Struct kas_widgets::GripPart

pub struct GripPart { /* private fields */ }

A draggable grip part

Slider, ScrollBar and Splitter all require a component which supports click+drag behaviour. The appearance differs but event handling is the same: this widget is its implementation.

Layout

This widget is unusual in several ways:

1. Layout::size_rules does not request any size; the parent is expected to do this.
2. Layout::set_rect sets the track within which this grip may move; the parent should always call GripPart::set_size_and_offset afterwards to set the grip position.
3. Layout::draw does nothing. The parent should handle all drawing.

Event handling

This widget handles click/touch events on the widget, pushing a GripMsg to allow the parent to implement further handling.

Optionally, the parent may call GripPart::handle_press_on_track when a Event::PressStart occurs on the track area (which identifiers as the parent widget).

Implementations

impl GripPart

pub fn new() -> Self

Construct

pub fn set_size_and_offset(&mut self, size: Size, offset: Offset) -> Action

Set a new grip size and position

Returns Action::REDRAW if a redraw is required.

pub fn track(&self) -> Rect

Get the current track Rect

pub fn offset(&self) -> Offset

Get the current grip position

pub fn max_offset(&self) -> Offset

Get the maximum allowed offset

The grip position is clamped between ZERO and this offset relative to the track. This value depends on size of the grip and the track.

pub fn set_offset(&mut self, offset: Offset) -> (Offset, Action)

Set a new grip position

Returns the new position (after clamping input) and an action: empty if the grip hasn’t moved; REDRAW if it has (though this widget is not directly responsible for drawing, so this may not be accurate).

pub fn handle_press_on_track( &mut self, mgr: &mut EventMgr<'_>, press: &Press ) -> Offset

Handle an event on the track itself

If it is desired to make the grip move when the track area is clicked, then the parent widget should call this method when receiving Event::PressStart.

Returns the new grip position relative to the track.

The grip position is not adjusted; the caller should also call Self::set_offset to do so. This is separate to allow adjustment of the posision; e.g. Slider pins the position to the nearest detent.

Trait Implementations

impl Clone for GripPart

fn clone(&self) -> GripPart

Returns a copy of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Debug for GripPart

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Default for GripPart

fn default() -> GripPart

Returns the “default value” for a type.

impl Layout for GripPart

This implementation is unusual in that:

1. size_rules always returns SizeRules::EMPTY
2. set_rect sets the track within which this grip may move; the parent should call GripPart::set_size_and_offset after set_rect (otherwise the grip’s position will not be updated)
3. draw does nothing: the parent is expected to do all drawing

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

Get size rules for the given axis

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

Set size and position

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

Draw a widget and its children

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

Translate a coordinate to a WidgetId

impl Widget for GripPart

fn handle_event(&mut self, mgr: &mut EventMgr<'_>, event: Event) -> Response

Handle an Event sent to this widget

fn pre_configure(&mut self, _: &mut ConfigMgr<'_>, id: WidgetId)

Pre-configuration

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

Configure widget

fn navigable(&self) -> bool

Is this widget navigable via Tab key?

fn translation(&self) -> Offset

Get translation of children relative to this widget

fn nav_next( &mut self, mgr: &mut ConfigMgr<'_>, reverse: bool, from: Option<usize> ) -> Option<usize>

Navigation in spatial order

fn steal_event( &mut self, mgr: &mut EventMgr<'_>, id: &WidgetId, event: &Event ) -> Response

Potentially steal an event before it reaches a child

fn handle_unused(&mut self, mgr: &mut EventMgr<'_>, event: Event) -> Response

Handle an event sent to child index but left unhandled

fn handle_message(&mut self, mgr: &mut EventMgr<'_>)

Handler for messages from children/descendants

fn handle_scroll(&mut self, mgr: &mut EventMgr<'_>, scroll: Scroll)

Handler for scrolling

impl WidgetChildren for GripPart

fn num_children(&self) -> usize

Get the number of child widgets

fn get_child(&self, _index: usize) -> Option<&dyn Widget>

Get a reference to a child widget by index, or None if the index is out of bounds.

fn get_child_mut(&mut self, _index: usize) -> Option<&mut dyn Widget>

Mutable variant of get

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

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

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

Make an identifier for a child

impl WidgetCore for GripPart

fn id_ref(&self) -> &WidgetId

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 as_widget(&self) -> &dyn Widget

Erase type

fn as_widget_mut(&mut self) -> &mut dyn Widget

Erase type