Re: [MacPerl] Installing modules.

["Mark Manning/Muniz Eng." <markem@flash.net>]

Jay Bedsole wrote:
> 
> Chris asked:
> 
> >Has anyone ever run across an image file actually marked .pm for
> > pixmap? Where are they used, and on what platforms?
> 
> I've seen .pm (pixmap) files on SUN workstations. I believe this
> is a rather old format that has been supplanted by .xpm (the X
> windows derivative), though I think this is even somewhat obsoleted
> by .xbm (X bitmap). I'd be surprised if the old pixmap format found
> it's way onto Macs more frequently than perl modules...
> 
> Even if a pixmap file did find it's way onto a Mac, I'm not
> sure there's anything that one could do with it. I know IC is
> mapping .pm to GraphicConverter, but I think GraphicConverter
> only operates on .xpm files (unless it's an undocumented feature).
> I tried to dig up an old .pm file from one of our SUN workstations
> to test this theory and could no longer find one...

I had to respond to this because the information being presented is
entirely wrong.  Well, ok - not entirely - but mostly.

There are two types of images which X Windows supports.  These are
bitmaps and pixmaps.  Bitmaps are black and white images only (and thus
the name BITmaps - ie 0 or 1 only).  Pixmaps on the other hand are
really very generic picture files.  They are the best medium for moving
pictures around from system to system because there are no problems with
big endian/little endian numbers.  The only drawback to pixmaps is that
the number of available colors is limited by what characters are
available on your computer.  Thus, you are limited to A-Z, a-z, 0-9, and
the other special characters on your keyboard.  Meta characters, Control
characters, and even Alt+ characters are not usually used.

Going back to the subject though, the .pm files were pixmap files before
X windows came along.  Then came bitmap files because they were small
and could easily be worked with.  Finally came the pixmap files for X
Windows.  None of them are replacing the other though.  They all just
exist as various methods for representing pictures on a computer.

Now, on the Mac side of things - All you'd need to do is to write some
programs which will handle these various file formats (like what the guy
who wrote Graphicsconverter did) and you too can read these things into
memory and display them.  All you have to do is to allow for the various
names which X windows assigns to the colors.  This can be easily done by
just asking someone you know who uses Linux or Unix to send you the RGB
list for their system.  There's about two hundred and fifty-six of
them.  :-)

PS: One of the nice things about Unix/Linux is that almost every
important file is in ascii.  So you don't have to have some kind of a
special editor to read the file.  :-)

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