ghosh@hubcap.UUCP (Amitava Ghosh) (02/23/88)
I believe that all macpaint documents are stored in compressed form.
I know how i can uncompress it on the Mac using UnPackBits routine.
I have a need , where I would like to do the uncompressing on the mainframe
after I have transferred the compressed document over (since it will reduce
the amount of data I would have to transfer). Can anyone tell me or point
me to a source where I can find out the compression algorithm. I have looked
in Inside Macintosh and I was unable to find any info. Also, does someone
have info on the format of the Macpaint document itself.
Thanks in advance for any info.
Amitava Ghosh
Email: Bitnet ghosh@clemson
internet ghosh@prism.clemson.edu
UUCP ...!hubcap!ghosh sas1@sphinx.uchicago.edu (Stuart Schmukler) (02/24/88)
There are a number of programs that handle macpaint documents on a mainframe. MACHP.PAS.1 MACIMP.PAS.1 MACPTX.PAS.1 MACQMS.PAS.1 MACIMP.C.1 MACLGP.C.1 MACQMS.C.1 PAINT2QMS.C.1 PAINTIMP.C.1 are the ones in the SUMEX-AIM archive. But, since you are on BITNET you should try the archive at PUCC via: TELL MACSERV AT PUCC HELP under VM/CMS. SaS PS: I am not sure that the syntax is 'exactly' correct check with the local systems people to be safe.
gs1g+@andrew.cmu.edu (Gregory Jacob Stein) (02/26/88)
There is a Tech Note which describes the packing algorithm used in PackBits. Note, though, that Apple reserves the right to change this at any time. Greg
rick@kimbal.UUCP (Rick Kimball) (02/27/88)
In article <oW96M2y00XoH8Qo0=9@andrew.cmu.edu>, gs1g+@andrew.cmu.edu (Gregory Jacob Stein) writes: > > There is a Tech Note which describes the packing algorithm used in PackBits. > Note, though, that Apple reserves the right to change this at any time. > > Greg Here's another kind of answer (the kind I like ... show me the way ... don't give me theory). A while back I wrote a program that runs on my UNIX-PC. It reads MacPaint files and displays them on the console. I had to write my own UnPackBits function for UNIX. Here it is: -------------- Snip Snip Snip -------------- /* Name: UnPackBits.c Synopsis: UnPackBits( char **src, **dst, short rowBytes ); Description: See Apple Tech Notes: #86: MacPaint Document Format #171: PackBits Data Format This software is Copyright (c) 1987 by Rick Kimball. Permission is hereby granted to copy, reproduce, redistribute or otherwise use this software as long as: there is no monetary profit gained specifically from the use or reproduction or this software, it is not sold, rented, traded or otherwise marketed, and this copyright notice is included prominently in any copy made. The author make no claims as to the fitness or correctness of this software for any use whatsoever, and it is provided as is. Any use of this software is at the user's own risk. Sample Call Sequence: char **srcPtr, **dstPtr; char macPaintFile[(576/8)*720]; char bitImage[51840]; ... srcPtr = (char **)&macPaintFile[512]; dstPtr = (char **)&bitImage[0]; for( x = 0; x < 720; x++) { UnPackBits(&srcPtr,&dstPtr, 576/8); } ... */ #define HIGH_BIT_ON 0x80 UnPackBits(src, dst, cnt) register unsigned char **src; register unsigned char **dst; register short cnt; { register short noOfBytes; register unsigned char bit15; if ( cnt <= 0 ) return(0); bit15 = HIGH_BIT_ON; while ( cnt ) { if ( **src & bit15 ) /* Is High bit set ? */ { noOfBytes = abs((char)*(*src)++); cnt -= ++noOfBytes; while( noOfBytes-- ) { *(*dst)++ = **src; } (*src)++; } else /* It is a normal zero based counter */ { noOfBytes = (char)*(*src)++; cnt -= ++noOfBytes; while( noOfBytes-- ) { *(*dst)++ = *(*src)++; } } } return(0); } -- Rick Kimball Software Design Group Maitland, FL 32751 (305) 660-0006 UUCP: rick@kimbal, ...codas!flnexus!kimbal!rick