Struct CumulativeHeights

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pub struct CumulativeHeights { /* private fields */ }

Expand description

Prefix-sum cache for variable-height row scroll lookups.

Build once per frame (or whenever the row set changes) with CumulativeHeights::build, then call row_at_offset and visible_range as needed during rendering.

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impl CumulativeHeights

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pub fn build<S: RowSource + ?Sized>(source: &S) -> Self

Build the prefix-sum array from a RowSource.

Calls RowSource::row_height once per row and accumulates the results.

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pub fn total_height(&self) -> f32

Total height of all rows in logical pixels.

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pub fn row_at_offset(&self, scroll_offset: f32) -> usize

Return the index of the first row whose top edge is at or before scroll_offset.

Uses a binary search for O(log n) lookup.

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pub fn visible_range( &self, scroll_offset: f32, viewport_height: f32, ) -> Range<usize>

Return the range of row indices that are (at least partially) visible in a viewport starting at scroll_offset with height viewport_height.

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impl UnwindSafe for CumulativeHeights

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