Re: Lisa Fonts

From: Shirl <shirlgato_at_email.domain.hidden>
Date: Sun, 08 Apr 2007 09:30:23 -0600


I would be suprised if the Lisa font files were compressed. The Lisa had plenty of memory for RAM-based data. The ROM icon compression AFAIK was needed since the Lisa's 16KB ROM was full.

>From: "Rebecca Bettencourt" <beckiergb_at_email.domain.hidden>
>To: "LisaList" <lisalist_at_email.domain.hidden>
>Subject: Re: Lisa Fonts
>Date: Sat, Apr 7, 2007, 3:51 AM

> Running the font files through that algorithm (with modifications to
> handle an arbitrary number of compressed bytes) gives me some
> interesting patterns, so it's a possibility. Of course just because
> it's interesting doesn't mean I'm barking up the right tree. A
> compression scheme like that would explain some of the patterns I'm
> noticing between the font file and the metrics file, but the bytes
> around the patterns are not consistent. Are there any compression
> scheme reverse engineering specialists around here? :)
> Is there a way to get LisaEm to produce trace logs, just to see what's
> going on?
> (Let's hope Google Groups lets this one through... :| )
> On Apr 6, 2:58 pm, Ray Arachelian <r..._at_email.domain.hidden> wrote:
>> Hi Rebecca,
>> I'm not sure if this will help or not, however, the Lisa boot ROM
>> compresses its icons with some sort of RLE algorithm that stores a flag
>> in bit 0. Here's the source code to decode them - it's a bit obfuscated
>> because that's a fairly straight translation from the 68K assembly to C.
>> Perhaps the same format is used for the fonts?
>> Rebecca Bettencourt wrote:
>> > It
>> > doesn't contain a raw bitmap as far as I know. My current theory is
>> > that it is somehow compressed, since there are certain patterns
>> > mapping bytes in the font part to bytes in the metrics part. So I'm
>> > asking if anybody has documentation on the Lisa font manager, or
>> > disassemblies from when the Lisa is drawing text, or anything else
>> > helpful.

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. Received on 2015-07-15 16:37:14

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