Re: PDF on debian
On Sun 12 Mar 2023 at 16:52:37 -0000, Curt wrote:
> On 2023-03-12, Dan Ritter <dsr@randomstring.org> wrote:
> >> >
> >> > Many (most?) printers do not understand PostScript. The
> >> > printing system itself is based on processing PDFs.
> >> >
> >>
> >> Oh.
> >> Times have changed!
> >> I thought it was the other way around.
> >
> > You are correct, Yassine.
> >
> > PostScript is an interpreted language. PDF is a compressed
> > archive data format which includes simplified PostScript commands,
> > images, fonts, and other chunks of data.
> >
> > Apart from Windows-derived GDI printers, the majority of laser
> > and inkjet printers have a PostScript interpreter built in, even
> > if its primary use is in interpreting PDF files.
> >
>
> https://en.wikipedia.org/wiki/PostScript
>
> However, the cost of implementation was high; computers output raw PS code that
> would be interpreted by the printer into a raster image at the printer's
> natural resolution. This required high performance microprocessors and ample
> memory. The LaserWriter used a 12 MHz Motorola 68000, making it faster than any
> of the Macintosh computers to which it attached. When the laser printer engines
> themselves cost over a thousand dollars the added cost of PS was marginal. But
> as printer mechanisms fell in price, the cost of implementing PS became too
> great a fraction of overall printer cost; in addition, with desktop computers
> becoming more powerful, it no longer made sense to offload the rasterization
> work onto the resource-constrained printer. By 2001, few lower-end printer
> models came with support for PostScript, largely due to growing competition
> from much cheaper non-PostScript ink jet printers, and new software-based
> methods to render PostScript images on the computer, making them suitable for
> any printer; PDF, a descendant of PostScript, provides one such method, and has
> largely replaced PostScript as de facto standard for electronic document
> distribution.
>
> On high-end printers, PostScript processors remain common, and their use can
> dramatically reduce the CPU work involved in printing documents, transferring
> the work of rendering PostScript images from the computer to the printer.
Histoty is always interesting, but relating it to the modern situation
is necessary. PostScript hasn't any special place in today's Debian
printing system; it no longer has a *central* part to play in the
printing process and hasn't for ten years. Its part in processing a file
through the filtering system has been taken by PDF.
Granted, a printer whose *PPD* stipulates PostScript will be given it,
usaally through the auspices of Ghostscript. Apart from that, it hasn't
any importance. Most modern printers are focussed on accepting Apple
and PWG raster and PDF, whic will be fine when CUPS ceases to support
PPDs in a couple of years.
--
Brian.
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