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Re: PDF on debian



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

As processor prices fell, this turned around. The ARM or MIPS
processor and RAM inside a $100 laser printer is a tiny fraction of the
cost, and completely capable of running PostScript.

Now, the licensing cost from Adobe for PostScript is terribly
high, but open source rode to the rescue: most printers say "PS
compatible" rather than PostScript(tm). They tend to run Linux
and GhostScript -- here's the Debian package description:

  Description: interpreter for the PostScript language and for PDF GPL
  Ghostscript is used for PostScript/PDF preview and printing.  Usually as
  a back-end to a program such as ghostview, it can display PostScript and
  PDF documents in an X11 environment.

  Furthermore, it can render PostScript and PDF files as graphics to be
  printed on non-PostScript printers. Supported printers include common
  dot-matrix, inkjet and laser models.

>  ; in addition, with desktop computers
>  becoming more powerful, it no longer made sense to offload the rasterization
>  work onto the resource-constrained printer

This is called the cycle of reincarnation: it happens over and
over again, with functions being implemented in separate devices,
then being integrated into a motherboard or SOC or chipset or
even the CPU itself, and then occasionally coming back out for
improved performance, which may then be re-integrated...

-dsr-


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