The renderer applies every ancestor's transform, so a scaled null above a
camera already carries the camera's children. A Scale key with one shared
ease gets a separate Z ease before its speed is scaled.
Position speeds stretch with the path's direction at each key and Scale's Z
speed with the factor, so the ease keeps its shape. A 3D layer under a 2D
parent scales its own Z only when no 3D ancestor's Scale already carries it.
A 2D parent's Scale carries no depth, so its 3D children scale their own Z.
Percentage guides keep their percent exactly instead of drifting by rounding.
Tests now check the specific errors and cover a layer parented to a camera.
Like After Effects' File > Scripts > Scale Composition.jsx: a factor, or a new
width or height that keeps the aspect ratio, in one undo step. Layers whose
parent has a Scale follow that parent; nested precomps and expressions are
left as they are. No dialog yet.
Refs #2208
Every undoable edit keeps the previous project for undo, so the comp it touches
is shared and Arc::make_mut deep-copies it: every layer and every keyframe. An
edit therefore costs time in proportion to the comp's size, and a script that
sets many keyframes in a big comp goes quadratic (a 1,600-layer build with
~100k sampled keys took ~45 minutes).
Comp::layers is now a Layers collection backed by Vec<Arc<Layer>>: copying the
stack copies pointers, and only the layer an edit changes is copied. The API
mirrors Vec<Layer>; serialized form is unchanged (a list of layers).
Comp::layer_mut and the iter_mut().filter/find call sites use find_mut /
iter_mut_where so they copy only the layers they actually change.
- prop.addKey in a 400-layer comp: 1.36 ms -> 0.16 ms per key (flat in comp size)
- the 1,600-layer script build: ~45 min -> 47 s, frames pixel-identical
- regression tests: an edit leaves the other layers shared with undo; layers
round-trip as a plain list
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01VkpGcKfWyCudfSsQNiWAaG
bflatastic