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From: carolyn@cbmvax.cbm.UUCP (Carolyn Scheppner)
Newsgroups: net.micro.amiga
Subject: Re: Are "DPAINT" and "IMAGES" files Compatible???
Message-ID: <282@cbmvax.cbmvax.cbm.UUCP>
Date: Thu, 22-May-86 11:36:53 EDT
Article-I.D.: cbmvax.282
Posted: Thu May 22 11:36:53 1986
Date-Received: Sat, 24-May-86 22:18:42 EDT
References: <3276@vax4.fluke.UUCP> <49@intelca.UUCP>
Reply-To: carolyn@cbmvax.UUCP (Carolyn Scheppner)
Distribution: net
Organization: Commodore Technology, West Chester, PA
Lines: 39


    DPaint, Aegis Images and Graphicraft all save their pics in an IFF
ILBM (Interleaved BitMap) format.  Each of these programs will at least
load the other's lo-res pics.  However, there are some quirks.
Aegis Images only recognizes files that end with ".pic".  The version
that I have also seems to have problems recognizing .pics stored in RAM:.
It did load DPaint and Graphicraft files from disk if they were renamed
to end in ".pic".  Graphicraft's only problem when loading DPaint and
Images files is that the load is rather slow.  Both DPaint and Images
files are compacted and Graphicraft seems to use a very small buffer for
uncompacting.  This is probably because Graphicraft was designed so it
could be run on a 256K machine.

    Any properly written chunk-oriented IFF ILBM loader should be able
to handle at least the lo-res painting files from all three programs.
Ideally, it would also handle any padding/clipping needed to load a
portion of a bitmap or a higher/lower res bitmap.  For examples of
IFF loaders, see ShowILBM.c and SeeILBM.c on the latest IFF disk.
     
    There ARE differences between DPaint, Images, and Graphicraft files.
DPaint and Images save a compacted BODY, Graphicraft an uncompacted BODY.
This is specified in their BMHD (BitMapHeader chunk).  DPaint files
include 4 CRNG chunks for color cycling information.  Graphicraft files
include a slightly different CCRT chunk for color cycling and a CAMG
(ViewPort modes) chunk.  But a proper chunk-oriented loader should just
look at each chunk, taking what it wants and skipping what it doesn't.
Between the BMHD and the BODY (the two necessary chunks), it should not
expect any particular chunks in any particular order.

    That's what IFF's all about.

     
     
--
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Carolyn Scheppner -- CBM   >>Amiga Technical Support<<
                     UUCP  ...{allegra,caip,ihnp4,seismo}!cbmvax!carolyn
                     PHONE 215-431-9180
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