POV-Ray : Newsgroups : povray.animations : How does the mandel value scale? Using ImageMagick to generate a fractal zo= Server Time: 9 Dec 2018 22:02:10 GMT
  How does the mandel value scale? Using ImageMagick to generate a fractal zo= (Message 1 to 1 of 1)  
From: peyrol
Subject: How does the mandel value scale? Using ImageMagick to generate a fractal zo=
Date: 10 Aug 2018 08:45:00
Message: <web.5b6d48fa8a4f23ba9abf9e400@news.povray.org>
I like the fractalzoom sample file provided in the animations folder for POVray.
I want to extend the first zoom in that file beyond the iterative limit it uses.
but I cannot predict what limit to use if I continue to zoom in at the same
magnification rate per frame, nor do I know what color map values to use to
provide good detail. That particular region that I am zooming into looks very
busy.

My notion is to shell out to call an ImageMagick script after each frame. This
script will check a rectangular region in the center of the image and count the
number of pure white pixels, which is the color corresponding to the upper bound
of the color map provided. If the region passes a threshold white pixel count
value, the iterative maximum will get increased, and new colors will be
introduced. This change will happen smoothly over the course of one second's
worth of frames, which in my case is 30. ImageMagick will not get called during
those frames.

At the end of that second, I want the old colors to still map to the same
iterative limits they were at before. For example, the original POVray script
had color map boundary values at 0, 0.25, 0.5, 0.75, and 1. Suppose the
iterative limit L increases by one order of magnitude to 10*L. Should the pure
white boundary value, which was at 1, become 0.1 which corresponds to a linear
scale? Or should it be ln(L)/ln(10*L) which is a logarithmic scale? Or something
else?

Thanks for any clue. Someone must surely have already dealt with this issue.


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