Trait kas_core::Scrollable

pub trait Scrollable: Widget {
    fn scroll_axes(&self, size: Size) -> (bool, bool);
    fn max_scroll_offset(&self) -> Offset;
    fn scroll_offset(&self) -> Offset;
    fn set_scroll_offset(
        &mut self,
        mgr: &mut EventMgr<'_>,
        offset: Offset
    ) -> Offset;
}

Additional functionality on scrollable widgets

This trait should be implemented by widgets supporting scrolling, enabling a parent to control scrolling.

If the widget scrolls itself it should set a scroll action via EventMgr::set_scroll.

Required Methods

fn scroll_axes(&self, size: Size) -> (bool, bool)

Given size size, returns whether (horiz, vert) scrolling is required

fn max_scroll_offset(&self) -> Offset

Get the maximum scroll offset

Note: the minimum scroll offset is always zero.

fn scroll_offset(&self) -> Offset

Get the current scroll offset

Contents of the scroll region are translated by this offset (to convert coordinates from the outer region to the scroll region, add this offset).

The offset is restricted between Offset::ZERO and Self::max_scroll_offset.

fn set_scroll_offset(&mut self, mgr: &mut EventMgr<'_>, offset: Offset) -> Offset

Set the scroll offset

This may be used for programmatic scrolling, e.g. by a wrapping widget with scroll controls. Note that calling this method directly on the scrolling widget will not update any controls in a wrapping widget.

The offset is clamped to the available scroll range and applied. The resulting offset is returned.

Implementors