In article <bdd2ff5e-6ad9-8ba0-bd36-f9ef4a9c6...@eandem.co.uk> Mike Williams
<ob...@eandem.co.uk> wrote:
> Hiya
>
> On 10/27/17 14:31, Ingo Schwarze wrote:
> > [ sending this particular one back to the list
> > because it contains something useful for everyone and nothing private ]
>
> Replying to list to archive comments even if not acted on.
>
> > Hi Jan,
> >
> > Jan Stary wrote on Fri, Oct 27, 2017 at 12:46:00PM +0200:
> >
> >> I produced a PS output with "man -Tps rm > rm.ps",
> >> with output paper set to a3, a4, and a5 in man.conf.
> >> This results, respectively, in
> >>
> >> %%DocumentMedia: Default 841 1190 0 () ()
> >> %%DocumentMedia: Default 595 841 0 () ()
> >> %%DocumentMedia: Default 419 595 0 () ()
> >>
> >> which apparently are the right dimensions. However,
> >> the Minolta will print all of them on A4 paper,
> >> although it does have a stash of A3 and A5 too.
> >>
> >> That's where I thought it might take a hint from the DSC comment,
> >> if I changed the "Default" to "A3" or "A4" or "A5", or if mandoc(1)
> >> itself put that in the DSC comments. I rewrote it manually before
> >> each printing, but the Minolta still prints them all on an A4:
> >
> > That's interesting, but anecdotal. It is neither surprising that
> > a specific printer selects paper as configured (in whichever way),
> > as opposed to inspecting fikes it is sent; nor would it be surprising
> > if other printers, or even the same one, or printer drivers on the
> > print server, could be configured to inspect the contents of
> > PostScript files to select paper.
> >
> > The trouble is, i just don't know what firmwares and softwares do,
> > what they should do according to standards, and where to look for
> > standards in this respect.
> >
> > Does anybody else know?
>
> The DSC comments are not part of the PS specification (the reference
> manual quoted earlier) and a PS interpreter would not normally take
> notice of the them. The comments are aimed at document printing systems
> which can just look for the comments and manage the printing of the file
> amongst other files and a range of available printers - such as queuing
> for a printer which supports/has the media listed by the DSC comment.
>
> Some PS interpreters may look for and act on the comments, but this
> would not be "standard" behaviour. For the %%DocumentMedia: comment the
> name used is for human consumption, it is the numeric values that are
> used for any media handling decisions. The %%DocumentMedia: comment
> lists all media sizes used by the document but does not say which page
> uses which size of media so could not be used to select media for any
> particular page. If the media size is important for a page then there
> should be a PS setpagedevice call like the following:
>
> <</PageSize [595 842]>>setpagedevice
In my other message I was about to mention that in the document
generated by groff I inspected, besides the comment, I found this other
line:
%%BeginFeature: *PageSize Default
<< /PageSize [ 595 842 ] /ImagingBBox null >> setpagedevice
It's in the place I put an image. I tried modifying the values here too
to see if this line was taken in care by gv too, but it seems it's not.
>
> The PS interpreter will perform media selection based on the values -
> use matching media, next largest, scale/rotate content, ask operator,
> etc. - see section 6.2.1 of the PS reference manual for way more detail.
>
> This is what is needed for the Minolta printer to use the other media
> sizes it has available. A quick edit of the PS file to add the above
> line with the appropriate media sizes for A3 or A5 should prove that.
>
> Basically don't rely on DSC comments to do media selection.
>
> I don't know gv but it will be working as a virtual printer with some
> standard media sizes to use when rendering a file. It sounds like it
> adds the list of media from any %%DocumentMedia: comments to provide
> additional media sizes it may not have by default. Ah, in the State
> menu there is the option "Respect document structure". If I unselect
> this the page size used by gv changes from the letter used in the -Tps
> output to the default A4 used by gv.
>
> It may be useful to use a media name such as man-A4, man-letter, etc.
> (to indicate the source of the file and media size used) for any systems
> that do process the DCS comments. That will avoid duplicates appearing
> in generated media lists.
>
> As for PDF, no there is no way to name the media size being used. There
> is no equivalent of the DSC comments for PDF. Media selection is always
> done based the dimensions in the /MediaBox array, the same way as the
> /PageSize array in PS, and it is up to the processor to decide how to
> handle the media size request.
>
> Finally, the -Tpdf output is not a valid PDF. It is missing the endobj
> keyword from several of the object definitions. This will cause
> warnings or errors when processing. I haven't updated to 6.2 yet so
> that may have been fixed by now, apologies if it has.
>
> >> Hm, so I can remove man.conf altogether,
> >> because even the default "letter" manpages
> >> will get printed on A4, which is what I want.
> >
> > That's a bad idea. The purpose of the -Opaper= option is not to
> > select paper, but to adjust the width and height that the document
> > content will require, and the primary purpose of the DocumentMedia
> > DSC instruction isn't selecting paper either. but to inform how
> > the content was arranged. If you use -Opaper=letter, margins will
> > be reasonable for letter size paper, but ugly for A4: Since letter
> > paper is wider than A4 but not as tall, printing on A4 without
> > -Opaper=a4 will usually result in an awkwardly narrow right margin
> > and in wasted space at the bottom.
> >
> > Yours,
> > Ingo
> >
>
> Cheers.
Walter
