Re: editing gifs with Perl

Since the primary question has already been answered, I'll leave it at that, but I will mention that it is really not that wise to be using gif's too often anymore as recently the company that owns the GIF compression algorithm has started to assert its rights.

If all you want is an image with transparency (or you don't take advantage of the animation capability) then I suggest you look at the PNG format, which GD does support. PNG is very similar to GIF, but it uses a different compression algorithm and can't be animated (yet, I hear rumors that they are working on that...)

Well, there's my advice, take it or leave it, just be careful with those gifs, I doubt anyone here can conveniently afford a legal battle.

Update: Oh yeah, several other file types also use the same compression algorithm, there was a discussion about this not too long ago... anyone that knows where it was feel free to post it as a reply or /msg me and i'll update this post again...

My code doesn't have bugs, it just develops random features.

Flame ~ Lead Programmer: GMS | GMS

Comment on Re: editing gifs with Perl

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Re:^2 editing gifs with Perl by rozallin (Curate) on Dec 18, 2002 at 21:25 UTC
PNG is very similar to GIF, but it uses a different compression algorithm and can't be animated (yet, I hear rumors that they are working on that...) The PNG equivalent of Animated GIFs are MNGs (Multiple-image Network Graphics.) As implied by the name, MNG was based on the PNG format to handle animated graphics. In addition to sharing a number of PNG's best features, it offers the following animation features: Object/sprite based animation Much better compression than animated GIFs Frame differencing support Nested loops (useful for complex animations) But MNGs are currently still in development and very few programs support it as of yet (the only program that springs to my mind is Netscape 6). -- Rozallin J. Thompson The Webmistress who doesn't hesitate to use strict;	[reply]
Re: Re:^2 editing gifs with Perl by Flame (Deacon) on Dec 19, 2002 at 14:28 UTC
Well that's useful to know, what about Mozilla? My code doesn't have bugs, it just develops random features. Flame ~ Lead Programmer: GMS \| GMS	[reply]
Re:^4 editing gifs with Perl by rozallin (Curate) on Dec 20, 2002 at 02:11 UTC
According to libmng.com, the MNG format is only natively supported by Mozilla, Netscape 6 (or higher) and KDE Konqueror. There are plug-ins available for other browsers but I've never used these so I cannot say how effective they are, if they work at all. -- Rozallin J. Thompson The Webmistress who doesn't hesitate to use strict;	[reply]
Re:x2 editing gifs with Perl by grinder (Bishop) on Dec 18, 2002 at 17:07 UTC
recently the company that owns the GIF compression algorithm has started to assert its rights. Heh! Well in that case they (Unisys) had better hurry and start suing people, because the clock is ticking and the patent is due to expire in six months (June 2003). Funny how things turn out, we were told to burn our GIFs and embrace PNG, and here we are in 2002, and GIFs are just as pervasive as ever. And now it seems that in six months time we won't even have to bother any more. I wonder how long it will take for the meme to die? Mind you, I like PNGs from an ethical point of view, but they suffer from a big flaw over GIFs: they are bigger. If you want all the functionality the specification has to offer they are indeed très cool, but if you just want to replace GIFs you're worse off in terms of space. Some more reading material on the GIF patent issue: http://cse.stanford.edu/class/cs201/projects-99-00/software-patents/lzw.html - general info on the issue the patent database entry (the URL is too long to display properly without destroying the layout). print@_{sort keys %_},$/if%_=split//,'= & *a?b:e\f/h^h!j+n,o@o;r$s-t%t#u'	[reply]
PNG by Mr. Muskrat (Canon) on Dec 18, 2002 at 18:00 UTC
The Portable Network Graphics (or PNG) file format features lossless compression, alpha channels, gamma correction and two-dimensional interlacing. PNGs (generally) compress better than GIFs by 5 - 25%. PNG supports 48-bit truecolor and 16-bit grayscale. Just remember that using truecolor images come at a cost of greatly increased file size. Recommended reading: everything at the PNG Home Site.	[reply]
Re: PNG by rozallin (Curate) on Dec 18, 2002 at 21:37 UTC
Unfortunately, PNGs are still not universally supported, and thus you run the risk that some users will not be able to see inline PNGs. And even the browsers that do support PNGs don't fully support all the nifty, useful features. Versions 4 and Up of the "Big Two" (except IE 4 for the Macintosh) can view PNG images but support for advanced features such as gamma correction and alpha transparency remain broken and buggy. -- Rozallin J. Thompson The Webmistress who doesn't hesitate to use strict;	[reply]


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