This CL cleans up the sky/framework/animation as follows:
1) I've moved code that's used only by the custom elements framework into
sky/framework/elements/animation. This code is based on AnimationDelegates
rather than Streams.
2) Rename ScrollCurve to ScrollBehavior because it encapsulates more behavior
than just a curve.
3) Make the Generator interface explicit and mark subclasses as actual
subclasses.
4) Move Simulation into generators.dart because it implements the Generator
interface.
5) Move Animation out of generators.dart because it does not implement the
Generator interface.
R=eseidel@chromium.org
Review URL: https://codereview.chromium.org/1001373002
This CL uses a simple physics simulation to drive overscroll animations.
We model settling the overscroll as a particle climbing a hill, which
gives us a pleasing parabolic trajectory.
This CL also includes machinery for spring-based simulations. We'll use
these to drive the drawer animation.
R=eseidel@chromium.org
Review URL: https://codereview.chromium.org/999423004
This CL teaches Scrollable how to settle back to a scroll offset of 0.0 after a
fling or a scroll. There's still some room for improvement:
1) Some of this logic should be factored out into the scroll curve object.
2) We don't produce the correct animation curves when we fling into the
overscroll region because we wait for the fling velocity to reach zero
before we start the settling animation.
R=ojan@chromium.org, eseidel@chromium.org
Review URL: https://codereview.chromium.org/1005753002
Intead of hard-coding the notion of bounded scrolling into Scrollable, this CL
factors out a ScrollCurve class that applies the bounds. In the future, we'll
refine this mechanism to implement overflow scrolling.
R=eseidel@chromium.org
Review URL: https://codereview.chromium.org/1005633002
