Implement `Toggler` widget for iced_native

1 files changed, 262 insertions, 0 deletions

diff --git a/native/src/widget/toggler.rs b/native/src/widget/toggler.rs
new file mode 100644
index 00000000..250abac4
--- /dev/null
+++ b/native/src/widget/toggler.rs
@@ -0,0 +1,262 @@
+//! Show toggle controls using togglers.
+use std::hash::Hash;
+
+use crate::{
+    event, layout, mouse, row, text, Align, Clipboard, Element, Event, Hasher,
+    HorizontalAlignment, Layout, Length, Point, Rectangle, Row, Text,
+    VerticalAlignment, Widget,
+};
+
+/// A toggler widget
+///
+/// # Example
+///
+/// ```
+/// # type Toggler<Message> = iced_native::Toggler<Message, iced_native::renderer::Null>;
+/// #
+/// pub enum Message {
+///     TogglerToggled(bool),
+/// }
+///
+/// let is_active = true;
+///
+/// Toggler::new(is_active, "Toggle me!", |b| Message::TogglerToggled(b))
+/// ```
+///
+#[allow(missing_debug_implementations)]
+pub struct Toggler<Message, Renderer: self::Renderer + text::Renderer> {
+    is_active: bool,
+    on_toggle: Box<dyn Fn(bool) -> Message>,
+    label: String,
+    width: Length,
+    size: u16,
+    text_size: Option<u16>,
+    font: Renderer::Font,
+    style: Renderer::Style,
+}
+
+impl<Message, Renderer: self::Renderer + text::Renderer>
+    Toggler<Message, Renderer>
+{
+    /// Creates a new [`Toggler`].
+    ///
+    /// It expects:
+    ///   * a boolean describing whether the [`Toggler`] is checked or not
+    ///   * the label of the [`Toggler`]
+    ///   * a function that will be called when the [`Toggler`] is toggled. It
+    ///     will receive the new state of the [`Toggler`] and must produce a
+    ///     `Message`.
+    ///
+    /// [`Toggler`]: struct.Toggler.html
+    pub fn new<F>(is_active: bool, label: impl Into<String>, f: F) -> Self
+    where
+        F: 'static + Fn(bool) -> Message,
+    {
+        Toggler {
+            is_active,
+            on_toggle: Box::new(f),
+            label: label.into(),
+            width: Length::Fill,
+            size: <Renderer as self::Renderer>::DEFAULT_SIZE,
+            text_size: None,
+            font: Renderer::Font::default(),
+            style: Renderer::Style::default(),
+        }
+    }
+
+    /// Sets the size of the [`Toggler`].
+    ///
+    /// [`Toggler`]: struct.Toggler.html
+    pub fn size(mut self, size: u16) -> Self {
+        self.size = size;
+        self
+    }
+
+    /// Sets the width of the [`Toggler`].
+    ///
+    /// [`Toggler`]: struct.Toggler.html
+    pub fn width(mut self, width: Length) -> Self {
+        self.width = width;
+        self
+    }
+
+    /// Sets the text size o the [`Toggler`].
+    ///
+    /// [`Toggler`]: struct.Toggler.html
+    pub fn text_size(mut self, text_size: u16) -> Self {
+        self.text_size = Some(text_size);
+        self
+    }
+
+    /// Sets the [`Font`] of the text of the [`Toggler`]
+    ///
+    /// [`Toggler`]: struct.Toggler.html
+    /// [`Font`]: ../../struct.Font.html
+    pub fn font(mut self, font: Renderer::Font) -> Self {
+        self.font = font;
+        self
+    }
+
+    /// Sets the style of the [`Toggler`].
+    ///
+    /// [`Toggler`]: struct.Toggler.html
+    pub fn style(mut self, style: impl Into<Renderer::Style>) -> Self {
+        self.style = style.into();
+        self
+    }
+}
+
+impl<Message, Renderer> Widget<Message, Renderer> for Toggler<Message, Renderer>
+where
+    Renderer: self::Renderer + text::Renderer + row::Renderer,
+{
+    fn width(&self) -> Length {
+        self.width
+    }
+
+    fn height(&self) -> Length {
+        Length::Shrink
+    }
+
+    fn layout(
+        &self,
+        renderer: &Renderer,
+        limits: &layout::Limits,
+    ) -> layout::Node {
+        Row::<(), Renderer>::new()
+            .width(self.width)
+            .align_items(Align::Center)
+            .push(
+                Text::new(&self.label)
+                    .font(self.font)
+                    .width(self.width)
+                    .size(self.text_size.unwrap_or(renderer.default_size())),
+            )
+            .push(
+                Row::new()
+                    .width(Length::Units(2 * self.size))
+                    .height(Length::Units(self.size)),
+            )
+            .layout(renderer, limits)
+    }
+
+    fn on_event(
+        &mut self,
+        event: Event,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        _renderer: &Renderer,
+        _clipboard: &mut dyn Clipboard,
+        messages: &mut Vec<Message>,
+    ) -> event::Status {
+        match event {
+            Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left)) => {
+                let mouse_over = layout.bounds().contains(cursor_position);
+
+                if mouse_over {
+                    messages.push((self.on_toggle)(!self.is_active));
+
+                    event::Status::Captured
+                } else {
+                    event::Status::Ignored
+                }
+            }
+            _ => event::Status::Ignored,
+        }
+    }
+
+    fn draw(
+        &self,
+        renderer: &mut Renderer,
+        defaults: &Renderer::Defaults,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        _viewport: &Rectangle,
+    ) -> Renderer::Output {
+        let bounds = layout.bounds();
+        let mut children = layout.children();
+
+        let label_layout = children.next().unwrap();
+        let toggler_layout = children.next().unwrap();
+        let toggler_bounds = toggler_layout.bounds();
+
+        let label = text::Renderer::draw(
+            renderer,
+            defaults,
+            label_layout.bounds(),
+            &self.label,
+            self.text_size.unwrap_or(renderer.default_size()),
+            self.font,
+            None,
+            HorizontalAlignment::Left,
+            VerticalAlignment::Center,
+        );
+
+        let is_mouse_over = bounds.contains(cursor_position);
+
+        self::Renderer::draw(
+            renderer,
+            toggler_bounds,
+            self.is_active,
+            is_mouse_over,
+            label,
+            &self.style,
+        )
+    }
+
+    fn hash_layout(&self, state: &mut Hasher) {
+        struct Marker;
+        std::any::TypeId::of::<Marker>().hash(state);
+
+        self.label.hash(state)
+    }
+}
+
+/// The renderer of a [`Toggler`].
+///
+/// Your [renderer] will need to implement this trait before being
+/// able to use a [`Toggler`] in your user interface.
+///
+/// [`Toggler`]: struct.Toggler.html
+/// [renderer]: ../../renderer/index.html
+pub trait Renderer: crate::Renderer {
+    /// The style supported by this renderer.
+    type Style: Default;
+
+    /// The default size of a [`Toggler`].
+    ///
+    /// [`Toggler`]: struct.Toggler.html
+    const DEFAULT_SIZE: u16;
+
+    /// Draws a [`Toggler`].
+    ///
+    /// It receives:
+    ///   * the bounds of the [`Toggler`]
+    ///   * whether the [`Toggler`] is activated or not
+    ///   * whether the mouse is over the [`Toggler`] or not
+    ///   * the drawn label of the [`Toggler`]
+    ///   * the style of the [`Toggler`]
+    ///
+    /// [`Toggler`]: struct.Toggler.html
+    fn draw(
+        &mut self,
+        bounds: Rectangle,
+        is_active: bool,
+        is_mouse_over: bool,
+        label: Self::Output,
+        style: &Self::Style,
+    ) -> Self::Output;
+}
+
+impl<'a, Message, Renderer> From<Toggler<Message, Renderer>>
+    for Element<'a, Message, Renderer>
+where
+    Renderer: 'a + self::Renderer + text::Renderer + row::Renderer,
+    Message: 'a,
+{
+    fn from(
+        toggler: Toggler<Message, Renderer>,
+    ) -> Element<'a, Message, Renderer> {
+        Element::new(toggler)
+    }
+}