What kind of transform is this?

Question

I have a function that linearly "remaps" a value from a given interval to an other interval?

The function remaps a value from a given interval [oldMin, oldMax] to another interval [newMin, newMax] using this formula:

newVal = newMin + (newMax - newMin) * (oldVal - oldMin) / (oldMax - oldMin)

If it helps identify what type of transform it is, the above formula is just a reformulation of the following equation. All I did was re-arrange the terms to express newVal on the left hand side of the equation so it is a function of all the other parameters:

Is there a standard name for the remapping transformation?

Answer 1

This is known as Linear Interpolation.

Very common and powerful, in game development it's shorthand is "Lerp"

It is used to map one value (in a range) to another value (in a range). For example one might map health to color (for tinting the health bar) or time to rotation (for animation).

Answer 2

Mathematically, it's an affine transformation -- a linear transformation composed with a translation (from oldMin to newMin).