A85: Re: Compressing pictures

To: <assembly-85@lists.ticalc.org>
Subject: A85: Re: Compressing pictures
From: "Dines Justesen" <c958362@student.dtu.dk>
Date: Thu, 6 Nov 1997 23:15:03 +0100
Reply-To: assembly-85@lists.ticalc.org

The commonly used method for compressing pictures are ZCP by Stephan
Jantzen, you find more info, an encoder and a decoder at ticalc. Another
possible methos is one suggested by me :) before ZCP was made, it is really
simpel to implement and have been used before.

For each byte bit7 indicates wether the pixel should be black or white
(1/0). The other pixels determines how many pixels of this could you should
draw. So FF=128 black pixels 7F=128 white pixels. This is a lot simpler than
ZCP, but ZCP will probably compress the pic more.

Dines

-----Original Message-----
From: Michael Cook <MBCook@concentric.net>
To: A85 <assembly-85@lists.ticalc.org>
Date: 6. november 1997 22:39
Subject: A85: Compressing pictures


>I need a way to compress a 128 by 64 b&w pic to use as a
>title screen. It currently takes up 1024 bytes and the
>routine+pic must be less than that.
>
>Michael Cook
>MBCook@Concentric.net
>
>