Decouple iced from coffee

src/widget/radio.rs

@@ -0,0 +1,219 @@
+//! Create choices using radio buttons.
+use crate::input::{mouse, ButtonState};
+use crate::widget::{text, Column, Row, Text};
+use crate::{
+    Align, Element, Event, Hasher, Layout, MouseCursor, Node, Point, Rectangle,
+    Widget,
+};
+
+use std::hash::Hash;
+
+/// A circular button representing a choice.
+///
+/// It implements [`Widget`] when the [`core::Renderer`] implements the
+/// [`radio::Renderer`] trait.
+///
+/// [`Widget`]: ../../core/trait.Widget.html
+/// [`core::Renderer`]: ../../core/trait.Renderer.html
+/// [`radio::Renderer`]: trait.Renderer.html
+///
+/// # Example
+/// ```
+/// use iced::{Column, Radio};
+///
+/// #[derive(Debug, Clone, Copy)]
+/// pub enum Color {
+///     Black,
+/// }
+///
+/// impl Default for Color {
+///     fn default() -> Color {
+///         Color::Black
+///     }
+/// }
+///
+/// #[derive(Debug, Clone, Copy, PartialEq, Eq)]
+/// pub enum Choice {
+///     A,
+///     B,
+/// }
+///
+/// #[derive(Debug, Clone, Copy)]
+/// pub enum Message {
+///     RadioSelected(Choice),
+/// }
+///
+/// let selected_choice = Some(Choice::A);
+///
+/// Radio::<Color, Message>::new(Choice::A, "This is A", selected_choice, Message::RadioSelected)
+///     .label_color(Color::Black);
+/// ```
+///
+/// ![Checkbox drawn by the built-in renderer](https://github.com/hecrj/coffee/blob/bda9818f823dfcb8a7ad0ff4940b4d4b387b5208/images/ui/radio.png?raw=true)
+pub struct Radio<Color, Message> {
+    is_selected: bool,
+    on_click: Message,
+    label: String,
+    label_color: Color,
+}
+
+impl<Color, Message> std::fmt::Debug for Radio<Color, Message>
+where
+    Color: std::fmt::Debug,
+    Message: std::fmt::Debug,
+{
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.debug_struct("Radio")
+            .field("is_selected", &self.is_selected)
+            .field("on_click", &self.on_click)
+            .field("label", &self.label)
+            .field("label_color", &self.label_color)
+            .finish()
+    }
+}
+
+impl<Color, Message> Radio<Color, Message>
+where
+    Color: Default,
+{
+    /// Creates a new [`Radio`] button.
+    ///
+    /// It expects:
+    ///   * the value related to the [`Radio`] button
+    ///   * the label of the [`Radio`] button
+    ///   * the current selected value
+    ///   * a function that will be called when the [`Radio`] is selected. It
+    ///   receives the value of the radio and must produce a `Message`.
+    ///
+    /// [`Radio`]: struct.Radio.html
+    pub fn new<F, V>(value: V, label: &str, selected: Option<V>, f: F) -> Self
+    where
+        V: Eq + Copy,
+        F: 'static + Fn(V) -> Message,
+    {
+        Radio {
+            is_selected: Some(value) == selected,
+            on_click: f(value),
+            label: String::from(label),
+            label_color: Color::default(),
+        }
+    }
+
+    /// Sets the [`Color`] of the label of the [`Radio`].
+    ///
+    /// [`Color`]: ../../../../graphics/struct.Color.html
+    /// [`Radio`]: struct.Radio.html
+    pub fn label_color(mut self, color: Color) -> Self {
+        self.label_color = color;
+        self
+    }
+}
+
+impl<Color, Message, Renderer> Widget<Message, Renderer>
+    for Radio<Color, Message>
+where
+    Color: 'static + Copy + Default + std::fmt::Debug,
+    Renderer: self::Renderer + text::Renderer<Color>,
+    Message: Copy + std::fmt::Debug,
+{
+    fn node(&self, renderer: &Renderer) -> Node {
+        Row::<(), Renderer>::new()
+            .spacing(15)
+            .align_items(Align::Center)
+            .push(Column::new().width(28).height(28))
+            .push(Text::new(&self.label))
+            .node(renderer)
+    }
+
+    fn on_event(
+        &mut self,
+        event: Event,
+        layout: Layout<'_>,
+        cursor_position: Point,
+        messages: &mut Vec<Message>,
+    ) {
+        match event {
+            Event::Mouse(mouse::Event::Input {
+                button: mouse::Button::Left,
+                state: ButtonState::Pressed,
+            }) => {
+                if layout.bounds().contains(cursor_position) {
+                    messages.push(self.on_click);
+                }
+            }
+            _ => {}
+        }
+    }
+
+    fn draw(
+        &self,
+        renderer: &mut Renderer,
+        layout: Layout<'_>,
+        cursor_position: Point,
+    ) -> MouseCursor {
+        let children: Vec<_> = layout.children().collect();
+
+        let mut text_bounds = children[1].bounds();
+        text_bounds.y -= 2.0;
+
+        text::Renderer::draw(
+            renderer,
+            text_bounds,
+            &self.label,
+            20.0,
+            self.label_color,
+            text::HorizontalAlignment::Left,
+            text::VerticalAlignment::Top,
+        );
+
+        self::Renderer::draw(
+            renderer,
+            cursor_position,
+            children[0].bounds(),
+            layout.bounds(),
+            self.is_selected,
+        )
+    }
+
+    fn hash(&self, state: &mut Hasher) {
+        self.label.hash(state);
+    }
+}
+
+/// The renderer of a [`Radio`] button.
+///
+/// Your [`core::Renderer`] will need to implement this trait before being
+/// able to use a [`Radio`] button in your user interface.
+///
+/// [`Radio`]: struct.Radio.html
+/// [`core::Renderer`]: ../../core/trait.Renderer.html
+pub trait Renderer {
+    /// Draws a [`Radio`] button.
+    ///
+    /// It receives:
+    ///   * the current cursor position
+    ///   * the bounds of the [`Radio`]
+    ///   * the bounds of the label of the [`Radio`]
+    ///   * whether the [`Radio`] is selected or not
+    ///
+    /// [`Radio`]: struct.Radio.html
+    fn draw(
+        &mut self,
+        cursor_position: Point,
+        bounds: Rectangle<f32>,
+        label_bounds: Rectangle<f32>,
+        is_selected: bool,
+    ) -> MouseCursor;
+}
+
+impl<'a, Color, Message, Renderer> From<Radio<Color, Message>>
+    for Element<'a, Message, Renderer>
+where
+    Color: 'static + Copy + Default + std::fmt::Debug,
+    Renderer: self::Renderer + text::Renderer<Color>,
+    Message: 'static + Copy + std::fmt::Debug,
+{
+    fn from(checkbox: Radio<Color, Message>) -> Element<'a, Message, Renderer> {
+        Element::new(checkbox)
+    }
+}