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Diffstat (limited to '')
| -rw-r--r-- | src/widget/button.rs | 281 |
1 files changed, 281 insertions, 0 deletions
diff --git a/src/widget/button.rs b/src/widget/button.rs new file mode 100644 index 00000000..35fa6ca8 --- /dev/null +++ b/src/widget/button.rs @@ -0,0 +1,281 @@ +//! Allow your users to perform actions by pressing a button. +//! +//! A [`Button`] has some local [`State`] and a [`Class`]. +//! +//! [`Button`]: struct.Button.html +//! [`State`]: struct.State.html +//! [`Class`]: enum.Class.html + +use crate::input::{mouse, ButtonState}; +use crate::{ + Align, Element, Event, Hasher, Layout, MouseCursor, Node, Point, Rectangle, + Style, Widget, +}; + +use std::hash::Hash; + +/// A generic widget that produces a message when clicked. +/// +/// It implements [`Widget`] when the associated [`core::Renderer`] implements +/// the [`button::Renderer`] trait. +/// +/// [`Widget`]: ../../core/trait.Widget.html +/// [`core::Renderer`]: ../../core/trait.Renderer.html +/// [`button::Renderer`]: trait.Renderer.html +/// +/// # Example +/// +/// ``` +/// use iced::{button, Button}; +/// +/// pub enum Message { +/// ButtonClicked, +/// } +/// +/// let state = &mut button::State::new(); +/// +/// Button::new(state, "Click me!") +/// .on_press(Message::ButtonClicked); +/// ``` +pub struct Button<'a, Message> { + state: &'a mut State, + label: String, + class: Class, + on_press: Option<Message>, + style: Style, +} + +impl<'a, Message> std::fmt::Debug for Button<'a, Message> +where + Message: std::fmt::Debug, +{ + fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result { + f.debug_struct("Button") + .field("state", &self.state) + .field("label", &self.label) + .field("class", &self.class) + .field("on_press", &self.on_press) + .field("style", &self.style) + .finish() + } +} + +impl<'a, Message> Button<'a, Message> { + /// Creates a new [`Button`] with some local [`State`] and the given label. + /// + /// The default [`Class`] of a new [`Button`] is [`Class::Primary`]. + /// + /// [`Button`]: struct.Button.html + /// [`State`]: struct.State.html + /// [`Class`]: enum.Class.html + /// [`Class::Primary`]: enum.Class.html#variant.Primary + pub fn new(state: &'a mut State, label: &str) -> Self { + Button { + state, + label: String::from(label), + class: Class::Primary, + on_press: None, + style: Style::default().min_width(100), + } + } + + /// Sets the width of the [`Button`] in pixels. + /// + /// [`Button`]: struct.Button.html + pub fn width(mut self, width: u32) -> Self { + self.style = self.style.width(width); + self + } + + /// Makes the [`Button`] fill the horizontal space of its container. + /// + /// [`Button`]: struct.Button.html + pub fn fill_width(mut self) -> Self { + self.style = self.style.fill_width(); + self + } + + /// Sets the alignment of the [`Button`] itself. + /// + /// This is useful if you want to override the default alignment given by + /// the parent container. + /// + /// [`Button`]: struct.Button.html + pub fn align_self(mut self, align: Align) -> Self { + self.style = self.style.align_self(align); + self + } + + /// Sets the [`Class`] of the [`Button`]. + /// + /// + /// [`Button`]: struct.Button.html + /// [`Class`]: enum.Class.html + pub fn class(mut self, class: Class) -> Self { + self.class = class; + self + } + + /// Sets the message that will be produced when the [`Button`] is pressed. + /// + /// [`Button`]: struct.Button.html + pub fn on_press(mut self, msg: Message) -> Self { + self.on_press = Some(msg); + self + } +} + +impl<'a, Message, Renderer> Widget<Message, Renderer> for Button<'a, Message> +where + Renderer: self::Renderer, + Message: Copy + std::fmt::Debug, +{ + fn node(&self, _renderer: &Renderer) -> Node { + Node::new(self.style.height(50)) + } + + 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, + }) => { + if let Some(on_press) = self.on_press { + let bounds = layout.bounds(); + + match state { + ButtonState::Pressed => { + self.state.is_pressed = + bounds.contains(cursor_position); + } + ButtonState::Released => { + let is_clicked = self.state.is_pressed + && bounds.contains(cursor_position); + + self.state.is_pressed = false; + + if is_clicked { + messages.push(on_press); + } + } + } + } + } + _ => {} + } + } + + fn draw( + &self, + renderer: &mut Renderer, + layout: Layout<'_>, + cursor_position: Point, + ) -> MouseCursor { + renderer.draw( + cursor_position, + layout.bounds(), + self.state, + &self.label, + self.class, + ) + } + + fn hash(&self, state: &mut Hasher) { + self.style.hash(state); + } +} + +/// The local state of a [`Button`]. +/// +/// [`Button`]: struct.Button.html +#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)] +pub struct State { + is_pressed: bool, +} + +impl State { + /// Creates a new [`State`]. + /// + /// [`State`]: struct.State.html + pub fn new() -> State { + State::default() + } + + /// Returns whether the associated [`Button`] is currently being pressed or + /// not. + /// + /// [`Button`]: struct.Button.html + pub fn is_pressed(&self) -> bool { + self.is_pressed + } +} + +/// The type of a [`Button`]. +/// +///  +/// +/// [`Button`]: struct.Button.html +#[derive(Debug, Clone, Copy, PartialEq, Eq)] +pub enum Class { + /// The [`Button`] performs the main action. + /// + /// [`Button`]: struct.Button.html + Primary, + + /// The [`Button`] performs an alternative action. + /// + /// [`Button`]: struct.Button.html + Secondary, + + /// The [`Button`] performs a productive action. + /// + /// [`Button`]: struct.Button.html + Positive, +} + +/// The renderer of a [`Button`]. +/// +/// Your [`core::Renderer`] will need to implement this trait before being +/// able to use a [`Button`] in your user interface. +/// +/// [`Button`]: struct.Button.html +/// [`core::Renderer`]: ../../core/trait.Renderer.html +pub trait Renderer { + /// Draws a [`Button`]. + /// + /// It receives: + /// * the current cursor position + /// * the bounds of the [`Button`] + /// * the local state of the [`Button`] + /// * the label of the [`Button`] + /// * the [`Class`] of the [`Button`] + /// + /// [`Button`]: struct.Button.html + /// [`State`]: struct.State.html + /// [`Class`]: enum.Class.html + fn draw( + &mut self, + cursor_position: Point, + bounds: Rectangle<f32>, + state: &State, + label: &str, + class: Class, + ) -> MouseCursor; +} + +impl<'a, Message, Renderer> From<Button<'a, Message>> + for Element<'a, Message, Renderer> +where + Renderer: self::Renderer, + Message: 'static + Copy + std::fmt::Debug, +{ + fn from(button: Button<'a, Message>) -> Element<'a, Message, Renderer> { + Element::new(button) + } +} |