Struct ScrollRegion 

pub struct ScrollRegion<W: Viewport + Widget> { /* private fields */ }

A region which supports scrolling of content through a viewport

This region supports scrolling via mouse wheel and click/touch drag as well as using scroll bars (optional).

Size

Kas’s size model allows widgets to advertise two sizes: the minimum size and the ideal size. This distinction is used to full effect here:

• The ideal size is that of the inner content, thus avoiding any need to scroll content.
• The minimum size is an arbitrary size defined by the theme (SizeCx::min_scroll_size).

Generic usage

Though this widget is generic over any Viewport, it is primarily intended for usage with ClipRegion; the primary constructor Self::new_clip uses this while Self::new_viewport allows usage with other implementations of Viewport.

It should be noted that scroll bar positioning does not respect the inner widget’s margins, since the result looks poor when content is scrolled. Instead the inner widget should force internal margins by wrapping contents with a (zero-sized) frame.

Messages

kas::messages::SetScrollOffset may be used to set the scroll offset.

Implementations

impl<Inner: Widget> ScrollRegion<ClipRegion<Inner>>

pub fn new_clip(inner: Inner) -> Self

Construct a scroll region using a ClipRegion

This is probably the constructor you want unless the inner widget already implements Viewport.

Uses ScrollBarMode::Auto by default.

impl<W: Viewport + Widget> ScrollRegion<W>

pub fn new_viewport(inner: W) -> Self

Construct over a Viewport

Uses ScrollBarMode::Auto by default.

pub fn with_fixed_bars(self, horiz: bool, vert: bool) -> Self

where Self: Sized,

Set fixed visibility of scroll bars (inline)

pub fn with_invisible_bars(self, horiz: bool, vert: bool) -> Self

where Self: Sized,

Set fixed, invisible bars (inline)

In this mode scroll bars are either enabled but invisible until mouse over or disabled completely.

pub fn scroll_bar_mode(&self) -> ScrollBarMode

Get current mode of scroll bars

pub fn set_scroll_bar_mode( &mut self, cx: &mut ConfigCx<'_>, mode: ScrollBarMode, )

Set scroll bar mode

pub fn inner(&self) -> &W

Access inner widget directly

pub fn inner_mut(&mut self) -> &mut W

Access inner widget directly

Trait Implementations

impl<W: Debug + Viewport + Widget> Debug for ScrollRegion<W>

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

Formats the value using the given formatter.

impl<W: Default + Viewport + Widget> Default for ScrollRegion<W>

fn default() -> ScrollRegion<W>

Returns the “default value” for a type.

impl<W: Viewport + Widget> Events for ScrollRegion<W>

fn probe(&self, coord: Coord) -> Id

Probe a coordinate for a widget’s Id

fn mouse_over_icon(&self) -> Option<CursorIcon>

The mouse pointer icon to use on mouse over

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

Configure self

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

Handle an Event

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

Handler for messages from children/descendants

fn handle_resize( &mut self, cx: &mut ConfigCx<'_>, _: &Self::Data, ) -> Option<ActionResize>

Handler for resize requests

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

Handler for scrolling

const REDRAW_ON_MOUSE_OVER: bool = false

Does this widget have a different appearance on mouse over?

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

Make an identifier for a child

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

Configure self (post-child-configuration actions)

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

Update self using input data

fn recurse_indices(&self) -> ChildIndices

Recursion control

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

Mouse focus handler

fn child_nav_focus(&mut self, cx: &mut EventCx<'_>, id: Id)

Notification that a child received navigation focus

impl<W: Viewport + Widget> Layout for ScrollRegion<W>

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

Calculate size requirements for an axis

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

Set size and position

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

Draw a widget and its children

fn rect(&self) -> Rect

Get the widget’s region

impl<W: Viewport + Widget> Tile for ScrollRegion<W>

fn role(&self, _: &mut dyn RoleCx) -> Role<'_>

Describe the widget’s role

fn translation(&self, index: usize) -> Offset

Get translation of child index relative to this widget

fn as_tile(&self) -> &dyn Tile

Get as a dyn Tile

fn id_ref(&self) -> &Id

Get a reference to the widget’s identifier

fn identify(&self) -> IdentifyWidget<'_>

Return a Display-able widget identifier

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

Access a child as a dyn Tile, if available

fn child_indices(&self) -> ChildIndices

Get child indices available to recursion

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

Probe a coordinate for a widget’s Id

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

Navigation in spatial order

fn id(&self) -> Id

Get the widget’s identifier

fn navigable(&self) -> bool

Whether this widget supports navigation focus

fn tooltip(&self) -> Option<&str>

Tooltip

fn role_child_properties(&self, cx: &mut dyn RoleCx, index: usize)

Specify additional role properties for child index

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

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

impl<W: Viewport + Widget> Widget for ScrollRegion<W>

type Data = <W as Widget>::Data

Input data type

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

Erase type

fn child_node<'__n>( &'__n mut self, data: &'__n Self::Data, index: usize, ) -> Option<Node<'__n>>

Access a child as a Node, if available