Re: GS/OS Hires/Double-Hires File Recognition Problem

[Cyrus Roton <croton@ridgecrest.ca.us>]

On 22 Dec 1995, RUBYWAND wrote:

> 
>     Last time I checked, GS/OS (System 6.0.1)  still insists that "hires"
> files must be length $2000 and "double-hires" files must be length $4000.
> Most hires pics are length $1FF8 (to save a sector of storage under DOS
> 3.3);  and, some double-hires pics are length $3FF8.
> 
>    This creates problems with painter programs (like Platinum Paint) 
> which use GS/OS criteria to decide if a file can be imported. For example,
> $1FF8 length pic files are not recognized as "hires".
> 
>    Is there a patch for the System 6.0.1 tool involved? (I think it is
> Tool 23.)  If so, where can it be downloaded? 

If a true hires file is saved (BSAVE) with length less than $2000, then it 
will be missing some pixels. I seem to remember something about extra, 
unused, bytes at the end of each hires line, and some program to save the 
picture without those extra bytes. I feel sure that, if that is the case, 
you would have to have a special program to load the file back into 
memory with all the data bytes going into the proper places. However, 
such a file would be considerably smaller than $1FFF.

I do not see how a hires picture can be saved with length $1FF8, but 
would be interested in finding out. Have you tried to BLOAD the file and 
then BSAVE it with the proper length? If you do, BLOAD into the hires 
area of memory (after selecting that area for viewing) and see if really 
is a hires pic.

Cyrus Roton   croton@ridgecrest.ca.us
Ridgecrest Apple User Group