Regional difference belongs in chrome and copy, not core gesture logic

What it is

Pinch remains inter-finger span, long-press remains duration, swipe remains heading plus speed—the physics of the recognizer and the classifier should not fork by country. Regional difference lives in mirrored navigation, illustration, help copy, and whether a given hand is shown. Changing pinch gain for one nation and killing double-tap for another strips both travellers and developers of a shared model.

Why it happens

Core logic is a cross-app skill: someone who learned pinch should not meet another geometry after a border. Forked recognizers also explode the test matrix by locale, and bugs will not reproduce. What should change is the culturally mapped layer: RTL mirroring is direction semantics, not a speed formula; a taboo hand is art, not touchesMoved. Split strings and resources by region; keep one gesture state machine, so the “same app” is still the same app. Exceptions must be rare and named as mirroring, not as another physics.

Studying it

List gestures and tag each as logic / mapping / skin. Logic items run the same script under several locales; trajectory classification should match. Mapping items (back direction) may follow layoutDirection. If a locale’s failures come from a translation that turned “double-tap” into another action, that is copy—do not retune a threshold.

Where it stops holding

Legally forced feature differences (a region that forbids a class of gambling gesture) may turn a whole feature off; that is product availability, not a new recognizer. If the OS itself has no two-finger panel in a region, the app follows the OS; that is still not a private physics fork. Reading-direction mirroring belongs to the mapping layer, already handled in the direction leaf, and is not a core-logic fork.

Applying it

• One global state machine and threshold table; locale swaps strings, art, and whether the navigation axis is mirrored.
• Treat if (country == …) pinchGain = as a defect in review.
• Replay the same trajectory scripts under several language packs: labels should match; back direction flips only under the RTL pack.

Related

• Same group: C3.34.1 Some gesture directions follow regional reading habits · C3.34.2 Some hand motions can offend and should not be shipped worldwide as one · C3.34.3 Teaching images of hands need skin-tone and hand-shape representation
• Adjacent: C3.19 Gesture conflicts and disambiguation · C3.29 Gesture velocity thresholds
• Search: internationalization · recognizer physics · locale mirroring