Appendix C GIF Save File Format
Since version 5.0, Fractint has had the <S>ave-to-disk command, which
stores screen images in the extremely compact, flexible .GIF (Graphics
Interchange Format) widely supported on CompuServe. Version 7.0 added
the <R>estore-from-disk capability.
Until version 14, Fractint saved images as .FRA files, which were a non-
standard extension of the then-current GIF87a specification. The reason
was that GIF87a did not offer a place to store the extra information
needed by Fractint to implement the <R> feature -- i.e., the parameters
that let you keep zooming, etc. as if the restored file had just been
created in this session. The .FRA format worked with all of the popular
GIF decoders that we tested, but these were not true GIF files. For one
thing, information after the GIF terminator (which is where we put the
extra info) has the potential to confuse the online GIF viewers used on
CompuServe. For another, it is the opinion of some GIF developers that
the addition of this extra information violates the GIF87a spec. That's
why we used the default filetype .FRA instead.
Since version 14, Fractint has used a genuine .GIF format, using the
GIF89a spec - an upwardly compatible extension of GIF87a, released by
CompuServe on August 1 1990. This new spec allows the placement of
application data within "extension blocks". In version 14 we changed
our default savename extension from .FRA to .GIF.
There is one significant advantage to the new GIF89a format compared to
the old GIF87a-based .FRA format for Fractint purposes: the new .GIF
files may be uploaded to the CompuServe graphics forums fractal
information intact. Therefore anyone downloading a Fractint image from
CompuServe will also be downloading all the information needed to
regenerate the image.
Fractint can still read .FRA files generated by earlier versions. If
for some reason you wish to save files in the older GIF87a format, for
example because your favorite GIF decoder has not yet been upgraded to
GIF89a, use the command-line parameter "GIF87a=yes". Then any saved
files will use the original GIF87a format without any application-
specific information.
An easy way to convert an older .FRA file into true .GIF format suitable
for uploading is something like this at the DOS prompt:
FRACTINT MYFILE.FRA SAVENAME=MYFILE.GIF BATCH=YES
Fractint will load MYFILE.FRA, save it in true .GIF format as
MYFILE.GIF, and return to DOS.
GIF and "Graphics Interchange Format" are trademarks of CompuServe
Incorporated, an H&R Block Company.