Re: Hi-res picture packer?

[gnudutch <gnudutch@gmail.com>]

Hi Rob,

> There were no packed pictures that could be BRUN that I know of, as
> that would mean the decompression algorithm would need to be included
> with the picture, and that extra overhead would kind of defeat the
> space savings from a decompressed file to begin with.  

Yup I don't know how they did it but it was able to crunch the 17
block image into less than 10 blocks including the BRUN loader. I know
I'm not imagining this because I made slide show discs this way that
carried over 20 pics each. The nice part was being able to BRUN them
because the Beagle type loaders are too cumbersome. And the loader
would even draw the picture in with a nice wipe effect.

> There are a
> number of ways to make a graphic BRUNnable.  The simplest would be to
> put a small header at the beginning of each graphic like this:
>
> $1FED: 2C 54 C0 2C 57 C0 2C 52 C0 2C 50 C0 20 C FD 2C 51 C0 60

Thanks, I've seen this trick but it seems mostly a novelty, since
there is no space savings.

> If you want higher compression, I wrote a graphics compression program
> that compresses a little better than Scrunch and saves on average 2-3
> extra blocks under Prodos or 4-6 sectors under Dos3.3
>
> I have also expanded the compression algorithm to handle double hi-res
> graphics and can save from 3-7 blocks under Prodos over Double Scrunch
>
> Rob

Yeah I'd love to see your work, could you point me to it?

--g