Paul wrote:
1. True colour:
Instead of 256 colours, I generate a palette which stretches from 0 to maxiter which has calculated RGB triplets and these are plotted to memory instead of the normal palette. The palette only requires 6 integers to creat as opposed to 256 in a normal 256 colour palette. This part is real easy. I have it working for 16 bit iteration values. So the iteration count is used to index through the rgb palette table as before. The only consequence is that it is //// not reversable //// and a set of RGB triplets may be duplicated in the table so an array of integers is needed for getpixel()
Could the original iteration values of pixels be recovered from a True Color Fractint fractal image file at a later time by appending the six values and maxiter that generated the color triplets in an extension block appended to the image file? This would allow a different coloring to be applied to a True Color Fractint fractal image file at a later time. Perhaps this could be done as a stand alone application, perhaps as a Fractint feature. If a True Color Fractint fractal image file contained the six values and maxiter along with the image could you: - use the six values and maxiter to re-generate the table of original RGB triplets; - step through the file's pixels and look up the pixel's RGB triplet (various look-up methods come to mind) and thus - find the original iteration count of that pixel from the triplet's location in the RGB triplet table. - then use a different six values and the original maxiter to generate a new set of RGB triplets; - then build a new output image of RGB triplet pixels in the same way that the original .png image was created; - write out the newly colored output image to a file. It appears that the six values and maxiter could to be added to a .png file: http://en.wikipedia.org/wiki/Png says 'ancillary chunks' can be stored in a .png image: "Other image attributes that can be stored in PNG files include gamma values, background color, and textual metadata information." "tEXt can store text that can be represented in ISO 8859-1, with one name=value pair for each chunk." Paul, How are the six values and maxiter used to create the RGB triplets? Do you happen to know how other true color fractal programs create/specify their RGB triplets? - Hal Lane ######################### # hallane@earthlink.net <mailto:hallane@earthlink.net> # ######################### -- No virus found in this outgoing message. Checked by AVG Free Edition. Version: 7.1.410 / Virus Database: 268.17.18/662 - Release Date: 1/31/07