PointerSample typedef

PointerSample = ({double sliverX, double sliverY, double viewportDy, double viewportHeight})

One pointer conversion: everything the drag pipeline derives from a pointer position, computed from a SINGLE viewport lookup per event.

  • sliverY: sliver-local y, the space ReorderRenderPort.findRowAtPaintedY consumes (first tree row at 0). Differs from viewport scroll space by the tree sliver's precedingScrollExtent.
  • sliverX: viewport-local x, identical to sliver-local x for a vertical-axis tree. Consumed by the depth hint.
  • viewportDy / viewportHeight: viewport-local vertical position and extent, consumed by autoscroll edge-zone evaluation.

Implementation

typedef PointerSample = ({
  double sliverX,
  double sliverY,
  double viewportDy,
  double viewportHeight,
});