info-mac@uw-beaver (info-mac) (07/19/84)
From: Walter.Smith@CMU-CS-SPICE Is anyone working on a MacPaint to Press file conversion program? Now that all these companies are typesetting Macintosh graphics, that seems like an obvious step. We wouldn't have to wait for the Apple laser printer to get quick high-quality output. And since the typesetting places are charging around $25/page, it would be a lot cheaper. Another thing the typesetters can do is typeset MacWrite documents. Perhaps a device driver can be written that creates press files so that high- resolution graphics can be done. On the other hand, perhaps there is a better way. - Walter Smith (wrs@cmu-cs-spice)
info-mac@uw-beaver.UUCP (07/27/84)
From: Ed Pattermann <PATTERMANN@SUMEX-AIM.ARPA>
I have written a program called MACaid which converts MACINTOSH files to
IMPRESS format (for IMAGEN printers). It has a few bells and whistles to be
added yet, but all in all, it works. For those interested, here is a
description of the format of MACpaint files. This format is the common
interchange format for full-page bitmap images on the MACintosh.
The first 512 bytes of the file are the header. The first four bytes comprise
the version number, followed by 38*8 = 304 bytes of patterns. The remaining
204 bytes of the header are reserved for future expansion. If the version
number is zero, the patterns are ignored. Hence, programs that wish to create
files to be read into MACpaint can just write out 512 bytes of zero as the
header.
Following the header are 720 compressed scanlines of data which form the 576
wide by 720 tall bitmap. The bitmap is compressed as follows ;
Any run of three or more equal bytes is compressed into a count byte and a
single data byte. Runs of unequal bytes are passed on literally, preceded also
by a count byte. I.E.
<count byte> <data byte> count = -1..-127 --> replicate byte 2..128 times
<count byte> <n data bytes> count = 0.. 127 --> copy 1..128 bytes uncompressed
count = -128 ignored for backward compatibility
That's it. A nice simple scheme. Thanks to Bill Atkinson for providing this
info.
I have used the new MACTERMINAL Beta Release (version .5) to upload MAC files
to our 2060 via the MODEM7 protocol. It all works very well. If anyone is
interested, I will make a copy of MACaid available on the INFO-MAC directory
once it is ready for distribution. It is a TOPS20 program written in Rutgers
Pascal.
-- Ed
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