New edit process

src/widgets/hard_mouse_area.rs

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+use iced::widget::MouseArea;
+use iced_core::widget::{Operation, Tree, tree};
+use iced_core::{
+    Clipboard, Element, Event, Layout, Length, Point, Rectangle, Shell, Size, Vector, Widget,
+    layout, mouse, overlay, renderer, touch,
+};
+
+pub fn hard_mouse_area<'a, Message, Theme, Renderer>(
+    widget: impl Into<Element<'a, Message, Theme, Renderer>>,
+) -> HardMouseArea<'a, Message, Theme, Renderer>
+where
+    Renderer: iced_core::Renderer,
+{
+    HardMouseArea::new(widget)
+}
+
+pub struct HardMouseArea<'a, Message, Theme = iced::Theme, Renderer = iced::Renderer> {
+    content: Element<'a, Message, Theme, Renderer>,
+    on_press: Option<Message>,
+    on_release: Option<Message>,
+    on_double_click: Option<Message>,
+    on_right_press: Option<Message>,
+    on_right_release: Option<Message>,
+    on_middle_press: Option<Message>,
+    on_middle_release: Option<Message>,
+    on_scroll: Option<Box<dyn Fn(mouse::ScrollDelta) -> Message + 'a>>,
+    on_enter: Option<Message>,
+    on_move: Option<Box<dyn Fn(Point) -> Message + 'a>>,
+    on_exit: Option<Message>,
+    interaction: Option<mouse::Interaction>,
+}
+
+impl<'a, Message, Theme, Renderer> HardMouseArea<'a, Message, Theme, Renderer> {
+    /// The message to emit on a left button press.
+    #[must_use]
+    pub fn on_press(mut self, message: Message) -> Self {
+        self.on_press = Some(message);
+        self
+    }
+
+    /// The message to emit on a left button release.
+    #[must_use]
+    pub fn on_release(mut self, message: Message) -> Self {
+        self.on_release = Some(message);
+        self
+    }
+
+    /// The message to emit on a double click.
+    ///
+    /// If you use this with [`on_press`]/[`on_release`], those
+    /// event will be emit as normal.
+    ///
+    /// The events stream will be: on_press -> on_release -> on_press
+    /// -> on_double_click -> on_release -> on_press ...
+    ///
+    /// [`on_press`]: Self::on_press
+    /// [`on_release`]: Self::on_release
+    #[must_use]
+    pub fn on_double_click(mut self, message: Message) -> Self {
+        self.on_double_click = Some(message);
+        self
+    }
+
+    /// The message to emit on a right button press.
+    #[must_use]
+    pub fn on_right_press(mut self, message: Message) -> Self {
+        self.on_right_press = Some(message);
+        self
+    }
+
+    /// The message to emit on a right button release.
+    #[must_use]
+    pub fn on_right_release(mut self, message: Message) -> Self {
+        self.on_right_release = Some(message);
+        self
+    }
+
+    /// The message to emit on a middle button press.
+    #[must_use]
+    pub fn on_middle_press(mut self, message: Message) -> Self {
+        self.on_middle_press = Some(message);
+        self
+    }
+
+    /// The message to emit on a middle button release.
+    #[must_use]
+    pub fn on_middle_release(mut self, message: Message) -> Self {
+        self.on_middle_release = Some(message);
+        self
+    }
+
+    /// The message to emit when scroll wheel is used
+    #[must_use]
+    pub fn on_scroll(mut self, on_scroll: impl Fn(mouse::ScrollDelta) -> Message + 'a) -> Self {
+        self.on_scroll = Some(Box::new(on_scroll));
+        self
+    }
+
+    /// The message to emit when the mouse enters the area.
+    #[must_use]
+    pub fn on_enter(mut self, message: Message) -> Self {
+        self.on_enter = Some(message);
+        self
+    }
+
+    /// The message to emit when the mouse moves in the area.
+    #[must_use]
+    pub fn on_move(mut self, on_move: impl Fn(Point) -> Message + 'a) -> Self {
+        self.on_move = Some(Box::new(on_move));
+        self
+    }
+
+    /// The message to emit when the mouse exits the area.
+    #[must_use]
+    pub fn on_exit(mut self, message: Message) -> Self {
+        self.on_exit = Some(message);
+        self
+    }
+
+    /// The [`mouse::Interaction`] to use when hovering the area.
+    #[must_use]
+    pub fn interaction(mut self, interaction: mouse::Interaction) -> Self {
+        self.interaction = Some(interaction);
+        self
+    }
+}
+
+/// Local state of the [`HardMouseArea`].
+#[derive(Default)]
+struct State {
+    is_hovered: bool,
+    bounds: Rectangle,
+    cursor_position: Option<Point>,
+    previous_click: Option<mouse::Click>,
+}
+
+impl<'a, Message, Theme, Renderer> HardMouseArea<'a, Message, Theme, Renderer> {
+    /// Creates a [`HardMouseArea`] with the given content.
+    pub fn new(content: impl Into<Element<'a, Message, Theme, Renderer>>) -> Self {
+        HardMouseArea {
+            content: content.into(),
+            on_press: None,
+            on_release: None,
+            on_double_click: None,
+            on_right_press: None,
+            on_right_release: None,
+            on_middle_press: None,
+            on_middle_release: None,
+            on_scroll: None,
+            on_enter: None,
+            on_move: None,
+            on_exit: None,
+            interaction: None,
+        }
+    }
+}
+
+impl<Message, Theme, Renderer> Widget<Message, Theme, Renderer>
+    for HardMouseArea<'_, Message, Theme, Renderer>
+where
+    Renderer: renderer::Renderer,
+    Message: Clone,
+{
+    fn tag(&self) -> tree::Tag {
+        tree::Tag::of::<State>()
+    }
+
+    fn state(&self) -> tree::State {
+        tree::State::new(State::default())
+    }
+
+    fn children(&self) -> Vec<Tree> {
+        vec![Tree::new(&self.content)]
+    }
+
+    fn diff(&self, tree: &mut Tree) {
+        tree.diff_children(std::slice::from_ref(&self.content));
+    }
+
+    fn size(&self) -> Size<Length> {
+        self.content.as_widget().size()
+    }
+
+    fn layout(
+        &mut self,
+        tree: &mut Tree,
+        renderer: &Renderer,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        self.content
+            .as_widget_mut()
+            .layout(&mut tree.children[0], renderer, limits)
+    }
+
+    fn operate(
+        &mut self,
+        tree: &mut Tree,
+        layout: Layout<'_>,
+        renderer: &Renderer,
+        operation: &mut dyn Operation,
+    ) {
+        self.content
+            .as_widget_mut()
+            .operate(&mut tree.children[0], layout, renderer, operation);
+    }
+
+    fn update(
+        &mut self,
+        tree: &mut Tree,
+        event: &Event,
+        layout: Layout<'_>,
+        cursor: mouse::Cursor,
+        renderer: &Renderer,
+        clipboard: &mut dyn Clipboard,
+        shell: &mut Shell<'_, Message>,
+        viewport: &Rectangle,
+    ) {
+        if self.on_move.is_none() && let Event::Mouse(mouse::Event::CursorMoved {..}) = event {
+            self.content.as_widget_mut().update(
+                &mut tree.children[0],
+                event,
+                layout,
+                cursor,
+                renderer,
+                clipboard,
+                shell,
+                viewport,
+            );
+        }
+
+        if self.on_enter.is_none() && let Event::Mouse(mouse::Event::CursorEntered {..}) = event {
+            self.content.as_widget_mut().update(
+                &mut tree.children[0],
+                event,
+                layout,
+                cursor,
+                renderer,
+                clipboard,
+                shell,
+                viewport,
+            );
+        }
+        if self.on_exit.is_none() && let Event::Mouse(mouse::Event::CursorLeft {..}) = event {
+            self.content.as_widget_mut().update(
+                &mut tree.children[0],
+                event,
+                layout,
+                cursor,
+                renderer,
+                clipboard,
+                shell,
+                viewport,
+            );
+        }
+        
+        if shell.is_event_captured() {
+            return;
+        }
+
+        update(self, tree, event, layout, cursor, shell);
+    }
+
+    fn mouse_interaction(
+        &self,
+        tree: &Tree,
+        layout: Layout<'_>,
+        cursor: mouse::Cursor,
+        viewport: &Rectangle,
+        renderer: &Renderer,
+    ) -> mouse::Interaction {
+        let content_interaction = self.content.as_widget().mouse_interaction(
+            &tree.children[0],
+            layout,
+            cursor,
+            viewport,
+            renderer,
+        );
+
+        match (self.interaction, content_interaction) {
+            (Some(interaction), mouse::Interaction::None) if cursor.is_over(layout.bounds()) => {
+                interaction
+            }
+            _ => content_interaction,
+        }
+    }
+
+    fn draw(
+        &self,
+        tree: &Tree,
+        renderer: &mut Renderer,
+        theme: &Theme,
+        renderer_style: &renderer::Style,
+        layout: Layout<'_>,
+        cursor: mouse::Cursor,
+        viewport: &Rectangle,
+    ) {
+        self.content.as_widget().draw(
+            &tree.children[0],
+            renderer,
+            theme,
+            renderer_style,
+            layout,
+            cursor,
+            viewport,
+        );
+    }
+
+    fn overlay<'b>(
+        &'b mut self,
+        tree: &'b mut Tree,
+        layout: Layout<'b>,
+        renderer: &Renderer,
+        viewport: &Rectangle,
+        translation: Vector,
+    ) -> Option<overlay::Element<'b, Message, Theme, Renderer>> {
+        self.content.as_widget_mut().overlay(
+            &mut tree.children[0],
+            layout,
+            renderer,
+            viewport,
+            translation,
+        )
+    }
+}
+
+impl<'a, Message, Theme, Renderer> From<HardMouseArea<'a, Message, Theme, Renderer>>
+    for Element<'a, Message, Theme, Renderer>
+where
+    Message: 'a + Clone,
+    Theme: 'a,
+    Renderer: 'a + renderer::Renderer,
+{
+    fn from(
+        area: HardMouseArea<'a, Message, Theme, Renderer>,
+    ) -> Element<'a, Message, Theme, Renderer> {
+        Element::new(area)
+    }
+}
+
+/// Processes the given [`Event`] and updates the [`State`] of an [`HardMouseArea`]
+/// accordingly.
+fn update<Message: Clone, Theme, Renderer>(
+    widget: &mut HardMouseArea<'_, Message, Theme, Renderer>,
+    tree: &mut Tree,
+    event: &Event,
+    layout: Layout<'_>,
+    cursor: mouse::Cursor,
+    shell: &mut Shell<'_, Message>,
+) {
+    let state: &mut State = tree.state.downcast_mut();
+
+    let cursor_position = cursor.position();
+    let bounds = layout.bounds();
+
+    if state.cursor_position != cursor_position || state.bounds != bounds {
+        let was_hovered = state.is_hovered;
+
+        state.is_hovered = cursor.is_over(layout.bounds());
+        state.cursor_position = cursor_position;
+        state.bounds = bounds;
+
+        match (
+            widget.on_enter.as_ref(),
+            widget.on_move.as_ref(),
+            widget.on_exit.as_ref(),
+        ) {
+            (Some(on_enter), _, _) if state.is_hovered && !was_hovered => {
+                shell.publish(on_enter.clone());
+            }
+            (_, Some(on_move), _) if state.is_hovered => {
+                if let Some(position) = cursor.position_in(layout.bounds()) {
+                    shell.publish(on_move(position));
+                }
+            }
+            (_, _, Some(on_exit)) if !state.is_hovered && was_hovered => {
+                shell.publish(on_exit.clone());
+            }
+            _ => {}
+        }
+    }
+
+    if !cursor.is_over(layout.bounds()) {
+        return;
+    }
+
+    match event {
+        Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left))
+        | Event::Touch(touch::Event::FingerPressed { .. }) => {
+            if let Some(message) = widget.on_press.as_ref() {
+                shell.publish(message.clone());
+                shell.capture_event();
+            }
+
+            if let Some(position) = cursor_position
+                && let Some(message) = widget.on_double_click.as_ref()
+            {
+                let new_click =
+                    mouse::Click::new(position, mouse::Button::Left, state.previous_click);
+
+                if new_click.kind() == mouse::click::Kind::Double {
+                    shell.publish(message.clone());
+                }
+
+                state.previous_click = Some(new_click);
+
+                // Even if this is not a double click, but the press is nevertheless
+                // processed by us and should not be popup to parent widgets.
+                shell.capture_event();
+            }
+        }
+        Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Left))
+        | Event::Touch(touch::Event::FingerLifted { .. }) => {
+            if let Some(message) = widget.on_release.as_ref() {
+                shell.publish(message.clone());
+            }
+        }
+        Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Right)) => {
+            if let Some(message) = widget.on_right_press.as_ref() {
+                shell.publish(message.clone());
+                shell.capture_event();
+            }
+        }
+        Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Right)) => {
+            if let Some(message) = widget.on_right_release.as_ref() {
+                shell.publish(message.clone());
+            }
+        }
+        Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Middle)) => {
+            if let Some(message) = widget.on_middle_press.as_ref() {
+                shell.publish(message.clone());
+                shell.capture_event();
+            }
+        }
+        Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Middle)) => {
+            if let Some(message) = widget.on_middle_release.as_ref() {
+                shell.publish(message.clone());
+            }
+        }
+        Event::Mouse(mouse::Event::WheelScrolled { delta }) => {
+            if let Some(on_scroll) = widget.on_scroll.as_ref() {
+                shell.publish(on_scroll(*delta));
+                shell.capture_event();
+            }
+        }
+        _ => {}
+    }
+}