iced_aw/widget/selection_list/
list.rs

1//! Build and show dropdown `ListMenus`.
2
3use crate::selection_list::Catalog;
4
5use iced_core::{
6    Border, Clipboard, Color, Element, Event, Layout, Length, Padding, Pixels, Point, Rectangle,
7    Shell, Size, Widget,
8    alignment::Vertical,
9    layout::{Limits, Node},
10    mouse::{self, Cursor},
11    renderer, touch,
12    widget::text::{LineHeight, Wrapping},
13    widget::{
14        Tree,
15        tree::{State, Tag},
16    },
17};
18use std::{
19    collections::hash_map::DefaultHasher,
20    fmt::Display,
21    hash::{Hash, Hasher},
22    marker::PhantomData,
23};
24
25/// The Private [`List`] Handles the Actual list rendering.
26#[allow(missing_debug_implementations)]
27pub struct List<'a, T: 'a, Message, Theme, Renderer>
28where
29    T: Clone + Display + Eq + Hash,
30    [T]: ToOwned<Owned = Vec<T>>,
31    Renderer: renderer::Renderer + iced_core::text::Renderer<Font = iced_core::Font>,
32    Theme: Catalog,
33{
34    /// Options pointer to hold all rendered strings
35    pub options: &'a [T],
36    /// Hovered Item Pointer
37    /// Label Font
38    pub font: Renderer::Font,
39    /// Style for Font colors and Box hover colors.
40    pub class: <Theme as Catalog>::Class<'a>,
41    /// Function Pointer On Select to call on Mouse button press.
42    pub on_selected: Box<dyn Fn(usize, T) -> Message>,
43    /// The padding Width
44    pub padding: Padding,
45    /// The Text Size
46    pub text_size: f32,
47    /// Set the Selected ID manually.
48    pub selected: Option<usize>,
49    /// Shadow Type holder for Renderer.
50    pub phantomdata: PhantomData<Renderer>,
51}
52
53/// The Private [`ListState`] Handles the State of the inner list.
54#[derive(Debug, Clone, Default)]
55pub struct ListState {
56    /// Statehood of ``hovered_option``
57    pub hovered_option: Option<usize>,
58    /// The index in the list of options of the last chosen Item Clicked for Processing
59    pub last_selected_index: Option<(usize, u64)>,
60    // String Build Cache
61    //pub options: Vec<String>,
62}
63
64impl<T, Message, Theme, Renderer> Widget<Message, Theme, Renderer>
65    for List<'_, T, Message, Theme, Renderer>
66where
67    T: Clone + Display + Eq + Hash,
68    Renderer: renderer::Renderer + iced_core::text::Renderer<Font = iced_core::Font>,
69    Theme: Catalog,
70{
71    fn tag(&self) -> Tag {
72        Tag::of::<ListState>()
73    }
74
75    fn state(&self) -> State {
76        State::new(ListState::default())
77    }
78
79    fn diff(&self, state: &mut Tree) {
80        let list_state = state.state.downcast_mut::<ListState>();
81
82        if let Some(id) = self.selected {
83            if let Some(option) = self.options.get(id) {
84                let mut hasher = DefaultHasher::new();
85                option.hash(&mut hasher);
86
87                list_state.last_selected_index = Some((id, hasher.finish()));
88            } else {
89                list_state.last_selected_index = None;
90            }
91        } else if let Some((id, hash)) = list_state.last_selected_index {
92            if let Some(option) = self.options.get(id) {
93                let mut hasher = DefaultHasher::new();
94                option.hash(&mut hasher);
95
96                if hash != hasher.finish() {
97                    list_state.last_selected_index = None;
98                }
99            } else {
100                list_state.last_selected_index = None;
101            }
102        }
103
104        //list_state.options = self.options.iter().map(ToString::to_string).collect();
105    }
106
107    fn size(&self) -> Size<Length> {
108        Size::new(Length::Fill, Length::Shrink)
109    }
110
111    fn layout(&mut self, _tree: &mut Tree, _renderer: &Renderer, limits: &Limits) -> Node {
112        use std::f32;
113        let limits = limits.height(Length::Fill).width(Length::Fill);
114
115        #[allow(clippy::cast_precision_loss)]
116        let intrinsic = Size::new(
117            limits.max().width,
118            (self.text_size + self.padding.y()) * self.options.len() as f32,
119        );
120
121        Node::new(intrinsic)
122    }
123
124    fn update(
125        &mut self,
126        state: &mut Tree,
127        event: &Event,
128        layout: Layout<'_>,
129        cursor: Cursor,
130        _renderer: &Renderer,
131        _clipboard: &mut dyn Clipboard,
132        shell: &mut Shell<Message>,
133        _viewport: &Rectangle,
134    ) {
135        let bounds = layout.bounds();
136        let list_state = state.state.downcast_mut::<ListState>();
137        let cursor = cursor.position().unwrap_or_default();
138
139        if bounds.contains(cursor) {
140            match event {
141                Event::Mouse(mouse::Event::CursorMoved { .. }) => {
142                    list_state.hovered_option = Some(
143                        ((cursor.y - bounds.y) / (self.text_size + self.padding.y())) as usize,
144                    );
145
146                    shell.request_redraw();
147                }
148                Event::Mouse(mouse::Event::ButtonPressed(mouse::Button::Left))
149                | Event::Touch(touch::Event::FingerPressed { .. }) => {
150                    list_state.hovered_option = Some(
151                        ((cursor.y - bounds.y) / (self.text_size + self.padding.y())) as usize,
152                    );
153
154                    if let Some(index) = list_state.hovered_option
155                        && let Some(option) = self.options.get(index)
156                    {
157                        let mut hasher = DefaultHasher::new();
158                        option.hash(&mut hasher);
159                        list_state.last_selected_index = Some((index, hasher.finish()));
160                    }
161
162                    list_state.last_selected_index.iter().for_each(|last| {
163                        if let Some(option) = self.options.get(last.0) {
164                            shell.publish((self.on_selected)(last.0, option.clone()));
165                            shell.capture_event();
166                        }
167                    });
168
169                    shell.request_redraw();
170                }
171                _ => {}
172            }
173        } else if list_state.hovered_option.is_some() {
174            list_state.hovered_option = None;
175            shell.request_redraw();
176        }
177    }
178
179    fn mouse_interaction(
180        &self,
181        _state: &Tree,
182        layout: Layout<'_>,
183        cursor: Cursor,
184        _viewport: &Rectangle,
185        _renderer: &Renderer,
186    ) -> mouse::Interaction {
187        let bounds = layout.bounds();
188
189        if bounds.contains(cursor.position().unwrap_or_default()) {
190            mouse::Interaction::Pointer
191        } else {
192            mouse::Interaction::default()
193        }
194    }
195
196    fn draw(
197        &self,
198        state: &Tree,
199        renderer: &mut Renderer,
200        theme: &Theme,
201        _style: &renderer::Style,
202        layout: Layout<'_>,
203        _cursor: Cursor,
204        viewport: &Rectangle,
205    ) {
206        use std::f32;
207
208        let bounds = layout.bounds();
209        let option_height = self.text_size + self.padding.y();
210        let offset = viewport.y - bounds.y;
211        let start = (offset / option_height) as usize;
212        let end = ((offset + viewport.height) / option_height).ceil() as usize;
213        let list_state = state.state.downcast_ref::<ListState>();
214
215        for i in start..end.min(self.options.len()) {
216            let is_selected = list_state.last_selected_index.is_some_and(|u| u.0 == i);
217            let is_hovered = list_state.hovered_option == Some(i);
218
219            let bounds = Rectangle {
220                x: bounds.x,
221                y: bounds.y + option_height * i as f32,
222                width: bounds.width,
223                height: self.text_size + self.padding.y(),
224            };
225
226            if (is_selected || is_hovered) && (bounds.width > 0.) && (bounds.height > 0.) {
227                renderer.fill_quad(
228                    renderer::Quad {
229                        bounds,
230                        border: Border {
231                            radius: (0.0).into(),
232                            width: 0.0,
233                            color: Color::TRANSPARENT,
234                        },
235                        ..renderer::Quad::default()
236                    },
237                    if is_selected {
238                        theme
239                            .style(&self.class, crate::style::Status::Selected)
240                            .background
241                    } else {
242                        theme
243                            .style(&self.class, crate::style::Status::Hovered)
244                            .background
245                    },
246                );
247            }
248
249            let text_color = if is_selected {
250                theme
251                    .style(&self.class, crate::style::Status::Selected)
252                    .text_color
253            } else if is_hovered {
254                theme
255                    .style(&self.class, crate::style::Status::Hovered)
256                    .text_color
257            } else {
258                theme
259                    .style(&self.class, crate::style::Status::Active)
260                    .text_color
261            };
262
263            renderer.fill_text(
264                iced_core::text::Text {
265                    content: self.options[i].to_string(),
266                    bounds: Size::new(f32::INFINITY, bounds.height),
267                    size: Pixels(self.text_size),
268                    font: self.font,
269                    align_x: iced_widget::text::Alignment::Left,
270                    align_y: Vertical::Center,
271                    line_height: LineHeight::default(),
272                    shaping: iced_widget::text::Shaping::Advanced,
273                    wrapping: Wrapping::default(),
274                },
275                Point::new(bounds.x, bounds.center_y()),
276                text_color,
277                bounds,
278            );
279        }
280    }
281}
282
283impl<'a, T, Message, Theme, Renderer> From<List<'a, T, Message, Theme, Renderer>>
284    for Element<'a, Message, Theme, Renderer>
285where
286    T: Clone + Display + Eq + Hash,
287    Message: 'a,
288    Renderer: 'a + renderer::Renderer + iced_core::text::Renderer<Font = iced_core::Font>,
289    Theme: 'a + Catalog,
290{
291    fn from(list: List<'a, T, Message, Theme, Renderer>) -> Self {
292        Element::new(list)
293    }
294}
iced_aw/widget/selection_list/list.rs

iced_aw/widget/selection_list/
list.rs
