324 lines
9 KiB
Rust
324 lines
9 KiB
Rust
//! Display an interactive selector of a single value from a range of values.
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//!
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//! A [`Slider`] has some local [`State`].
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//!
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//! [`Slider`]: struct.Slider.html
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//! [`State`]: struct.State.html
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use crate::{
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layout, mouse, Clipboard, Element, Event, Hasher, Layout, Length, Point,
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Rectangle, Size, Widget,
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};
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use std::{hash::Hash, ops::RangeInclusive};
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/// An horizontal bar and a handle that selects a single value from a range of
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/// values.
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///
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/// A [`Slider`] will try to fill the horizontal space of its container.
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///
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/// The [`Slider`] range of numeric values is generic and its step size defaults
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/// to 1 unit.
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///
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/// [`Slider`]: struct.Slider.html
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///
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/// # Example
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/// ```
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/// # use iced_native::{slider, renderer::Null};
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/// #
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/// # pub type Slider<'a, T, Message> = iced_native::Slider<'a, T, Message, Null>;
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/// pub enum Message {
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/// SliderChanged(f32),
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/// }
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///
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/// let state = &mut slider::State::new();
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/// let value = 50.0;
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///
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/// Slider::new(state, 0.0..=100.0, value, Message::SliderChanged);
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/// ```
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///
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/// 
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#[allow(missing_debug_implementations)]
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pub struct Slider<'a, T, Message, Renderer: self::Renderer> {
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state: &'a mut State,
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range: RangeInclusive<T>,
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step: T,
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value: T,
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on_change: Box<dyn Fn(T) -> Message>,
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on_release: Option<Message>,
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width: Length,
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style: Renderer::Style,
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}
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impl<'a, T, Message, Renderer> Slider<'a, T, Message, Renderer>
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where
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T: Copy + From<u8> + std::cmp::PartialOrd,
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Renderer: self::Renderer,
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{
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/// Creates a new [`Slider`].
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///
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/// It expects:
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/// * the local [`State`] of the [`Slider`]
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/// * an inclusive range of possible values
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/// * the current value of the [`Slider`]
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/// * a function that will be called when the [`Slider`] is dragged.
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/// It receives the new value of the [`Slider`] and must produce a
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/// `Message`.
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///
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/// [`Slider`]: struct.Slider.html
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/// [`State`]: struct.State.html
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pub fn new<F>(
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state: &'a mut State,
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range: RangeInclusive<T>,
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value: T,
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on_change: F,
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) -> Self
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where
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F: 'static + Fn(T) -> Message,
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{
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let value = if value >= *range.start() {
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value
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} else {
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*range.start()
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};
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let value = if value <= *range.end() {
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value
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} else {
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*range.end()
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};
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Slider {
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state,
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value,
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range,
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step: T::from(1),
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on_change: Box::new(on_change),
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on_release: None,
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width: Length::Fill,
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style: Renderer::Style::default(),
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}
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}
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/// Sets the release message of the [`Slider`].
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/// This is called when the mouse is released from the slider.
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///
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/// Typically, the user's interaction with the slider is finished when this message is produced.
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/// This is useful if you need to spawn a long-running task from the slider's result, where
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/// the default on_change message could create too many events.
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///
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/// [`Slider`]: struct.Slider.html
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pub fn on_release(mut self, on_release: Message) -> Self {
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self.on_release = Some(on_release);
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self
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}
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/// Sets the width of the [`Slider`].
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///
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/// [`Slider`]: struct.Slider.html
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pub fn width(mut self, width: Length) -> Self {
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self.width = width;
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self
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}
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/// Sets the style of the [`Slider`].
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///
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/// [`Slider`]: struct.Slider.html
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pub fn style(mut self, style: impl Into<Renderer::Style>) -> Self {
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self.style = style.into();
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self
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}
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/// Sets the step size of the [`Slider`].
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///
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/// [`Slider`]: struct.Slider.html
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pub fn step(mut self, step: T) -> Self {
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self.step = step;
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self
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}
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}
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/// The local state of a [`Slider`].
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///
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/// [`Slider`]: struct.Slider.html
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#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
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pub struct State {
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is_dragging: bool,
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}
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impl State {
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/// Creates a new [`State`].
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///
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/// [`State`]: struct.State.html
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pub fn new() -> State {
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State::default()
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}
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}
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impl<'a, T, Message, Renderer> Widget<Message, Renderer>
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for Slider<'a, T, Message, Renderer>
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where
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T: Copy + Into<f64> + num_traits::FromPrimitive,
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Renderer: self::Renderer,
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Message: Clone,
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{
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fn width(&self) -> Length {
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self.width
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}
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fn height(&self) -> Length {
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Length::Shrink
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}
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fn layout(
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&self,
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renderer: &Renderer,
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limits: &layout::Limits,
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) -> layout::Node {
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let limits = limits
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.width(self.width)
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.height(Length::Units(renderer.height() as u16));
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let size = limits.resolve(Size::ZERO);
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layout::Node::new(size)
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}
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fn on_event(
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&mut self,
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event: Event,
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layout: Layout<'_>,
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cursor_position: Point,
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messages: &mut Vec<Message>,
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_renderer: &Renderer,
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_clipboard: Option<&dyn Clipboard>,
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) {
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let mut change = || {
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let bounds = layout.bounds();
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if cursor_position.x <= bounds.x {
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messages.push((self.on_change)(*self.range.start()));
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} else if cursor_position.x >= bounds.x + bounds.width {
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messages.push((self.on_change)(*self.range.end()));
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} else {
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let step = self.step.into();
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let start = (*self.range.start()).into();
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let end = (*self.range.end()).into();
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let percent = f64::from(cursor_position.x - bounds.x)
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/ f64::from(bounds.width);
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let steps = (percent * (end - start) / step).round();
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let value = steps * step + start;
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if let Some(value) = T::from_f64(value) {
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messages.push((self.on_change)(value));
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}
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}
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};
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match event {
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Event::Mouse(mouse_event) => match mouse_event {
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mouse::Event::ButtonPressed(mouse::Button::Left) => {
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if layout.bounds().contains(cursor_position) {
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change();
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self.state.is_dragging = true;
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}
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}
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mouse::Event::ButtonReleased(mouse::Button::Left) => {
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if self.state.is_dragging {
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if let Some(on_release) = self.on_release.clone() {
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messages.push(on_release);
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}
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self.state.is_dragging = false;
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}
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}
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mouse::Event::CursorMoved { .. } => {
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if self.state.is_dragging {
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change();
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}
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}
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_ => {}
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},
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_ => {}
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}
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}
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fn draw(
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&self,
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renderer: &mut Renderer,
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_defaults: &Renderer::Defaults,
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layout: Layout<'_>,
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cursor_position: Point,
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) -> Renderer::Output {
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let start = *self.range.start();
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let end = *self.range.end();
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renderer.draw(
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layout.bounds(),
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cursor_position,
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start.into() as f32..=end.into() as f32,
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self.value.into() as f32,
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self.state.is_dragging,
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&self.style,
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)
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}
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fn hash_layout(&self, state: &mut Hasher) {
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struct Marker;
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std::any::TypeId::of::<Marker>().hash(state);
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self.width.hash(state);
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}
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}
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/// The renderer of a [`Slider`].
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///
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/// Your [renderer] will need to implement this trait before being
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/// able to use a [`Slider`] in your user interface.
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///
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/// [`Slider`]: struct.Slider.html
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/// [renderer]: ../../renderer/index.html
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pub trait Renderer: crate::Renderer {
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/// The style supported by this renderer.
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type Style: Default;
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/// Returns the height of the [`Slider`].
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///
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/// [`Slider`]: struct.Slider.html
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fn height(&self) -> u32;
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/// Draws a [`Slider`].
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///
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/// It receives:
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/// * the current cursor position
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/// * the bounds of the [`Slider`]
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/// * the local state of the [`Slider`]
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/// * the range of values of the [`Slider`]
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/// * the current value of the [`Slider`]
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///
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/// [`Slider`]: struct.Slider.html
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/// [`State`]: struct.State.html
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/// [`Class`]: enum.Class.html
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fn draw(
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&mut self,
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bounds: Rectangle,
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cursor_position: Point,
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range: RangeInclusive<f32>,
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value: f32,
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is_dragging: bool,
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style: &Self::Style,
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) -> Self::Output;
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}
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impl<'a, T, Message, Renderer> From<Slider<'a, T, Message, Renderer>>
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for Element<'a, Message, Renderer>
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where
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T: 'a + Copy + Into<f64> + num_traits::FromPrimitive,
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Renderer: 'a + self::Renderer,
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Message: 'a + Clone,
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{
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fn from(
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slider: Slider<'a, T, Message, Renderer>,
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) -> Element<'a, Message, Renderer> {
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Element::new(slider)
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}
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}
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