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From: Woody on 2 May 2010 13:43
Simon Dobbs <simondobbs(a)froglet.net> wrote:

> On Sun, 2 May 2010 12:50:58 +0100, Woody wrote
> (in article <1jhv72m.1rcvx0y5juxwfN%usenet(a)alienrat.co.uk>):

> > There is a lot more info in the developer section, that is just a
> > confirmation. Basically the graphics in windows is cached in PDF images
> > (which is why OSX uses PDF naturally as it does), whereas in NeXT,
> > graphics were stored as PS code, which was executed when it needed to
> > draw, which is a lot slower.
>
> That's why I thought that macs used pdf as the page description language now-
> surely if all documents are rendered as pdf by the operating system, it is a
> simple step to use that as the page description to all printers

It would be easy enough for printers to accept PDF, but even PDF is
pretty complex to handle, especially in rotation and transparancy,
whereas a simple printer needs a lot less detail.

It is easy enough to write drivers to convert to what the printers
actually need, so the page is composited in memory and then redrawn as
an absolute page.

--
Woody

www.alienrat.com
From: Rowland McDonnell on 2 May 2010 17:41
Simon Dobbs <simondobbs(a)froglet.net> wrote:

[snip]

> That's why I thought that macs used pdf as the page description language now-
> surely if all documents are rendered as pdf by the operating system, it is a
> simple step to use that as the page description to all printers

It would be, if all printers could understand PDF, but most printers do
not.

Rowland.

--
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From: Woody on 2 May 2010 18:08
Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote:

> Woody <usenet(a)alienrat.co.uk> wrote:
>
> > Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote:
> >
> > > Woody <usenet(a)alienrat.co.uk> wrote:
> > >
> > > > Simon Dobbs <simondobbs(a)froglet.net> wrote:
> > > >
> > > > > forgive my ignorance, and my inability to cut a longish thread,
> > > > > but I thought that Macs had now lost postsript as the printing
> > > > > file format of preference in favour of the acrobat file format.
> > > >
> > > > The compositing of views is done in the same way PDF yes, which is a lot
> > > > simpler than postscript.
> > >
> > > Eh? Explain - I thought that the two were sufficiently similar that
> > > there wasn't a lot of difference in that line, except that PS has more
> > > programmability, which makes pdf safer.
> >
> > PDF is a superset,
>
> <puzzled> Really? I thought it was more like a subset with a few
> additions needed due to the programmability that had been removed.

No, it is a superset, it has had things added and other things improved.
It has also had things removed as well.

> > > I thought that the reason Apple dropped Display PDF is because Adobe put
> > > the licence fee too high, and that Display PDF (being as much an Adobe
> > > product as PS, innit?) needed a licence paying whoever's using it.
> >
> > No, pdf is an open standard (but created by adobe) that requires no
> > license to use,
>
> PDF might be that - but we're talking about Display PDF, which isn't
> quite the same.

Why isn't it?

> >postscript is a licensed product of adobe that requires
> > a license to use, that is why all printers didn't do postscript.
>
> I've known that for a while - but decent free PS emulation via gs has
> been available for a very long time to get round that problem.

Maybe, but what are the chances of apple implimenting an emulation of
postscript without adobe objecting?
For a start it wasn't available when OSX was started.

> > > > Compositing any view (PDF view, screen view or printer view) works in
> > > > the same way.
> > >
> > > Macs don't use Display PDF, do they?
> >
> > They do. Have a look at the section on quartz on there OSX overview
> > page:
> > <http://developer.apple.com/technologies/mac/graphics-and-animation.html
>
> Given that all it says on the subject is:
>
> `Quartz 2D's rich graphics capabilities are based on the Portable
> Document Format (PDF)'
>
> you could have pasted it here just as easily as the url...

I could indeed.

> > There is a lot more info in the developer section, that is just a
> > confirmation.
>
> Oh! Righto. I'd got the idea that they'd dropped that way of doing it.

No. It is the way the whole quartz system works. You can tell if you are
doing low level graphics to it. It is unlike most other computer display
systems where you composite information

> > Basically the graphics in windows is cached in PDF images
> > (which is why OSX uses PDF naturally as it does),
>
> But where does the actual PDF-ness of things come in to it, then?

Basically it is the graphics compositing thing. You can cache a load of
images in everything, what PDF gives you is a set of transformation
matrixes for how those graphics are applied to each other. This means it
gives you a good way to distort, or change those graphics for fancy
graphics effects.

> I don't see why anything else wouldn't do just as well for a container
> format.

Well, it could well be done in another way, but PDF gives you some other
facitilies. Nothing you couldn't actually do another way, but you have
to pick one thing, and that is what they picked.

> > whereas in NeXT,
> > graphics were stored as PS code, which was executed when it needed to
> > draw, which is a lot slower.
>
> But surely NeXT could have been designed to cache images in a similar
> way, using PS as the container format just as OS X uses PDF that way?

It could have done. Ultimately the licensing issues were the major ones,
especially at the time when adobe really didn't want to do any favours
for apple. If they had known that OSX was going to be successfull, they
would have probably tried to do something about the licensing.

> > ahh, here, from the original reviews of the technical previews of OSX:
> > <http://arstechnica.com/reviews/1q00/macos-x-gui/macos-x-gui-4.html>
>
> What was done back then isn't necessarily what ended up in 10.6...

What we have now is an improved version, but it is still the same thing.

--
Woody

www.alienrat.com
From: Woody on 2 May 2010 18:08
Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote:

> Woody <usenet(a)alienrat.co.uk> wrote:
>
> > Simon Dobbs <simondobbs(a)froglet.net> wrote:
> >
> > > Woody wrote:
> >
> > > > There is a lot more info in the developer section, that is just a
> > > > confirmation. Basically the graphics in windows is cached in PDF
> > > > images (which is why OSX uses PDF naturally as it does), whereas in
> > > > NeXT, graphics were stored as PS code, which was executed when it
> > > > needed to draw, which is a lot slower.
> > >
> > > That's why I thought that macs used pdf as the page description language
> > > now- surely if all documents are rendered as pdf by the operating
> > > system, it is a simple step to use that as the page description to all
> > > printers
> >
> > It would be easy enough for printers to accept PDF, but even PDF is
> > pretty complex to handle, especially in rotation and transparancy,
> > whereas a simple printer needs a lot less detail.
>
> I wouldn't say less detail. It's more that if you want to interpret
> PDF, you need a full on computer inside the printer - the code to do
> most of that job is available for free I expect (he said, looking at the
> various tools used in the TeX world).
>
> And there are cheaper ways to build a printer than to give them the sort
> of computing power needed to permit rendering of PDF pages in a
> reasonable time.

Umm.. that is what I said, the printer needs less detail. It just needs
a bitmap.


--
Woody

www.alienrat.com
From: Rowland McDonnell on 3 May 2010 13:34
Woody <usenet(a)alienrat.co.uk> wrote:

> Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote:
>
> > Woody <usenet(a)alienrat.co.uk> wrote:
> >
> > > Rowland McDonnell <real-address-in-sig(a)flur.bltigibbet.invalid> wrote:
> > >
> > > > Woody <usenet(a)alienrat.co.uk> wrote:
> > > >
> > > > > Simon Dobbs <simondobbs(a)froglet.net> wrote:
> > > > >
> > > > > > forgive my ignorance, and my inability to cut a longish thread,
> > > > > > but I thought that Macs had now lost postsript as the printing
> > > > > > file format of preference in favour of the acrobat file format.
> > > > >
> > > > > The compositing of views is done in the same way PDF yes, which is
> > > > > a lot
> > > > > simpler than postscript.
> > > >
> > > > Eh? Explain - I thought that the two were sufficiently similar that
> > > > there wasn't a lot of difference in that line, except that PS has more
> > > > programmability, which makes pdf safer.
> > >
> > > PDF is a superset,
> >
> > <puzzled> Really? I thought it was more like a subset with a few
> > additions needed due to the programmability that had been removed.
>
> No, it is a superset, it has had things added and other things improved.
> It has also had things removed as well.

If it's had things removed and things added, it's neither a superset nor
a subset but an intersecting set.

> > > > I thought that the reason Apple dropped Display PDF is because Adobe put
> > > > the licence fee too high, and that Display PDF (being as much an Adobe
> > > > product as PS, innit?) needed a licence paying whoever's using it.
> > >
> > > No, pdf is an open standard (but created by adobe) that requires no
> > > license to use,
> >
> > PDF might be that - but we're talking about Display PDF, which isn't
> > quite the same.
>
> Why isn't it?

<puzzled> Why ask such a stupid question?

> > >postscript is a licensed product of adobe that requires
> > > a license to use, that is why all printers didn't do postscript.
> >
> > I've known that for a while - but decent free PS emulation via gs has
> > been available for a very long time to get round that problem.
>
> Maybe, but what are the chances of apple implimenting an emulation of
> postscript without adobe objecting?

<puzzled> Huh? Haven't you heard of GhostScript?

Seems to me that Adobe couldn't do a thing to stop Apple using it - and
it hasn't tried to stop other firms implementing
not-paying-Adobe-anything PS emulation that I've ever heard of.

I've got an HP printer with PS emulation in it behind me now.

> For a start it wasn't available when OSX was started.

And yet gs was available back in the days when the `next gen Mac OS
project' was called Taligent. GhostScript was released in 1988.

That's 1988 - the year System 6 was released. I think you'll find that
it was still around when the OS X project was begun in the System 7 era
(System 7 came out in 1991).

"Efforts to develop Pink started around 1989, although at the time the
effort was primarily a research effort." - Pink ended up being called
Taligent, which was dropped for the OPENSTEP development line, which
started in 1996 (at the earliest, being the year Apple bought NeXT).

Come the `start' of the MacOS X project (the start of the particular
line of work at Apple which gave us what we've got), printers with PS
emulation (rather than real life licenced Adobe PostScript) were
commonplace and GhostScript had been out for EIGHT years.

So what are you on about?

> > > > > Compositing any view (PDF view, screen view or printer view) works in
> > > > > the same way.
> > > >
> > > > Macs don't use Display PDF, do they?
> > >
> > > They do. Have a look at the section on quartz on there OSX overview
> > > page:
> > > <http://developer.apple.com/technologies/mac/graphics-and-animation.html
> >
> > Given that all it says on the subject is:
> >
> > `Quartz 2D's rich graphics capabilities are based on the Portable
> > Document Format (PDF)'
> >
> > you could have pasted it here just as easily as the url...
>
> I could indeed.

So you were just being a pain for the sake of it, then?

> > > There is a lot more info in the developer section, that is just a
> > > confirmation.
> >
> > Oh! Righto. I'd got the idea that they'd dropped that way of doing it.
>
> No. It is the way the whole quartz system works. You can tell if you are
> doing low level graphics to it. It is unlike most other computer display
> systems where you composite information

Can you explain what that means?

> > > Basically the graphics in windows is cached in PDF images
> > > (which is why OSX uses PDF naturally as it does),
> >
> > But where does the actual PDF-ness of things come in to it, then?
>
> Basically it is the graphics compositing thing. You can cache a load of
> images in everything, what PDF gives you is a set of transformation
> matrixes for how those graphics are applied to each other. This means it
> gives you a good way to distort, or change those graphics for fancy
> graphics effects.

Can't that be done just as readily in PS?

> > I don't see why anything else wouldn't do just as well for a container
> > format.
>
> Well, it could well be done in another way, but PDF gives you some other
> facitilies.

Anything which is missing from PS?

> Nothing you couldn't actually do another way, but you have
> to pick one thing, and that is what they picked.

Erm, yers - and the point of that point was what?

> > > whereas in NeXT,
> > > graphics were stored as PS code, which was executed when it needed to
> > > draw, which is a lot slower.
> >
> > But surely NeXT could have been designed to cache images in a similar
> > way, using PS as the container format just as OS X uses PDF that way?
>
> It could have done. Ultimately the licensing issues were the major ones,
> especially at the time when adobe really didn't want to do any favours
> for apple.

<puzzled> What does that have to do with NeXT?

>If they had known that OSX was going to be successfull, they
> would have probably tried to do something about the licensing.

Eh? What do you mean?

> > > ahh, here, from the original reviews of the technical previews of OSX:
> > > <http://arstechnica.com/reviews/1q00/macos-x-gui/macos-x-gui-4.html>
> >
> > What was done back then isn't necessarily what ended up in 10.6...
>
> What we have now is an improved version, but it is still the same thing.

I'd need to read up on it - your word is not exactly reliable...

Rowland.

--
Remove the animal for email address: rowland.mcdonnell(a)dog.physics.org
Sorry - the spam got to me
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