Merge pull request #1594 from mmstick/listener

`MouseArea` widget

Author: hecrj

native/src/widget.rs

@@ -17,6 +17,7 @@ pub mod column;
 pub mod container;
 pub mod helpers;
 pub mod image;
+pub mod mouse_area;
 pub mod operation;
 pub mod pane_grid;
 pub mod pick_list;
@@ -51,6 +52,8 @@ pub use helpers::*;
 #[doc(no_inline)]
 pub use image::Image;
 #[doc(no_inline)]
+pub use mouse_area::MouseArea;
+#[doc(no_inline)]
 pub use pane_grid::PaneGrid;
 #[doc(no_inline)]
 pub use pick_list::PickList;

native/src/widget/helpers.rs

@@ -314,3 +314,13 @@ where
 {
     widget::Svg::new(handle)
 }
+
+/// A container intercepting mouse events.
+pub fn mouse_area<'a, Message, Renderer>(
+    widget: impl Into<Element<'a, Message, Renderer>>,
+) -> widget::MouseArea<'a, Message, Renderer>
+where
+    Renderer: crate::Renderer,
+{
+    widget::MouseArea::new(widget)
+}

native/src/widget/mouse_area.rs

@@ -0,0 +1,311 @@
+//! A container for capturing mouse events.
+
+use crate::event::{self, Event};
+use crate::layout;
+use crate::mouse;
+use crate::overlay;
+use crate::renderer;
+use crate::touch;
+use crate::widget::{tree, Operation, Tree};
+use crate::{
+    Clipboard, Element, Layout, Length, Point, Rectangle, Shell, Widget,
+};
+
+/// Emit messages on mouse events.
+#[allow(missing_debug_implementations)]
+pub struct MouseArea<'a, Message, Renderer> {
+    content: Element<'a, Message, Renderer>,
+    on_press: Option<Message>,
+    on_release: Option<Message>,
+    on_right_press: Option<Message>,
+    on_right_release: Option<Message>,
+    on_middle_press: Option<Message>,
+    on_middle_release: Option<Message>,
+}
+
+impl<'a, Message, Renderer> MouseArea<'a, Message, 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 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
+    }
+}
+
+/// Local state of the [`MouseArea`].
+#[derive(Default)]
+struct State {
+    // TODO: Support on_mouse_enter and on_mouse_exit
+}
+
+impl<'a, Message, Renderer> MouseArea<'a, Message, Renderer> {
+    /// Creates a [`MouseArea`] with the given content.
+    pub fn new(content: impl Into<Element<'a, Message, Renderer>>) -> Self {
+        MouseArea {
+            content: content.into(),
+            on_press: None,
+            on_release: None,
+            on_right_press: None,
+            on_right_release: None,
+            on_middle_press: None,
+            on_middle_release: None,
+        }
+    }
+}
+
+impl<'a, Message, Renderer> Widget<Message, Renderer>
+    for MouseArea<'a, Message, Renderer>
+where
+    Renderer: crate::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 width(&self) -> Length {
+        self.content.as_widget().width()
+    }
+
+    fn height(&self) -> Length {
+        self.content.as_widget().height()
+    }
+
+    fn layout(
+        &self,
+        renderer: &Renderer,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        self.content.as_widget().layout(renderer, limits)
+    }
+
+    fn operate(
+        &self,
+        tree: &mut Tree,
+        layout: Layout<'_>,
+        renderer: &Renderer,
+        operation: &mut dyn Operation<Message>,
+    ) {
+        self.content.as_widget().operate(
+            &mut tree.children[0],
+            layout,
+            renderer,
+            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 {
+        if let event::Status::Captured = self.content.as_widget_mut().on_event(
+            &mut tree.children[0],
+            event.clone(),
+            layout,
+            cursor_position,
+            renderer,
+            clipboard,
+            shell,
+        ) {
+            return event::Status::Captured;
+        }
+
+        update(self, &event, layout, cursor_position, shell)
+    }
+
+    fn mouse_interaction(
+        &self,
+        tree: &Tree,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        viewport: &Rectangle,
+        renderer: &Renderer,
+    ) -> mouse::Interaction {
+        self.content.as_widget().mouse_interaction(
+            &tree.children[0],
+            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,
+    ) {
+        self.content.as_widget().draw(
+            &tree.children[0],
+            renderer,
+            theme,
+            renderer_style,
+            layout,
+            cursor_position,
+            viewport,
+        );
+    }
+
+    fn overlay<'b>(
+        &'b mut self,
+        tree: &'b mut Tree,
+        layout: Layout<'_>,
+        renderer: &Renderer,
+    ) -> Option<overlay::Element<'b, Message, Renderer>> {
+        self.content.as_widget_mut().overlay(
+            &mut tree.children[0],
+            layout,
+            renderer,
+        )
+    }
+}
+
+impl<'a, Message, Renderer> From<MouseArea<'a, Message, Renderer>>
+    for Element<'a, Message, Renderer>
+where
+    Message: 'a + Clone,
+    Renderer: 'a + crate::Renderer,
+{
+    fn from(
+        area: MouseArea<'a, Message, Renderer>,
+    ) -> Element<'a, Message, Renderer> {
+        Element::new(area)
+    }
+}
+
+/// Processes the given [`Event`] and updates the [`State`] of an [`MouseArea`]
+/// accordingly.
+fn update<Message: Clone, Renderer>(
+    widget: &mut MouseArea<'_, Message, Renderer>,
+    event: &Event,
+    layout: Layout<'_>,
+    cursor_position: Point,
+    shell: &mut Shell<'_, Message>,
+) -> event::Status {
+    if !layout.bounds().contains(cursor_position) {
+        return event::Status::Ignored;
+    }
+
+    if let Some(message) = widget.on_press.as_ref() {
+        if let Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left))
+        | Event::Touch(touch::Event::FingerPressed { .. }) = event
+        {
+            shell.publish(message.clone());
+
+            return event::Status::Captured;
+        }
+    }
+
+    if let Some(message) = widget.on_release.as_ref() {
+        if let Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Left))
+        | Event::Touch(touch::Event::FingerLifted { .. }) = event
+        {
+            shell.publish(message.clone());
+
+            return event::Status::Captured;
+        }
+    }
+
+    if let Some(message) = widget.on_right_press.as_ref() {
+        if let Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Right)) =
+            event
+        {
+            shell.publish(message.clone());
+
+            return event::Status::Captured;
+        }
+    }
+
+    if let Some(message) = widget.on_right_release.as_ref() {
+        if let Event::Mouse(mouse::Event::ButtonReleased(
+            mouse::Button::Right,
+        )) = event
+        {
+            shell.publish(message.clone());
+
+            return event::Status::Captured;
+        }
+    }
+
+    if let Some(message) = widget.on_middle_press.as_ref() {
+        if let Event::Mouse(mouse::Event::ButtonPressed(
+            mouse::Button::Middle,
+        )) = event
+        {
+            shell.publish(message.clone());
+
+            return event::Status::Captured;
+        }
+    }
+
+    if let Some(message) = widget.on_middle_release.as_ref() {
+        if let Event::Mouse(mouse::Event::ButtonReleased(
+            mouse::Button::Middle,
+        )) = event
+        {
+            shell.publish(message.clone());
+
+            return event::Status::Captured;
+        }
+    }
+
+    event::Status::Ignored
+}

src/widget.rs

@@ -47,6 +47,14 @@ pub mod container {
         iced_native::widget::Container<'a, Message, Renderer>;
 }
 
+pub mod mouse_area {
+    //! Intercept mouse events on a widget.
+
+    /// A container intercepting mouse events.
+    pub type MouseArea<'a, Message, Renderer = crate::Renderer> =
+        iced_native::widget::MouseArea<'a, Message, Renderer>;
+}
+
 pub mod pane_grid {
     //! Let your users split regions of your application and organize layout dynamically.
     //!