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Article #960

MacPaint format: The easy way

#960
From: Ephraim Vishniac
Date: Mon, 08 Apr 1985 20:34
21 lines
1493 bytes
My thanks to the several people who responded to my query about the use
of PackBits to create MacPaint-format documents.  While I still haven't
mastered PackBits, I did find an easy way of creating documents in an
acceptable format.

The trick is that the data doesn't have to be compressed, even if it is
compressible.  So, just stick a 71 (decimal, that's 0x47 for you C fans)
in front of each pixel-line of 72 bytes.  You'll wind up with a file
about 53K long.  To compress it, just open it with MacPaint and then save
it - MacPaint will do the compression.  Using this method lets us do the
conversion on another machine without re-implementing packbits.

Summary of stupid MacPaint format:
	512 byte header (all zero)
	720 lines, each 73 bytes: 0x47 followed by 72 bytes of image data
total: 53,072 bytes.

-- 
Ephraim Vishniac
  [apollo, bbncca, cadmus, decvax, harvard, linus, masscomp]!wanginst!vishniac
  vishniac%Wang-Inst@Csnet-Relay
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Path: arc1-ca.pugleaf.net!utzoo!linus!wanginst!vishniac
From: vishniac@wanginst.UUCP (Ephraim Vishniac)
Newsgroups: net.micro.mac
Subject: MacPaint format: The easy way
Message-ID: <468@wanginst.UUCP>
Date: Mon, 8-Apr-85 15:34:57 EST
Article-I.D.: wanginst.468
Posted: Mon Apr  8 15:34:57 1985
Date-Received: Tue, 9-Apr-85 04:28:53 EST
Distribution: net
Organization: Wang Institute, Tyngsboro, Ma.  01879
Lines: 21