Re: Encoding GIFFs on an Apple II

["mdj" <mdj.mdj@gmail.com>]

Simon D. Williams wrote:
> Mark McDougall wrote:
> > OK, perhaps we're arguing semantics here? There *is* an uncompressed GIF
> > format, the motivation for which derived from the desire to avoid paying
> > royalties to Unisys for the LZW compression scheme.
>
> I'd like to avoid paying royalties too ;-)

I believe the LZW patent has now expired...

> If anyone has the means to generate an uncompressed GIF I'd like to see
> an example (Photoshop doesn't seem to have that option)... if it were
> 280x192 black&white that would be even better!

I've never seen a program do uncompressed GIF myself, and really, it's
a bit pointless as your resultant filesize is likely to be bigger than
8kb ;-)

You could directly save monochrome hires as a bitmap and only use 6.7k
per image - add RLE and for 'line art' style images you'll get pretty
damn good compression, and it's very fast.

RLE is terrible for 'photographic' style images, but you're not likely
to deal with many of those...

Note that you'll need have alternate encoding systems for colour or
monochrome. For images that combine the two, you'll need a specific
Apple II graphics compression routine.

What exactly are you wanting to do? Store and retrieve Apple II
graphics ON the Apple II, or handle interchange? If it's interchange
you're after, you'll need to deal with the fact that most image formats
assume that the pixel are square (as they are on every computer post
the VGA era) and that on the Apple II that's far from the case ...

Matt