FA-80669 / Bidirectional text layout / Member archive

Bidi selection highlight: slot sorting · case 04

RTL selections are drawn as many one-unit fragments.

Member previewVariant 4 · 3 implementations · 8 checks per implementation

Case contract

Input [levels, anchor, focus]. The logical selection covers characters min..max-1. Each selected character occupies its unit visual slot (level reversal); merge adjacent slots into [x0, x1) rectangles sorted by x. Return the rectangles.

Why this case matters

Mixed right-to-left and left-to-right text must resolve levels and visual order exactly, or words, numbers and carets land in the wrong place.

One recorded failure

Sample boundary fixture

This sample comes from the broken implementation of a controlled reproducer.

Boundary fixture	Actual	Expected	Outcome
regression: slot sorting	`[[4, 5], [3, 4], [2, 3], [1, 2], [0, 1]]`	`[[0, 5]]`	Failed

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