Paul, I am thoroughly impressed by your grasp of graphics file formats. You have solved my problem overnight and, yes, the GIF that you referenced is indeed what it should be; a map of the solutions to the equation z^3-1 = 0, using Newton's method. (A Practical Fractal?) Your "fix" is to a byte which the author describes as Byte 03, ( he has a Byte 00); "No. of bits for 1 pixel from 1 plane". I can't remember why I have this underlined in the book, and with a "?" attached. However you have hit the nail on the head. I'll try modifying the TP Unit to do just that. My sincere thanks, John W. ----- Original Message ----- From: "Paul N. Lee" <Paul.N.Lee@Worldnet.att.net> To: <fractint@mailman.xmission.com> Sent: Tuesday, November 18, 2003 1:28 AM Subject: Re: [Fractint] Doesn't look like a fractal!
John Wilson wrote:
I'd like to take advantage of your offer....
Only had time for a quick look this night, maybe more time tomorrow, but here is the preliminary analysis....
The two files you sent me do contain the PCX Identifier within the Header. They indicate a Version 3.0 format, which means that the files should be readable by: PC Paintbrush 3.0 PC Paintbrush Plus PC Paintbrush Plus for Windows Publisher's Paintbrush They are using a simple byte-wise run-length encoding (RLE) scheme. And both files are the same size in pixels: 640 x 350 (with a DPI setting as the same).
The bits per pixel per plane in the image data is set to four (4), which normally means 16-color images. There supposedly are four (4) color planes that contain the image data. But this seems to be where the problem is. Usually the number of color planes is also used to determine the maximum number of colors a PCX image may have. The number of bits per pixel per plane is multiplied by the number of color panes and shifted to the left by one: MaxNumberOfColors = (1L << (BitsPerPixel * NumBitPlanes))
I modified the fourth byte from a value of hex(04) to a value of hex(01) to see the effect it would have. The following image is what opened up when I double-clicked the modified PCX file (now saved as a GIF): http://www.nahee.com/Fractals/NEWTON02.gif
Do you know if that is what the image should look like??
Sincerely, P.N.L. ------------------------------------------------- http://home.att.net/~Paul.N.Lee/PNL_Fractals.html http://www.Nahee.com/Fractals/
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