Ease

A generic implementation of standard easing functions for use in animation or robotics.

For examples of "standard" easing algorithms (in this case used in CSS animations) take a look at easings.net

Installation

Available in Hex, the package can be installed by adding ease to your list of dependencies in mix.exs:

def deps do
  [{:ease, "~> 0.2.0"}]
end

Documentation can be found at https://hexdocs.pm/ease.

Usage

You can use an easing function directly from within your own loop, provided that you can supply the four arguments needed;

• current_time - the elapsed "time" in the loop, ie if your duration is ten, and you want to find the position for half way through the duration then you set it to 5. Units are arbitrary (steps, ms, whatever).
• start_value - the initial value or position at current_time of zero.
• change_in_value- how much the start_value should be changed by the end of the animation, ie the expected final value minus the start_value.
• duration - the duration of the animation, in the same units as current_time.

Given a quadratic ease-in of 1..10, over 1 unit of time, where would we be when half-way through:

iex> Ease.ease_in_quad(0.5, 1, 10, 1)
3.25

Plot the {x, y} positions for a circular ease-in:

iex> ys = 1..10
...> xs = Ease.map(ys, :ease_in_circular)
...> Enum.zip(xs, ys)
[{1.0, 1}, {1.0557280900008417, 2}, {1.2250356126078779, 3},
 {1.5147186257614298, 4}, {1.9377422517014504, 5}, {2.5166852264521173, 6},
 {3.291796067500631, 7}, {4.34314575050762, 8}, {5.876894374382339, 9},
 {10.0, 10}]

License

Source code is licensed under the terms of the MIT license, the text of which is included in the LICENSE file in this distribution.