iced-widget-kit 0.1.0

use iced_core::{
    Background, Border, Clipboard, Color, Element, Event, Layout, Length, Padding, Rectangle,
    Shadow, Shell, Size, Theme, Vector, Widget,
    layout::{self, Limits, Node},
    mouse::{self, Cursor, Interaction},
    overlay,
    renderer::Quad,
    touch,
    widget::{
        Operation, Tree,
        tree::{self, Tag},
    },
    window,
};

const INDICATOR_HEIGHT: f32 = 2.0;

pub struct Item<'a, Id, Message, Theme = iced_core::Theme, Renderer = iced_widget::Renderer>
where
    Theme: Catalog,
{
    width: Length,
    height: Length,
    pub(super) id: Id,
    content: Element<'a, Message, Theme, Renderer>,
    pub(super) padding: Padding,
    clip: bool,
    pub(super) class: Theme::Class<'a>,
    pub(super) status: Option<Status>,
}

impl<'a, Id, Message, Theme, Renderer> Item<'a, Id, Message, Theme, Renderer>
where
    Theme: Catalog,
{
    /// Creates a new [`Item`] which the provided content.
    pub fn new(id: Id, content: impl Into<Element<'a, Message, Theme, Renderer>>) -> Self {
        Self {
            width: Length::Shrink,
            height: 32.into(),
            id,
            content: content.into(),
            padding: [0.0, 10.0].into(),
            clip: true,
            class: Theme::default(),
            status: None,
        }
    }

    /// Sets the width of the [`SelectorBar`](super::SelectorBar).
    #[must_use]
    pub fn width(mut self, width: impl Into<Length>) -> Self {
        self.width = width.into();
        self
    }

    /// Sets the height of the [`SelectorBar`](super::SelectorBar).
    #[must_use]
    pub fn height(mut self, height: impl Into<Length>) -> Self {
        self.height = height.into();
        self
    }

    /// Sets the spacing between [`Item`]s.
    #[must_use]
    pub fn padding(mut self, padding: impl Into<Padding>) -> Self {
        self.padding = padding.into();
        self
    }

    /// Sets whether the contents of the [`Item`] should be clipped on
    /// overflow.
    #[must_use]
    pub fn clip(mut self, clip: bool) -> Self {
        self.clip = clip;
        self
    }

    pub(crate) fn is_hovered(&self) -> bool {
        self.status
            .is_some_and(|status| matches!(status, Status::Hovered))
    }

    pub(crate) fn is_pressed(&self) -> bool {
        self.status
            .is_some_and(|status| matches!(status, Status::Pressed))
    }
}

#[derive(Debug, Default)]
struct State {
    is_pressed: bool,
}

impl<'a, Id, Message, Theme, Renderer> Widget<Message, Theme, Renderer>
    for Item<'a, Id, Message, Theme, Renderer>
where
    Theme: Catalog,
    Renderer: iced_core::Renderer,
{
    fn tag(&self) -> Tag {
        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> {
        Size::new(self.width, self.height)
    }

    fn layout(&mut self, tree: &mut Tree, renderer: &Renderer, limits: &Limits) -> Node {
        layout::padded(limits, self.width, self.height, self.padding, |limits| {
            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,
    ) {
        operation.container(None, layout.bounds());

        operation.traverse(&mut |operation| {
            self.content.as_widget_mut().operate(
                &mut tree.children[0],
                layout.children().next().unwrap(),
                renderer,
                operation,
            );
        });
    }

    fn update(
        &mut self,
        tree: &mut Tree,
        event: &Event,
        layout: Layout<'_>,
        cursor: Cursor,
        renderer: &Renderer,
        clipboard: &mut dyn Clipboard,
        shell: &mut Shell<'_, Message>,
        viewport: &Rectangle,
    ) {
        self.content.as_widget_mut().update(
            &mut tree.children[0],
            event,
            layout.children().next().unwrap(),
            cursor,
            renderer,
            clipboard,
            shell,
            viewport,
        );

        match event {
            Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left))
            | Event::Touch(touch::Event::FingerPressed { .. }) => {
                if cursor.is_over(layout.bounds()) {
                    let state = tree.state.downcast_mut::<State>();
                    state.is_pressed = true;
                    shell.capture_event();
                }
            }
            Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Left))
            | Event::Touch(touch::Event::FingerLifted { .. }) => {
                let state = tree.state.downcast_mut::<State>();

                if state.is_pressed {
                    state.is_pressed = false;
                    shell.capture_event();
                }
            }
            _ => {}
        }

        let current_status = if cursor.is_over(layout.bounds()) {
            let state = tree.state.downcast_mut::<State>();

            if state.is_pressed {
                Status::Pressed
            } else {
                Status::Hovered
            }
        } else {
            Status::Active
        };

        if let Event::Window(window::Event::RedrawRequested(_)) = event {
            self.status = Some(current_status);
        } else if self.status.is_some_and(|status| status != current_status) {
            shell.request_redraw();
        }
    }

    fn mouse_interaction(
        &self,
        tree: &Tree,
        layout: Layout<'_>,
        cursor: Cursor,
        viewport: &Rectangle,
        renderer: &Renderer,
    ) -> Interaction {
        self.content.as_widget().mouse_interaction(
            &tree.children[0],
            layout.child(0),
            cursor,
            viewport,
            renderer,
        )
    }

    fn draw(
        &self,
        tree: &Tree,
        renderer: &mut Renderer,
        theme: &Theme,
        style: &iced_core::renderer::Style,
        layout: Layout<'_>,
        cursor: Cursor,
        viewport: &Rectangle,
    ) {
        let bounds = if self.clip {
            layout.bounds().intersection(viewport).unwrap_or(*viewport)
        } else {
            *viewport
        };

        let item_style = theme.style(&self.class, self.status.unwrap_or_default());

        // Draw Item background
        renderer.fill_quad(
            Quad {
                bounds,
                border: item_style.border,
                shadow: item_style.shadow,
                snap: item_style.snap,
            },
            item_style.background.unwrap_or(Color::TRANSPARENT.into()),
        );

        // Draw contents
        let child_layout = layout.children().next().unwrap();

        self.content.as_widget().draw(
            &tree.children[0],
            renderer,
            theme,
            style,
            child_layout,
            cursor,
            viewport,
        );

        // Draw pending Indicator. Active Indicator drawn by SelectorBar.
        if let Some(status) = &self.status {
            let style = item_style.pending_indicator;
            let bounds = child_layout.bounds();

            match status {
                Status::Active => {}
                Status::Hovered | Status::Pressed => {
                    renderer.fill_quad(
                        Quad {
                            bounds: Rectangle {
                                x: bounds.x,
                                y: bounds.y + bounds.height - INDICATOR_HEIGHT,
                                width: bounds.width,
                                height: INDICATOR_HEIGHT,
                            },
                            border: style.border,
                            shadow: style.shadow,
                            snap: style.snap,
                        },
                        style.background.unwrap_or(Color::TRANSPARENT.into()),
                    );
                }
            }
        }
    }

    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.child(0),
            renderer,
            viewport,
            translation,
        )
    }
}

#[derive(Clone, Copy, Debug, Default, PartialEq)]
pub enum Status {
    #[default]
    Active,
    Hovered,
    Pressed,
}

#[derive(Debug)]
pub struct Style {
    pub background: Option<Background>,
    pub border: Border,
    pub shadow: Shadow,
    pub snap: bool,
    pub active_indicator: Indicator,
    pub pending_indicator: Indicator,
}

#[derive(Debug)]
pub struct Indicator {
    pub background: Option<Background>,
    pub border: Border,
    pub shadow: Shadow,
    pub snap: bool,
}

pub trait Catalog {
    type Class<'a>;

    fn default<'a>() -> Self::Class<'a>;
    fn style(&self, class: &Self::Class<'_>, status: Status) -> Style;
}

pub type StyleFn<'a, Theme> = Box<dyn Fn(&Theme, Status) -> Style + 'a>;

impl Catalog for Theme {
    type Class<'a> = StyleFn<'a, Self>;

    fn default<'a>() -> Self::Class<'a> {
        Box::new(default)
    }

    fn style(&self, class: &Self::Class<'_>, status: Status) -> Style {
        class(self, status)
    }
}

pub fn default(theme: &Theme, status: Status) -> Style {
    let palette = theme.extended_palette();

    let active_color = match status {
        Status::Active => palette.primary.base.color,
        Status::Hovered => palette.primary.base.color,
        Status::Pressed => palette.primary.weak.color,
    };

    let pending_color = match status {
        Status::Active => palette.secondary.base.color,
        Status::Hovered => palette.secondary.base.color,
        Status::Pressed => palette.secondary.weak.color,
    };

    let border = Border::default();

    Style {
        background: Some(palette.background.base.color.into()),
        border,
        shadow: Shadow::default(),
        snap: true,
        active_indicator: Indicator {
            background: Some(active_color.into()),
            border,
            shadow: Shadow::default(),
            snap: true,
        },
        pending_indicator: Indicator {
            background: Some(pending_color.into()),
            border,
            shadow: Shadow::default(),
            snap: true,
        },
    }
}