Merge pull request #1154 from nicksenger/overlay-components

Implement `overlay` for `Component`

lazy/src/component.rs

@@ -4,10 +4,12 @@ use iced_native::mouse;
 use iced_native::overlay;
 use iced_native::renderer;
 use iced_native::{
-    Clipboard, Element, Hasher, Length, Point, Rectangle, Shell, Widget,
+    Clipboard, Element, Hasher, Length, Point, Rectangle, Shell, Size, Widget,
 };
 
 use ouroboros::self_referencing;
+use std::cell::RefCell;
+use std::hash::Hash;
 use std::marker::PhantomData;
 
 pub fn view<'a, C, Message, Renderer>(
@@ -19,16 +21,22 @@ where
     Renderer: iced_native::Renderer + 'a,
 {
     Element::new(Instance {
-        state: Some(
+        state: RefCell::new(Some(
             StateBuilder {
                 component: Box::new(component),
-                cache_builder: |state| Cache {
+                cache_builder: |state| {
-                    element: state.view(),
+                    Some(
-                    message: PhantomData,
+                        CacheBuilder {
+                            element: state.view(),
+                            message: PhantomData,
+                            overlay_builder: |_| None,
+                        }
+                        .build(),
+                    )
                 },
             }
             .build(),
-        ),
+        )),
     })
 }
 
@@ -41,7 +49,7 @@ pub trait Component<Message, Renderer> {
 }
 
 struct Instance<'a, Message, Renderer, Event> {
-    state: Option<State<'a, Message, Renderer, Event>>,
+    state: RefCell<Option<State<'a, Message, Renderer, Event>>>,
 }
 
 #[self_referencing]
@@ -50,12 +58,51 @@ struct State<'a, Message: 'a, Renderer: 'a, Event: 'a> {
 
     #[borrows(mut component)]
     #[covariant]
-    cache: Cache<'this, Message, Renderer, Event>,
+    cache: Option<Cache<'this, Message, Renderer, Event>>,
 }
 
-struct Cache<'a, Message, Renderer, Event> {
+#[self_referencing]
+struct Cache<'a, Message, Renderer: 'a, Event: 'a> {
     element: Element<'a, Event, Renderer>,
     message: PhantomData<Message>,
+
+    #[borrows(mut element)]
+    #[covariant]
+    overlay: Option<overlay::Element<'this, Event, Renderer>>,
+}
+
+impl<'a, Message, Renderer, Event> Instance<'a, Message, Renderer, Event> {
+    fn with_element<T>(
+        &self,
+        f: impl FnOnce(&Element<'_, Event, Renderer>) -> T,
+    ) -> T {
+        self.with_element_mut(|element| f(element))
+    }
+
+    fn with_element_mut<T>(
+        &self,
+        f: impl FnOnce(&mut Element<'_, Event, Renderer>) -> T,
+    ) -> T {
+        self.state
+            .borrow_mut()
+            .as_mut()
+            .unwrap()
+            .with_cache_mut(|cache| {
+                let mut element = cache.take().unwrap().into_heads().element;
+                let result = f(&mut element);
+
+                *cache = Some(
+                    CacheBuilder {
+                        element,
+                        message: PhantomData,
+                        overlay_builder: |_| None,
+                    }
+                    .build(),
+                );
+
+                result
+            })
+    }
 }
 
 impl<'a, Message, Renderer, Event> Widget<Message, Renderer>
@@ -64,11 +111,11 @@ where
     Renderer: iced_native::Renderer,
 {
     fn width(&self) -> Length {
-        self.state.as_ref().unwrap().borrow_cache().element.width()
+        self.with_element(|element| element.width())
     }
 
     fn height(&self) -> Length {
-        self.state.as_ref().unwrap().borrow_cache().element.height()
+        self.with_element(|element| element.height())
     }
 
     fn layout(
@@ -76,12 +123,7 @@ where
         renderer: &Renderer,
         limits: &layout::Limits,
     ) -> layout::Node {
-        self.state
+        self.with_element(|element| element.layout(renderer, limits))
-            .as_ref()
-            .unwrap()
-            .borrow_cache()
-            .element
-            .layout(renderer, limits)
     }
 
     fn on_event(
@@ -96,21 +138,25 @@ where
         let mut local_messages = Vec::new();
         let mut local_shell = Shell::new(&mut local_messages);
 
-        let event_status =
+        let event_status = self.with_element_mut(|element| {
-            self.state.as_mut().unwrap().with_cache_mut(|cache| {
+            element.on_event(
-                cache.element.on_event(
+                event,
-                    event,
+                layout,
-                    layout,
+                cursor_position,
-                    cursor_position,
+                renderer,
-                    renderer,
+                clipboard,
-                    clipboard,
+                &mut local_shell,
-                    &mut local_shell,
+            )
-                )
+        });
-            });
 
         if !local_messages.is_empty() {
-            let mut component =
+            let mut component = self
-                self.state.take().unwrap().into_heads().component;
+                .state
+                .borrow_mut()
+                .take()
+                .unwrap()
+                .into_heads()
+                .component;
 
             for message in local_messages
                 .into_iter()
@@ -119,12 +165,18 @@ where
                 shell.publish(message);
             }
 
-            self.state = Some(
+            *self.state.borrow_mut() = Some(
                 StateBuilder {
                     component,
-                    cache_builder: |state| Cache {
+                    cache_builder: |state| {
-                        element: state.view(),
+                        Some(
-                        message: PhantomData,
+                            CacheBuilder {
+                                element: state.view(),
+                                message: PhantomData,
+                                overlay_builder: |_| None,
+                            }
+                            .build(),
+                        )
                     },
                 }
                 .build(),
@@ -144,22 +196,15 @@ where
         cursor_position: Point,
         viewport: &Rectangle,
     ) {
-        self.state.as_ref().unwrap().borrow_cache().element.draw(
+        self.with_element(|element| {
-            renderer,
+            element.draw(renderer, style, layout, cursor_position, viewport);
-            style,
+        });
-            layout,
-            cursor_position,
-            viewport,
-        )
     }
 
     fn hash_layout(&self, state: &mut Hasher) {
-        self.state
+        self.with_element(|element| {
-            .as_ref()
+            element.hash_layout(state);
-            .unwrap()
+        });
-            .borrow_cache()
-            .element
-            .hash_layout(state)
     }
 
     fn mouse_interaction(
@@ -168,19 +213,199 @@ where
         cursor_position: Point,
         viewport: &Rectangle,
     ) -> mouse::Interaction {
-        self.state
+        self.with_element(|element| {
-            .as_ref()
+            element.mouse_interaction(layout, cursor_position, viewport)
-            .unwrap()
+        })
-            .borrow_cache()
-            .element
-            .mouse_interaction(layout, cursor_position, viewport)
     }
 
     fn overlay(
         &mut self,
-        _layout: Layout<'_>,
+        layout: Layout<'_>,
     ) -> Option<overlay::Element<'_, Message, Renderer>> {
-        // TODO: Rethink overlay composability
+        let has_overlay = self
-        None
+            .state
+            .borrow_mut()
+            .as_mut()
+            .unwrap()
+            .with_cache_mut(|cache| {
+                let element = cache.take().unwrap().into_heads().element;
+
+                *cache = Some(
+                    CacheBuilder {
+                        element,
+                        message: PhantomData,
+                        overlay_builder: |element| element.overlay(layout),
+                    }
+                    .build(),
+                );
+
+                cache.as_ref().unwrap().borrow_overlay().is_some()
+            });
+
+        has_overlay.then(|| {
+            overlay::Element::new(
+                layout.position(),
+                Box::new(Overlay { instance: self }),
+            )
+        })
+    }
+}
+
+struct Overlay<'a, 'b, Message, Renderer, Event> {
+    instance: &'b mut Instance<'a, Message, Renderer, Event>,
+}
+
+impl<'a, 'b, Message, Renderer, Event>
+    Overlay<'a, 'b, Message, Renderer, Event>
+{
+    fn with_overlay_maybe<T>(
+        &self,
+        f: impl FnOnce(&overlay::Element<'_, Event, Renderer>) -> T,
+    ) -> Option<T> {
+        self.instance
+            .state
+            .borrow()
+            .as_ref()
+            .unwrap()
+            .borrow_cache()
+            .as_ref()
+            .unwrap()
+            .borrow_overlay()
+            .as_ref()
+            .map(f)
+    }
+
+    fn with_overlay_mut_maybe<T>(
+        &self,
+        f: impl FnOnce(&mut overlay::Element<'_, Event, Renderer>) -> T,
+    ) -> Option<T> {
+        self.instance
+            .state
+            .borrow_mut()
+            .as_mut()
+            .unwrap()
+            .with_cache_mut(|cache| {
+                cache
+                    .as_mut()
+                    .unwrap()
+                    .with_overlay_mut(|overlay| overlay.as_mut().map(f))
+            })
+    }
+}
+
+impl<'a, 'b, Message, Renderer, Event> overlay::Overlay<Message, Renderer>
+    for Overlay<'a, 'b, Message, Renderer, Event>
+where
+    Renderer: iced_native::Renderer,
+{
+    fn layout(
+        &self,
+        renderer: &Renderer,
+        bounds: Size,
+        position: Point,
+    ) -> layout::Node {
+        self.with_overlay_maybe(|overlay| {
+            let vector = position - overlay.position();
+
+            overlay.layout(renderer, bounds).translate(vector)
+        })
+        .unwrap_or_default()
+    }
+
+    fn draw(
+        &self,
+        renderer: &mut Renderer,
+        style: &renderer::Style,
+        layout: Layout<'_>,
+        cursor_position: Point,
+    ) {
+        self.with_overlay_maybe(|overlay| {
+            overlay.draw(renderer, style, layout, cursor_position);
+        });
+    }
+
+    fn mouse_interaction(
+        &self,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        viewport: &Rectangle,
+    ) -> mouse::Interaction {
+        self.with_overlay_maybe(|overlay| {
+            overlay.mouse_interaction(layout, cursor_position, viewport)
+        })
+        .unwrap_or_default()
+    }
+
+    fn hash_layout(&self, state: &mut Hasher, position: Point) {
+        struct Marker;
+        std::any::TypeId::of::<Marker>().hash(state);
+
+        (position.x as u32).hash(state);
+        (position.y as u32).hash(state);
+
+        self.with_overlay_maybe(|overlay| {
+            overlay.hash_layout(state);
+        });
+    }
+
+    fn on_event(
+        &mut self,
+        event: iced_native::Event,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        renderer: &Renderer,
+        clipboard: &mut dyn Clipboard,
+        shell: &mut Shell<'_, Message>,
+    ) -> iced_native::event::Status {
+        let mut local_messages = Vec::new();
+        let mut local_shell = Shell::new(&mut local_messages);
+
+        let event_status = self
+            .with_overlay_mut_maybe(|overlay| {
+                overlay.on_event(
+                    event,
+                    layout,
+                    cursor_position,
+                    renderer,
+                    clipboard,
+                    &mut local_shell,
+                )
+            })
+            .unwrap_or_else(|| iced_native::event::Status::Ignored);
+
+        if !local_messages.is_empty() {
+            let mut component =
+                self.instance.state.take().unwrap().into_heads().component;
+
+            for message in local_messages
+                .into_iter()
+                .filter_map(|message| component.update(message))
+            {
+                shell.publish(message);
+            }
+
+            self.instance.state = RefCell::new(Some(
+                StateBuilder {
+                    component,
+                    cache_builder: |state| {
+                        Some(
+                            CacheBuilder {
+                                element: state.view(),
+                                message: PhantomData,
+                                overlay_builder: |element| {
+                                    element.overlay(layout)
+                                },
+                            }
+                            .build(),
+                        )
+                    },
+                }
+                .build(),
+            ));
+
+            shell.invalidate_layout();
+        }
+
+        event_status
     }
 }

native/src/layout/node.rs

@@ -1,4 +1,4 @@
-use crate::{Alignment, Point, Rectangle, Size};
+use crate::{Alignment, Point, Rectangle, Size, Vector};
 
 /// The bounds of an element and its children.
 #[derive(Debug, Clone, Default)]
@@ -80,4 +80,12 @@ impl Node {
         self.bounds.x = position.x;
         self.bounds.y = position.y;
     }
+
+    /// Translates the [`Node`] by the given translation.
+    pub fn translate(self, translation: Vector) -> Self {
+        Self {
+            bounds: self.bounds + translation,
+            ..self
+        }
+    }
 }