Struct kas_widgets::ScrollBar

pub struct ScrollBar<D: Directional> { /* private fields */ }

A scroll bar

Scroll bars allow user-input of a value between 0 and a defined maximum, and allow the size of the handle to be specified.

Messages

On value change, pushes a value of type ScrollMsg.

Layout

It is safe to not call size_rules before set_rect for this type.

Implementations

impl<D> ScrollBar<D>where D: Default + Directional,

pub fn new() -> Self

Construct a scroll bar

Default values are assumed for all parameters.

impl<D: Directional> ScrollBar<D>

pub fn new_with_direction(direction: D) -> Self

Construct a scroll bar with the given direction

Default values are assumed for all parameters.

pub fn direction(&self) -> Direction

Get the scroll bar’s direction

pub fn set_invisible(&mut self, invisible: bool)

Set invisible property

An “invisible” scroll bar is only drawn on mouse-hover

pub fn with_invisible(self, invisible: bool) -> Self

Set invisible property (inline)

An “invisible” scroll bar is only drawn on mouse-hover

pub fn with_limits(self, max_value: i32, handle_value: i32) -> Self

Set the initial page length

See ScrollBar::set_limits.

pub fn with_value(self, value: i32) -> Self

Set the initial value

pub fn set_limits(&mut self, max_value: i32, handle_value: i32) -> Action

Set the page limits

The max_value parameter specifies the maximum possible value. (The minimum is always 0.) For a scroll region, this should correspond to the maximum possible offset.

The handle_value parameter specifies the size of the handle relative to the maximum value: the handle size relative to the length of the scroll bar is handle_value / (max_value + handle_value). For a scroll region, this should correspond to the size of the visible region. The minimum value is 1.

The choice of units is not important (e.g. can be pixels or lines), so long as both parameters use the same units.

Returns Action::REDRAW if a redraw is required.

pub fn max_value(&self) -> i32

Read the current max value

See also the ScrollBar::set_limits documentation.

pub fn handle_value(&self) -> i32

Read the current handle value

See also the ScrollBar::set_limits documentation.

pub fn value(&self) -> i32

Get the current value

pub fn set_value(&mut self, mgr: &mut EventState, value: i32) -> bool

Set the value

Returns true if the value changes.

Trait Implementations

impl<D: Clone + Directional> Clone for ScrollBar<D>

fn clone(&self) -> ScrollBar<D>

Returns a copy of the value.

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

Performs copy-assignment from source.

impl<D: Debug + Directional> Debug for ScrollBar<D>

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

Formats the value using the given formatter.

impl<D: Default + Directional> Default for ScrollBar<D>

fn default() -> ScrollBar<D>

Returns the “default value” for a type.

impl<D: Directional> Layout for ScrollBar<D>

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

Get size rules for the given axis

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

Set size and position

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

Translate a coordinate to a WidgetId

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

Draw a widget and its children

impl<D: Directional> Widget for ScrollBar<D>

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

Handle an Event sent to this widget

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

Handler for messages from children/descendants

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

Handler for scrolling

impl<D: Directional> WidgetChildren for ScrollBar<D>

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<D: Directional> WidgetCore for ScrollBar<D>

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