iced_widget/overlay/
menu.rs

1//! Build and show dropdown menus.
2use crate::core::alignment;
3use crate::core::border::{self, Border};
4use crate::core::layout::{self, Layout};
5use crate::core::mouse;
6use crate::core::overlay;
7use crate::core::renderer;
8use crate::core::text::{self, Text};
9use crate::core::touch;
10use crate::core::widget::tree::{self, Tree};
11use crate::core::window;
12use crate::core::{
13    Background, Clipboard, Color, Event, Length, Padding, Pixels, Point,
14    Rectangle, Size, Theme, Vector,
15};
16use crate::core::{Element, Shell, Widget};
17use crate::scrollable::{self, Scrollable};
18
19/// A list of selectable options.
20pub struct Menu<
21    'a,
22    'b,
23    T,
24    Message,
25    Theme = crate::Theme,
26    Renderer = crate::Renderer,
27> where
28    Theme: Catalog,
29    Renderer: text::Renderer,
30    'b: 'a,
31{
32    state: &'a mut State,
33    options: &'a [T],
34    hovered_option: &'a mut Option<usize>,
35    on_selected: Box<dyn FnMut(T) -> Message + 'a>,
36    on_option_hovered: Option<&'a dyn Fn(T) -> Message>,
37    width: f32,
38    padding: Padding,
39    text_size: Option<Pixels>,
40    text_line_height: text::LineHeight,
41    text_shaping: text::Shaping,
42    font: Option<Renderer::Font>,
43    class: &'a <Theme as Catalog>::Class<'b>,
44}
45
46impl<'a, 'b, T, Message, Theme, Renderer>
47    Menu<'a, 'b, T, Message, Theme, Renderer>
48where
49    T: ToString + Clone,
50    Message: 'a,
51    Theme: Catalog + 'a,
52    Renderer: text::Renderer + 'a,
53    'b: 'a,
54{
55    /// Creates a new [`Menu`] with the given [`State`], a list of options,
56    /// the message to produced when an option is selected, and its [`Style`].
57    pub fn new(
58        state: &'a mut State,
59        options: &'a [T],
60        hovered_option: &'a mut Option<usize>,
61        on_selected: impl FnMut(T) -> Message + 'a,
62        on_option_hovered: Option<&'a dyn Fn(T) -> Message>,
63        class: &'a <Theme as Catalog>::Class<'b>,
64    ) -> Self {
65        Menu {
66            state,
67            options,
68            hovered_option,
69            on_selected: Box::new(on_selected),
70            on_option_hovered,
71            width: 0.0,
72            padding: Padding::ZERO,
73            text_size: None,
74            text_line_height: text::LineHeight::default(),
75            text_shaping: text::Shaping::default(),
76            font: None,
77            class,
78        }
79    }
80
81    /// Sets the width of the [`Menu`].
82    pub fn width(mut self, width: f32) -> Self {
83        self.width = width;
84        self
85    }
86
87    /// Sets the [`Padding`] of the [`Menu`].
88    pub fn padding<P: Into<Padding>>(mut self, padding: P) -> Self {
89        self.padding = padding.into();
90        self
91    }
92
93    /// Sets the text size of the [`Menu`].
94    pub fn text_size(mut self, text_size: impl Into<Pixels>) -> Self {
95        self.text_size = Some(text_size.into());
96        self
97    }
98
99    /// Sets the text [`text::LineHeight`] of the [`Menu`].
100    pub fn text_line_height(
101        mut self,
102        line_height: impl Into<text::LineHeight>,
103    ) -> Self {
104        self.text_line_height = line_height.into();
105        self
106    }
107
108    /// Sets the [`text::Shaping`] strategy of the [`Menu`].
109    pub fn text_shaping(mut self, shaping: text::Shaping) -> Self {
110        self.text_shaping = shaping;
111        self
112    }
113
114    /// Sets the font of the [`Menu`].
115    pub fn font(mut self, font: impl Into<Renderer::Font>) -> Self {
116        self.font = Some(font.into());
117        self
118    }
119
120    /// Turns the [`Menu`] into an overlay [`Element`] at the given target
121    /// position.
122    ///
123    /// The `target_height` will be used to display the menu either on top
124    /// of the target or under it, depending on the screen position and the
125    /// dimensions of the [`Menu`].
126    pub fn overlay(
127        self,
128        position: Point,
129        viewport: Rectangle,
130        target_height: f32,
131    ) -> overlay::Element<'a, Message, Theme, Renderer> {
132        overlay::Element::new(Box::new(Overlay::new(
133            position,
134            viewport,
135            self,
136            target_height,
137        )))
138    }
139}
140
141/// The local state of a [`Menu`].
142#[derive(Debug)]
143pub struct State {
144    tree: Tree,
145}
146
147impl State {
148    /// Creates a new [`State`] for a [`Menu`].
149    pub fn new() -> Self {
150        Self {
151            tree: Tree::empty(),
152        }
153    }
154}
155
156impl Default for State {
157    fn default() -> Self {
158        Self::new()
159    }
160}
161
162struct Overlay<'a, 'b, Message, Theme, Renderer>
163where
164    Theme: Catalog,
165    Renderer: crate::core::Renderer,
166{
167    position: Point,
168    viewport: Rectangle,
169    state: &'a mut Tree,
170    list: Scrollable<'a, Message, Theme, Renderer>,
171    width: f32,
172    target_height: f32,
173    class: &'a <Theme as Catalog>::Class<'b>,
174}
175
176impl<'a, 'b, Message, Theme, Renderer> Overlay<'a, 'b, Message, Theme, Renderer>
177where
178    Message: 'a,
179    Theme: Catalog + scrollable::Catalog + 'a,
180    Renderer: text::Renderer + 'a,
181    'b: 'a,
182{
183    pub fn new<T>(
184        position: Point,
185        viewport: Rectangle,
186        menu: Menu<'a, 'b, T, Message, Theme, Renderer>,
187        target_height: f32,
188    ) -> Self
189    where
190        T: Clone + ToString,
191    {
192        let Menu {
193            state,
194            options,
195            hovered_option,
196            on_selected,
197            on_option_hovered,
198            width,
199            padding,
200            font,
201            text_size,
202            text_line_height,
203            text_shaping,
204            class,
205        } = menu;
206
207        let list = Scrollable::new(List {
208            options,
209            hovered_option,
210            on_selected,
211            on_option_hovered,
212            font,
213            text_size,
214            text_line_height,
215            text_shaping,
216            padding,
217            class,
218        });
219
220        state.tree.diff(&list as &dyn Widget<_, _, _>);
221
222        Self {
223            position,
224            viewport,
225            state: &mut state.tree,
226            list,
227            width,
228            target_height,
229            class,
230        }
231    }
232}
233
234impl<Message, Theme, Renderer> crate::core::Overlay<Message, Theme, Renderer>
235    for Overlay<'_, '_, Message, Theme, Renderer>
236where
237    Theme: Catalog,
238    Renderer: text::Renderer,
239{
240    fn layout(&mut self, renderer: &Renderer, bounds: Size) -> layout::Node {
241        let space_below =
242            bounds.height - (self.position.y + self.target_height);
243        let space_above = self.position.y;
244
245        let limits = layout::Limits::new(
246            Size::ZERO,
247            Size::new(
248                bounds.width - self.position.x,
249                if space_below > space_above {
250                    space_below
251                } else {
252                    space_above
253                },
254            ),
255        )
256        .width(self.width);
257
258        let node = self.list.layout(self.state, renderer, &limits);
259        let size = node.size();
260
261        node.move_to(if space_below > space_above {
262            self.position + Vector::new(0.0, self.target_height)
263        } else {
264            self.position - Vector::new(0.0, size.height)
265        })
266    }
267
268    fn update(
269        &mut self,
270        event: &Event,
271        layout: Layout<'_>,
272        cursor: mouse::Cursor,
273        renderer: &Renderer,
274        clipboard: &mut dyn Clipboard,
275        shell: &mut Shell<'_, Message>,
276    ) {
277        let bounds = layout.bounds();
278
279        self.list.update(
280            self.state, event, layout, cursor, renderer, clipboard, shell,
281            &bounds,
282        );
283    }
284
285    fn mouse_interaction(
286        &self,
287        layout: Layout<'_>,
288        cursor: mouse::Cursor,
289        renderer: &Renderer,
290    ) -> mouse::Interaction {
291        self.list.mouse_interaction(
292            self.state,
293            layout,
294            cursor,
295            &self.viewport,
296            renderer,
297        )
298    }
299
300    fn draw(
301        &self,
302        renderer: &mut Renderer,
303        theme: &Theme,
304        defaults: &renderer::Style,
305        layout: Layout<'_>,
306        cursor: mouse::Cursor,
307    ) {
308        let bounds = layout.bounds();
309
310        let style = Catalog::style(theme, self.class);
311
312        renderer.fill_quad(
313            renderer::Quad {
314                bounds,
315                border: style.border,
316                ..renderer::Quad::default()
317            },
318            style.background,
319        );
320
321        self.list.draw(
322            self.state, renderer, theme, defaults, layout, cursor, &bounds,
323        );
324    }
325}
326
327struct List<'a, 'b, T, Message, Theme, Renderer>
328where
329    Theme: Catalog,
330    Renderer: text::Renderer,
331{
332    options: &'a [T],
333    hovered_option: &'a mut Option<usize>,
334    on_selected: Box<dyn FnMut(T) -> Message + 'a>,
335    on_option_hovered: Option<&'a dyn Fn(T) -> Message>,
336    padding: Padding,
337    text_size: Option<Pixels>,
338    text_line_height: text::LineHeight,
339    text_shaping: text::Shaping,
340    font: Option<Renderer::Font>,
341    class: &'a <Theme as Catalog>::Class<'b>,
342}
343
344struct ListState {
345    is_hovered: Option<bool>,
346}
347
348impl<T, Message, Theme, Renderer> Widget<Message, Theme, Renderer>
349    for List<'_, '_, T, Message, Theme, Renderer>
350where
351    T: Clone + ToString,
352    Theme: Catalog,
353    Renderer: text::Renderer,
354{
355    fn tag(&self) -> tree::Tag {
356        tree::Tag::of::<Option<bool>>()
357    }
358
359    fn state(&self) -> tree::State {
360        tree::State::new(ListState { is_hovered: None })
361    }
362
363    fn size(&self) -> Size<Length> {
364        Size {
365            width: Length::Fill,
366            height: Length::Shrink,
367        }
368    }
369
370    fn layout(
371        &mut self,
372        _tree: &mut Tree,
373        renderer: &Renderer,
374        limits: &layout::Limits,
375    ) -> layout::Node {
376        use std::f32;
377
378        let text_size =
379            self.text_size.unwrap_or_else(|| renderer.default_size());
380
381        let text_line_height = self.text_line_height.to_absolute(text_size);
382
383        let size = {
384            let intrinsic = Size::new(
385                0.0,
386                (f32::from(text_line_height) + self.padding.vertical())
387                    * self.options.len() as f32,
388            );
389
390            limits.resolve(Length::Fill, Length::Shrink, intrinsic)
391        };
392
393        layout::Node::new(size)
394    }
395
396    fn update(
397        &mut self,
398        tree: &mut Tree,
399        event: &Event,
400        layout: Layout<'_>,
401        cursor: mouse::Cursor,
402        renderer: &Renderer,
403        _clipboard: &mut dyn Clipboard,
404        shell: &mut Shell<'_, Message>,
405        _viewport: &Rectangle,
406    ) {
407        match event {
408            Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left)) => {
409                if cursor.is_over(layout.bounds())
410                    && let Some(index) = *self.hovered_option
411                    && let Some(option) = self.options.get(index)
412                {
413                    shell.publish((self.on_selected)(option.clone()));
414                    shell.capture_event();
415                }
416            }
417            Event::Mouse(mouse::Event::CursorMoved { .. }) => {
418                if let Some(cursor_position) =
419                    cursor.position_in(layout.bounds())
420                {
421                    let text_size = self
422                        .text_size
423                        .unwrap_or_else(|| renderer.default_size());
424
425                    let option_height =
426                        f32::from(self.text_line_height.to_absolute(text_size))
427                            + self.padding.vertical();
428
429                    let new_hovered_option =
430                        (cursor_position.y / option_height) as usize;
431
432                    if *self.hovered_option != Some(new_hovered_option)
433                        && let Some(option) =
434                            self.options.get(new_hovered_option)
435                    {
436                        if let Some(on_option_hovered) = self.on_option_hovered
437                        {
438                            shell.publish(on_option_hovered(option.clone()));
439                        }
440
441                        shell.request_redraw();
442                    }
443
444                    *self.hovered_option = Some(new_hovered_option);
445                }
446            }
447            Event::Touch(touch::Event::FingerPressed { .. }) => {
448                if let Some(cursor_position) =
449                    cursor.position_in(layout.bounds())
450                {
451                    let text_size = self
452                        .text_size
453                        .unwrap_or_else(|| renderer.default_size());
454
455                    let option_height =
456                        f32::from(self.text_line_height.to_absolute(text_size))
457                            + self.padding.vertical();
458
459                    *self.hovered_option =
460                        Some((cursor_position.y / option_height) as usize);
461
462                    if let Some(index) = *self.hovered_option
463                        && let Some(option) = self.options.get(index)
464                    {
465                        shell.publish((self.on_selected)(option.clone()));
466                        shell.capture_event();
467                    }
468                }
469            }
470            _ => {}
471        }
472
473        let state = tree.state.downcast_mut::<ListState>();
474
475        if let Event::Window(window::Event::RedrawRequested(_now)) = event {
476            state.is_hovered = Some(cursor.is_over(layout.bounds()));
477        } else if state.is_hovered.is_some_and(|is_hovered| {
478            is_hovered != cursor.is_over(layout.bounds())
479        }) {
480            shell.request_redraw();
481        }
482    }
483
484    fn mouse_interaction(
485        &self,
486        _state: &Tree,
487        layout: Layout<'_>,
488        cursor: mouse::Cursor,
489        _viewport: &Rectangle,
490        _renderer: &Renderer,
491    ) -> mouse::Interaction {
492        let is_mouse_over = cursor.is_over(layout.bounds());
493
494        if is_mouse_over {
495            mouse::Interaction::Pointer
496        } else {
497            mouse::Interaction::default()
498        }
499    }
500
501    fn draw(
502        &self,
503        _state: &Tree,
504        renderer: &mut Renderer,
505        theme: &Theme,
506        _style: &renderer::Style,
507        layout: Layout<'_>,
508        _cursor: mouse::Cursor,
509        viewport: &Rectangle,
510    ) {
511        let style = Catalog::style(theme, self.class);
512        let bounds = layout.bounds();
513
514        let text_size =
515            self.text_size.unwrap_or_else(|| renderer.default_size());
516        let option_height =
517            f32::from(self.text_line_height.to_absolute(text_size))
518                + self.padding.vertical();
519
520        let offset = viewport.y - bounds.y;
521        let start = (offset / option_height) as usize;
522        let end = ((offset + viewport.height) / option_height).ceil() as usize;
523
524        let visible_options = &self.options[start..end.min(self.options.len())];
525
526        for (i, option) in visible_options.iter().enumerate() {
527            let i = start + i;
528            let is_selected = *self.hovered_option == Some(i);
529
530            let bounds = Rectangle {
531                x: bounds.x,
532                y: bounds.y + (option_height * i as f32),
533                width: bounds.width,
534                height: option_height,
535            };
536
537            if is_selected {
538                renderer.fill_quad(
539                    renderer::Quad {
540                        bounds: Rectangle {
541                            x: bounds.x + style.border.width,
542                            width: bounds.width - style.border.width * 2.0,
543                            ..bounds
544                        },
545                        border: border::rounded(style.border.radius),
546                        ..renderer::Quad::default()
547                    },
548                    style.selected_background,
549                );
550            }
551
552            renderer.fill_text(
553                Text {
554                    content: option.to_string(),
555                    bounds: Size::new(f32::INFINITY, bounds.height),
556                    size: text_size,
557                    line_height: self.text_line_height,
558                    font: self.font.unwrap_or_else(|| renderer.default_font()),
559                    align_x: text::Alignment::Default,
560                    align_y: alignment::Vertical::Center,
561                    shaping: self.text_shaping,
562                    wrapping: text::Wrapping::default(),
563                },
564                Point::new(bounds.x + self.padding.left, bounds.center_y()),
565                if is_selected {
566                    style.selected_text_color
567                } else {
568                    style.text_color
569                },
570                *viewport,
571            );
572        }
573    }
574}
575
576impl<'a, 'b, T, Message, Theme, Renderer>
577    From<List<'a, 'b, T, Message, Theme, Renderer>>
578    for Element<'a, Message, Theme, Renderer>
579where
580    T: ToString + Clone,
581    Message: 'a,
582    Theme: 'a + Catalog,
583    Renderer: 'a + text::Renderer,
584    'b: 'a,
585{
586    fn from(list: List<'a, 'b, T, Message, Theme, Renderer>) -> Self {
587        Element::new(list)
588    }
589}
590
591/// The appearance of a [`Menu`].
592#[derive(Debug, Clone, Copy, PartialEq)]
593pub struct Style {
594    /// The [`Background`] of the menu.
595    pub background: Background,
596    /// The [`Border`] of the menu.
597    pub border: Border,
598    /// The text [`Color`] of the menu.
599    pub text_color: Color,
600    /// The text [`Color`] of a selected option in the menu.
601    pub selected_text_color: Color,
602    /// The background [`Color`] of a selected option in the menu.
603    pub selected_background: Background,
604}
605
606/// The theme catalog of a [`Menu`].
607pub trait Catalog: scrollable::Catalog {
608    /// The item class of the [`Catalog`].
609    type Class<'a>;
610
611    /// The default class produced by the [`Catalog`].
612    fn default<'a>() -> <Self as Catalog>::Class<'a>;
613
614    /// The default class for the scrollable of the [`Menu`].
615    fn default_scrollable<'a>() -> <Self as scrollable::Catalog>::Class<'a> {
616        <Self as scrollable::Catalog>::default()
617    }
618
619    /// The [`Style`] of a class with the given status.
620    fn style(&self, class: &<Self as Catalog>::Class<'_>) -> Style;
621}
622
623/// A styling function for a [`Menu`].
624pub type StyleFn<'a, Theme> = Box<dyn Fn(&Theme) -> Style + 'a>;
625
626impl Catalog for Theme {
627    type Class<'a> = StyleFn<'a, Self>;
628
629    fn default<'a>() -> StyleFn<'a, Self> {
630        Box::new(default)
631    }
632
633    fn style(&self, class: &StyleFn<'_, Self>) -> Style {
634        class(self)
635    }
636}
637
638/// The default style of the list of a [`Menu`].
639pub fn default(theme: &Theme) -> Style {
640    let palette = theme.extended_palette();
641
642    Style {
643        background: palette.background.weak.color.into(),
644        border: Border {
645            width: 1.0,
646            radius: 0.0.into(),
647            color: palette.background.strong.color,
648        },
649        text_color: palette.background.weak.text,
650        selected_text_color: palette.primary.strong.text,
651        selected_background: palette.primary.strong.color.into(),
652    }
653}
iced_widget/overlay/menu.rs

iced_widget/overlay/
menu.rs
