Curve Fitting Algorithm in the Curve Editor?

A place to talk about anything else with other Pixelmator users.
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2018-10-31 01:49:21

As a fellow iOS/macos developer, I have been a long-time customer, user, and fan of Pixelmator and Pixelmator Pro, and I wanted to ask a question that I hope one of the developers can chime in on.



What is the curve-fitting algorithm used in the curve editor?

Image



To the best of my knowledge, I believe it's a form of Lagrange Interpolating Polynomial (capped at the bounds of the editor)?



Thank you,

keehun
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2018-10-31 08:06:38

Hi, Keehun Nam.

It is cubic spline interpolation. You can find more information here: https://en.wikipedia.org/wiki/Spline_interpolation

This method is commonly used to implement Curves functionality. That is why we used it — to not be a surprise to our users.
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2018-10-31 15:37:49

Thank you very much for that information, Anton!