From: gfoot AT mc31 DOT merton DOT ox DOT ac DOT uk (George Foot) Newsgroups: comp.os.msdos.djgpp Subject: Re: fli/flc files.. Date: 27 Feb 1997 21:48:23 GMT Organization: Oxford University Distribution: world Message-ID: <5f4vf7$m9s@news.ox.ac.uk> References: <9702271202 DOT AA11514 AT syntegra DOT bt DOT co DOT uk> <8waMLRALkeFzEw4B AT talula DOT demon DOT co DOT uk> NNTP-Posting-Host: mc31.merton.ox.ac.uk Lines: 29 To: djgpp AT delorie DOT com DJ-Gateway: from newsgroup comp.os.msdos.djgpp Shawn Hargreaves (Shawn AT talula DOT demon DOT co DOT uk) wrote: : Nigel Taylor writes: : >The question is regarding moving within the animation, is it possible : >in any way to move BACKWARDS through an animation?? I cant see a : >function to do this but it doesnt seem a particularly difficult task : >to carry out unless there is something odd about the way that a FLI : >stores data and it is impossible to restore the "previous frame" ?? : Unfortunately, this is impossible, because of the way the FLI format is : constructed. The frames in an FLI file are compressed with a crude RLE : system, both within each image and from one frame to the next, so each : frame of the file only contains information about the pixels that have : changed since the previous frame. This means that the only way to play : it in reverse is to store uncompressed copies of each frame (this would : take a _lot_ of space), or to reopen the file and play through from the : beginning to the required position... Or write a FLI reverser, i.e. make a routine which creates the animation in reverse. In this way, to step back a frame you would display the changes from the reversed file, and to step forward a frame you would use the normal file. This could perhaps be done internally, in memory, rather than on disk. It's just an idea - I don't know anything about FLI, so maybe it's not possible. -- George Foot Merton College, Oxford.