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, Shadow, 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        menu_height: Length,
132    ) -> overlay::Element<'a, Message, Theme, Renderer> {
133        overlay::Element::new(Box::new(Overlay::new(
134            position,
135            viewport,
136            self,
137            target_height,
138            menu_height,
139        )))
140    }
141}
142
143/// The local state of a [`Menu`].
144#[derive(Debug)]
145pub struct State {
146    tree: Tree,
147}
148
149impl State {
150    /// Creates a new [`State`] for a [`Menu`].
151    pub fn new() -> Self {
152        Self {
153            tree: Tree::empty(),
154        }
155    }
156}
157
158impl Default for State {
159    fn default() -> Self {
160        Self::new()
161    }
162}
163
164struct Overlay<'a, 'b, Message, Theme, Renderer>
165where
166    Theme: Catalog,
167    Renderer: text::Renderer,
168{
169    position: Point,
170    viewport: Rectangle,
171    tree: &'a mut Tree,
172    list: Scrollable<'a, Message, Theme, Renderer>,
173    width: f32,
174    target_height: f32,
175    class: &'a <Theme as Catalog>::Class<'b>,
176}
177
178impl<'a, 'b, Message, Theme, Renderer> Overlay<'a, 'b, Message, Theme, Renderer>
179where
180    Message: 'a,
181    Theme: Catalog + scrollable::Catalog + 'a,
182    Renderer: text::Renderer + 'a,
183    'b: 'a,
184{
185    pub fn new<T>(
186        position: Point,
187        viewport: Rectangle,
188        menu: Menu<'a, 'b, T, Message, Theme, Renderer>,
189        target_height: f32,
190        menu_height: Length,
191    ) -> Self
192    where
193        T: Clone + ToString,
194    {
195        let Menu {
196            state,
197            options,
198            hovered_option,
199            on_selected,
200            on_option_hovered,
201            width,
202            padding,
203            font,
204            text_size,
205            text_line_height,
206            text_shaping,
207            class,
208        } = menu;
209
210        let list = Scrollable::new(List {
211            options,
212            hovered_option,
213            on_selected,
214            on_option_hovered,
215            font,
216            text_size,
217            text_line_height,
218            text_shaping,
219            padding,
220            class,
221        })
222        .height(menu_height);
223
224        state.tree.diff(&list as &dyn Widget<_, _, _>);
225
226        Self {
227            position,
228            viewport,
229            tree: &mut state.tree,
230            list,
231            width,
232            target_height,
233            class,
234        }
235    }
236}
237
238impl<Message, Theme, Renderer> crate::core::Overlay<Message, Theme, Renderer>
239    for Overlay<'_, '_, Message, Theme, Renderer>
240where
241    Theme: Catalog,
242    Renderer: text::Renderer,
243{
244    fn layout(&mut self, renderer: &Renderer, bounds: Size) -> layout::Node {
245        let space_below =
246            bounds.height - (self.position.y + self.target_height);
247        let space_above = self.position.y;
248
249        let limits = layout::Limits::new(
250            Size::ZERO,
251            Size::new(
252                bounds.width - self.position.x,
253                if space_below > space_above {
254                    space_below
255                } else {
256                    space_above
257                },
258            ),
259        )
260        .width(self.width);
261
262        let node = self.list.layout(self.tree, renderer, &limits);
263        let size = node.size();
264
265        node.move_to(if space_below > space_above {
266            self.position + Vector::new(0.0, self.target_height)
267        } else {
268            self.position - Vector::new(0.0, size.height)
269        })
270    }
271
272    fn update(
273        &mut self,
274        event: &Event,
275        layout: Layout<'_>,
276        cursor: mouse::Cursor,
277        renderer: &Renderer,
278        clipboard: &mut dyn Clipboard,
279        shell: &mut Shell<'_, Message>,
280    ) {
281        let bounds = layout.bounds();
282
283        self.list.update(
284            self.tree, event, layout, cursor, renderer, clipboard, shell,
285            &bounds,
286        );
287    }
288
289    fn mouse_interaction(
290        &self,
291        layout: Layout<'_>,
292        cursor: mouse::Cursor,
293        renderer: &Renderer,
294    ) -> mouse::Interaction {
295        self.list.mouse_interaction(
296            self.tree,
297            layout,
298            cursor,
299            &self.viewport,
300            renderer,
301        )
302    }
303
304    fn draw(
305        &self,
306        renderer: &mut Renderer,
307        theme: &Theme,
308        defaults: &renderer::Style,
309        layout: Layout<'_>,
310        cursor: mouse::Cursor,
311    ) {
312        let bounds = layout.bounds();
313
314        let style = Catalog::style(theme, self.class);
315
316        renderer.fill_quad(
317            renderer::Quad {
318                bounds,
319                border: style.border,
320                shadow: style.shadow,
321                ..renderer::Quad::default()
322            },
323            style.background,
324        );
325
326        self.list.draw(
327            self.tree, renderer, theme, defaults, layout, cursor, &bounds,
328        );
329    }
330}
331
332struct List<'a, 'b, T, Message, Theme, Renderer>
333where
334    Theme: Catalog,
335    Renderer: text::Renderer,
336{
337    options: &'a [T],
338    hovered_option: &'a mut Option<usize>,
339    on_selected: Box<dyn FnMut(T) -> Message + 'a>,
340    on_option_hovered: Option<&'a dyn Fn(T) -> Message>,
341    padding: Padding,
342    text_size: Option<Pixels>,
343    text_line_height: text::LineHeight,
344    text_shaping: text::Shaping,
345    font: Option<Renderer::Font>,
346    class: &'a <Theme as Catalog>::Class<'b>,
347}
348
349struct ListState {
350    is_hovered: Option<bool>,
351}
352
353impl<T, Message, Theme, Renderer> Widget<Message, Theme, Renderer>
354    for List<'_, '_, T, Message, Theme, Renderer>
355where
356    T: Clone + ToString,
357    Theme: Catalog,
358    Renderer: text::Renderer,
359{
360    fn tag(&self) -> tree::Tag {
361        tree::Tag::of::<Option<bool>>()
362    }
363
364    fn state(&self) -> tree::State {
365        tree::State::new(ListState { is_hovered: None })
366    }
367
368    fn size(&self) -> Size<Length> {
369        Size {
370            width: Length::Fill,
371            height: Length::Shrink,
372        }
373    }
374
375    fn layout(
376        &mut self,
377        _tree: &mut Tree,
378        renderer: &Renderer,
379        limits: &layout::Limits,
380    ) -> layout::Node {
381        use std::f32;
382
383        let text_size =
384            self.text_size.unwrap_or_else(|| renderer.default_size());
385
386        let text_line_height = self.text_line_height.to_absolute(text_size);
387
388        let size = {
389            let intrinsic = Size::new(
390                0.0,
391                (f32::from(text_line_height) + self.padding.y())
392                    * self.options.len() as f32,
393            );
394
395            limits.resolve(Length::Fill, Length::Shrink, intrinsic)
396        };
397
398        layout::Node::new(size)
399    }
400
401    fn update(
402        &mut self,
403        tree: &mut Tree,
404        event: &Event,
405        layout: Layout<'_>,
406        cursor: mouse::Cursor,
407        renderer: &Renderer,
408        _clipboard: &mut dyn Clipboard,
409        shell: &mut Shell<'_, Message>,
410        _viewport: &Rectangle,
411    ) {
412        match event {
413            Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left)) => {
414                if cursor.is_over(layout.bounds())
415                    && let Some(index) = *self.hovered_option
416                    && let Some(option) = self.options.get(index)
417                {
418                    shell.publish((self.on_selected)(option.clone()));
419                    shell.capture_event();
420                }
421            }
422            Event::Mouse(mouse::Event::CursorMoved { .. }) => {
423                if let Some(cursor_position) =
424                    cursor.position_in(layout.bounds())
425                {
426                    let text_size = self
427                        .text_size
428                        .unwrap_or_else(|| renderer.default_size());
429
430                    let option_height =
431                        f32::from(self.text_line_height.to_absolute(text_size))
432                            + self.padding.y();
433
434                    let new_hovered_option =
435                        (cursor_position.y / option_height) as usize;
436
437                    if *self.hovered_option != Some(new_hovered_option)
438                        && let Some(option) =
439                            self.options.get(new_hovered_option)
440                    {
441                        if let Some(on_option_hovered) = self.on_option_hovered
442                        {
443                            shell.publish(on_option_hovered(option.clone()));
444                        }
445
446                        shell.request_redraw();
447                    }
448
449                    *self.hovered_option = Some(new_hovered_option);
450                }
451            }
452            Event::Touch(touch::Event::FingerPressed { .. }) => {
453                if let Some(cursor_position) =
454                    cursor.position_in(layout.bounds())
455                {
456                    let text_size = self
457                        .text_size
458                        .unwrap_or_else(|| renderer.default_size());
459
460                    let option_height =
461                        f32::from(self.text_line_height.to_absolute(text_size))
462                            + self.padding.y();
463
464                    *self.hovered_option =
465                        Some((cursor_position.y / option_height) as usize);
466
467                    if let Some(index) = *self.hovered_option
468                        && let Some(option) = self.options.get(index)
469                    {
470                        shell.publish((self.on_selected)(option.clone()));
471                        shell.capture_event();
472                    }
473                }
474            }
475            _ => {}
476        }
477
478        let state = tree.state.downcast_mut::<ListState>();
479
480        if let Event::Window(window::Event::RedrawRequested(_now)) = event {
481            state.is_hovered = Some(cursor.is_over(layout.bounds()));
482        } else if state.is_hovered.is_some_and(|is_hovered| {
483            is_hovered != cursor.is_over(layout.bounds())
484        }) {
485            shell.request_redraw();
486        }
487    }
488
489    fn mouse_interaction(
490        &self,
491        _tree: &Tree,
492        layout: Layout<'_>,
493        cursor: mouse::Cursor,
494        _viewport: &Rectangle,
495        _renderer: &Renderer,
496    ) -> mouse::Interaction {
497        let is_mouse_over = cursor.is_over(layout.bounds());
498
499        if is_mouse_over {
500            mouse::Interaction::Pointer
501        } else {
502            mouse::Interaction::default()
503        }
504    }
505
506    fn draw(
507        &self,
508        _tree: &Tree,
509        renderer: &mut Renderer,
510        theme: &Theme,
511        _style: &renderer::Style,
512        layout: Layout<'_>,
513        _cursor: mouse::Cursor,
514        viewport: &Rectangle,
515    ) {
516        let style = Catalog::style(theme, self.class);
517        let bounds = layout.bounds();
518
519        let text_size =
520            self.text_size.unwrap_or_else(|| renderer.default_size());
521        let option_height =
522            f32::from(self.text_line_height.to_absolute(text_size))
523                + self.padding.y();
524
525        let offset = viewport.y - bounds.y;
526        let start = (offset / option_height) as usize;
527        let end = ((offset + viewport.height) / option_height).ceil() as usize;
528
529        let visible_options = &self.options[start..end.min(self.options.len())];
530
531        for (i, option) in visible_options.iter().enumerate() {
532            let i = start + i;
533            let is_selected = *self.hovered_option == Some(i);
534
535            let bounds = Rectangle {
536                x: bounds.x,
537                y: bounds.y + (option_height * i as f32),
538                width: bounds.width,
539                height: option_height,
540            };
541
542            if is_selected {
543                renderer.fill_quad(
544                    renderer::Quad {
545                        bounds: Rectangle {
546                            x: bounds.x + style.border.width,
547                            width: bounds.width - style.border.width * 2.0,
548                            ..bounds
549                        },
550                        border: border::rounded(style.border.radius),
551                        ..renderer::Quad::default()
552                    },
553                    style.selected_background,
554                );
555            }
556
557            renderer.fill_text(
558                Text {
559                    content: option.to_string(),
560                    bounds: Size::new(f32::INFINITY, bounds.height),
561                    size: text_size,
562                    line_height: self.text_line_height,
563                    font: self.font.unwrap_or_else(|| renderer.default_font()),
564                    align_x: text::Alignment::Default,
565                    align_y: alignment::Vertical::Center,
566                    shaping: self.text_shaping,
567                    wrapping: text::Wrapping::default(),
568                },
569                Point::new(bounds.x + self.padding.left, bounds.center_y()),
570                if is_selected {
571                    style.selected_text_color
572                } else {
573                    style.text_color
574                },
575                *viewport,
576            );
577        }
578    }
579}
580
581impl<'a, 'b, T, Message, Theme, Renderer>
582    From<List<'a, 'b, T, Message, Theme, Renderer>>
583    for Element<'a, Message, Theme, Renderer>
584where
585    T: ToString + Clone,
586    Message: 'a,
587    Theme: 'a + Catalog,
588    Renderer: 'a + text::Renderer,
589    'b: 'a,
590{
591    fn from(list: List<'a, 'b, T, Message, Theme, Renderer>) -> Self {
592        Element::new(list)
593    }
594}
595
596/// The appearance of a [`Menu`].
597#[derive(Debug, Clone, Copy, PartialEq)]
598pub struct Style {
599    /// The [`Background`] of the menu.
600    pub background: Background,
601    /// The [`Border`] of the menu.
602    pub border: Border,
603    /// The text [`Color`] of the menu.
604    pub text_color: Color,
605    /// The text [`Color`] of a selected option in the menu.
606    pub selected_text_color: Color,
607    /// The background [`Color`] of a selected option in the menu.
608    pub selected_background: Background,
609    /// The [`Shadow`] of the menu.
610    pub shadow: Shadow,
611}
612
613/// The theme catalog of a [`Menu`].
614pub trait Catalog: scrollable::Catalog {
615    /// The item class of the [`Catalog`].
616    type Class<'a>;
617
618    /// The default class produced by the [`Catalog`].
619    fn default<'a>() -> <Self as Catalog>::Class<'a>;
620
621    /// The default class for the scrollable of the [`Menu`].
622    fn default_scrollable<'a>() -> <Self as scrollable::Catalog>::Class<'a> {
623        <Self as scrollable::Catalog>::default()
624    }
625
626    /// The [`Style`] of a class with the given status.
627    fn style(&self, class: &<Self as Catalog>::Class<'_>) -> Style;
628}
629
630/// A styling function for a [`Menu`].
631pub type StyleFn<'a, Theme> = Box<dyn Fn(&Theme) -> Style + 'a>;
632
633impl Catalog for Theme {
634    type Class<'a> = StyleFn<'a, Self>;
635
636    fn default<'a>() -> StyleFn<'a, Self> {
637        Box::new(default)
638    }
639
640    fn style(&self, class: &StyleFn<'_, Self>) -> Style {
641        class(self)
642    }
643}
644
645/// The default style of the list of a [`Menu`].
646pub fn default(theme: &Theme) -> Style {
647    let palette = theme.extended_palette();
648
649    Style {
650        background: palette.background.weak.color.into(),
651        border: Border {
652            width: 1.0,
653            radius: 0.0.into(),
654            color: palette.background.strong.color,
655        },
656        text_color: palette.background.weak.text,
657        selected_text_color: palette.primary.strong.text,
658        selected_background: palette.primary.strong.color.into(),
659        shadow: Shadow::default(),
660    }
661}
iced_widget/overlay/menu.rs

iced_widget/overlay/
menu.rs
