Gravitas is a collection of equations for making UI elements move in response to touch gestures.
Each simulation models a single value and generally has a setup function that takes the initial position and velocity. Normally you would compute these in response to a touch gesture ending. All of the simulations are parametric over time and have been algebraically integrated (rather than using a numerical integration method at runtime). The advantage of algebraic integration is lower CPU overhead, and no odd behavior if frames are dropped.
a position with velocity that slows down due to drag.
a position under the influence of gravity (or any other constant acceleration), as defined by Newton's 2nd Law:
Pager is similar to
A SnapPoint is either an end point or a point of attraction. Every pager needs at least two snap points to define the extents
a combination of friction and springs to create a touch-driven scrolling simulation.
a position controlled by a spring as defined by Hooke's law,
Any number can be either between two snap points, or beyond one of the extents.
common methods implemented by every simulation allowing easy integration into an animation system.