Re: Printing MAC bitmaps on GS

[nathan@cco.caltech.edu (Nathan Mates)]

In article <3hemq1$rb2@news.service.uci.edu>,
Leif Strand <eaiu636@taurus.oac.uci.edu> wrote:
>In article <3hc7la$ckk@gap.cco.caltech.edu>,
>Nathan Mates <nathan@cco.caltech.edu> wrote:
>>   I have read brochures for Mac clip art collections, and they say
>>that they are pretty much 300dpi.

>These are probably PostScript clip art collections (they do exist).
>If not, they are definitely not MacPaint files.  

   They tend to be TIFFs (which programs like Prism can convert), or
other stuff. I don't think the original poster wanted MacPaint (1984,
B&W) stuff to print the same, he wanted mac bitmaps in general.

>In either case,
>SuperConvert can not convert them to the GS to begin with, so they
>don't pertain to the original question:  printing a MacPaint bitmap
>from the GS as it would be printed from a Mac.

   Grow up from Superconvert and Macpaint, please. Macpaint (as running
on this 128K Mac original that you mentioned a few posts back that
can't handle 300dpi bitmaps) is obsolete, we're talking about modern
Mac programs.



>Again, can SuperConvert convert the relevant file formats?

   What's this fascination with Superconvert? Prism, IQ,
LordHighGiffer can read in some intermediate format supported by a mac
program. 



>Ever look at a Postscript file?  It isn't a bitmap (300 dpi or
>otherwise).  I think this is the source of your misunderstanding.
>Postscript files consist of the textual source code of programs
>written in a postfix graphical description language.  These
>programs are run by an interpreter in the laserwriter. 

   Only partway true. You can have stuff in graphical postscript
format, and you can also feed it a bitmap as part of the description
of a page. The bitmap is converted to an hex format and eats gobs of
space, but you can (and lots of programs do) put a bitmap into a
postscript file.  The LaserWriter driver on the GS and Mac, as well as
converter programs like the Unix 'xv' all do bitmaps.

   I could dump a bitmap from a PS image to this group, but it'd
be a waste of space and useless. You merely need to update your
knowledge of GS and mac programs, as well as how PostScript stuff
is rendered.




>The Mac host program or the printer driver on the Mac never has
>a 300 dpi image.  Resolutions over 72 dpi are achieved by sending
>Postscript commands (not pixmaps at all) to the printer, which the
>printer renders at the highest resolution possible.  It would be
>the LW that scales a 72 dpi for printing at 300 dpi.

   Once again, dead wrong. Bitmaps (which can be at any resolution
within the PS definition, be it 5 to 3000dpi) can be contained within
the PS file. The printer then scales this bitmap to the output
resolution of the printer and prints that. But, converting a bunch of
pixels to PS commands (moveto and draw square) is too much of a hack
when the bitmaps can and are put into the files.




>Oh, so you do know the difference between a draw program and a paint
>program?  Why did you bring all this draw program business into the
>discussion?  We were speaking of making conversions of Mac B&W bitmaps
>on the GS look as good, when printed, as they do on the Mac.  And
>AWGS _can_ do true graphical objects, but because of some fluke, it
>can only print them right in the Page Layout module (or so I've read).

   Mac B&W bitmaps can be at 300dpi. If you are are starting with a
300dpi, grabbing a screen shot (MacPaint format) of that and
converting it to the GS with SuperSuckinConvert, you've thrown out
everything. But, the mac with all of the 300dpi info can print it out
nicely.

   Plus, AWGS's pain module can print things in the right aspect ratio;
I've done it lots of times.





>Gee, could it be I know what I'm talking about?  

   Could it also be that you're just misinformed?

>Two things.  First,
>Postscript files are not bitmaps, but programs that can render graphical
>objects at any desired resolution (so the "source material" has
>infinite resolution).

   Get this through your little skull: POSTSCRIPT CAN INCLUDE BITMAPS.

>  Bitmaps are 72 dpi and are sent to the
>laserwriter at 72 dpi; 

    Bitmaps can be at any resolution you feel like. I can scan in a
picture at 600dpi on the mac at work. It's stored on disk in bitmap
form (TIFF and/or whatever form Adobe Photoshop uses), and when I
print, it's not converted to PS draw commands, but a bitmap is slugged
around. The GS tends to have only pictures at the screen's 72 dpi 
resolution, but that's the fault of not having any variable resolution
paint/draw progs.


>this includes output from paint programs and
>fonts in some cases.  Second, pixel resolution is not the same as
>dot resolution.  Go to a _paint_ program.  Draw a skewed line.  Print
>it with no printer effects (no 50% reduction, no condensed).  Print
>it on a Imagewriter or a Laserwriter, I don't care.  Now, doesn't the
>line on the printout look as "chunky" as it does on the screen?

   Yes, that's because a paint program at 72dpi did that line. Stop
running off the topic. Macs can and do have 300dpi bitmaps, and it's
not because of their use or disuse of PostScript. A Mac can print a
300dpi image at high quality to a HP deskjet printer, which isn't PS,
because it's got 300dpi worth of source data to work with, no more, no
less.

   Any further discussion should be taken to email; this is getting
increasingly irrevelant and off-topic.

Nathan Mates
-- 
* Nathan Mates   http://www.ugcs.caltech.edu/~nathan/              <*>
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