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
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To:	djgpp AT delorie DOT com
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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 <gfoot AT mc31 DOT merton DOT ox DOT ac DOT uk>
Merton College, Oxford.

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