Re: Why are printers such a hassle?

From: Robert Heller (heller_at_deepsoft.com)
Date: 02/22/05 

Date: Tue, 22 Feb 2005 23:52:55 +0100

  Lawrence DčOliveiro <ldo@geek-central.gen.new_zealand>,
  In a message on Wed, 23 Feb 2005 10:56:24 +1300, wrote :

LD> In article <1aed5$421b90ee$cb248f0$26527@nf1.news-service.com>,
LD> Robert Heller <heller@deepsoft.com> wrote:
LD>
LD> > Bill Chapman <nowhere@nospam.net>,
LD> > In a message on Tue, 22 Feb 2005 18:48:11 GMT, wrote :
LD> >
LD> >BC> Why is it that every printer comes with a CD-Rom containing it's driver?
LD> >BC>
LD> >BC> Why doesn't ANSI just come up with some standards for ways printers are
LD> >BC> to behave, then you just write one driver for each OS to handle that
LD> >BC> standard, and then you can use any printer you want from any
LD> >BC> manufacturer that conforms to that standard?
LD> >
LD> >There is a standard: PostScript. Been around forever.
LD>
LD> As someone who has been using PostScript since soon after it first came
LD> out (1986), I can say it's not all it's cracked up to be. It can't give
LD> you true WYSIWYG, because the graphics model is built around making
LD> marks on a piece of paper, whereas desktop applications tend to use
LD> graphics models designed for interactive screen use. So you need a
LD> driver to translate the graphics for printing, which introduces its own
LD> possibilities for things to go wrong.

PostScript was never meant to be WYSIWYG!!!! A 'driver' is of course
needed (by WYSIWYG desktop applications). Duh!

LD>
LD> Of course, things have improved a bit, now that PostScript printers can
LD> understand TrueType fonts natively, and page complexity restrictions
LD> have eased, that kind of thing.
LD>
LD> But I still think the best kind of printer is a dumb printer: all you do
LD> is send it a full-page raster bitmap and say "print this". That way all
LD> the smarts about graphics rendering, colour matching, fonts etc reside
LD> on your PC. No need for a special driver, since you send the printer the
LD> same kind of bitmap you would render for screen display (except perhaps
LD> at a different resolution and mapped to a different colour gamut, but
LD> any decent graphics model will take that in its stride). Hence you get
LD> true WYSIWYG right out of the box.

This is fine, expect for two problems:

What exactly is the raster bitmap format? Who defines this standard?
Note that as printers increase in pixel and color depth resolution, the
raster bitmap format has to change to handle this and sending a
massively higher resolution raster bitmap to a low-end printer is plain
stupid (and generally runs into buffering problems anyway).

It is a vastly inefficient format for mostly textual content and thus has
a high I/O overhead.

PostScript provides a way around all of this. The PostScript *engine*
on the printer itself knows the pixel and color depth resolution and
renders things as things make sense. Font glyphs are 'cached' and
looked up as text characters are processed. A 'sparse' page is
transmitted to the printer in an efficient manor. And if there is an
issue of colour gamut or other such issues, it is possible that the
graphics software can generate a proper bitmap *that can be included*
in the PostScript -- PostScript does support bitmaped images.

LD>
LD> >Note: under *Mess-Windows*, PostScript printers need driver software
LD> >because MS-Windows *does not include NATIVE support for PostScript*.
LD> >All other O/Ss do.
LD>
LD> I think this is wrong.

No it is right. There is no native support for PostScript under
MS-Windows. There is no such thing as a Microsoft-supplied generic
PostScript driver. All of the drivers for PostScript printers shipped
with MS-Windows were written and supplied by the various printer makers,
not by Microsoft. Linux, *BSD and all flavors of commercial UNIX
include support for 'PostScript' printers out-of-the-box -- PostScript is
a standard output format for virtually all UNIX utilities that 'generate
hard copy': *TeX (dvips), groff, Netscape/Mozilla, xwd, etc. MacOS from
day one included the idea of a generic PostScript printer as part of the
base O/S install, with a driver supplied by Apple.

LD>

                                     \/
Robert Heller ||InterNet: heller@cs.umass.edu
http://vis-www.cs.umass.edu/~heller || heller@deepsoft.com
http://www.deepsoft.com /\FidoNet: 1:321/153

                             

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