Where in a Fract???.gif file does the Fractint data appear? I have a question and want to be on sound ground before I raise it. All I can identify is that the file starts with GIF98a and near the end there is a little plain text that is "fractint001 Fractal" with the space actually being y with an umlaut over it. Nothing else identifiable as plain text. The point I particularly want to know about is how the V screen parameters are included. My Fractint computer had a disastrous breakdown a couple of months ago and am trying to recover and also evaluate ver 99. I ran across a floppy disk that was labeled "Problems" and am passing along one of them. Here is my Newpar.par file which includes the formula. The original parameter file was run on Fractint 99 and then recorded again. It doesn't show as much of the problem that showed originally but as you zoom in amazing things happen. At some magnifications the apparent high count areas disappear and at other magnifications they are massively messed up. Start parameter file. Julia { ; Parameter file recorded on Win 98 system in DOS mode ; Version 2002 Patchlevel 3 ; Only a trace of original problem ; Fractint Version 2099 Patchlevel 8 ; Fractint Version 2099 Patchlevel 8 reset=2099 type=julia4 passes=1 center-mag=6.199e-006/-2.265e-006/2.109716 params=-1.0296017527580259/0.19608962535858149 float=y maxiter=4097 colors=00000000z<3>PPzVVz``z<3>zzzzzzzzzz00z00<4>zS0zY0zc0<3>zz0<227>zz0 } Problem { ; Zoom on high count area. ; Version 2002 Patchlevel 3 ; Fractint Version 2099 Patchlevel 8 ; Fractint Version 2099 Patchlevel 8 reset=2099 type=julia4 passes=1 center-mag=0.42653/0.312698/17.29275 params=-1.0296017527580259/0.19608962535858149 float=y maxiter=4097 colors=00000000z<3>PPzVVz``z<3>zzzzzzzzzz00z00<4>zS0zY0zc0<3>zz0<227>zz0 } InandOut { ; After various zooms. ; Version 2002 Patchlevel 3 ; Fractint Version 2099 Patchlevel 8 ; Fractint Version 2099 Patchlevel 8 reset=2099 type=julia4 center-mag=0.427258/0.296879/9.281967/1.0001 params=-1.0296017527580259/0.19608962535858149 float=y maxiter=511 colors=00000000z<3>PPzVVz``z<3>zzzzzzzzzz00z00<4>zS0zY0zc0<3>zz0<227>zz0 } frm:julia4 {; Chuck Ebbert added 13 Jan 1993 ; p1=Parameter (default (.6,.55) ) ; bailout is real(p2) (default 4) ; force c=(.6,.55) if p1=0 z = pixel, c = ((0.6,0.55) * (|p1|<=0) + p1 ) t = (4 * (real(p2)<=0) + real(p2) * (0<p2) ): z = sqr(z*z) + c |z| <= t } End parameter file. Charles
Charles,
Where in a Fract???.gif file does the Fractint data appear? I have a question and want to be on sound ground before I raise it. All I can identify is that the file starts with GIF98a and near the end there is a little plain text that is "fractint001 Fractal" with the space actually being y with an umlaut over it. Nothing else identifiable as plain text. The point I particularly want to know about is how the V screen parameters are included.
It should be shortly after the GIF89a, as part of the standard GIF file format. You would need to look at the GIF specification. I don't believe we save any data from the <v> screen in the Fractint specific data segments. There is a very old DOS program called F-DATA by Marc Reinig, that can extract Fractint specific data from GIFs. It is not up-to-date so it won't see new parameters, but it is real good with the basics. I suspect if you would like to use it I'll have to email it to you, since a Google search didn't find it.
My Fractint computer had a disastrous breakdown a couple of months ago and am trying to recover and also evaluate ver 99. I ran across a floppy disk that was labeled "Problems" and am passing along one of them.
Here is my Newpar.par file which includes the formula. The original parameter file was run on Fractint 99 and then recorded again. It doesn't show as much of the problem that showed originally but as you zoom in amazing things happen. At some magnifications the apparent high count areas disappear and at other magnifications they are massively messed up.
These PARs need to have periodicity adjusted. Using either 0 or 10 will work. If that doesn't fix the problem you are seeing, let me know. Jonathan
Jonathan Osuch wrote:
Charles,
Where in a Fract???.gif file does the Fractint data appear? I have a question and want to be on sound ground before I raise it. All I can identify is that the file starts with GIF98a and near the end there is a little plain text that is "fractint001 Fractal" with the space actually being y with an umlaut over it. Nothing else identifiable as plain text. The point I particularly want to know about is how the V screen parameters are included.
It should be shortly after the GIF89a, as part of the standard GIF file format.
Actually, I believe it is at the end of the graphic file format, when FractInt saves the image file. A GIF file is different from most other common bitmap format in the sense that it is stream-based. It consists of a series of data packets, called _blocks_, along with additional protocol information. The GIF89a format begins off with a Header (only six bytes in size, and is used only to identify the file type), a Logical Screen Description (seven bytes long), and an optional Global Color Table. Each image also contains a Logical Image Descriptor, an optional Local Color Table, and a block of image data. The Trailer in every GIF89a file contains the same value found in the 87a files, which is a single byte of data as the last character (a hex 3B). With the 89a version, four new "block" features were added to the GIF format called Control Extensions. All of these Control Extension blocks begin with a hex 21, followed by another Label byte: Graphics Control Extension (hex F9) Plain Text Extension (hex 01) Comment Extension (hex FE) Application Extension (hex FF) The latter one is what is being used by FractInt for storing the data to recreate an image. Take for example Jim Muth's image for today. The one that I generated for the hosted 640x480 pixel image was 344,911 bytes in size. At the hex location of 540F3 (byte 344,308) is the beginning of the Application Extension block that contains the FractInt data, and looks something like this: hex - 21FF0B6672616374696E74303033425D616E64656C62726F746D697834 char - ! ÿ ¤ f r a c t i n t 0 0 3 B m a n d e l b r o t m i x 4 There are more bytes within this first Application Extension block, and then there is another Application Extension block which is also written by FractInt. Notice the third byte of this block has a hex value of 0B, which is the Blocksize field (the number of bytes in the Identifier and AuthentCode fields). The reason that you do not see displayable text type data is because a lot of these values that are stored by FractInt are not in a character format, but are Hexadecimal values. Which means if you see a couple of "words" that had x"8002" and x"E001", that would actually be the decimal numeric values of 640 and 480 respectively. Sincerely, P.N.L. ------------------------------------------------- http://home.att.net/~Paul.N.Lee/PNL_Fractals.html http://www.Nahee.com/Fractals/
On Fri, 2007-03-09 at 02:32 -0600, Paul N. Lee wrote:
Where in a Fract???.gif file does the Fractint data appear? I have a question and want to be on sound ground before I raise it. All I can identify is that the file starts with GIF98a and near the end there is a little plain text that is "fractint001 Fractal" with the space actually being y with an umlaut over it. Nothing else identifiable as plain text. The point I particularly want to know about is how the V screen parameters are included.
It should be shortly after the GIF89a, as part of the standard GIF file format.
Actually, I believe it is at the end of the graphic file format, when FractInt saves the image file.
That is where the Fractint data is, yes. But, the answer to Charles' question about where the <v> screen data is, is that Fractint does not save it. The only information about the resolution of the GIF would be the stuff saved as part of the GIF specification (ie, right after GIF89a). Jonathan
Worth noting, that the 4 bytes (starting at position 7, 2 for each) defining the width & height, are individually reversed. Example - today's FOTD starts (in Hex): 47 49 46 38 39 61 80 02 E0 01 ; GIF89a€.à. G I F 8 9 a 80 02 gets reversed ie 0280 - in decimal - 640 E0 01 gets reversed ie 01E0 - in decimal - 480 Hope this helps Paddy
-----Original Message----- From: fractint-bounces+padski=padski.com@mailman.xmission.com [mailto:fractint-bounces+padski=padski.com@mailman.xmission.com] On Behalf Of Jonathan Osuch Sent: Friday, March 09, 2007 1:53 PM To: Fractint and General Fractals Discussion Subject: Re: [Fractint] GIF File format
On Fri, 2007-03-09 at 02:32 -0600, Paul N. Lee wrote:
Where in a Fract???.gif file does the Fractint data appear? I have a question and want to be on sound ground before I raise it. All I can identify is that the file starts with GIF98a and near the end there is a little plain text that is "fractint001 Fractal" with the space actually being y with an umlaut over it. Nothing else identifiable as plain text. The point I particularly want to know about is how the V screen parameters are included.
It should be shortly after the GIF89a, as part of the standard GIF file format.
Actually, I believe it is at the end of the graphic file format, when FractInt saves the image file.
That is where the Fractint data is, yes. But, the answer to Charles' question about where the <v> screen data is, is that Fractint does not save it. The only information about the resolution of the GIF would be the stuff saved as part of the GIF specification (ie, right after GIF89a).
Jonathan
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Aha, as it says here after a search... Byte Ordering - Unless otherwise stated, multi-byte numeric fields are ordered with the Least Significant Byte first Paddy
-----Original Message----- From: fractint-bounces+padski=padski.com@mailman.xmission.com [mailto:fractint-bounces+padski=padski.com@mailman.xmission.com] On Behalf Of Paddy Duncan Sent: Friday, March 09, 2007 3:18 PM To: 'Fractint and General Fractals Discussion' Subject: RE: [Fractint] GIF File format
Worth noting, that the 4 bytes (starting at position 7, 2 for each) defining the width & height, are individually reversed. Example - today's FOTD starts (in Hex): 47 49 46 38 39 61 80 02 E0 01 ; GIF89a€.à. G I F 8 9 a
80 02 gets reversed ie 0280 - in decimal - 640 E0 01 gets reversed ie 01E0 - in decimal - 480
Hope this helps Paddy
-----Original Message----- From: fractint-bounces+padski=padski.com@mailman.xmission.com [mailto:fractint-bounces+padski=padski.com@mailman.xmission.com] On Behalf Of Jonathan Osuch Sent: Friday, March 09, 2007 1:53 PM To: Fractint and General Fractals Discussion Subject: Re: [Fractint] GIF File format
On Fri, 2007-03-09 at 02:32 -0600, Paul N. Lee wrote:
Where in a Fract???.gif file does the Fractint data appear? I have a question and want to be on sound ground before I raise it. All I can identify is that the file starts with GIF98a and near the end there is a little plain text that is "fractint001 Fractal" with the space actually being y with an umlaut over it. Nothing else identifiable as plain text. The point I particularly want to know about is how the V screen parameters are included.
It should be shortly after the GIF89a, as part of the standard GIF file format.
Actually, I believe it is at the end of the graphic file format, when FractInt saves the image file.
That is where the Fractint data is, yes. But, the answer to Charles' question about where the <v> screen data is, is that Fractint does not save it. The only information about the resolution of the GIF would be the stuff saved as part of the GIF specification (ie, right after GIF89a).
Jonathan
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Paddy wrote:
Worth noting, that the 4 bytes (starting at position 7, 2 for each) defining the width & height, are individually reversed. Example - today's FOTD starts (in Hex): 47 49 46 38 39 61 80 02 E0 01 ; GIF89aEUR.à. G I F 8 9 a
80 02 gets reversed ie 0280 - in decimal - 640 E0 01 gets reversed ie 01E0 - in decimal - 480
Whether they are "reversed" or not is a matter of religion. :-) The GIF specification states that byte order shall be little endian (least significant byte first). Those particular data items are only two bytes long, so the bytes are "swapped" from the way they are written in English. (But not Arabic :-). On a PC, all binary numeric data is written this way, it's not specific to GIF. At the time the GIF spec was written, PCs were Little Endian and just about everything else (Unix, and later Mac) were big endian. The point was that if GIF was to be independent of platform, byte order would have to be specified, so they specified little endian. With Intel hardware taking over almost all computing, little endian is now almost a standard. Your humble Fractint team had a big impact on the GIF spec, not that it was a democratic process, far from it. The members of the graphics developers forum opined and discussed and the GIF spec author lurked without every commenting. Then he just put out the Spec. Those of us in the graphics developers forum probably saw it first and gave plenty of feedback, but I don't recall any indication that the authjor paid attention. For GIF87a, fractint just appended fractal data after the GIF terminator, and when users uploaded files to CompuServe, their software stripped it and everyone howled. So GIF89a has an "extension block" scheme that provided a mechanism to place binary data safely inside the GIF file. The day the GIF89a spec came out, a new version of Fractint came out supporting it. My memory might not be correct, by I think I joined the Compuserve before Bert Tyler precisely to add GIF support to Bert's program. I didn't know Bert, but I admired his program, and I invited him to also join so we could both have access the the graphics developers forum. Bert's first versions of what became fractint could neither read nore write GIF. My first contribution was to add GIF support. This seems like a really, really long time ago. My first Fractint development computer was an intel 286 chip machine. The GIF spec can be found at this unofficial link, and probably many others: http://www.martinreddy.net/gfx/2d/GIF89a.txt Tim
Jonathan Osuch wrote:
On Fri, 2007-03-09 at 02:32 -0600, Paul N. Lee wrote:
Where in a Fract???.gif file does the Fractint data appear? I have a question and want to be on sound ground before I raise it. All I can identify is that the file starts with GIF98a and near the end there is a little plain text that is "fractint001 Fractal" with the space actually being y with an umlaut over it. Nothing else identifiable as plain text. The point I particularly want to know about is how the V screen parameters are included. It should be shortly after the GIF89a, as part of the standard GIF file format. Actually, I believe it is at the end of the graphic file format, when FractInt saves the image file.
That is where the Fractint data is, yes. But, the answer to Charles' question about where the <v> screen data is, is that Fractint does not save it. The only information about the resolution of the GIF would be the stuff saved as part of the GIF specification (ie, right after GIF89a).
Are you sure? Fractint stores at least both the screen resolution and the image size. I just generated two images both at size 640x480, one using the <v> screen and with a screen resolution of 1280x1040 and the other by using a screen resolution of 640x480 and saved them. On re-opening the first, the screen res Fractint tossed up was the 1280x1024 it had been generated in then displayed the image taking up only a small part of the screen and on hitting <v> the <v> screen info for that size was there. In the latter, the screen res on opening was 640x480 and the image occupied the whole screen and there were just the default <v> screen parameters. Mike
Jonathan Osuch wrote:
On Fri, 2007-03-09 at 02:32 -0600, Paul N. Lee wrote:
Where in a Fract???.gif file does the Fractint data appear? I have a question and want to be on sound ground before I raise it. All I can identify is that the file starts with GIF98a and near the end there is a little plain text that is "fractint001 Fractal" with the space actually being y with an umlaut over it. Nothing else identifiable as plain text. The point I particularly want to know about is how the V screen parameters are included. It should be shortly after the GIF89a, as part of the standard GIF file format. Actually, I believe it is at the end of the graphic file format, when FractInt saves the image file.
That is where the Fractint data is, yes. But, the answer to Charles' question about where the <v> screen data is, is that Fractint does not save it. The only information about the resolution of the GIF would be the stuff saved as part of the GIF specification (ie, right after GIF89a).
Are you sure? Fractint stores at least both the screen resolution and the image size. I just generated two images both at size 640x480, one using the <v> screen and with a screen resolution of 1280x1040 and the other by using a screen resolution of 640x480 and saved them. On re-opening the first, the screen res Fractint tossed up was the 1280x1024 it had been generated in then displayed the image taking up only a small part of the screen and on hitting <v> the <v> screen info for that size was there. In the latter, the screen res on opening was 640x480 and the image occupied the whole screen and there were just the default <v> screen parameters. Oh, and this is an opportunity to say how much I appreciate your efforts and those of all the folk who've contributed to Fractint over the years. In keeping with the instructions in the Fractint help, you have my admiration. Mike
On Fri, 2007-03-09 at 14:52 -0500, Michael Traynor wrote:
Where in a Fract???.gif file does the Fractint data appear? I have a question and want to be on sound ground before I raise it. All I can identify is that the file starts with GIF98a and near the end there is a little plain text that is "fractint001 Fractal" with the space actually being y with an umlaut over it. Nothing else identifiable as plain text. The point I particularly want to know about is how the V screen parameters are included. It should be shortly after the GIF89a, as part of the standard GIF file format. Actually, I believe it is at the end of the graphic file format, when FractInt saves the image file.
That is where the Fractint data is, yes. But, the answer to Charles' question about where the <v> screen data is, is that Fractint does not save it. The only information about the resolution of the GIF would be the stuff saved as part of the GIF specification (ie, right after GIF89a).
Are you sure? Fractint stores at least both the screen resolution and the image size.
Yes, I'm sure the View Window variables are not stored in the GIF file. These are variables such as viewxdots, viewydots, viewwindow, viewcrop, and viewreduction. For them to be stored in the GIF file, they would need to be in the fractal_info structure as defined in fractint.h, or possibly tacked on after (or before) the fractal_info structure is saved (see encoder.c). Then they would have to be restored. This is done in loadfile.c (decoder.c is lower level, the variables are restored in loadfile.c). Again, the View Windows variables do not appear to be saved to or restored from GIF files.
I just generated two images both at size 640x480, one using the <v> screen and with a screen resolution of 1280x1040 and the other by using a screen resolution of 640x480 and saved them. On re-opening the first, the screen res Fractint tossed up was the 1280x1024 it had been generated in then displayed the image taking up only a small part of the screen and on hitting <v> the <v> screen info for that size was there. In the latter, the screen res on opening was 640x480 and the image occupied the whole screen and there were just the default <v> screen parameters.
This can work because we have saved two different resolutions. The physical image size, say 1280x1040, is saved right after the GIF89a. The calculated image size using the View Window parameters, say 640x480, is saved as the variables xdots and ydots in the fractal_info structure.
From these two resolutions, we can calculate the variables for the View Window screen. This happens in loadfdos.c.
Jonathan
Jonathan Osuch wrote:
Charles F Crocker wrote:
Where in a Fract???.gif file does the Fractint data appear? ........ The point I particularly want to know about is how the V screen parameters are included.
It should be shortly after the GIF89a, as part of the standard GIF file format.
Paul N. Lee wrote:
Actually, I believe it is at the end of the graphic file format, when FractInt saves the image file.
That is where the Fractint data is, yes. But, the answer to Charles' question about where the <v> screen data is, is that Fractint does not save it.
Yes, Charles really asked two questions. I attempted to answer the very first question (the only one with an actual question mark), and you gave information about the GIF file's minimum resolution fields (located in the Logical Screen Descriptor block). I have not verified this, but I think that FractInt does store information about the image size in the Application Extension blocks that it writes, which is different from the GIF file fields that stores the minimum resolution fields. Sincerely, P.N.L. ------------------------------------------------- http://home.att.net/~Paul.N.Lee/PNL_Fractals.html http://www.Nahee.com/Fractals/
participants (6)
-
Charles F Crocker -
Jonathan Osuch -
Michael Traynor -
Paddy Duncan -
Paul N. Lee -
Tim Wegner