Draft ComboBox and Menu layer

native/src/layer/menu.rs

@@ -0,0 +1,305 @@
+use crate::{
+    container, layout, mouse, scrollable, Clipboard, Container, Element, Event,
+    Hasher, Layer, Layout, Length, Point, Rectangle, Scrollable, Size, Widget,
+};
+use std::borrow::Cow;
+
+pub struct Menu<'a, Message, Renderer: self::Renderer> {
+    container: Container<'a, Message, Renderer>,
+    is_open: &'a mut bool,
+    width: u16,
+}
+
+#[derive(Default)]
+pub struct State {
+    scrollable: scrollable::State,
+    hovered_option: Option<usize>,
+    is_open: bool,
+}
+
+impl State {
+    pub fn is_open(&self) -> bool {
+        self.is_open
+    }
+
+    pub fn open(&mut self, hovered_option: Option<usize>) {
+        self.is_open = true;
+        self.hovered_option = hovered_option;
+    }
+}
+
+impl<'a, Message, Renderer: self::Renderer> Menu<'a, Message, Renderer>
+where
+    Message: 'static,
+    Renderer: 'a,
+{
+    pub fn new<T: 'a>(
+        state: &'a mut State,
+        options: impl Into<Cow<'a, [T]>>,
+        on_selected: Box<dyn Fn(T) -> Message>,
+        width: u16,
+        text_size: u16,
+        padding: u16,
+    ) -> Self
+    where
+        T: Clone + ToString,
+        [T]: ToOwned<Owned = Vec<T>>,
+    {
+        let container = Container::new(
+            Scrollable::new(&mut state.scrollable).push(List::new(
+                &mut state.hovered_option,
+                options,
+                on_selected,
+                text_size,
+                padding,
+            )),
+        )
+        .padding(1);
+
+        Self {
+            container,
+            is_open: &mut state.is_open,
+            width,
+        }
+    }
+}
+
+impl<'a, Message, Renderer> Layer<Message, Renderer>
+    for Menu<'a, Message, Renderer>
+where
+    Renderer: self::Renderer,
+{
+    fn layout(
+        &self,
+        renderer: &Renderer,
+        bounds: Size,
+        position: Point,
+    ) -> layout::Node {
+        let limits = layout::Limits::new(
+            Size::ZERO,
+            Size::new(bounds.width - position.x, bounds.height - position.y),
+        )
+        .width(Length::Units(self.width));
+
+        let mut node = self.container.layout(renderer, &limits);
+
+        node.move_to(position);
+
+        node
+    }
+
+    fn hash_layout(&self, state: &mut Hasher, position: Point) {
+        use std::hash::Hash;
+
+        (position.x as u32).hash(state);
+        (position.y as u32).hash(state);
+    }
+
+    fn on_event(
+        &mut self,
+        event: Event,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        messages: &mut Vec<Message>,
+        renderer: &Renderer,
+        clipboard: Option<&dyn Clipboard>,
+    ) {
+        let bounds = layout.bounds();
+        let current_messages = messages.len();
+
+        self.container.on_event(
+            event.clone(),
+            layout,
+            cursor_position,
+            messages,
+            renderer,
+            clipboard,
+        );
+
+        match event {
+            Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left))
+                if !bounds.contains(cursor_position)
+                    || current_messages < messages.len() =>
+            {
+                *self.is_open = false;
+            }
+            _ => {}
+        }
+    }
+
+    fn draw(
+        &self,
+        renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
+        layout: Layout<'_>,
+        cursor_position: Point,
+    ) -> Renderer::Output {
+        let primitives =
+            self.container
+                .draw(renderer, defaults, layout, cursor_position);
+
+        renderer.decorate(layout.bounds(), cursor_position, primitives)
+    }
+}
+
+struct List<'a, T, Message>
+where
+    [T]: ToOwned,
+{
+    hovered_option: &'a mut Option<usize>,
+    options: Cow<'a, [T]>,
+    on_selected: Box<dyn Fn(T) -> Message>,
+    text_size: u16,
+    padding: u16,
+}
+
+impl<'a, T, Message> List<'a, T, Message>
+where
+    [T]: ToOwned,
+{
+    pub fn new(
+        hovered_option: &'a mut Option<usize>,
+        options: impl Into<Cow<'a, [T]>>,
+        on_selected: Box<dyn Fn(T) -> Message>,
+        text_size: u16,
+        padding: u16,
+    ) -> Self {
+        List {
+            hovered_option,
+            options: options.into(),
+            on_selected,
+            text_size,
+            padding,
+        }
+    }
+}
+
+impl<'a, T, Message, Renderer> Widget<'a, Message, Renderer>
+    for List<'a, T, Message>
+where
+    T: ToString + Clone,
+    [T]: ToOwned,
+    Renderer: self::Renderer,
+{
+    fn width(&self) -> Length {
+        Length::Fill
+    }
+
+    fn height(&self) -> Length {
+        Length::Shrink
+    }
+
+    fn layout(
+        &self,
+        _renderer: &Renderer,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        use std::f32;
+
+        let limits = limits.width(Length::Fill).height(Length::Shrink);
+
+        let size = {
+            let intrinsic = Size::new(
+                0.0,
+                f32::from(self.text_size + self.padding * 2)
+                    * self.options.len() as f32,
+            );
+
+            limits.resolve(intrinsic)
+        };
+
+        layout::Node::new(size)
+    }
+
+    fn hash_layout(&self, state: &mut Hasher) {
+        use std::hash::Hash as _;
+
+        0.hash(state);
+    }
+
+    fn on_event(
+        &mut self,
+        event: Event,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        messages: &mut Vec<Message>,
+        _renderer: &Renderer,
+        _clipboard: Option<&dyn Clipboard>,
+    ) {
+        match event {
+            Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left)) => {
+                let bounds = layout.bounds();
+
+                if bounds.contains(cursor_position) {
+                    if let Some(index) = *self.hovered_option {
+                        if let Some(option) = self.options.get(index) {
+                            messages.push((self.on_selected)(option.clone()));
+                        }
+                    }
+                }
+            }
+            Event::Mouse(mouse::Event::CursorMoved { .. }) => {
+                let bounds = layout.bounds();
+
+                if bounds.contains(cursor_position) {
+                    *self.hovered_option = Some(
+                        ((cursor_position.y - bounds.y)
+                            / f32::from(self.text_size + self.padding * 2))
+                            as usize,
+                    );
+                }
+            }
+            _ => {}
+        }
+    }
+
+    fn draw(
+        &self,
+        renderer: &mut Renderer,
+        _defaults: &Renderer::Defaults,
+        layout: Layout<'_>,
+        cursor_position: Point,
+    ) -> Renderer::Output {
+        self::Renderer::draw(
+            renderer,
+            layout.bounds(),
+            cursor_position,
+            &self.options,
+            *self.hovered_option,
+            self.text_size,
+            self.padding,
+        )
+    }
+}
+
+pub trait Renderer: scrollable::Renderer + container::Renderer {
+    fn decorate(
+        &mut self,
+        bounds: Rectangle,
+        cursor_position: Point,
+        primitive: Self::Output,
+    ) -> Self::Output;
+
+    fn draw<T: ToString>(
+        &mut self,
+        bounds: Rectangle,
+        cursor_position: Point,
+        options: &[T],
+        hovered_option: Option<usize>,
+        text_size: u16,
+        padding: u16,
+    ) -> Self::Output;
+}
+
+impl<'a, T, Message, Renderer> Into<Element<'a, Message, Renderer>>
+    for List<'a, T, Message>
+where
+    T: ToString + Clone,
+    [T]: ToOwned,
+    Message: 'static,
+    Renderer: self::Renderer,
+{
+    fn into(self) -> Element<'a, Message, Renderer> {
+        Element::new(self)
+    }
+}