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Path: utzoo!linus!wanginst!vishniac
From: vishniac@wanginst.UUCP (Ephraim Vishniac)
Newsgroups: net.micro.mac
Subject: Re: Macpaint files from programs
Message-ID: <1270@wanginst.UUCP>
Date: Mon, 4-Nov-85 08:10:27 EST
Article-I.D.: wanginst.1270
Posted: Mon Nov  4 08:10:27 1985
Date-Received: Tue, 5-Nov-85 21:26:16 EST
References: <2271@sdcc6.UUCP>
Organization: Wang Institute, Tyngsboro, Ma.  01879
Lines: 18

> Does anyone out there know how to write a screen bitmap into a MacPaint
> type document from program control.  I wan't my program to be able to 
> save images it creates in MacPaint type files.
> 
A MacPaint painting file is type "PNTG", creator "MPNT".  It consists
of a 512 byte header, which can be all zeroes, followed by the page
image.  The page image consists of 720 rows (ten inches worth).
A row consists of 72 bytes (576 pixels = 8 inches), compressed using
PackBits.  If you're too lazy to really use packbits, just precede
each row of data with a 71 (decimal) to indicate that 72 bytes of
uncompressed data follow.  The file will be compressed the first time
that it's re-saved from MacPaint.


-- 
Ephraim Vishniac
  [apollo, bbncca, cadmus, decvax, harvard, linus, masscomp]!wanginst!vishniac
  vishniac%Wang-Inst@Csnet-Relay