I’m a user from GimpChat, which first introduced me to G’MIC, via the GIMP plug-in. I’ve managed to use the “Cartesian Transform” (twice!) to distort images to fit desired outlines. However, I was only able to do it with the informed assistance of @garagecoder and @Souphead, who I see are well-known here too.
I am convinced that the G’MIC GIMP plug-in can do what I want; namely,
“create a new image in which the Intensity (I) of a pixel at a specific point has been set programmatically, and mathematically.”
However, I am confused by the Cartesian Tranform’s default paradigm, which appears to rely on “moving pixels at x and y to new locations based on two warping rules.” (This is undoubtedly an flameworthy misstatement of its function, but I am indeed confused, and this benighted interpretation actually did help me get the sought-for end in my examples.)
@Souphead had hinted that setting I(x,y) is probably feasible.
If so, here’s a quest:
"plot I(x,y) = sin(piR)/(piR), R=sqrt(x^2+y^2)"
[the venerable sinc() fcn]
The general goal is to learn the method for setting I(x,y) mathematically.
Let me also say that “to everyone who’s only learned how to use a hammer, every problem looks like a nail,” and I may have reached for Cartesian Transform out of desperation. Polar Transform didn’t look any more tractable, but I suspect the most flexible answer will involve Custom Code.