Create iced_widget subcrate and re-organize the whole codebase

widget/src/overlay/menu.rs

@@ -0,0 +1,519 @@
+//! Build and show dropdown menus.
+use crate::container::{self, Container};
+use crate::core::alignment;
+use crate::core::event::{self, Event};
+use crate::core::layout::{self, Layout};
+use crate::core::mouse;
+use crate::core::overlay;
+use crate::core::renderer;
+use crate::core::text::{self, Text};
+use crate::core::touch;
+use crate::core::widget::Tree;
+use crate::core::{
+    Clipboard, Color, Length, Padding, Pixels, Point, Rectangle, Size, Vector,
+};
+use crate::core::{Element, Shell, Widget};
+use crate::scrollable::{self, Scrollable};
+
+pub use iced_style::menu::{Appearance, StyleSheet};
+
+/// A list of selectable options.
+#[allow(missing_debug_implementations)]
+pub struct Menu<'a, T, Renderer = crate::Renderer>
+where
+    Renderer: text::Renderer,
+    Renderer::Theme: StyleSheet,
+{
+    state: &'a mut State,
+    options: &'a [T],
+    hovered_option: &'a mut Option<usize>,
+    last_selection: &'a mut Option<T>,
+    width: f32,
+    padding: Padding,
+    text_size: Option<f32>,
+    font: Option<Renderer::Font>,
+    style: <Renderer::Theme as StyleSheet>::Style,
+}
+
+impl<'a, T, Renderer> Menu<'a, T, Renderer>
+where
+    T: ToString + Clone,
+    Renderer: text::Renderer + 'a,
+    Renderer::Theme:
+        StyleSheet + container::StyleSheet + scrollable::StyleSheet,
+{
+    /// Creates a new [`Menu`] with the given [`State`], a list of options, and
+    /// the message to produced when an option is selected.
+    pub fn new(
+        state: &'a mut State,
+        options: &'a [T],
+        hovered_option: &'a mut Option<usize>,
+        last_selection: &'a mut Option<T>,
+    ) -> Self {
+        Menu {
+            state,
+            options,
+            hovered_option,
+            last_selection,
+            width: 0.0,
+            padding: Padding::ZERO,
+            text_size: None,
+            font: None,
+            style: Default::default(),
+        }
+    }
+
+    /// Sets the width of the [`Menu`].
+    pub fn width(mut self, width: f32) -> Self {
+        self.width = width;
+        self
+    }
+
+    /// Sets the [`Padding`] of the [`Menu`].
+    pub fn padding<P: Into<Padding>>(mut self, padding: P) -> Self {
+        self.padding = padding.into();
+        self
+    }
+
+    /// Sets the text size of the [`Menu`].
+    pub fn text_size(mut self, text_size: impl Into<Pixels>) -> Self {
+        self.text_size = Some(text_size.into().0);
+        self
+    }
+
+    /// Sets the font of the [`Menu`].
+    pub fn font(mut self, font: impl Into<Renderer::Font>) -> Self {
+        self.font = Some(font.into());
+        self
+    }
+
+    /// Sets the style of the [`Menu`].
+    pub fn style(
+        mut self,
+        style: impl Into<<Renderer::Theme as StyleSheet>::Style>,
+    ) -> Self {
+        self.style = style.into();
+        self
+    }
+
+    /// Turns the [`Menu`] into an overlay [`Element`] at the given target
+    /// position.
+    ///
+    /// The `target_height` will be used to display the menu either on top
+    /// of the target or under it, depending on the screen position and the
+    /// dimensions of the [`Menu`].
+    pub fn overlay<Message: 'a>(
+        self,
+        position: Point,
+        target_height: f32,
+    ) -> overlay::Element<'a, Message, Renderer> {
+        overlay::Element::new(
+            position,
+            Box::new(Overlay::new(self, target_height)),
+        )
+    }
+}
+
+/// The local state of a [`Menu`].
+#[derive(Debug)]
+pub struct State {
+    tree: Tree,
+}
+
+impl State {
+    /// Creates a new [`State`] for a [`Menu`].
+    pub fn new() -> Self {
+        Self {
+            tree: Tree::empty(),
+        }
+    }
+}
+
+impl Default for State {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+struct Overlay<'a, Message, Renderer>
+where
+    Renderer: crate::core::Renderer,
+    Renderer::Theme: StyleSheet + container::StyleSheet,
+{
+    state: &'a mut Tree,
+    container: Container<'a, Message, Renderer>,
+    width: f32,
+    target_height: f32,
+    style: <Renderer::Theme as StyleSheet>::Style,
+}
+
+impl<'a, Message, Renderer> Overlay<'a, Message, Renderer>
+where
+    Message: 'a,
+    Renderer: 'a,
+    Renderer: text::Renderer,
+    Renderer::Theme:
+        StyleSheet + container::StyleSheet + scrollable::StyleSheet,
+{
+    pub fn new<T>(menu: Menu<'a, T, Renderer>, target_height: f32) -> Self
+    where
+        T: Clone + ToString,
+    {
+        let Menu {
+            state,
+            options,
+            hovered_option,
+            last_selection,
+            width,
+            padding,
+            font,
+            text_size,
+            style,
+        } = menu;
+
+        let container = Container::new(Scrollable::new(List {
+            options,
+            hovered_option,
+            last_selection,
+            font,
+            text_size,
+            padding,
+            style: style.clone(),
+        }));
+
+        state.tree.diff(&container as &dyn Widget<_, _>);
+
+        Self {
+            state: &mut state.tree,
+            container,
+            width,
+            target_height,
+            style,
+        }
+    }
+}
+
+impl<'a, Message, Renderer> crate::core::Overlay<Message, Renderer>
+    for Overlay<'a, Message, Renderer>
+where
+    Renderer: text::Renderer,
+    Renderer::Theme: StyleSheet + container::StyleSheet,
+{
+    fn layout(
+        &self,
+        renderer: &Renderer,
+        bounds: Size,
+        position: Point,
+    ) -> layout::Node {
+        let space_below = bounds.height - (position.y + self.target_height);
+        let space_above = position.y;
+
+        let limits = layout::Limits::new(
+            Size::ZERO,
+            Size::new(
+                bounds.width - position.x,
+                if space_below > space_above {
+                    space_below
+                } else {
+                    space_above
+                },
+            ),
+        )
+        .width(self.width);
+
+        let mut node = self.container.layout(renderer, &limits);
+
+        node.move_to(if space_below > space_above {
+            position + Vector::new(0.0, self.target_height)
+        } else {
+            position - Vector::new(0.0, node.size().height)
+        });
+
+        node
+    }
+
+    fn on_event(
+        &mut self,
+        event: Event,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        renderer: &Renderer,
+        clipboard: &mut dyn Clipboard,
+        shell: &mut Shell<'_, Message>,
+    ) -> event::Status {
+        self.container.on_event(
+            self.state,
+            event,
+            layout,
+            cursor_position,
+            renderer,
+            clipboard,
+            shell,
+        )
+    }
+
+    fn mouse_interaction(
+        &self,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        viewport: &Rectangle,
+        renderer: &Renderer,
+    ) -> mouse::Interaction {
+        self.container.mouse_interaction(
+            self.state,
+            layout,
+            cursor_position,
+            viewport,
+            renderer,
+        )
+    }
+
+    fn draw(
+        &self,
+        renderer: &mut Renderer,
+        theme: &Renderer::Theme,
+        style: &renderer::Style,
+        layout: Layout<'_>,
+        cursor_position: Point,
+    ) {
+        let appearance = theme.appearance(&self.style);
+        let bounds = layout.bounds();
+
+        renderer.fill_quad(
+            renderer::Quad {
+                bounds,
+                border_color: appearance.border_color,
+                border_width: appearance.border_width,
+                border_radius: appearance.border_radius.into(),
+            },
+            appearance.background,
+        );
+
+        self.container.draw(
+            self.state,
+            renderer,
+            theme,
+            style,
+            layout,
+            cursor_position,
+            &bounds,
+        );
+    }
+}
+
+struct List<'a, T, Renderer>
+where
+    Renderer: text::Renderer,
+    Renderer::Theme: StyleSheet,
+{
+    options: &'a [T],
+    hovered_option: &'a mut Option<usize>,
+    last_selection: &'a mut Option<T>,
+    padding: Padding,
+    text_size: Option<f32>,
+    font: Option<Renderer::Font>,
+    style: <Renderer::Theme as StyleSheet>::Style,
+}
+
+impl<'a, T, Message, Renderer> Widget<Message, Renderer>
+    for List<'a, T, Renderer>
+where
+    T: Clone + ToString,
+    Renderer: text::Renderer,
+    Renderer::Theme: StyleSheet,
+{
+    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 text_size =
+            self.text_size.unwrap_or_else(|| renderer.default_size());
+
+        let size = {
+            let intrinsic = Size::new(
+                0.0,
+                (text_size * 1.2 + self.padding.vertical())
+                    * self.options.len() as f32,
+            );
+
+            limits.resolve(intrinsic)
+        };
+
+        layout::Node::new(size)
+    }
+
+    fn on_event(
+        &mut self,
+        _state: &mut Tree,
+        event: Event,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        renderer: &Renderer,
+        _clipboard: &mut dyn Clipboard,
+        _shell: &mut Shell<'_, Message>,
+    ) -> event::Status {
+        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) {
+                            *self.last_selection = Some(option.clone());
+                        }
+                    }
+                }
+            }
+            Event::Mouse(mouse::Event::CursorMoved { .. }) => {
+                let bounds = layout.bounds();
+
+                if bounds.contains(cursor_position) {
+                    let text_size = self
+                        .text_size
+                        .unwrap_or_else(|| renderer.default_size());
+
+                    *self.hovered_option = Some(
+                        ((cursor_position.y - bounds.y)
+                            / (text_size * 1.2 + self.padding.vertical()))
+                            as usize,
+                    );
+                }
+            }
+            Event::Touch(touch::Event::FingerPressed { .. }) => {
+                let bounds = layout.bounds();
+
+                if bounds.contains(cursor_position) {
+                    let text_size = self
+                        .text_size
+                        .unwrap_or_else(|| renderer.default_size());
+
+                    *self.hovered_option = Some(
+                        ((cursor_position.y - bounds.y)
+                            / (text_size * 1.2 + self.padding.vertical()))
+                            as usize,
+                    );
+
+                    if let Some(index) = *self.hovered_option {
+                        if let Some(option) = self.options.get(index) {
+                            *self.last_selection = Some(option.clone());
+                        }
+                    }
+                }
+            }
+            _ => {}
+        }
+
+        event::Status::Ignored
+    }
+
+    fn mouse_interaction(
+        &self,
+        _state: &Tree,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        _viewport: &Rectangle,
+        _renderer: &Renderer,
+    ) -> mouse::Interaction {
+        let is_mouse_over = layout.bounds().contains(cursor_position);
+
+        if is_mouse_over {
+            mouse::Interaction::Pointer
+        } else {
+            mouse::Interaction::default()
+        }
+    }
+
+    fn draw(
+        &self,
+        _state: &Tree,
+        renderer: &mut Renderer,
+        theme: &Renderer::Theme,
+        _style: &renderer::Style,
+        layout: Layout<'_>,
+        _cursor_position: Point,
+        viewport: &Rectangle,
+    ) {
+        let appearance = theme.appearance(&self.style);
+        let bounds = layout.bounds();
+
+        let text_size =
+            self.text_size.unwrap_or_else(|| renderer.default_size());
+        let option_height =
+            (text_size * 1.2 + self.padding.vertical()) as usize;
+
+        let offset = viewport.y - bounds.y;
+        let start = (offset / option_height as f32) as usize;
+        let end =
+            ((offset + viewport.height) / option_height as f32).ceil() as usize;
+
+        let visible_options = &self.options[start..end.min(self.options.len())];
+
+        for (i, option) in visible_options.iter().enumerate() {
+            let i = start + i;
+            let is_selected = *self.hovered_option == Some(i);
+
+            let bounds = Rectangle {
+                x: bounds.x,
+                y: bounds.y + (option_height * i) as f32,
+                width: bounds.width,
+                height: text_size * 1.2 + self.padding.vertical(),
+            };
+
+            if is_selected {
+                renderer.fill_quad(
+                    renderer::Quad {
+                        bounds,
+                        border_color: Color::TRANSPARENT,
+                        border_width: 0.0,
+                        border_radius: appearance.border_radius.into(),
+                    },
+                    appearance.selected_background,
+                );
+            }
+
+            renderer.fill_text(Text {
+                content: &option.to_string(),
+                bounds: Rectangle {
+                    x: bounds.x + self.padding.left,
+                    y: bounds.center_y(),
+                    width: f32::INFINITY,
+                    ..bounds
+                },
+                size: text_size,
+                font: self.font.unwrap_or_else(|| renderer.default_font()),
+                color: if is_selected {
+                    appearance.selected_text_color
+                } else {
+                    appearance.text_color
+                },
+                horizontal_alignment: alignment::Horizontal::Left,
+                vertical_alignment: alignment::Vertical::Center,
+            });
+        }
+    }
+}
+
+impl<'a, T, Message, Renderer> From<List<'a, T, Renderer>>
+    for Element<'a, Message, Renderer>
+where
+    T: ToString + Clone,
+    Message: 'a,
+    Renderer: 'a + text::Renderer,
+    Renderer::Theme: StyleSheet,
+{
+    fn from(list: List<'a, T, Renderer>) -> Self {
+        Element::new(list)
+    }
+}