iced_widget/
button.rs

1//! Buttons allow your users to perform actions by pressing them.
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//! # use iced::widget::Widget;
7//! # pub type State = ();
8//! use iced::widget::button;
9//!
10//! #[derive(Clone)]
11//! enum Message {
12//!     ButtonPressed,
13//! }
14//!
15//! fn view(state: &State) -> impl Widget<Message> {
16//!     button("Press me!").on_press(Message::ButtonPressed)
17//! }
18//! ```
19use crate::core::border::{self, Border};
20use crate::core::layout;
21use crate::core::mouse;
22use crate::core::overlay;
23use crate::core::renderer;
24use crate::core::theme::palette;
25use crate::core::touch;
26use crate::core::widget::tree::{self, Tree};
27use crate::core::widget::{Meta, Operation};
28use crate::core::window;
29use crate::core::{
30    Background, Color, Event, Layout, Length, Padding, Rectangle, Shadow, Shell, Size, Theme,
31    Vector, Widget,
32};
33
34/// A generic widget that produces a message when pressed.
35///
36/// # Example
37/// ```no_run
38/// # mod iced { pub mod widget { pub use iced_widget::*; } pub use iced_widget::Renderer; pub use iced_widget::core::*; }
39/// # use iced::widget::Widget;
40/// # pub type State = ();
41/// use iced::widget::button;
42///
43/// #[derive(Clone)]
44/// enum Message {
45///     ButtonPressed,
46/// }
47///
48/// fn view(state: &State) -> impl Widget<Message> {
49///     button("Press me!").on_press(Message::ButtonPressed)
50/// }
51/// ```
52///
53/// If a [`Button::on_press`] handler is not set, the resulting [`Button`] will
54/// be disabled:
55///
56/// ```no_run
57/// # mod iced { pub mod widget { pub use iced_widget::*; } pub use iced_widget::Renderer; pub use iced_widget::core::*; }
58/// # use iced::widget::Widget;
59/// # pub type State = ();
60/// use iced::widget::button;
61///
62/// #[derive(Clone)]
63/// enum Message {
64///     ButtonPressed,
65/// }
66///
67/// fn view(state: &State) -> impl Widget<Message> {
68///     button("I am disabled!")
69/// }
70/// ```
71pub struct Button<'a, Message, W = crate::Element<'a, Message>, Theme = crate::Theme>
72where
73    Theme: Catalog,
74{
75    content: W,
76    on_press: Option<OnPress<'a, Message>>,
77    width: Length,
78    height: Length,
79    padding: Padding,
80    clip: bool,
81    class: Theme::Class<'a>,
82    status: Option<Status>,
83}
84
85enum OnPress<'a, Message> {
86    Direct(Message),
87    Closure(Box<dyn Fn() -> Message + 'a>),
88}
89
90impl<Message: Clone> OnPress<'_, Message> {
91    fn get(&self) -> Message {
92        match self {
93            OnPress::Direct(message) => message.clone(),
94            OnPress::Closure(f) => f(),
95        }
96    }
97}
98
99impl<'a, Message, W, Theme> Button<'a, Message, W, Theme>
100where
101    Theme: Catalog,
102{
103    /// Creates a new [`Button`] with the given content.
104    pub fn new(content: W) -> Self {
105        Button {
106            content,
107            on_press: None,
108            width: Length::Fit,
109            height: Length::Fit,
110            padding: DEFAULT_PADDING,
111            clip: false,
112            class: Theme::default(),
113            status: None,
114        }
115    }
116
117    /// Sets the width of the [`Button`].
118    pub fn width(mut self, width: impl Into<Length>) -> Self {
119        self.width = width.into();
120        self
121    }
122
123    /// Sets the height of the [`Button`].
124    pub fn height(mut self, height: impl Into<Length>) -> Self {
125        self.height = height.into();
126        self
127    }
128
129    /// Sets the [`Padding`] of the [`Button`].
130    pub fn padding<P: Into<Padding>>(mut self, padding: P) -> Self {
131        self.padding = padding.into();
132        self
133    }
134
135    /// Sets the message that will be produced when the [`Button`] is pressed.
136    ///
137    /// Unless `on_press` is called, the [`Button`] will be disabled.
138    pub fn on_press(mut self, on_press: Message) -> Self {
139        self.on_press = Some(OnPress::Direct(on_press));
140        self
141    }
142
143    /// Sets the message that will be produced when the [`Button`] is pressed.
144    ///
145    /// This is analogous to [`Button::on_press`], but using a closure to produce
146    /// the message.
147    ///
148    /// This closure will only be called when the [`Button`] is actually pressed and,
149    /// therefore, this method is useful to reduce overhead if creating the resulting
150    /// message is slow.
151    pub fn on_press_with(mut self, on_press: impl Fn() -> Message + 'a) -> Self {
152        self.on_press = Some(OnPress::Closure(Box::new(on_press)));
153        self
154    }
155
156    /// Sets the message that will be produced when the [`Button`] is pressed,
157    /// if `Some`.
158    ///
159    /// If `None`, the [`Button`] will be disabled.
160    pub fn on_press_maybe(mut self, on_press: Option<Message>) -> Self {
161        self.on_press = on_press.map(OnPress::Direct);
162        self
163    }
164
165    /// Sets the message that will be produced when the [`Button`] is pressed,
166    /// if `Some`.
167    ///
168    /// This is analogous to [`Button::on_press`], but using a closure to produce
169    /// the message.
170    ///
171    /// This closure will only be called when the [`Button`] is actually pressed and,
172    /// therefore, this method is useful to reduce overhead if creating the resulting
173    /// message is slow.
174    ///
175    /// If `None`, the [`Button`] will be disabled.
176    pub fn on_press_maybe_with(mut self, on_press: Option<impl Fn() -> Message + 'a>) -> Self {
177        self.on_press = on_press.map(|on_press| OnPress::Closure(Box::new(on_press)));
178        self
179    }
180
181    /// Sets whether the contents of the [`Button`] should be clipped on
182    /// overflow.
183    pub fn clip(mut self, clip: bool) -> Self {
184        self.clip = clip;
185        self
186    }
187
188    /// Sets the style of the [`Button`].
189    #[must_use]
190    pub fn style(mut self, style: impl Fn(&Theme, Status) -> Style + 'a) -> Self
191    where
192        Theme::Class<'a>: From<StyleFn<'a, Theme>>,
193    {
194        self.class = (Box::new(style) as StyleFn<'a, Theme>).into();
195        self
196    }
197
198    /// Sets the style class of the [`Button`].
199    #[cfg(feature = "advanced")]
200    #[must_use]
201    pub fn class(mut self, class: impl Into<Theme::Class<'a>>) -> Self {
202        self.class = class.into();
203        self
204    }
205}
206
207#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
208struct State {
209    is_pressed: bool,
210}
211
212impl<'a, Message, W, Theme> Meta for Button<'a, Message, W, Theme> where Theme: Catalog {}
213
214impl<'a, Message, W, Theme, Renderer> Widget<Message, Theme, Renderer>
215    for Button<'a, Message, W, Theme>
216where
217    Message: 'a + Clone,
218    W: Widget<Message, Theme, Renderer>,
219    Renderer: 'a + crate::core::Renderer,
220    Theme: Catalog,
221{
222    fn tag(&self) -> tree::Tag {
223        tree::Tag::of::<State>()
224    }
225
226    fn state(&self) -> tree::State {
227        tree::State::new(State::default())
228    }
229
230    fn diff(&mut self, tree: &mut Tree) {
231        tree.diff_children(std::slice::from_mut(&mut self.content));
232
233        let size = self.content.size();
234        self.width = self.width.stack(size.width);
235        self.height = self.height.stack(size.height);
236    }
237
238    fn size(&self) -> Size<Length> {
239        Size {
240            width: self.width,
241            height: self.height,
242        }
243    }
244
245    fn layout(&mut self, tree: &mut Tree, renderer: &Renderer, limits: &layout::Limits) {
246        layout::padded(
247            tree,
248            limits,
249            self.width,
250            self.height,
251            self.padding,
252            |tree, limits| {
253                self.content.layout(tree, renderer, limits);
254
255                tree.size
256            },
257        );
258    }
259
260    fn operate(
261        &mut self,
262        tree: &mut Tree,
263        layout: Layout,
264        viewport: &Rectangle,
265        renderer: &Renderer,
266        operation: &mut dyn Operation,
267    ) {
268        operation.container(None, layout.bounds(), viewport);
269        operation.traverse(&mut |operation| {
270            let (layout, tree) = layout.iter_mut(&mut tree.children).next().unwrap();
271
272            self.content
273                .operate(tree, layout, viewport, renderer, operation);
274        });
275    }
276
277    fn update(
278        &mut self,
279        tree: &mut Tree,
280        event: &Event,
281        layout: Layout,
282        cursor: mouse::Cursor,
283        renderer: &Renderer,
284        shell: &mut Shell<'_, Message>,
285        viewport: &Rectangle,
286    ) {
287        let (content_layout, content_tree) = layout.iter_mut(&mut tree.children).next().unwrap();
288
289        self.content.update(
290            content_tree,
291            event,
292            content_layout,
293            cursor,
294            renderer,
295            shell,
296            viewport,
297        );
298
299        if shell.is_event_captured() {
300            return;
301        }
302
303        match event {
304            Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left))
305            | Event::Touch(touch::Event::FingerPressed { .. })
306                if self.on_press.is_some() =>
307            {
308                let bounds = layout.bounds();
309
310                if cursor.is_over(bounds) {
311                    let state = tree.state.downcast_mut::<State>();
312
313                    state.is_pressed = true;
314
315                    shell.capture_event();
316                }
317            }
318            Event::Mouse(mouse::Event::ButtonReleased(mouse::Button::Left))
319            | Event::Touch(touch::Event::FingerLifted { .. }) => {
320                if let Some(on_press) = &self.on_press {
321                    let state = tree.state.downcast_mut::<State>();
322
323                    if state.is_pressed {
324                        state.is_pressed = false;
325
326                        let bounds = layout.bounds();
327
328                        if cursor.is_over(bounds) {
329                            shell.publish(on_press.get());
330                        }
331                    }
332                }
333            }
334            Event::Touch(touch::Event::FingerLost { .. }) => {
335                let state = tree.state.downcast_mut::<State>();
336
337                state.is_pressed = false;
338            }
339            _ => {}
340        }
341
342        let current_status = if self.on_press.is_none() {
343            Status::Disabled
344        } else if cursor.is_over(layout.bounds()) {
345            let state = tree.state.downcast_ref::<State>();
346
347            if state.is_pressed {
348                Status::Pressed
349            } else {
350                Status::Hovered
351            }
352        } else {
353            Status::Active
354        };
355
356        if let Event::Window(window::Event::RedrawRequested(_now)) = event {
357            self.status = Some(current_status);
358        } else if self.status.is_some_and(|status| status != current_status) {
359            shell.request_redraw();
360        }
361    }
362
363    fn draw(
364        &self,
365        tree: &Tree,
366        renderer: &mut Renderer,
367        theme: &Theme,
368        _style: &renderer::Style,
369        layout: Layout,
370        cursor: mouse::Cursor,
371        viewport: &Rectangle,
372    ) {
373        let bounds = layout.bounds();
374        let (layout, tree) = layout.iter(&tree.children).next().unwrap();
375        let style = theme.style(&self.class, self.status.unwrap_or(Status::Disabled));
376
377        if style.background.is_some() || style.border.width > 0.0 || style.shadow.color.a > 0.0 {
378            renderer.fill_quad(
379                renderer::Quad {
380                    bounds,
381                    border: style.border,
382                    shadow: style.shadow,
383                    snap: style.snap,
384                },
385                style
386                    .background
387                    .unwrap_or(Background::Color(Color::TRANSPARENT)),
388            );
389        }
390
391        let viewport = if self.clip {
392            bounds.intersection(viewport).unwrap_or(*viewport)
393        } else {
394            *viewport
395        };
396
397        self.content.draw(
398            tree,
399            renderer,
400            theme,
401            &renderer::Style {
402                text_color: style.text_color,
403            },
404            layout,
405            cursor,
406            &viewport,
407        );
408    }
409
410    fn mouse_interaction(
411        &self,
412        _tree: &Tree,
413        layout: Layout,
414        cursor: mouse::Cursor,
415        _viewport: &Rectangle,
416        _renderer: &Renderer,
417    ) -> mouse::Interaction {
418        let is_mouse_over = cursor.is_over(layout.bounds());
419
420        if is_mouse_over && self.on_press.is_some() {
421            mouse::Interaction::Pointer
422        } else {
423            mouse::Interaction::default()
424        }
425    }
426
427    fn overlay<'b>(
428        &'b mut self,
429        tree: &'b mut Tree,
430        layout: Layout,
431        renderer: &Renderer,
432        viewport: &Rectangle,
433        translation: Vector,
434        window: Size,
435    ) -> Vec<overlay::Element<'b, Message, Theme, Renderer>> {
436        let (layout, tree) = layout.iter_mut(&mut tree.children).next().unwrap();
437
438        self.content
439            .overlay(tree, layout, renderer, viewport, translation, window)
440    }
441}
442
443/// The default [`Padding`] of a [`Button`].
444pub const DEFAULT_PADDING: Padding = Padding {
445    top: 5.0,
446    bottom: 5.0,
447    right: 10.0,
448    left: 10.0,
449};
450
451/// The possible status of a [`Button`].
452#[derive(Debug, Clone, Copy, PartialEq, Eq)]
453pub enum Status {
454    /// The [`Button`] can be pressed.
455    Active,
456    /// The [`Button`] can be pressed and it is being hovered.
457    Hovered,
458    /// The [`Button`] is being pressed.
459    Pressed,
460    /// The [`Button`] cannot be pressed.
461    Disabled,
462}
463
464/// The style of a button.
465///
466/// If not specified with [`Button::style`]
467/// the theme will provide the style.
468#[derive(Debug, Clone, Copy, PartialEq)]
469pub struct Style {
470    /// The [`Background`] of the button.
471    pub background: Option<Background>,
472    /// The text [`Color`] of the button.
473    pub text_color: Color,
474    /// The [`Border`] of the button.
475    pub border: Border,
476    /// The [`Shadow`] of the button.
477    pub shadow: Shadow,
478    /// Whether the button should be snapped to the pixel grid.
479    pub snap: bool,
480}
481
482impl Style {
483    /// Updates the [`Style`] with the given [`Background`].
484    pub fn with_background(self, background: impl Into<Background>) -> Self {
485        Self {
486            background: Some(background.into()),
487            ..self
488        }
489    }
490}
491
492impl Default for Style {
493    fn default() -> Self {
494        Self {
495            background: None,
496            text_color: Color::BLACK,
497            border: Border::default(),
498            shadow: Shadow::default(),
499            snap: renderer::CRISP,
500        }
501    }
502}
503
504/// The theme catalog of a [`Button`].
505///
506/// All themes that can be used with [`Button`]
507/// must implement this trait.
508///
509/// # Example
510/// ```no_run
511/// # use iced_widget::core::{Color, Background};
512/// # use iced_widget::button::{Catalog, Status, Style};
513/// # struct MyTheme;
514/// #[derive(Debug, Default)]
515/// pub enum ButtonClass {
516///     #[default]
517///     Primary,
518///     Secondary,
519///     Danger
520/// }
521///
522/// impl Catalog for MyTheme {
523///     type Class<'a> = ButtonClass;
524///     fn default<'a>() -> Self::Class<'a> {
525///         ButtonClass::default()
526///     }
527///
528///     fn style(&self, class: &Self::Class<'_>, status: Status) -> Style {
529///         let mut style = Style::default();
530///
531///         match class {
532///             ButtonClass::Primary => {
533///                 style.background = Some(Background::Color(Color::from_rgb(0.529, 0.808, 0.921)));
534///             },
535///             ButtonClass::Secondary => {
536///                 style.background = Some(Background::Color(Color::WHITE));
537///             },
538///             ButtonClass::Danger => {
539///                 style.background = Some(Background::Color(Color::from_rgb(0.941, 0.502, 0.502)));
540///             },
541///         }
542///
543///         style
544///     }
545/// }
546/// ```
547///
548/// Although, in order to use [`Button::style`]
549/// with `MyTheme`, [`Catalog::Class`] must implement
550/// `From<StyleFn<'_, MyTheme>>`.
551pub trait Catalog {
552    /// The item class of the [`Catalog`].
553    type Class<'a>;
554
555    /// The default class produced by the [`Catalog`].
556    fn default<'a>() -> Self::Class<'a>;
557
558    /// The [`Style`] of a class with the given status.
559    fn style(&self, class: &Self::Class<'_>, status: Status) -> Style;
560}
561
562/// A styling function for a [`Button`].
563pub type StyleFn<'a, Theme> = Box<dyn Fn(&Theme, Status) -> Style + 'a>;
564
565impl Catalog for Theme {
566    type Class<'a> = StyleFn<'a, Self>;
567
568    fn default<'a>() -> Self::Class<'a> {
569        Box::new(primary)
570    }
571
572    fn style(&self, class: &Self::Class<'_>, status: Status) -> Style {
573        class(self, status)
574    }
575}
576
577/// A primary button; denoting a main action.
578pub fn primary(theme: &Theme, status: Status) -> Style {
579    let palette = theme.palette();
580    let base = styled(palette.primary.base);
581
582    match status {
583        Status::Active | Status::Pressed => base,
584        Status::Hovered => Style {
585            background: Some(Background::Color(palette.primary.strong.color)),
586            ..base
587        },
588        Status::Disabled => disabled(base),
589    }
590}
591
592/// A secondary button; denoting a complementary action.
593pub fn secondary(theme: &Theme, status: Status) -> Style {
594    let palette = theme.palette();
595    let base = styled(palette.secondary.base);
596
597    match status {
598        Status::Active | Status::Pressed => base,
599        Status::Hovered => Style {
600            background: Some(Background::Color(palette.secondary.strong.color)),
601            ..base
602        },
603        Status::Disabled => disabled(base),
604    }
605}
606
607/// A success button; denoting a good outcome.
608pub fn success(theme: &Theme, status: Status) -> Style {
609    let palette = theme.palette();
610    let base = styled(palette.success.base);
611
612    match status {
613        Status::Active | Status::Pressed => base,
614        Status::Hovered => Style {
615            background: Some(Background::Color(palette.success.strong.color)),
616            ..base
617        },
618        Status::Disabled => disabled(base),
619    }
620}
621
622/// A warning button; denoting a risky action.
623pub fn warning(theme: &Theme, status: Status) -> Style {
624    let palette = theme.palette();
625    let base = styled(palette.warning.base);
626
627    match status {
628        Status::Active | Status::Pressed => base,
629        Status::Hovered => Style {
630            background: Some(Background::Color(palette.warning.strong.color)),
631            ..base
632        },
633        Status::Disabled => disabled(base),
634    }
635}
636
637/// A danger button; denoting a destructive action.
638pub fn danger(theme: &Theme, status: Status) -> Style {
639    let palette = theme.palette();
640    let base = styled(palette.danger.base);
641
642    match status {
643        Status::Active | Status::Pressed => base,
644        Status::Hovered => Style {
645            background: Some(Background::Color(palette.danger.strong.color)),
646            ..base
647        },
648        Status::Disabled => disabled(base),
649    }
650}
651
652/// A text button; useful for links.
653pub fn text(theme: &Theme, status: Status) -> Style {
654    let palette = theme.palette();
655
656    let base = Style {
657        text_color: palette.background.base.text,
658        ..Style::default()
659    };
660
661    match status {
662        Status::Active | Status::Pressed => base,
663        Status::Hovered => Style {
664            text_color: palette.background.base.text.scale_alpha(0.8),
665            ..base
666        },
667        Status::Disabled => disabled(base),
668    }
669}
670
671/// A button using background shades.
672pub fn background(theme: &Theme, status: Status) -> Style {
673    let palette = theme.palette();
674    let base = styled(palette.background.base);
675
676    match status {
677        Status::Active => base,
678        Status::Pressed => Style {
679            background: Some(Background::Color(palette.background.strong.color)),
680            ..base
681        },
682        Status::Hovered => Style {
683            background: Some(Background::Color(palette.background.weak.color)),
684            ..base
685        },
686        Status::Disabled => disabled(base),
687    }
688}
689
690/// A subtle button using weak background shades.
691pub fn subtle(theme: &Theme, status: Status) -> Style {
692    let palette = theme.palette();
693    let base = styled(palette.background.weakest);
694
695    match status {
696        Status::Active => base,
697        Status::Pressed => Style {
698            background: Some(Background::Color(palette.background.strong.color)),
699            ..base
700        },
701        Status::Hovered => Style {
702            background: Some(Background::Color(palette.background.weaker.color)),
703            ..base
704        },
705        Status::Disabled => disabled(base),
706    }
707}
708
709fn styled(pair: palette::Pair) -> Style {
710    Style {
711        background: Some(Background::Color(pair.color)),
712        text_color: pair.text,
713        border: border::rounded(2),
714        ..Style::default()
715    }
716}
717
718fn disabled(style: Style) -> Style {
719    Style {
720        background: style
721            .background
722            .map(|background| background.scale_alpha(0.5)),
723        text_color: style.text_color.scale_alpha(0.5),
724        ..style
725    }
726}
iced_widget/button.rs

iced_widget/
button.rs
