tree 8d7a1da4f266b6667830f10cec5b35e12af02466
parent a8fa49016cd43346b4b214775f540bec288ed55d
author Florin Malita <fmalita@chromium.org> 1579211164 -0500
committer Skia Commit-Bot <skia-commit-bot@chromium.org> 1579214592 +0000

[skottie] Refactor property animators

Currently, property animators use lambda captures (std::function<>) to push
values to adapters and then to the scene graph.  Some downsides:

  * complex lambda captures are expensive in terms of object code size
  * adapters with multiple animated properties don't synchronize/quiesce: each individual property tick triggers a SG
    synchronization, possibly with inconsistent state (as animator running
    order is unspecified)
  * there is no enforced scoping, resulting in fragile constructs when SG
    fragments are discarded

This CL introduces a simplified and more robust animator pattern:

  * property animators are scoped to explicit containers
  * instead of capturing arbitrary value functors, animators only capture
    a pointer to the target value

Some implementation details:

  * keyframe/interpolation logic is pretty much unchanged (just relocated)
  * introduced AnimatablePropertyContainer - a base class for animatable
    adapters
  * legacy binding functions are refactored based on the new mechanism
    (they now/transitionally inject adapter objects)
  * converted a handful of effects, to exercise trivial refactoring patterns
  * converted the text animator goo, to exercise non-trivial refactoring:
    - detecting value changes is now trickier (no more lambda magic)
    - value adjustments must be hoisted into adapter logic (no more lambda magic)
    - all dependent animated values (selectors, etc) must be scoped to the
      text adapter to avoid lifetime issues

TBR=
Change-Id: Ia5821982f251de0de58fd3f87812219ff7fcc726
Reviewed-on: https://skia-review.googlesource.com/c/skia/+/263938
Commit-Queue: Florin Malita <fmalita@chromium.org>
Reviewed-by: Mike Reed <reed@google.com>