d4_interpolate 1.0.0

Interpolate numbers, colors, strings, arrays, objects, whatever!

Interpolate numbers, colors, strings, arrays, objects, whatever!

This package provides a variety of interpolation methods for blending between two values. Values may be numbers, colors, strings, lists, or even deeply-nested maps. For example:

final i = interpolateNumber(10, 20);
i(0.0); // 10
i(0.2); // 12
i(0.5); // 15
i(1.0); // 20

The returned function i is called an interpolator. Given a starting value a and an ending value b, it takes a parameter t in the domain [0, 1] and returns the corresponding interpolated value between a and b. An interpolator typically returns a value equivalent to a at t = 0 and a value equivalent to b at t = 1.

You can interpolate more than just numbers. To find the perceptual midpoint between steelblue and brown:

interpolateLab("steelblue", "brown")(0.5); // "rgb(142, 92, 109)"

Here’s a more elaborate example demonstrating type inference used by interpolate:

final i = interpolate({"colors": ["red", "blue"]}, {"colors": ["white", "black"]});
i(0.0); // {colors: [rgb(255, 0, 0), rgb(0, 0, 255)]}
i(0.5); // {colors: [rgb(255, 128, 128), rgb(0, 0, 128)]}
i(1.0); // {colors: [rgb(255, 255, 255), rgb(0, 0, 0)]}

Note that the generic value interpolator detects not only nested maps and lists, but also color strings and numbers embedded in strings!