[cups] Printing to native XPS printers using CUPS

[Helge Blischke]

> Am 09.09.2017 um 02:03 schrieb Gernot Hassenpflug <aikishugyo at gmail.com>:
> 
> On Sat, Sep 9, 2017 at 4:47 AM, Helge Blischke <helgeblischke at web.de> wrote:
>> 
>>> Am 08.09.2017 um 06:15 schrieb Gernot Hassenpflug <aikishugyo at gmail.com>:
>>> 
>>> On Wed, Nov 4, 2015 at 6:50 PM, Helge Blischke <helgeblischke at web.de> wrote:
> /../
>>>> The gstoxps filter uses Ghostscript’s xpswrite device (notwithstanding the deficiencies of this device)
>>>> and consumes both PostScript and PDF (implicitly using Ghostscript’s PDF interpreter).
>>> 
>>> Hello all,
>>> It has been a while, but I see that in the latest Ghostscript 9.21
>>> released in March 2017, the following change is noted:
>>> 
>>> "The GhostXPS interpreter now provides the pdfwrite device with the
>>> data it requires to emit a ToUnicode CMap: thus allowing fully
>>> searchable PDFs to be created from XPS input (in the vast majority of
>>> cases)."
>>> 
>>> References:
>>> 9.21 release notes: https://www.ghostscript.com/doc/9.21/News.htm
>>> 9.18 notes on XPS: https://www.ghostscript.com/doc/9.21/History9.htm#Version9.18
>>> 
>>> I assume from the above that in general XPS input and output have been
>>> much improved since 2015, and surmise that it might be possible to use
>>> the filters to obtain a "better" output than before.
>>> Since my system (Debian sid) has ghostscript 9.21 I will probably be
>>> able to do a test on the weekend.
> /../
>>> I noticed there has been no update to Helge's experimental filter
>>> since 2012, perhaps if the gsxps source has changed, more parameters
>>> might be settable these days.
>>> I will check if gsxps is available on my Debian machine at home (not
>>> available on work Ubuntu machine with GS 9.18 installed) and see if
>>> help shows any more parameters usable.
>>> If anyone has information on this I'd be happy to hear about it.
>>> (The problem, IIRC, was that the output files are bitmaps and thus huge.)
> 
> Hello Helge,
> 
>> As for the „experimental“ filter, I’m rewriting this thing to a more general
>> gstofoo filter with foo specified by the name the filter is called as.
>> Currently, I test using the Ghostscript devices
>> pdfwrite, ps2write, xpswrite, pxlmono or pxlcolor,and txtwrite.
>> As soon as I succeed with testing all this stuff, I’ll publish it at sourceforge
> 
> Thanks for the feedback, that sounds like an interesting work in progress.
> 
>> BTW, as far as I can tell up to now, the xpswrite device hasn’t changed very much since.
> 
> Ah, to bad. So changing XPS to PDF has improved a lot (ghostXPS
> interpreter) but not the creation of XPS.
> Regards,
> Gernot

My last tests have shown that eps files generated by Ghostscript’s xpswrite device
(gs v Version 9.21) show up in MS Windows 10’s XPS-Viewer (but sometimes only the first page),
but fail to display correctly in XPS viewers available for MacOS/Linux (either nearly the complete page 
covered by a black rectangle or all images missing), whereas eps files created by the Windows XPS writer
are displayed correctly on both platforms.

Helge