@@ -521,7 +527,7 @@ where
     }
 }
 
-impl<'a, T, Message, Renderer> From<List<'a, T, Renderer>>
+impl<'a, T, Message, Renderer> From<List<'a, T, Message, Renderer>>
     for Element<'a, Message, Renderer>
 where
     T: ToString + Clone,
@@ -529,7 +535,7 @@ where
     Renderer: 'a + text::Renderer,
     Renderer::Theme: StyleSheet,
 {
-    fn from(list: List<'a, T, Renderer>) -> Self {
+    fn from(list: List<'a, T, Message, Renderer>) -> Self {
         Element::new(list)
     }
 }
diff --git a/widget/src/pick_list.rs b/widget/src/pick_list.rs
index dc53a9c8..832aae6b 100644
--- a/widget/src/pick_list.rs
+++ b/widget/src/pick_list.rs
@@ -157,11 +157,11 @@ where
         From<<Renderer::Theme as StyleSheet>::Style>,
 {
     fn tag(&self) -> tree::Tag {
-        tree::Tag::of::<State<T>>()
+        tree::Tag::of::<State>()
     }
 
     fn state(&self) -> tree::State {
-        tree::State::new(State::<T>::new())
+        tree::State::new(State::new())
     }
 
     fn width(&self) -> Length {
@@ -209,7 +209,7 @@ where
             self.on_selected.as_ref(),
             self.selected.as_ref(),
             &self.options,
-            || tree.state.downcast_mut::<State<T>>(),
+            || tree.state.downcast_mut::<State>(),
         )
     }
 
@@ -249,7 +249,7 @@ where
             self.selected.as_ref(),
             &self.handle,
             &self.style,
-            || tree.state.downcast_ref::<State<T>>(),
+            || tree.state.downcast_ref::<State>(),
         )
     }
 
@@ -259,7 +259,7 @@ where
         layout: Layout<'_>,
         renderer: &Renderer,
     ) -> Option<overlay::Element<'b, Message, Renderer>> {
-        let state = tree.state.downcast_mut::<State<T>>();
+        let state = tree.state.downcast_mut::<State>();
 
         overlay(
             layout,
@@ -269,6 +269,7 @@ where
             self.text_shaping,
             self.font.unwrap_or_else(|| renderer.default_font()),
             &self.options,
+            &self.on_selected,
             self.style.clone(),
         )
     }
@@ -295,15 +296,14 @@ where
 
 /// The local state of a [`PickList`].
 #[derive(Debug)]
-pub struct State<T> {
+pub struct State {
     menu: menu::State,
     keyboard_modifiers: keyboard::Modifiers,
     is_open: bool,
     hovered_option: Option<usize>,
-    last_selection: Option<T>,
 }
 
-impl<T> State<T> {
+impl State {
     /// Creates a new [`State`] for a [`PickList`].
     pub fn new() -> Self {
         Self {
@@ -311,12 +311,11 @@ impl<T> State<T> {
             keyboard_modifiers: keyboard::Modifiers::default(),
             is_open: bool::default(),
             hovered_option: Option::default(),
-            last_selection: Option::default(),
         }
     }
 }
 
-impl<T> Default for State<T> {
+impl Default for State {
     fn default() -> Self {
         Self::new()
     }
@@ -436,7 +435,7 @@ pub fn update<'a, T, Message>(
     on_selected: &dyn Fn(T) -> Message,
     selected: Option<&T>,
     options: &[T],
-    state: impl FnOnce() -> &'a mut State<T>,
+    state: impl FnOnce() -> &'a mut State,
 ) -> event::Status
 where
     T: PartialEq + Clone + 'a,
@@ -446,7 +445,7 @@ where
         | Event::Touch(touch::Event::FingerPressed { .. }) => {
             let state = state();
 
-            let event_status = if state.is_open {
+            if state.is_open {
                 // Event wasn't processed by overlay, so cursor was clicked either outside it's
                 // bounds or on the drop-down, either way we close the overlay.
                 state.is_open = false;
@@ -460,16 +459,6 @@ where
                 event::Status::Captured
             } else {
                 event::Status::Ignored
-            };
-
-            if let Some(last_selection) = state.last_selection.take() {
-                shell.publish((on_selected)(last_selection));
-
-                state.is_open = false;
-
-                event::Status::Captured
-            } else {
-                event_status
             }
         }
         Event::Mouse(mouse::Event::WheelScrolled {
@@ -544,12 +533,13 @@ pub fn mouse_interaction(
 /// Returns the current overlay of a [`PickList`].
 pub fn overlay<'a, T, Message, Renderer>(
     layout: Layout<'_>,
-    state: &'a mut State<T>,
+    state: &'a mut State,
     padding: Padding,
     text_size: Option<f32>,
     text_shaping: text::Shaping,
     font: Renderer::Font,
     options: &'a [T],
+    on_selected: &'a dyn Fn(T) -> Message,
     style: <Renderer::Theme as StyleSheet>::Style,
 ) -> Option<overlay::Element<'a, Message, Renderer>>
 where
@@ -570,7 +560,11 @@ where
             &mut state.menu,
             options,
             &mut state.hovered_option,
-            &mut state.last_selection,
+            |option| {
+                state.is_open = false;
+
+                (on_selected)(option)
+            },
         )
         .width(bounds.width)
         .padding(padding)
@@ -603,7 +597,7 @@ pub fn draw<'a, T, Renderer>(
     selected: Option<&T>,
     handle: &Handle<Renderer::Font>,
     style: &<Renderer::Theme as StyleSheet>::Style,
-    state: impl FnOnce() -> &'a State<T>,
+    state: impl FnOnce() -> &'a State,
 ) where
     Renderer: text::Renderer,
     Renderer::Theme: StyleSheet,