composedSlideAbsDeltaBound property

double get composedSlideAbsDeltaBound

A true upper bound on the COMPOSED per-row delta, the SUM companion of maxActiveSlideAbsDelta's max. getSlideDeltaNid SUMS the FLIP engine and the make-room preview, and a row can carry both at once (a drag started while the prior commit's FLIP is still animating), reaching up to slideMax + previewMax; a max-based bound under-estimates exactly there. Use THIS bound wherever a window must provably contain every composed painted position (render overreach widening, the bounded drop-target scan). Degenerates to the single engine's max whenever the other is idle (an idle engine's max is 0.0), so single-engine states pay no extra width. Both engine maxima are computed on demand, never stale.

The preview's contribution is its TERMINAL magnitude (max(|current|, |target|) per row), so this bound does not grow as a gap animates open: it already covers where those rows are going. That is what lets the sliver element widen its layout admission window once per retarget rather than on every tick, and it is why a consumer may compare this against a bound recorded at the last layout (RenderSliverTree.admittedSlideBound).

Implementation

double get composedSlideAbsDeltaBound =>
    _slide.maxAbsDelta + _preview.maxAbsDelta;