feat: rectangle tracker container

examples/cosmic-sctk/src/window.rs

@@ -5,12 +5,14 @@ use cosmic::{
     iced::widget::{
         column, container, horizontal_space, pick_list, progress_bar, radio, row, slider,
     },
-    iced::{self, Alignment, Application, Command, Length, wayland::SurfaceIdWrapper},
+    iced::{self, wayland::SurfaceIdWrapper, Alignment, Application, Command, Length},
     iced_lazy::responsive,
     theme::{self, Theme},
-    widget::{button, nav_button, nav_bar, nav_bar_page, nav_bar_section, header_bar, settings, scrollable, toggler},
-    Element,
-    ElementExt,
+    widget::{
+        button, header_bar, nav_bar, nav_bar_page, nav_bar_section, nav_button, scrollable,
+        settings, toggler, rectangle_tracker::{RectangleTracker, rectangle_tracker_subscription, RectangleUpdate},
+    },
+    Element, ElementExt
 };
 use std::{collections::BTreeMap, vec};
 use theme::Button as ButtonTheme;
@@ -29,6 +31,7 @@ pub struct Window {
     show_minimize: bool,
     show_maximize: bool,
     exit: bool,
+    rectangle_tracker: Option<RectangleTracker<u32>>,
 }
 
 impl Window {
@@ -49,7 +52,7 @@ impl Window {
 }
 
 #[allow(dead_code)]
-#[derive(Clone, Copy, Debug)]
+#[derive(Clone, Debug)]
 pub enum Message {
     Page(u8),
     Debug(bool),
@@ -66,6 +69,7 @@ pub enum Message {
     Minimize,
     Maximize,
     InputChanged,
+    Rectangle(RectangleUpdate<u32>)
 }
 
 impl Application for Window {
@@ -99,7 +103,7 @@ impl Application for Window {
             Message::SliderChanged(value) => self.slider_value = value,
             Message::CheckboxToggled(value) => {
                 self.checkbox_value = value;
-            },
+            }
             Message::TogglerToggled(value) => self.toggler_value = value,
             Message::PickListSelected(value) => self.pick_list_selected = Some(value),
             Message::Close => self.exit = true,
@@ -108,8 +112,11 @@ impl Application for Window {
             Message::Minimize => todo!(),
             Message::Maximize => todo!(),
             Message::RowSelected(row) => println!("Selected row {row}"),
-            Message::InputChanged => {},
-
+            Message::InputChanged => {}
+            Message::Rectangle(r) => match r {
+                RectangleUpdate::Rectangle(r) => {dbg!(r);},
+                RectangleUpdate::Init(t) => {self.rectangle_tracker.replace(t);},
+            },
         }
 
         Command::none()
@@ -124,7 +131,7 @@ impl Application for Window {
                 nav_button("Settings")
                     .on_sidebar_toggled(Message::ToggleSidebar)
                     .sidebar_active(self.sidebar_toggled)
-                    .into()
+                    .into(),
             );
 
         if self.show_maximize {
@@ -226,13 +233,21 @@ impl Application for Window {
                     ))
                 },
             );
+            let secondary = button(ButtonTheme::Secondary)
+            .text("Secondary")
+            .on_press(Message::ButtonPressed);
 
+            let secondary = if let Some(tracker) = self.rectangle_tracker.as_ref() {
+                tracker.container(0, secondary).into()
+            } else {
+                secondary.into()
+            };
             let content: Element<_> = settings::view_column(vec![
                 settings::view_section("Debug")
                     .add(settings::item("Debug theme", choose_theme))
                     .add(settings::item(
                         "Debug layout",
-                        toggler(String::from("Debug layout"), self.debug, Message::Debug)
+                        toggler(String::from("Debug layout"), self.debug, Message::Debug),
                     ))
                     .into(),
                 settings::view_section("Buttons")
@@ -241,10 +256,7 @@ impl Application for Window {
                             .text("Primary")
                             .on_press(Message::ButtonPressed)
                             .into(),
-                        button(ButtonTheme::Secondary)
-                            .text("Secondary")
-                            .on_press(Message::ButtonPressed)
-                            .into(),
+                        secondary,
                         button(ButtonTheme::Positive)
                             .text("Positive")
                             .on_press(Message::ButtonPressed)
@@ -256,7 +268,7 @@ impl Application for Window {
                         button(ButtonTheme::Text)
                             .text("Text")
                             .on_press(Message::ButtonPressed)
-                            .into()
+                            .into(),
                     ]))
                     .add(settings::item_row(vec![
                         button(ButtonTheme::Primary).text("Primary").into(),
@@ -267,28 +279,31 @@ impl Application for Window {
                     ]))
                     .into(),
                 settings::view_section("Controls")
-                    .add(settings::item("Toggler", toggler(None, self.toggler_value, Message::TogglerToggled)))
+                    .add(settings::item(
+                        "Toggler",
+                        toggler(None, self.toggler_value, Message::TogglerToggled),
+                    ))
                     .add(settings::item(
                         "Pick List (TODO)",
                         pick_list(
-                            vec!["Option 1", "Option 2", "Option 3", "Option 4",],
+                            vec!["Option 1", "Option 2", "Option 3", "Option 4"],
                             self.pick_list_selected,
-                            Message::PickListSelected
+                            Message::PickListSelected,
                         )
-                        .padding([8, 0, 8, 16])
+                        .padding([8, 0, 8, 16]),
                     ))
                     .add(settings::item(
                         "Slider",
                         slider(0.0..=100.0, self.slider_value, Message::SliderChanged)
-                            .width(Length::Units(250))
+                            .width(Length::Units(250)),
                     ))
                     .add(settings::item(
                         "Progress",
                         progress_bar(0.0..=100.0, self.slider_value)
                             .width(Length::Units(250))
-                            .height(Length::Units(4))
+                            .height(Length::Units(4)),
                     ))
-                    .into()
+                    .into(),
             ])
             .into();
 
@@ -323,8 +338,11 @@ impl Application for Window {
     fn theme(&self) -> Theme {
         self.theme
     }
-    
+
     fn close_requested(&self, id: SurfaceIdWrapper) -> Self::Message {
         Message::Close
     }
+    fn subscription(&self) -> iced::Subscription<Self::Message> {
+        rectangle_tracker_subscription(0).map(|(i, e)| Message::Rectangle(e))
+    }
 }

src/widget/mod.rs

@@ -19,9 +19,6 @@ pub use self::nav_button::{NavButton, nav_button};
 pub mod navigation;
 pub use navigation::*;
 
-pub mod popup;
-pub use popup::*;
-
 mod toggler;
 pub use toggler::toggler;
 
@@ -34,4 +31,6 @@ pub mod separator;
 pub use separator::{horizontal_rule, vertical_rule};
 
 pub mod spin_button;
-pub use spin_button::{SpinButton, spin_button};
+pub use spin_button::{SpinButton, spin_button};
+
+pub mod rectangle_tracker;

src/widget/popup.rs

@@ -1,314 +0,0 @@
-// Copyright 2022 System76 <info@system76.com>
-// SPDX-License-Identifier: MPL-2.0
-
-use iced::futures::channel::mpsc::{unbounded, UnboundedReceiver, UnboundedSender};
-use iced::futures::SinkExt;
-use iced::{
-    futures::StreamExt,
-    widget::{container, Container},
-    Rectangle,
-};
-use iced_native::alignment::{self, Alignment};
-use iced_native::command::platform_specific::wayland::popup::{SctkPopupSettings, SctkPositioner};
-use iced_native::event::{self, Event};
-use iced_native::layout;
-use iced_native::mouse;
-use iced_native::overlay;
-use iced_native::renderer;
-use iced_native::widget::{Operation, Tree};
-use iced_native::{
-    window, Background, Clipboard, Color, Element, Layout, Length, Padding, Point, Shell, Widget,
-};
-use std::u32;
-
-pub use iced_style::container::{Appearance, StyleSheet};
-pub struct SizeTrackingContainer<'a, Message, Renderer>
-where
-    Renderer: iced_native::Renderer,
-    Renderer::Theme: StyleSheet,
-{
-    container: Container<'a, Message, Renderer>,
-    tx: UnboundedSender<Rectangle<i32>>,
-}
-
-impl<'a, Message, Renderer> SizeTrackingContainer<'a, Message, Renderer>
-where
-    Renderer: iced_native::Renderer,
-    Renderer::Theme: StyleSheet,
-{
-    /// Creates an empty [`Container`].
-    pub fn new<T>(content: T, tx: UnboundedSender<Rectangle<i32>>) -> Self
-    where
-        T: Into<Element<'a, Message, Renderer>>,
-    {
-        SizeTrackingContainer {
-            container: container(content),
-            tx,
-        }
-    }
-
-    /// Sets the [`Padding`] of the [`Container`].
-    pub fn padding<P: Into<Padding>>(mut self, padding: P) -> Self {
-        self.container = self.container.padding(padding);
-        self
-    }
-
-    /// Sets the width of the [`Container`].
-    pub fn width(mut self, width: Length) -> Self {
-        self.container = self.container.width(width);
-        self
-    }
-
-    /// Sets the height of the [`Container`].
-    pub fn height(mut self, height: Length) -> Self {
-        self.container = self.container.height(height);
-        self
-    }
-
-    /// Sets the maximum width of the [`Container`].
-    pub fn max_width(mut self, max_width: u32) -> Self {
-        self.container = self.container.max_width(max_width);
-        self
-    }
-
-    /// Sets the maximum height of the [`Container`] in pixels.
-    pub fn max_height(mut self, max_height: u32) -> Self {
-        self.container = self.container.max_height(max_height);
-        self
-    }
-
-    /// Sets the content alignment for the horizontal axis of the [`Container`].
-    pub fn align_x(mut self, alignment: alignment::Horizontal) -> Self {
-        self.container = self.container.align_x(alignment);
-        self
-    }
-
-    /// Sets the content alignment for the vertical axis of the [`Container`].
-    pub fn align_y(mut self, alignment: alignment::Vertical) -> Self {
-        self.container = self.container.align_y(alignment);
-        self
-    }
-
-    /// Centers the contents in the horizontal axis of the [`Container`].
-    pub fn center_x(mut self) -> Self {
-        self.container = self.container.center_x();
-        self
-    }
-
-    /// Centers the contents in the vertical axis of the [`Container`].
-    pub fn center_y(mut self) -> Self {
-        self.container = self.container.center_y();
-        self
-    }
-
-    /// Sets the style of the [`Container`].
-    pub fn style(mut self, style: impl Into<<Renderer::Theme as StyleSheet>::Style>) -> Self {
-        self.container = self.container.style(style);
-        self
-    }
-}
-
-impl<'a, Message, Renderer> Widget<Message, Renderer>
-    for SizeTrackingContainer<'a, Message, Renderer>
-where
-    Renderer: iced_native::Renderer,
-    Renderer::Theme: container::StyleSheet,
-{
-    fn children(&self) -> Vec<Tree> {
-        self.container.children()
-    }
-
-    fn diff(&self, tree: &mut Tree) {
-        self.container.diff(tree)
-    }
-
-    fn width(&self) -> Length {
-        Widget::width(&self.container)
-    }
-
-    fn height(&self) -> Length {
-        Widget::height(&self.container)
-    }
-
-    fn layout(&self, renderer: &Renderer, limits: &layout::Limits) -> layout::Node {
-        self.container.layout(renderer, limits)
-    }
-
-    fn on_event(
-        &mut self,
-        tree: &mut Tree,
-        event: Event,
-        layout: Layout<'_>,
-        cursor_position: Point,
-        renderer: &Renderer,
-        clipboard: &mut dyn Clipboard,
-        shell: &mut Shell<'_, Message>,
-    ) -> event::Status {
-        self.container.on_event(
-            &mut tree.children[0],
-            event,
-            layout,
-            cursor_position,
-            renderer,
-            clipboard,
-            shell,
-        )
-    }
-
-    fn mouse_interaction(
-        &self,
-        tree: &Tree,
-        layout: Layout<'_>,
-        cursor_position: Point,
-        viewport: &Rectangle,
-        renderer: &Renderer,
-    ) -> mouse::Interaction {
-        self.container.mouse_interaction(
-            &tree.children[0],
-            layout,
-            cursor_position,
-            viewport,
-            renderer,
-        )
-    }
-
-    fn draw(
-        &self,
-        tree: &Tree,
-        renderer: &mut Renderer,
-        theme: &Renderer::Theme,
-        inherited_style: &renderer::Style,
-        layout: Layout<'_>,
-        cursor_position: Point,
-        viewport: &Rectangle,
-    ) {
-        let Rectangle {
-            x,
-            y,
-            width,
-            height,
-        } = layout.bounds();
-        let _ = self.tx.unbounded_send(Rectangle {
-            x: x as i32,
-            y: y as i32,
-            width: width as i32,
-            height: height as i32,
-        });
-        self.container.draw(
-            &tree.children[0],
-            renderer,
-            theme,
-            inherited_style,
-            layout,
-            cursor_position,
-            viewport,
-        );
-    }
-
-    fn overlay<'b>(
-        &'b self,
-        tree: &'b mut Tree,
-        layout: Layout<'_>,
-        renderer: &Renderer,
-    ) -> Option<overlay::Element<'b, Message, Renderer>> {
-        self.container
-            .overlay(&mut tree.children[0], layout, renderer)
-    }
-}
-
-pub struct PopupParentSubscription {
-    id: window::Id,
-    settings: SctkPopupSettings,
-}
-
-impl PopupParentSubscription {
-    pub fn new(id: window::Id, settings: SctkPopupSettings) -> Self {
-        Self { id, settings }
-    }
-
-    pub fn get_popup_container<'a, T, Message, Renderer>(
-        &self,
-        content: T,
-        tx: UnboundedSender<Rectangle<i32>>,
-    ) -> SizeTrackingContainer<'a, Message, Renderer>
-    where
-        T: Into<Element<'a, Message, Renderer>>,
-        Renderer: iced_native::Renderer,
-        Renderer::Theme: StyleSheet,
-    {
-        SizeTrackingContainer::new(content, tx.clone())
-    }
-
-    pub fn subscription(&self) -> iced::Subscription<(window::Id, PositionerUpdate)> {
-        popup_resize(self.id, self.settings.clone())
-    }
-}
-
-pub fn popup_resize(
-    id: window::Id,
-    settings: SctkPopupSettings,
-) -> iced::Subscription<(window::Id, PositionerUpdate)> {
-    iced_native::subscription::unfold(
-        id,
-        State::Init(settings.positioner.anchor_rect.clone()),
-        move |state| rectangle_size(id, state),
-    )
-    .with(settings)
-    .map(|(settings, (id, update))| match update {
-        RectangleUpdate::Update(rect) => {
-            let mut new_pos = settings.positioner.clone();
-            new_pos.anchor_rect = rect;
-            (id, PositionerUpdate::Update(new_pos))
-        }
-        RectangleUpdate::Finished => (id, PositionerUpdate::Finished),
-        RectangleUpdate::Sender(sender) => (id, PositionerUpdate::Sender(sender)),
-    })
-}
-
-#[derive(Debug, Clone)]
-pub enum PositionerUpdate {
-    Sender(UnboundedSender<Rectangle<i32>>),
-    Update(SctkPositioner),
-    Finished,
-}
-
-#[derive(Debug, Clone)]
-pub enum RectangleUpdate {
-    Sender(UnboundedSender<Rectangle<i32>>),
-    Update(Rectangle<i32>),
-    Finished,
-}
-
-pub enum State {
-    Init(Rectangle<i32>),
-    WaitForUpdate(Rectangle<i32>, UnboundedReceiver<Rectangle<i32>>),
-    Finished,
-}
-
-async fn rectangle_size<I: Copy>(id: I, state: State) -> (Option<(I, RectangleUpdate)>, State) {
-    match state {
-        State::Init(rectangle) => {
-            let (tx, rx) = unbounded();
-            (
-                Some((id, RectangleUpdate::Sender(tx))),
-                State::WaitForUpdate(rectangle, rx),
-            )
-        }
-        State::WaitForUpdate(old_rectangle, mut rx) => {
-            let response = rx.next().await;
-
-            match response {
-                Some(new_rectangle) => {
-                    let new_update = if new_rectangle == old_rectangle {
-                        None
-                    } else {
-                        Some((id, RectangleUpdate::Update(new_rectangle)))
-                    };
-                    (new_update, State::WaitForUpdate(new_rectangle, rx))
-                }
-                None => (Some((id, RectangleUpdate::Finished)), State::Finished),
-            }
-        }
-        State::Finished => iced::futures::future::pending().await,
-    }
-}

src/widget/rectangle_tracker/mod.rs

@@ -0,0 +1,244 @@
+mod subscription;
+
+use iced::futures::channel::mpsc::UnboundedSender;
+use iced::widget::Container;
+pub use subscription::*;
+
+use iced_native::alignment;
+use iced_native::event::{self, Event};
+use iced_native::layout;
+use iced_native::mouse;
+use iced_native::overlay;
+use iced_native::renderer;
+use iced_native::widget::{Operation, Tree};
+use iced_native::{Clipboard, Element, Layout, Length, Padding, Point, Rectangle, Shell, Widget};
+use std::{fmt::Debug, hash::Hash};
+
+pub use iced_style::container::{Appearance, StyleSheet};
+
+#[derive(Clone, Debug)]
+pub struct RectangleTracker<I> {
+    tx: UnboundedSender<(I, Rectangle)>,
+}
+
+impl<I> RectangleTracker<I>
+where
+    I: Hash + Copy + Send + Sync + Debug,
+{
+    pub fn container<'a, Message: 'static, T>(
+        &self,
+        id: I,
+        content: T,
+    ) -> RectangleTrackingContainer<'a, Message, crate::Renderer, I>
+    where
+        I: 'a,
+        T: Into<Element<'a, Message, crate::Renderer>>,
+    {
+        RectangleTrackingContainer::new(content, id, self.tx.clone())
+    }
+}
+
+/// An element decorating some content.
+///
+/// It is normally used for alignment purposes.
+#[allow(missing_debug_implementations)]
+pub struct RectangleTrackingContainer<'a, Message, Renderer, I>
+where
+    Renderer: iced_native::Renderer,
+    Renderer::Theme: StyleSheet,
+{
+    tx: UnboundedSender<(I, Rectangle)>,
+    id: I,
+    container: Container<'a, Message, Renderer>,
+}
+
+impl<'a, Message, Renderer, I> RectangleTrackingContainer<'a, Message, Renderer, I>
+where
+    Renderer: iced_native::Renderer,
+    Renderer::Theme: StyleSheet,
+    I: 'a + Hash + Copy + Send + Sync + Debug,
+{
+    /// Creates an empty [`Container`].
+    pub(crate) fn new<T>(content: T, id: I, tx: UnboundedSender<(I, Rectangle)>) -> Self
+    where
+        T: Into<Element<'a, Message, Renderer>>,
+    {
+        RectangleTrackingContainer {
+            id,
+            tx,
+            container: Container::new(content),
+        }
+    }
+
+    /// Sets the [`Padding`] of the [`Container`].
+    pub fn padding<P: Into<Padding>>(mut self, padding: P) -> Self {
+        self.container = self.container.padding(padding);
+        self
+    }
+
+    /// Sets the width of the [`self.`].
+    pub fn width(mut self, width: Length) -> Self {
+        self.container = self.container.width(width);
+        self
+    }
+
+    /// Sets the height of the [`Container`].
+    pub fn height(mut self, height: Length) -> Self {
+        self.container = self.container.height(height);
+        self
+    }
+
+    /// Sets the maximum width of the [`Container`].
+    pub fn max_width(mut self, max_width: u32) -> Self {
+        self.container = self.container.max_width(max_width);
+        self
+    }
+
+    /// Sets the maximum height of the [`Container`] in pixels.
+    pub fn max_height(mut self, max_height: u32) -> Self {
+        self.container = self.container.max_height(max_height);
+        self
+    }
+
+    /// Sets the content alignment for the horizontal axis of the [`Container`].
+    pub fn align_x(mut self, alignment: alignment::Horizontal) -> Self {
+        self.container = self.container.align_x(alignment);
+        self
+    }
+
+    /// Sets the content alignment for the vertical axis of the [`Container`].
+    pub fn align_y(mut self, alignment: alignment::Vertical) -> Self {
+        self.container = self.container.align_y(alignment);
+        self
+    }
+
+    /// Centers the contents in the horizontal axis of the [`Container`].
+    pub fn center_x(mut self) -> Self {
+        self.container = self.container.center_x();
+        self
+    }
+
+    /// Centers the contents in the vertical axis of the [`Container`].
+    pub fn center_y(mut self) -> Self {
+        self.container = self.container.center_y();
+        self
+    }
+
+    /// Sets the style of the [`Container`].
+    pub fn style(mut self, style: impl Into<<Renderer::Theme as StyleSheet>::Style>) -> Self {
+        self.container = self.container.style(style);
+        self
+    }
+}
+
+impl<'a, Message, Renderer, I> Widget<Message, Renderer>
+    for RectangleTrackingContainer<'a, Message, Renderer, I>
+where
+    Renderer: iced_native::Renderer,
+    Renderer::Theme: StyleSheet,
+    I: 'a + Hash + Copy + Send + Sync + Debug,
+{
+    fn children(&self) -> Vec<Tree> {
+        self.container.children()
+    }
+
+    fn diff(&self, tree: &mut Tree) {
+        self.container.diff(tree);
+    }
+
+    fn width(&self) -> Length {
+        Widget::width(&self.container)
+    }
+
+    fn height(&self) -> Length {
+        Widget::height(&self.container)
+    }
+
+    fn layout(&self, renderer: &Renderer, limits: &layout::Limits) -> layout::Node {
+        self.container.layout(renderer, limits)
+    }
+
+    fn operate(&self, tree: &mut Tree, layout: Layout<'_>, operation: &mut dyn Operation<Message>) {
+        self.container.operate(tree, layout, operation)
+    }
+
+    fn on_event(
+        &mut self,
+        tree: &mut Tree,
+        event: Event,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        renderer: &Renderer,
+        clipboard: &mut dyn Clipboard,
+        shell: &mut Shell<'_, Message>,
+    ) -> event::Status {
+        self.container.on_event(
+            tree,
+            event,
+            layout,
+            cursor_position,
+            renderer,
+            clipboard,
+            shell,
+        )
+    }
+
+    fn mouse_interaction(
+        &self,
+        tree: &Tree,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        viewport: &Rectangle,
+        renderer: &Renderer,
+    ) -> mouse::Interaction {
+        self.container
+            .mouse_interaction(tree, layout, cursor_position, viewport, renderer)
+    }
+
+    fn draw(
+        &self,
+        tree: &Tree,
+        renderer: &mut Renderer,
+        theme: &Renderer::Theme,
+        renderer_style: &renderer::Style,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        viewport: &Rectangle,
+    ) {
+        let _ = self.tx.unbounded_send((self.id, layout.bounds()));
+
+        self.container.draw(
+            tree,
+            renderer,
+            theme,
+            renderer_style,
+            layout,
+            cursor_position,
+            viewport,
+        )
+    }
+
+    fn overlay<'b>(
+        &'b self,
+        tree: &'b mut Tree,
+        layout: Layout<'_>,
+        renderer: &Renderer,
+    ) -> Option<overlay::Element<'b, Message, Renderer>> {
+        self.container.overlay(tree, layout, renderer)
+    }
+}
+
+impl<'a, Message, Renderer, I> From<RectangleTrackingContainer<'a, Message, Renderer, I>>
+    for Element<'a, Message, Renderer>
+where
+    Message: 'a,
+    Renderer: 'a + iced_native::Renderer,
+    Renderer::Theme: StyleSheet,
+    I: 'a + Hash + Copy + Send + Sync + Debug,
+{
+    fn from(
+        column: RectangleTrackingContainer<'a, Message, Renderer, I>,
+    ) -> Element<'a, Message, Renderer> {
+        Element::new(column)
+    }
+}

src/widget/rectangle_tracker/subscription.rs

@@ -0,0 +1,75 @@
+use iced::{
+    futures::{
+        channel::mpsc::{unbounded, UnboundedReceiver},
+        StreamExt,
+    },
+    subscription, Rectangle,
+};
+use std::{fmt::Debug, hash::Hash, collections::HashMap};
+
+use super::RectangleTracker;
+
+pub fn rectangle_tracker_subscription<
+    I: 'static + Hash + Copy + Send + Sync + Debug,
+    R: 'static + Hash + Copy + Send + Sync + Debug + Eq,
+>(
+    id: I,
+) -> iced::Subscription<(I, RectangleUpdate<R>)> {
+    subscription::unfold(id, State::Ready, move |state| start_listening(id, state))
+}
+
+pub enum State<I> {
+    Ready,
+    Waiting(UnboundedReceiver<(I, Rectangle)>, HashMap<I, Rectangle>),
+    Finished,
+}
+
+async fn start_listening<I: Copy, R: 'static + Hash + Copy + Send + Sync + Debug + Eq>(
+    id: I,
+    state: State<R>,
+) -> (Option<(I, RectangleUpdate<R>)>, State<R>) {
+    match state {
+        State::Ready => {
+            let (tx, rx) = unbounded();
+
+            return (
+                Some((id, RectangleUpdate::Init(RectangleTracker { tx }))),
+                State::Waiting(rx, HashMap::new()),
+            );
+        }
+        State::Waiting(mut rx, mut map) => match rx.next().await {
+            Some(u) => 
+            {
+                if let Some(prev) = map.get(&u.0) {
+                    let new = u.1;
+                    if prev.width != new.width || prev.height != new.height || prev.x != new.x || prev.y != new.y {
+                        map.insert(u.0, new);
+                        return (
+                            Some((id, RectangleUpdate::Rectangle(u))),
+                            State::Waiting(rx, map),
+                        );
+                    }
+                } else {
+                    map.insert(u.0, u.1);
+                    return (
+                        Some((id, RectangleUpdate::Rectangle(u))),
+                        State::Waiting(rx, map),
+                    );
+                }
+                return (None, State::Waiting(rx, map))
+                
+        },
+            None => (None, State::Finished),
+        },
+        State::Finished => iced::futures::future::pending().await,
+    }
+}
+
+#[derive(Clone, Debug)]
+pub enum RectangleUpdate<I>
+where
+    I: 'static + Hash + Copy + Send + Sync + Debug,
+{
+    Rectangle((I, Rectangle)),
+    Init(RectangleTracker<I>),
+}