iced_widget/keyed/
column.rs

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1//! Keyed columns distribute content vertically while keeping continuity.
2use crate::core::layout;
3use crate::core::mouse;
4use crate::core::overlay;
5use crate::core::renderer;
6use crate::core::widget::Operation;
7use crate::core::widget::tree::{self, Tree};
8use crate::core::{
9    Alignment, Clipboard, Element, Event, Layout, Length, Padding, Pixels,
10    Rectangle, Shell, Size, Vector, Widget,
11};
12
13/// A container that distributes its contents vertically while keeping continuity.
14///
15/// # Example
16/// ```no_run
17/// # mod iced { pub mod widget { pub use iced_widget::*; } }
18/// # pub type State = ();
19/// # pub type Element<'a, Message> = iced_widget::core::Element<'a, Message, iced_widget::Theme, iced_widget::Renderer>;
20/// use iced::widget::{keyed_column, text};
21///
22/// enum Message {
23///     // ...
24/// }
25///
26/// fn view(state: &State) -> Element<'_, Message> {
27///     keyed_column((0..=100).map(|i| {
28///         (i, text!("Item {i}").into())
29///     })).into()
30/// }
31/// ```
32#[allow(missing_debug_implementations)]
33pub struct Column<
34    'a,
35    Key,
36    Message,
37    Theme = crate::Theme,
38    Renderer = crate::Renderer,
39> where
40    Key: Copy + PartialEq,
41{
42    spacing: f32,
43    padding: Padding,
44    width: Length,
45    height: Length,
46    max_width: f32,
47    align_items: Alignment,
48    keys: Vec<Key>,
49    children: Vec<Element<'a, Message, Theme, Renderer>>,
50}
51
52impl<'a, Key, Message, Theme, Renderer>
53    Column<'a, Key, Message, Theme, Renderer>
54where
55    Key: Copy + PartialEq,
56    Renderer: crate::core::Renderer,
57{
58    /// Creates an empty [`Column`].
59    pub fn new() -> Self {
60        Self::from_vecs(Vec::new(), Vec::new())
61    }
62
63    /// Creates a [`Column`] from already allocated [`Vec`]s.
64    ///
65    /// Keep in mind that the [`Column`] will not inspect the [`Vec`]s, which means
66    /// it won't automatically adapt to the sizing strategy of its contents.
67    ///
68    /// If any of the children have a [`Length::Fill`] strategy, you will need to
69    /// call [`Column::width`] or [`Column::height`] accordingly.
70    pub fn from_vecs(
71        keys: Vec<Key>,
72        children: Vec<Element<'a, Message, Theme, Renderer>>,
73    ) -> Self {
74        Self {
75            spacing: 0.0,
76            padding: Padding::ZERO,
77            width: Length::Shrink,
78            height: Length::Shrink,
79            max_width: f32::INFINITY,
80            align_items: Alignment::Start,
81            keys,
82            children,
83        }
84    }
85
86    /// Creates a [`Column`] with the given capacity.
87    pub fn with_capacity(capacity: usize) -> Self {
88        Self::from_vecs(
89            Vec::with_capacity(capacity),
90            Vec::with_capacity(capacity),
91        )
92    }
93
94    /// Creates a [`Column`] with the given elements.
95    pub fn with_children(
96        children: impl IntoIterator<
97            Item = (Key, Element<'a, Message, Theme, Renderer>),
98        >,
99    ) -> Self {
100        let iterator = children.into_iter();
101
102        Self::with_capacity(iterator.size_hint().0).extend(iterator)
103    }
104
105    /// Sets the vertical spacing _between_ elements.
106    ///
107    /// Custom margins per element do not exist in iced. You should use this
108    /// method instead! While less flexible, it helps you keep spacing between
109    /// elements consistent.
110    pub fn spacing(mut self, amount: impl Into<Pixels>) -> Self {
111        self.spacing = amount.into().0;
112        self
113    }
114
115    /// Sets the [`Padding`] of the [`Column`].
116    pub fn padding<P: Into<Padding>>(mut self, padding: P) -> Self {
117        self.padding = padding.into();
118        self
119    }
120
121    /// Sets the width of the [`Column`].
122    pub fn width(mut self, width: impl Into<Length>) -> Self {
123        self.width = width.into();
124        self
125    }
126
127    /// Sets the height of the [`Column`].
128    pub fn height(mut self, height: impl Into<Length>) -> Self {
129        self.height = height.into();
130        self
131    }
132
133    /// Sets the maximum width of the [`Column`].
134    pub fn max_width(mut self, max_width: impl Into<Pixels>) -> Self {
135        self.max_width = max_width.into().0;
136        self
137    }
138
139    /// Sets the horizontal alignment of the contents of the [`Column`] .
140    pub fn align_items(mut self, align: Alignment) -> Self {
141        self.align_items = align;
142        self
143    }
144
145    /// Adds an element to the [`Column`].
146    pub fn push(
147        mut self,
148        key: Key,
149        child: impl Into<Element<'a, Message, Theme, Renderer>>,
150    ) -> Self {
151        let child = child.into();
152        let child_size = child.as_widget().size_hint();
153
154        self.width = self.width.enclose(child_size.width);
155        self.height = self.height.enclose(child_size.height);
156
157        self.keys.push(key);
158        self.children.push(child);
159        self
160    }
161
162    /// Adds an element to the [`Column`], if `Some`.
163    pub fn push_maybe(
164        self,
165        key: Key,
166        child: Option<impl Into<Element<'a, Message, Theme, Renderer>>>,
167    ) -> Self {
168        if let Some(child) = child {
169            self.push(key, child)
170        } else {
171            self
172        }
173    }
174
175    /// Extends the [`Column`] with the given children.
176    pub fn extend(
177        self,
178        children: impl IntoIterator<
179            Item = (Key, Element<'a, Message, Theme, Renderer>),
180        >,
181    ) -> Self {
182        children
183            .into_iter()
184            .fold(self, |column, (key, child)| column.push(key, child))
185    }
186}
187
188impl<Key, Message, Renderer> Default for Column<'_, Key, Message, Renderer>
189where
190    Key: Copy + PartialEq,
191    Renderer: crate::core::Renderer,
192{
193    fn default() -> Self {
194        Self::new()
195    }
196}
197
198struct State<Key>
199where
200    Key: Copy + PartialEq,
201{
202    keys: Vec<Key>,
203}
204
205impl<Key, Message, Theme, Renderer> Widget<Message, Theme, Renderer>
206    for Column<'_, Key, Message, Theme, Renderer>
207where
208    Renderer: crate::core::Renderer,
209    Key: Copy + PartialEq + 'static,
210{
211    fn tag(&self) -> tree::Tag {
212        tree::Tag::of::<State<Key>>()
213    }
214
215    fn state(&self) -> tree::State {
216        tree::State::new(State {
217            keys: self.keys.clone(),
218        })
219    }
220
221    fn children(&self) -> Vec<Tree> {
222        self.children.iter().map(Tree::new).collect()
223    }
224
225    fn diff(&self, tree: &mut Tree) {
226        let Tree {
227            state, children, ..
228        } = tree;
229
230        let state = state.downcast_mut::<State<Key>>();
231
232        tree::diff_children_custom_with_search(
233            children,
234            &self.children,
235            |tree, child| child.as_widget().diff(tree),
236            |index| {
237                self.keys.get(index).or_else(|| self.keys.last()).copied()
238                    != Some(state.keys[index])
239            },
240            |child| Tree::new(child.as_widget()),
241        );
242
243        if state.keys != self.keys {
244            state.keys.clone_from(&self.keys);
245        }
246    }
247
248    fn size(&self) -> Size<Length> {
249        Size {
250            width: self.width,
251            height: self.height,
252        }
253    }
254
255    fn layout(
256        &self,
257        tree: &mut Tree,
258        renderer: &Renderer,
259        limits: &layout::Limits,
260    ) -> layout::Node {
261        let limits = limits
262            .max_width(self.max_width)
263            .width(self.width)
264            .height(self.height);
265
266        layout::flex::resolve(
267            layout::flex::Axis::Vertical,
268            renderer,
269            &limits,
270            self.width,
271            self.height,
272            self.padding,
273            self.spacing,
274            self.align_items,
275            &self.children,
276            &mut tree.children,
277        )
278    }
279
280    fn operate(
281        &self,
282        tree: &mut Tree,
283        layout: Layout<'_>,
284        renderer: &Renderer,
285        operation: &mut dyn Operation,
286    ) {
287        operation.container(None, layout.bounds(), &mut |operation| {
288            self.children
289                .iter()
290                .zip(&mut tree.children)
291                .zip(layout.children())
292                .for_each(|((child, state), layout)| {
293                    child
294                        .as_widget()
295                        .operate(state, layout, renderer, operation);
296                });
297        });
298    }
299
300    fn update(
301        &mut self,
302        tree: &mut Tree,
303        event: &Event,
304        layout: Layout<'_>,
305        cursor: mouse::Cursor,
306        renderer: &Renderer,
307        clipboard: &mut dyn Clipboard,
308        shell: &mut Shell<'_, Message>,
309        viewport: &Rectangle,
310    ) {
311        for ((child, state), layout) in self
312            .children
313            .iter_mut()
314            .zip(&mut tree.children)
315            .zip(layout.children())
316        {
317            child.as_widget_mut().update(
318                state, event, layout, cursor, renderer, clipboard, shell,
319                viewport,
320            );
321        }
322    }
323
324    fn mouse_interaction(
325        &self,
326        tree: &Tree,
327        layout: Layout<'_>,
328        cursor: mouse::Cursor,
329        viewport: &Rectangle,
330        renderer: &Renderer,
331    ) -> mouse::Interaction {
332        self.children
333            .iter()
334            .zip(&tree.children)
335            .zip(layout.children())
336            .map(|((child, state), layout)| {
337                child.as_widget().mouse_interaction(
338                    state, layout, cursor, viewport, renderer,
339                )
340            })
341            .max()
342            .unwrap_or_default()
343    }
344
345    fn draw(
346        &self,
347        tree: &Tree,
348        renderer: &mut Renderer,
349        theme: &Theme,
350        style: &renderer::Style,
351        layout: Layout<'_>,
352        cursor: mouse::Cursor,
353        viewport: &Rectangle,
354    ) {
355        for ((child, state), layout) in self
356            .children
357            .iter()
358            .zip(&tree.children)
359            .zip(layout.children())
360        {
361            child
362                .as_widget()
363                .draw(state, renderer, theme, style, layout, cursor, viewport);
364        }
365    }
366
367    fn overlay<'b>(
368        &'b mut self,
369        tree: &'b mut Tree,
370        layout: Layout<'_>,
371        renderer: &Renderer,
372        translation: Vector,
373    ) -> Option<overlay::Element<'b, Message, Theme, Renderer>> {
374        overlay::from_children(
375            &mut self.children,
376            tree,
377            layout,
378            renderer,
379            translation,
380        )
381    }
382}
383
384impl<'a, Key, Message, Theme, Renderer>
385    From<Column<'a, Key, Message, Theme, Renderer>>
386    for Element<'a, Message, Theme, Renderer>
387where
388    Key: Copy + PartialEq + 'static,
389    Message: 'a,
390    Theme: 'a,
391    Renderer: crate::core::Renderer + 'a,
392{
393    fn from(column: Column<'a, Key, Message, Theme, Renderer>) -> Self {
394        Self::new(column)
395    }
396}
iced_widget/keyed/column.rs

iced_widget/keyed/
column.rs
