iced_widget/
toggler.rs

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1//! Togglers let users make binary choices by toggling a switch.
2//!
3//! # Example
4//! ```no_run
5//! # mod iced { pub mod widget { pub use iced_widget::*; } pub use iced_widget::Renderer; pub use iced_widget::core::*; }
6//! # pub type Element<'a, Message> = iced_widget::core::Element<'a, Message, iced_widget::Theme, iced_widget::Renderer>;
7//! #
8//! use iced::widget::toggler;
9//!
10//! struct State {
11//!    is_checked: bool,
12//! }
13//!
14//! enum Message {
15//!     TogglerToggled(bool),
16//! }
17//!
18//! fn view(state: &State) -> Element<'_, Message> {
19//!     toggler(state.is_checked)
20//!         .label("Toggle me!")
21//!         .on_toggle(Message::TogglerToggled)
22//!         .into()
23//! }
24//!
25//! fn update(state: &mut State, message: Message) {
26//!     match message {
27//!         Message::TogglerToggled(is_checked) => {
28//!             state.is_checked = is_checked;
29//!         }
30//!     }
31//! }
32//! ```
33use crate::core::alignment;
34use crate::core::layout;
35use crate::core::mouse;
36use crate::core::renderer;
37use crate::core::text;
38use crate::core::touch;
39use crate::core::widget;
40use crate::core::widget::tree::{self, Tree};
41use crate::core::window;
42use crate::core::{
43    Border, Clipboard, Color, Element, Event, Layout, Length, Pixels,
44    Rectangle, Shell, Size, Theme, Widget,
45};
46
47/// A toggler widget.
48///
49/// # Example
50/// ```no_run
51/// # mod iced { pub mod widget { pub use iced_widget::*; } pub use iced_widget::Renderer; pub use iced_widget::core::*; }
52/// # pub type Element<'a, Message> = iced_widget::core::Element<'a, Message, iced_widget::Theme, iced_widget::Renderer>;
53/// #
54/// use iced::widget::toggler;
55///
56/// struct State {
57///    is_checked: bool,
58/// }
59///
60/// enum Message {
61///     TogglerToggled(bool),
62/// }
63///
64/// fn view(state: &State) -> Element<'_, Message> {
65///     toggler(state.is_checked)
66///         .label("Toggle me!")
67///         .on_toggle(Message::TogglerToggled)
68///         .into()
69/// }
70///
71/// fn update(state: &mut State, message: Message) {
72///     match message {
73///         Message::TogglerToggled(is_checked) => {
74///             state.is_checked = is_checked;
75///         }
76///     }
77/// }
78/// ```
79#[allow(missing_debug_implementations)]
80pub struct Toggler<
81    'a,
82    Message,
83    Theme = crate::Theme,
84    Renderer = crate::Renderer,
85> where
86    Theme: Catalog,
87    Renderer: text::Renderer,
88{
89    is_toggled: bool,
90    on_toggle: Option<Box<dyn Fn(bool) -> Message + 'a>>,
91    label: Option<text::Fragment<'a>>,
92    width: Length,
93    size: f32,
94    text_size: Option<Pixels>,
95    text_line_height: text::LineHeight,
96    text_alignment: text::Alignment,
97    text_shaping: text::Shaping,
98    text_wrapping: text::Wrapping,
99    spacing: f32,
100    font: Option<Renderer::Font>,
101    class: Theme::Class<'a>,
102    last_status: Option<Status>,
103}
104
105impl<'a, Message, Theme, Renderer> Toggler<'a, Message, Theme, Renderer>
106where
107    Theme: Catalog,
108    Renderer: text::Renderer,
109{
110    /// The default size of a [`Toggler`].
111    pub const DEFAULT_SIZE: f32 = 16.0;
112
113    /// Creates a new [`Toggler`].
114    ///
115    /// It expects:
116    ///   * a boolean describing whether the [`Toggler`] is checked or not
117    ///   * An optional label for the [`Toggler`]
118    ///   * a function that will be called when the [`Toggler`] is toggled. It
119    ///     will receive the new state of the [`Toggler`] and must produce a
120    ///     `Message`.
121    pub fn new(is_toggled: bool) -> Self {
122        Toggler {
123            is_toggled,
124            on_toggle: None,
125            label: None,
126            width: Length::Shrink,
127            size: Self::DEFAULT_SIZE,
128            text_size: None,
129            text_line_height: text::LineHeight::default(),
130            text_alignment: text::Alignment::Default,
131            text_shaping: text::Shaping::default(),
132            text_wrapping: text::Wrapping::default(),
133            spacing: Self::DEFAULT_SIZE / 2.0,
134            font: None,
135            class: Theme::default(),
136            last_status: None,
137        }
138    }
139
140    /// Sets the label of the [`Toggler`].
141    pub fn label(mut self, label: impl text::IntoFragment<'a>) -> Self {
142        self.label = Some(label.into_fragment());
143        self
144    }
145
146    /// Sets the message that should be produced when a user toggles
147    /// the [`Toggler`].
148    ///
149    /// If this method is not called, the [`Toggler`] will be disabled.
150    pub fn on_toggle(
151        mut self,
152        on_toggle: impl Fn(bool) -> Message + 'a,
153    ) -> Self {
154        self.on_toggle = Some(Box::new(on_toggle));
155        self
156    }
157
158    /// Sets the message that should be produced when a user toggles
159    /// the [`Toggler`], if `Some`.
160    ///
161    /// If `None`, the [`Toggler`] will be disabled.
162    pub fn on_toggle_maybe(
163        mut self,
164        on_toggle: Option<impl Fn(bool) -> Message + 'a>,
165    ) -> Self {
166        self.on_toggle = on_toggle.map(|on_toggle| Box::new(on_toggle) as _);
167        self
168    }
169
170    /// Sets the size of the [`Toggler`].
171    pub fn size(mut self, size: impl Into<Pixels>) -> Self {
172        self.size = size.into().0;
173        self
174    }
175
176    /// Sets the width of the [`Toggler`].
177    pub fn width(mut self, width: impl Into<Length>) -> Self {
178        self.width = width.into();
179        self
180    }
181
182    /// Sets the text size o the [`Toggler`].
183    pub fn text_size(mut self, text_size: impl Into<Pixels>) -> Self {
184        self.text_size = Some(text_size.into());
185        self
186    }
187
188    /// Sets the text [`text::LineHeight`] of the [`Toggler`].
189    pub fn text_line_height(
190        mut self,
191        line_height: impl Into<text::LineHeight>,
192    ) -> Self {
193        self.text_line_height = line_height.into();
194        self
195    }
196
197    /// Sets the horizontal alignment of the text of the [`Toggler`]
198    pub fn text_alignment(
199        mut self,
200        alignment: impl Into<text::Alignment>,
201    ) -> Self {
202        self.text_alignment = alignment.into();
203        self
204    }
205
206    /// Sets the [`text::Shaping`] strategy of the [`Toggler`].
207    pub fn text_shaping(mut self, shaping: text::Shaping) -> Self {
208        self.text_shaping = shaping;
209        self
210    }
211
212    /// Sets the [`text::Wrapping`] strategy of the [`Toggler`].
213    pub fn text_wrapping(mut self, wrapping: text::Wrapping) -> Self {
214        self.text_wrapping = wrapping;
215        self
216    }
217
218    /// Sets the spacing between the [`Toggler`] and the text.
219    pub fn spacing(mut self, spacing: impl Into<Pixels>) -> Self {
220        self.spacing = spacing.into().0;
221        self
222    }
223
224    /// Sets the [`Renderer::Font`] of the text of the [`Toggler`]
225    ///
226    /// [`Renderer::Font`]: crate::core::text::Renderer
227    pub fn font(mut self, font: impl Into<Renderer::Font>) -> Self {
228        self.font = Some(font.into());
229        self
230    }
231
232    /// Sets the style of the [`Toggler`].
233    #[must_use]
234    pub fn style(mut self, style: impl Fn(&Theme, Status) -> Style + 'a) -> Self
235    where
236        Theme::Class<'a>: From<StyleFn<'a, Theme>>,
237    {
238        self.class = (Box::new(style) as StyleFn<'a, Theme>).into();
239        self
240    }
241
242    /// Sets the style class of the [`Toggler`].
243    #[cfg(feature = "advanced")]
244    #[must_use]
245    pub fn class(mut self, class: impl Into<Theme::Class<'a>>) -> Self {
246        self.class = class.into();
247        self
248    }
249}
250
251impl<Message, Theme, Renderer> Widget<Message, Theme, Renderer>
252    for Toggler<'_, Message, Theme, Renderer>
253where
254    Theme: Catalog,
255    Renderer: text::Renderer,
256{
257    fn tag(&self) -> tree::Tag {
258        tree::Tag::of::<widget::text::State<Renderer::Paragraph>>()
259    }
260
261    fn state(&self) -> tree::State {
262        tree::State::new(widget::text::State::<Renderer::Paragraph>::default())
263    }
264
265    fn size(&self) -> Size<Length> {
266        Size {
267            width: self.width,
268            height: Length::Shrink,
269        }
270    }
271
272    fn layout(
273        &self,
274        tree: &mut Tree,
275        renderer: &Renderer,
276        limits: &layout::Limits,
277    ) -> layout::Node {
278        let limits = limits.width(self.width);
279
280        layout::next_to_each_other(
281            &limits,
282            if self.label.is_some() {
283                self.spacing
284            } else {
285                0.0
286            },
287            |_| layout::Node::new(Size::new(2.0 * self.size, self.size)),
288            |limits| {
289                if let Some(label) = self.label.as_deref() {
290                    let state = tree
291                    .state
292                    .downcast_mut::<widget::text::State<Renderer::Paragraph>>();
293
294                    widget::text::layout(
295                        state,
296                        renderer,
297                        limits,
298                        label,
299                        widget::text::Format {
300                            width: self.width,
301                            height: Length::Shrink,
302                            line_height: self.text_line_height,
303                            size: self.text_size,
304                            font: self.font,
305                            align_x: self.text_alignment,
306                            align_y: alignment::Vertical::Top,
307                            shaping: self.text_shaping,
308                            wrapping: self.text_wrapping,
309                        },
310                    )
311                } else {
312                    layout::Node::new(Size::ZERO)
313                }
314            },
315        )
316    }
317
318    fn update(
319        &mut self,
320        _state: &mut Tree,
321        event: &Event,
322        layout: Layout<'_>,
323        cursor: mouse::Cursor,
324        _renderer: &Renderer,
325        _clipboard: &mut dyn Clipboard,
326        shell: &mut Shell<'_, Message>,
327        _viewport: &Rectangle,
328    ) {
329        let Some(on_toggle) = &self.on_toggle else {
330            return;
331        };
332
333        match event {
334            Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left))
335            | Event::Touch(touch::Event::FingerPressed { .. }) => {
336                let mouse_over = cursor.is_over(layout.bounds());
337
338                if mouse_over {
339                    shell.publish(on_toggle(!self.is_toggled));
340                    shell.capture_event();
341                }
342            }
343            _ => {}
344        }
345
346        let current_status = if self.on_toggle.is_none() {
347            Status::Disabled
348        } else if cursor.is_over(layout.bounds()) {
349            Status::Hovered {
350                is_toggled: self.is_toggled,
351            }
352        } else {
353            Status::Active {
354                is_toggled: self.is_toggled,
355            }
356        };
357
358        if let Event::Window(window::Event::RedrawRequested(_now)) = event {
359            self.last_status = Some(current_status);
360        } else if self
361            .last_status
362            .is_some_and(|status| status != current_status)
363        {
364            shell.request_redraw();
365        }
366    }
367
368    fn mouse_interaction(
369        &self,
370        _state: &Tree,
371        layout: Layout<'_>,
372        cursor: mouse::Cursor,
373        _viewport: &Rectangle,
374        _renderer: &Renderer,
375    ) -> mouse::Interaction {
376        if cursor.is_over(layout.bounds()) {
377            if self.on_toggle.is_some() {
378                mouse::Interaction::Pointer
379            } else {
380                mouse::Interaction::NotAllowed
381            }
382        } else {
383            mouse::Interaction::default()
384        }
385    }
386
387    fn draw(
388        &self,
389        tree: &Tree,
390        renderer: &mut Renderer,
391        theme: &Theme,
392        style: &renderer::Style,
393        layout: Layout<'_>,
394        _cursor: mouse::Cursor,
395        viewport: &Rectangle,
396    ) {
397        /// Makes sure that the border radius of the toggler looks good at every size.
398        const BORDER_RADIUS_RATIO: f32 = 32.0 / 13.0;
399
400        /// The space ratio between the background Quad and the Toggler bounds, and
401        /// between the background Quad and foreground Quad.
402        const SPACE_RATIO: f32 = 0.05;
403
404        let mut children = layout.children();
405        let toggler_layout = children.next().unwrap();
406
407        if self.label.is_some() {
408            let label_layout = children.next().unwrap();
409            let state: &widget::text::State<Renderer::Paragraph> =
410                tree.state.downcast_ref();
411
412            crate::text::draw(
413                renderer,
414                style,
415                label_layout.bounds(),
416                state.raw(),
417                crate::text::Style::default(),
418                viewport,
419            );
420        }
421
422        let bounds = toggler_layout.bounds();
423        let style = theme
424            .style(&self.class, self.last_status.unwrap_or(Status::Disabled));
425
426        let border_radius = bounds.height / BORDER_RADIUS_RATIO;
427        let space = (SPACE_RATIO * bounds.height).round();
428
429        let toggler_background_bounds = Rectangle {
430            x: bounds.x + space,
431            y: bounds.y + space,
432            width: bounds.width - (2.0 * space),
433            height: bounds.height - (2.0 * space),
434        };
435
436        renderer.fill_quad(
437            renderer::Quad {
438                bounds: toggler_background_bounds,
439                border: Border {
440                    radius: border_radius.into(),
441                    width: style.background_border_width,
442                    color: style.background_border_color,
443                },
444                ..renderer::Quad::default()
445            },
446            style.background,
447        );
448
449        let toggler_foreground_bounds = Rectangle {
450            x: bounds.x
451                + if self.is_toggled {
452                    bounds.width - 2.0 * space - (bounds.height - (4.0 * space))
453                } else {
454                    2.0 * space
455                },
456            y: bounds.y + (2.0 * space),
457            width: bounds.height - (4.0 * space),
458            height: bounds.height - (4.0 * space),
459        };
460
461        renderer.fill_quad(
462            renderer::Quad {
463                bounds: toggler_foreground_bounds,
464                border: Border {
465                    radius: border_radius.into(),
466                    width: style.foreground_border_width,
467                    color: style.foreground_border_color,
468                },
469                ..renderer::Quad::default()
470            },
471            style.foreground,
472        );
473    }
474}
475
476impl<'a, Message, Theme, Renderer> From<Toggler<'a, Message, Theme, Renderer>>
477    for Element<'a, Message, Theme, Renderer>
478where
479    Message: 'a,
480    Theme: Catalog + 'a,
481    Renderer: text::Renderer + 'a,
482{
483    fn from(
484        toggler: Toggler<'a, Message, Theme, Renderer>,
485    ) -> Element<'a, Message, Theme, Renderer> {
486        Element::new(toggler)
487    }
488}
489
490/// The possible status of a [`Toggler`].
491#[derive(Debug, Clone, Copy, PartialEq, Eq)]
492pub enum Status {
493    /// The [`Toggler`] can be interacted with.
494    Active {
495        /// Indicates whether the [`Toggler`] is toggled.
496        is_toggled: bool,
497    },
498    /// The [`Toggler`] is being hovered.
499    Hovered {
500        /// Indicates whether the [`Toggler`] is toggled.
501        is_toggled: bool,
502    },
503    /// The [`Toggler`] is disabled.
504    Disabled,
505}
506
507/// The appearance of a toggler.
508#[derive(Debug, Clone, Copy, PartialEq)]
509pub struct Style {
510    /// The background [`Color`] of the toggler.
511    pub background: Color,
512    /// The width of the background border of the toggler.
513    pub background_border_width: f32,
514    /// The [`Color`] of the background border of the toggler.
515    pub background_border_color: Color,
516    /// The foreground [`Color`] of the toggler.
517    pub foreground: Color,
518    /// The width of the foreground border of the toggler.
519    pub foreground_border_width: f32,
520    /// The [`Color`] of the foreground border of the toggler.
521    pub foreground_border_color: Color,
522}
523
524/// The theme catalog of a [`Toggler`].
525pub trait Catalog: Sized {
526    /// The item class of the [`Catalog`].
527    type Class<'a>;
528
529    /// The default class produced by the [`Catalog`].
530    fn default<'a>() -> Self::Class<'a>;
531
532    /// The [`Style`] of a class with the given status.
533    fn style(&self, class: &Self::Class<'_>, status: Status) -> Style;
534}
535
536/// A styling function for a [`Toggler`].
537///
538/// This is just a boxed closure: `Fn(&Theme, Status) -> Style`.
539pub type StyleFn<'a, Theme> = Box<dyn Fn(&Theme, Status) -> Style + 'a>;
540
541impl Catalog for Theme {
542    type Class<'a> = StyleFn<'a, Self>;
543
544    fn default<'a>() -> Self::Class<'a> {
545        Box::new(default)
546    }
547
548    fn style(&self, class: &Self::Class<'_>, status: Status) -> Style {
549        class(self, status)
550    }
551}
552
553/// The default style of a [`Toggler`].
554pub fn default(theme: &Theme, status: Status) -> Style {
555    let palette = theme.extended_palette();
556
557    let background = match status {
558        Status::Active { is_toggled } | Status::Hovered { is_toggled } => {
559            if is_toggled {
560                palette.primary.strong.color
561            } else {
562                palette.background.strong.color
563            }
564        }
565        Status::Disabled => palette.background.weak.color,
566    };
567
568    let foreground = match status {
569        Status::Active { is_toggled } => {
570            if is_toggled {
571                palette.primary.strong.text
572            } else {
573                palette.background.base.color
574            }
575        }
576        Status::Hovered { is_toggled } => {
577            if is_toggled {
578                Color {
579                    a: 0.5,
580                    ..palette.primary.strong.text
581                }
582            } else {
583                palette.background.weak.color
584            }
585        }
586        Status::Disabled => palette.background.base.color,
587    };
588
589    Style {
590        background,
591        foreground,
592        foreground_border_width: 0.0,
593        foreground_border_color: Color::TRANSPARENT,
594        background_border_width: 0.0,
595        background_border_color: Color::TRANSPARENT,
596    }
597}
iced_widget/toggler.rs

iced_widget/
toggler.rs
