Struct ListWindow 

pub struct ListWindow {
    pub estimated_item_height: f32,
    pub overscan: usize,
    pub gap: f32,
    pub scroll_offset: f32,
    /* private fields */
}

Fields

estimated_item_height: f32

overscan: usize

gap: f32

scroll_offset: f32

Implementations

impl ListWindow

pub fn new(estimated_item_height: f32, overscan: usize, gap: f32) -> ListWindow

pub fn record(&mut self, key: &str, height: f32) -> bool

Remember one row’s laid-out height. Returns true when it changed.

pub fn estimate(&self) -> f32

The extent of an unmeasured item (item_extents): the mean measured extent once any item was measured (keeps the scroll extent stable, so a fling lands on the real end in one pass), else estimated_item_height (the theme’s $control.row, round 2 §5).

pub fn measured_mean(&self) -> Option<f32>

The mean measured extent (None before the first pass).

pub fn extents<'a>(&self, keys: impl Iterator<Item = &'a str>) -> Vec<f64>

Every item’s extent in key order (measured, else the estimate).

pub fn height_of(&self, key: &str) -> f32

pub fn forget(&mut self, key: &str)

pub fn clear(&mut self)

pub fn offsets_cached(&mut self, keys: &Arc<Vec<String>>) -> Arc<Vec<f32>>

Self::offsets memoized per keys list (by identity) until a height or the gap changes: a scroll step reuses them (O(log n) per step).

pub fn sticky_header_cached( &mut self, keys: &Arc<Vec<String>>, header_rows: &[usize], scroll: f64, ) -> Option<(StickyHeader, f64)>

The pinned header (sticky_header) on the memoized offsets (Self::offsets_cached): a row’s extent = the next offset − the gap, so nothing per row is recomputed. Header rows past the keys are ignored; header_rows ascending. Returns the pin and the row’s own offset.

pub fn offsets<'a>(&self, keys: impl Iterator<Item = &'a str>) -> Vec<f32>

Offsets of every row’s top plus the total height at the end. Linear in the row count (one pass, no allocation per row beyond the output); the surface calls it once per layout pass.

pub fn content_height<'a>(&self, keys: impl Iterator<Item = &'a str>) -> f32

Total content height for count rows (estimated where unmeasured).

pub fn visible_range(&self, offsets: &[f32], viewport: f32) -> VisibleRange

The items to lay out for a viewport of viewport (on the list’s axis) at the current scroll offset, overscan on both ends: every item intersecting [scroll, scroll + viewport) (an item ending exactly at scroll counts), virtual_window on memoized offsets, O(log n). offsets = Self::offsets.

Trait Implementations

impl Clone for ListWindow

fn clone(&self) -> Self

Returns a duplicate of the value.

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

Performs copy-assignment from source.

impl Debug for ListWindow

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

Formats the value using the given formatter.