Shared layout
When a thing on one screen becomes a thing on the next, the eye wants to follow one object, not watch one disappear and another appear.
The collection's flight is a shared-layout transition without a library. A copy of the hero image travels inside the room's own layer, scaled uniformly so the artwork never stretches, while an animated clip changes its outline from the card's shape to the viewer's. Both ends are measured once; if the viewport changes mid-flight the animation jumps to its end rather than landing off target. Open is 720ms, close is 560ms, on the same curve as the reflow.
- Uniform scale plus animated clip: the image never distorts, and cover reconciles with contain
- Measure both ends at the moment of the move, not at mount
- The metadata follows the object in and leaves ahead of it on the way out
When not to: navigation drill-in inside a dense tool is a clean slide with both panels mounted; content-area route changes are instant with a fade. Shared layout is for the one object the person chose.