PS/PDF API Change Proposal: (Re: [cairo] Semantics of transparent objects)

[Alexander Larsson]

On Thu, 2006-02-09 at 12:26 -0800, Carl Worth wrote:
> On Wed, 18 Jan 2006 20:01:04 -0500, Michael Sweet wrote:
> > Carl Worth wrote:
> > > ...
> > > Obviously, there _are_ a lot of printing-specific options, settings,
> > > and metadata that users will need to provide. And the point has been
> > > made above that these need to be available on a per-page basis.
> > > 
> > > I'm wondering if we can't just use cairo_t for these, and specify that
> > > the time to set them is before any drawing operation on any given
> > > page. That is, just after cairo_create or cairo_show_page, and before
> > > any of cairo_stroke, cairo_fill, cairo_paint, cairo_mask,
> > > cairo_show_text/glyphs on that page.
> > 
> > That would work.  IMHO, the only "required" per-page attributes are
> > the media attributes: media color (the color of the paper, not whether
> > the output is in color), page size, media source, media type, and
> > media weight.
> 
> What's not clear to me yet is what cairo is supposed to do with these
> options. From the recent discussion on the desktop_printing list[*]
> it's been made quite clear that applications should emit
> printer-independent PostScript and that that should be passed along
> with printer-specific options to CUPS.
> 
> So, cairo fits in on the PostScript-generation side of things. And if
> it should then always be generating printer-independent PostScript
> then I don't see why it should see any printer-specific settings, (or
> even what it could do with them if it shouldn't put them into the
> PostScript output).
> 
> Or are all the attributes you describe above printer-independent? I
> don't know for sure what you mean by "media source" for example. Is
> that the printer's paper tray? If so, that's clearly printer-specific.

In a private mail, Mike pointed out the %%IncludeFeature in DSC. This
seems to allow us to do some of these things in a device-independent
way.

I found some DSC docs at:
http://atrey.karlin.mff.cuni.cz/~milanek/PostScript/Reference/DSC3.html

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 Alexander Larsson                                            Red Hat, Inc 
                   alexl at redhat.com    alla at lysator.liu.se 
He's a leather-clad sweet-toothed gangster who dotes on his loving old ma. 
She's a cosmopolitan junkie soap star from out of town. They fight crime!