Re: (no subject)

Anton,

> On Aug 30, 2023, at 3:50 PM, Anton Thomasson <[email protected]> wrote:
> 
> Hi
> 
> Thanks for your reply!
> 
> I'm afraid i still don't get it.
> What little i understand about PDF rotation is that it tells the viewer to rotate a page when displaying it.
> I.e. not what has been applied, but what to apply. (I.e. a "595 x 842 pts, rot 90" page displays as landscape).
> (Spec says: "The number of degrees by which the page shall be rotated clockwise when displayed or printed.")

So the PDF rotation hint *does* tell the viewer how to rotate the content, *because* it has already been rotated for printing...

> I tried printing a portrait PDF with choosing landscape in the dialog just now (Xreader via CUPS on Linux Mint).
> What happened then was it came out rotated, scaled down and put to one side, as if printing number-up=2, but with just one page.
> That is quite useless (and number-up exists), so i suspect that's not what it is supposed to do?

Actually yes.  Specifying "orientation-requested=4" (4 == landscape) tells the printer that you want the content rotated to landscape.  Scaling is covered separately (print-scaling).

> It makes me all the more puzzled as to why the printer would need to be informed of it then.
> What relation does this have to IPP orientation-requested?

The page header fields are intended for providing per-page overrides as needed, but for PWG Raster things like Orientation there is no Printer-side processing to do unless the Printer needs to print it differently, e.g. long edge feed pages with a short-edge feed image.

> Backsides i have then hang of. Thanks for the excellent documentation on that.
> 
> Perhaps i can better describe my confusion with some questions:
> - If i have a landscape document and auto-rotate it to portrait before rasterizing, do i then set some value in this field? If so, what use can be made of it?

It allows the printer to know which way to rotate the page image if a short-edge feed image is provided to a long-edge feed tray.

> - If the printer has orientation-requested-default=4, should i be producing a landscape-shaped raster? (i.e. 7016x4961 instead of 4961x7016)

No, you use the orientation chosen by the user - the default value is used for the Client UI and on the Printer if the Client doesn't supply one.

> (and set Orientation and LeadingEdge  to match)
> - If the user chooses "landscape" for a portrait document going to a portrait-fed printer, what is supposed to happen?

The Client produces page images that are rotated to landscape.

________________________
Michael Sweet