Lift keeps the current scale; it does not reset

What it is

A pinch tunes an observation state that is supposed to remain, not a preview that only holds while fingers are down. After both fingers lift, scale should stay at that last frame so people can pan, read, or pinch again. Snapping back to 100%, or to the scale at page entry, throws away the aim they just finished. The pinch becomes a trial that cannot commit.

Why it happens

Scale is a persistent property of the document or view, in the same family as scroll offset. Lift ends input, not state. If a product implements pinch as “hold to preview smaller,” lift-reset is a modal preview, not a zoom primitive—and during the preview there are no free fingers to tap or select. Persistent scale lets later gestures stack on the new ratio: shrink to see the whole, then one-finger pan to the next building. Returning to a default scale should be an explicit act (double-tap to fit, a “fit screen” button), not a reading of “lift” as reset, because lift happens at the end of every pinch.

Studying it

Split the task: pinch to a named scale, then after lift use one finger to bring a detail into view. If lift resets, the second half is impossible. Log whether scale changes in the 500 ms after lift, and whether people immediately pinch again. Control: an explicit fit-screen button. Questionnaire items about “does zoom remember” often collapse into a settings question; behavior logs are cleaner.

Where it stops holding

A temporary loupe, or hold-to-peek at private content, is supposed to be live only while held; lift must restore. That is not pinch-zoom. Some maps reset scale on rotate or tab switch; that is state drop at a session boundary and should be named, not hidden inside lift. An animation that eases to the nearest detent after lift still counts as persist if detents are dense; if the nearest detent is 100%, it is a reset wearing snap’s clothes.

Applying it

• Write the current scale into view state and do not change it on lift. Offer a visible “fit screen” or a double-tap-to-fit as the explicit reset.
• Do not use a lift animation to carry scale back to the entry value.
• Pinch to about 60%, lift, wait a second, then pan with one finger. Scale should still be about 60%. If the picture grows by itself, state was quietly dropped.

Related

• Same group: C3.08.1 Scale is set continuously by change in the two-finger span · C3.08.2 The zoom anchor is the two-finger midpoint so content under the pinch does not drift · C3.08.3 Min and max scale should rubber-band at the limit · C3.08.5 Pinch is unavailable in a one-handed grip and needs an alternative path
• Adjacent: C3.02 Double tap · C3.09 Spread-to-zoom in
• Search: persistent zoom · view scale · pinch lift