Struct kas_widgets::List

pub struct List<W: Widget, D: Directional> { /* private fields */ }

A generic row/column widget

This type is roughly Vec but for widgets. Generics:

• W: Widget — type of widget
• D: Directional — fixed or run-time direction of layout

Alternatives

Some more specific type-defs are available:

• Row and Column fix the direction D
• BoxList fixes the widget type to Box<dyn Widget<Data = Data>>
• BoxRow and BoxColumn fix both type parameters

Performance

Configuring and resizing elements is O(n) in the number of children. Drawing and event handling is O(log n) in the number of children (assuming only a small number are visible at any one time).

Messages

If a handler is specified via Self::on_messages then this handler is called when a child pushes a message. This allows associating the child’s index with a message.

Implementations

impl<W: Widget, D> List<W, D>

where D: Default + Directional,

pub fn new(widgets: impl Into<Vec<W>>) -> Self

Construct a new instance

This constructor is available where the direction is determined by the type: for D: Directional + Default. In other cases, use Self::new_dir.

impl<W: Widget> List<W, Left>

pub fn left(widgets: impl Into<Vec<W>>) -> Self

Construct a new instance

impl<W: Widget> List<W, Right>

pub fn right(widgets: impl Into<Vec<W>>) -> Self

Construct a new instance

impl<W: Widget> List<W, Up>

pub fn up(widgets: impl Into<Vec<W>>) -> Self

Construct a new instance

impl<W: Widget> List<W, Down>

pub fn down(widgets: impl Into<Vec<W>>) -> Self

Construct a new instance

impl<W: Widget> List<W, Direction>

pub fn set_direction(&mut self, direction: Direction) -> Action

Set the direction of contents

impl<W: Widget, D: Directional> List<W, D>

pub fn new_dir(widgets: impl Into<Vec<W>>, direction: D) -> Self

Construct a new instance with explicit direction

pub fn map_message<M, N, H>(self, handler: H) -> Self

where M: Debug + 'static, N: Debug + 'static, H: Fn(usize, M) -> N + 'static,

Add a child handler to map messages of type M to N

Example

use kas::messages::Select;
use kas_widgets::{Row, Tab};

#[derive(Clone, Debug)]
struct MsgSelectIndex(usize);

let tabs: Row<Tab> = Row::new([]).map_message(|index, Select| MsgSelectIndex(index));

pub fn on_message<M, H>(self, handler: H) -> Self

where M: Debug + 'static, H: Fn(&mut AdaptEventCx<'_, '_>, usize, M) + 'static,

Add a child handler for messages of type M

Where multiple message types must be handled or access to the AdaptEventCx is required, use Self::on_messages instead.

pub fn on_messages<H>(self, handler: H) -> Self

where H: Fn(&mut AdaptEventCx<'_, '_>, &W::Data, usize) -> bool + 'static,

Add a child message handler (inline style)

This handler is called when a child pushes a message: f(cx, index), where index is the child’s index.

pub fn edit<F: FnOnce(&mut Vec<W>)>(&mut self, f: F) -> Action

Edit the list of children directly

This may be used to edit children before window construction. It may also be used from a running UI, but in this case a full reconfigure of the window’s widgets is required (triggered by the the return value, Action::RECONFIGURE).

pub fn direction(&self) -> Direction

Get the direction of contents

pub fn layout_storage(&mut self) -> &mut impl RowStorage

Access layout storage

The number of columns/rows is [Self.len].

pub fn is_empty(&self) -> bool

True if there are no child widgets

pub fn len(&self) -> usize

Returns the number of child widgets

pub fn clear(&mut self)

Remove all child widgets

pub fn get(&self, index: usize) -> Option<&W>

Returns a reference to the child, if any

pub fn get_mut(&mut self, index: usize) -> Option<&mut W>

Returns a mutable reference to the child, if any

pub fn push( &mut self, cx: &mut ConfigCx<'_>, data: &W::Data, widget: W ) -> usize

Append a child widget

The new child is configured immediately. Action::RESIZE is triggered.

Returns the new element’s index.

pub fn pop(&mut self, cx: &mut EventState) -> Option<W>

Remove the last child widget (if any) and return

Triggers Action::RESIZE.

pub fn insert( &mut self, cx: &mut ConfigCx<'_>, data: &W::Data, index: usize, widget: W )

Inserts a child widget position index

Panics if index > len.

The new child is configured immediately. Triggers Action::RESIZE.

pub fn remove(&mut self, cx: &mut EventState, index: usize) -> W

Removes the child widget at position index

Panics if index is out of bounds.

Triggers Action::RESIZE.

pub fn replace( &mut self, cx: &mut ConfigCx<'_>, data: &W::Data, index: usize, w: W ) -> W

Replace the child at index

Panics if index is out of bounds.

The new child is configured immediately. Triggers Action::RESIZE.

pub fn extend<T>(&mut self, cx: &mut ConfigCx<'_>, data: &W::Data, iter: T)

where T: IntoIterator<Item = W>,

Append child widgets from an iterator

New children are configured immediately. Triggers Action::RESIZE.

pub fn resize_with<F>( &mut self, cx: &mut ConfigCx<'_>, data: &W::Data, len: usize, f: F )

where F: Fn(usize) -> W,

Resize, using the given closure to construct new widgets

New children are configured immediately. Triggers Action::RESIZE.

pub fn iter(&self) -> impl Iterator<Item = &W>

Iterate over childern

pub fn iter_mut(&mut self) -> impl Iterator<Item = &mut W>

Mutably iterate over childern

Trait Implementations

impl<W: Widget, D: Directional> AutoLayout for List<W, D>

fn size_rules(&mut self, sizer: SizeCx<'_>, axis: AxisInfo) -> SizeRules

Get size rules for the given axis

fn set_rect(&mut self, cx: &mut ConfigCx<'_>, rect: Rect)

Set size and position

fn find_id(&mut self, coord: Coord) -> Option<Id>

Translate a coordinate to an Id

fn draw(&mut self, draw: DrawCx<'_>)

Draw a widget and its children

impl<W: Widget, D> Default for List<W, D>

where D: Default + Directional,

fn default() -> Self

Returns the “default value” for a type.

impl<W: Widget, D: Directional> Events for List<W, D>

fn make_child_id(&mut self, index: usize) -> Id

Make a fresh id based on self.next then insert into self.id_map

fn configure(&mut self, _: &mut ConfigCx<'_>)

Configure self

fn handle_messages(&mut self, cx: &mut EventCx<'_>, data: &Self::Data)

Handler for messages from children/descendants

fn steal_event( &mut self, _: &mut EventCx<'_>, _: &Self::Data, _: &Id, _: &Event ) -> IsUsed

Potentially steal an event before it reaches a child

fn handle_event( &mut self, _: &mut EventCx<'_>, _: &Self::Data, _: Event ) -> IsUsed

Handle an Event

fn configure_recurse(&mut self, cx: &mut ConfigCx<'_>, data: &Self::Data)

Configure children

fn update(&mut self, cx: &mut ConfigCx<'_>, data: &Self::Data)

Update self using input data

fn update_recurse(&mut self, cx: &mut ConfigCx<'_>, data: &Self::Data)

Update children

fn navigable(&self) -> bool

Is this widget navigable via Tab key?

fn handle_hover(&mut self, cx: &mut EventCx<'_>, state: bool) -> IsUsed

Mouse focus handler

fn handle_scroll( &mut self, cx: &mut EventCx<'_>, data: &Self::Data, scroll: Scroll )

Handler for scrolling

impl<W: Widget, D: Directional + Default> FromIterator<W> for List<W, D>

fn from_iter<T>(iter: T) -> Self

where T: IntoIterator<Item = W>,

Creates a value from an iterator.

impl<W: Widget, D: Directional> Index<usize> for List<W, D>

type Output = W

The returned type after indexing.

fn index(&self, index: usize) -> &Self::Output

Performs the indexing (container[index]) operation.

impl<W: Widget, D: Directional> IndexMut<usize> for List<W, D>

fn index_mut(&mut self, index: usize) -> &mut Self::Output

Performs the mutable indexing (container[index]) operation.

impl<W: Widget, D: Directional> Layout for List<W, D>

fn num_children(&self) -> usize

Get the number of child widgets

fn get_child(&self, index: usize) -> Option<&dyn Layout>

Access a child as a dyn Layout

fn find_child_index(&self, id: &Id) -> Option<usize>

Find the child which is an ancestor of this id, if any

fn as_layout(&self) -> &dyn Layout

Get as a dyn Layout

fn id_ref(&self) -> &Id

Get the widget’s identifier

fn rect(&self) -> Rect

Get the widget’s region, relative to its parent.

fn widget_name(&self) -> &'static str

Get the name of the widget struct

fn size_rules(&mut self, sizer: SizeCx<'_>, axis: AxisInfo) -> SizeRules

Get size rules for the given axis

fn set_rect(&mut self, cx: &mut ConfigCx<'_>, rect: Rect)

Set size and position

fn nav_next(&self, reverse: bool, from: Option<usize>) -> Option<usize>

Navigation in spatial order

fn find_id(&mut self, coord: Coord) -> Option<Id>

Translate a coordinate to an Id

fn draw(&mut self, draw: DrawCx<'_>)

Draw a widget and its children

fn translation(&self) -> Offset

Get translation of children relative to this widget

impl<W: Widget, D: Directional> Widget for List<W, D>

type Data = <W as Widget>::Data

Input data type

fn for_child_node( &mut self, data: &W::Data, index: usize, closure: Box<dyn FnOnce(Node<'_>) + '_> )

Call closure on child with given index, if index < self.num_children().

fn as_node<'a>(&'a mut self, data: &'a Self::Data) -> Node<'a>

Erase type