FA-80688 / Bidirectional text layout / Member archive

Bidi hit testing: left clamp · case 03

Clicks left of the line hit characters at the far end.

Member previewVariant 3 · 3 implementations · 8 checks per implementation

Case contract

Input [levels, x in half-character units]. Clamp to a visual slot (each character 2 units). The right half of an LTR character or the left half of an RTL character is its trailing side. Points before the line use the left half of slot 0, beyond it the right half of the last slot. Return [logical index, trailing, caret offset].

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: left clamp	`[0, true, 1]`	`[6, true, 7]`	Failed

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This record includes three runnable implementations, regression fixtures, execution results, and source hashes.

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