[pdftex] XObject name

Igor Khomyakov igorkh at optonline.net
Sat Apr 16 14:14:47 CEST 2005


Thanh,

Thank you for revisiting this. It seems that the only benefit this feature
gives us is that it allows to defer the typesetting of fixed-sized displays
(e.g. total number of pages, etc.) until required data is available, and
therefore allows to eliminate second document pass (i.e. speed things up).
If it is not trivial to implement and may complicate things, I agree that it
might not be a good idea to implement it.

Best regards,
Igor. 

-----Original Message-----
From: pdftex-bounces at tug.org [mailto:pdftex-bounces at tug.org] On Behalf Of
The Thanh Han
Sent: Friday, April 15, 2005 11:40 PM
To: pdftex at tug.org
Subject: Re: [pdftex] XObject name

Indeed I was digging my mail boxes and couldn't find any mail
where I promised to do that :).

Usually I add new features immediately when asked if
they are easy to implement and can't break things.
Complicated extensions require more consideration. The
feature you have asked for is not something trivial to
implement, while you didn't give me an example good enough
to convince me why this feature can be useful. So I didn't
consider to implement it, as I have other things to do as
well.

Regards,
Thanh


On Thu, Apr 14, 2005 at 11:51:23PM -0400, Igor Khomyakov wrote:
> Thanh,
> 
> Please accept my apologies for the misleading email --- you decided
against
> forward xform references because of the unknown xform dimensions. Please
> find all relevant email (including my thoughts on how to workaround the
> problem) below --- it would be great if you could give it another try. 
> 
> Best regards,
> Igor.
> 
> 
> ----- Original Message -----
> From: "Igor Khomyakov" <igorkh at optonline.net>
> To: <pdftex at tug.org>; "The Thanh Han" <hanthethanh at users.sourceforge.net>
> Sent: Friday, March 28, 2003 5:24 AM
> Subject: Re: [pdftex] \pdfobj extended [was: Forward looking object
> references]
> 
> 
> > One possible solution is to assume zero width, height, and depth for 
> > \pdfrefxform that points to a reserved xformnum. We can think of these 
> > references as of special kind of \pdfliterals that also have zero
> dimensions
> > but importantly pdftex knows their relative position, and therefore it 
> > is very convenient to include some useful pdf drawings, etc. If one 
> > needs to specify the sizes, he or she can "box" the \pdfrefxform as in 
> > the
> following
> > example:
> >
> >    \hbox to ... {\vbox to ... {\pdfrefxform\count1}
> >
> > The real typesetting of the xform (the media box, etc) occurs when we
> issue
> > \pdfxform command -- at this time we already have the sizes of the
xform.
> >
> > The "xform forward references" should be very good for single-pass 
> > typesetting of little fit-into-single-page things that should appear 
> > in a document before their content (value) is known. For example: the 
> > total number of pages (the example below in my previous email), or 
> > some summary table, or a short table of contents that should be put at 
> > the beginning of
> a
> > document. I think that this functionality will be the most appreciated 
> > by reporting applications that can save a lot by avoiding the second
pass.
> >
> > The other two reasons to implement this functionality are: 1) PDF 
> > format supports it, and 2) since we already can reserve and use the 
> > numbers for objects, it would be more consistent to have similar 
> > functionality for xforms and ximages ;)
> >
> >
> > Best regards,
> > Igor.
> >
> > ----- Original Message -----
> > From: "The Thanh Han" <hanthethanh at users.sourceforge.net>
> > To: <pdftex at tug.org>
> > Sent: Thursday, March 27, 2003 9:48 PM
> > Subject: Re: [pdftex] \pdfobj extended [was: Forward looking object 
> > references]
> >
> >
> > > I was thinking of it -- unfortunately it doesn't seem possible, as 
> > > in order to use \pdfrefxform, the contents of the form must be known 
> > > so pdftex can calculate how much space the form takes.
> > >
> > > It might be done using some tricks with primitives related pdfobj 
> > > and pdfxform -- I am not sure but one can give a try. It ot course 
> > > requires that you know pretty well how pdf works. Heiko, Hans or 
> > > Martin can certainly say more about this.
> > >
> > > Theoretically it would be possible to make \pdfxform and \pdfximage 
> > > work this way (given that when using with useobjnum, the form/image 
> > > dimensions must be given). But what it would be good for? If there 
> > > is a really good reason for doing it I will give another try ;)
> > >
> > > Thanh
> > >
> > > On Wed, Mar 26, 2003 at 10:19:02PM -0500, Igor Khomyakov wrote:
> > > > Thanh,
> > > >
> > > > Are you planning to implement the same functionality
> > > > (reserveobjnum/useobjnum) for \pdfxform and \pdfximage? For example:
> > > >
> > > > ------------------------------------------------
> > > > \pdfxform reservexformnum
> > > > \count1=\pdflasxform
> > > > Page 1 of \hbox{\pdfrefxform\count1} \hrule First page content ...
> > > > \vfill\eject
> > > > Page 2 of \hbox{\pdfrefxform\count1} \hrule Second page content 
> > > > ...
> > > > \setbox0=\hbox{\folio}
> > > > \pdfxform usexformnum \count1 0
> > > > \pdfrefxform\pdflastxform
> > > > \bye
> > > > --------------------------------------------------------
> > > >
> > > > Thanks!
> > > > Igor.
> > > >
> > > > PS: I compiled and ran the new version on Solaris 2.6 -- works
nicely!
> > > >
> > > >
> > > > ----- Original Message -----
> > > > From: "The Thanh Han" <hanthethanh at hotpop.com>
> > > > To: <pdftex at tug.org>
> > > > Sent: Wednesday, March 26, 2003 3:36 AM
> > > > Subject: [pdftex] \pdfobj extended [was: Forward looking object
> > references]
> > > >
> > > >
> > > > > Hi,
> > > > >
> > > > >
> > > > > I extended the syntax of \pdfobj to:
> > > > >
> > > > > \pdfobj <object type spec>                              (h, v, m)
> > > > > <object type spec> --> reserveobjnum
> > > > >                     | [useobjnum <number>] [stream [<attr 
> > > > > spec>]]
> > <object
> > > > contents>
> > > > > <object contents> --> <file spec>
> > > > >                     | <general text>
> > > > >
> > > > > When the optinal keyword `reserveobjnum' and `useobjnum' is not
> given,
> > > > > the behaviour is unchanged.
> > > > >
> > > > > Usage example:
> > > > >
> > > > > \pdfobj reserveobjnum
> > > > > \count0=\pdflastobj
> > > > >
> > > > > ....
> > > > >
> > > > > \pdfobj useobjnum \count0 {test} \pdfrefobj\pdflastobj
> > > > >
> > > > > (or one can use \immediate\pdfobj useobjnum ...  instead of
> > \pdfrefobj)
> > > > >
> > > > > If you use multiple \pdfobj useobjnum with the same object 
> > > > > number,
> the
> > > > > result is undefined ;)
> > > > >
> > > > > The whole sources tarball is available at 
> > > > > http://vinux.sourceforge.net/pdftex
> > > > >
> > > > > Further patches will be uploaded to tis location as well.
> > > > >
> > > > > Or one can use the texlive p4 server instead.
> > > > >
> > > > > Thanh
> > > > > _______________________________________________
> > > > > pdftex mailing list
> > > > > pdftex at tug.org
> > > > > http://tug.org/mailman/listinfo/pdftex
> > > _______________________________________________
> > > pdftex mailing list
> > > pdftex at tug.org
> > > http://tug.org/mailman/listinfo/pdftex
> >
> > _______________________________________________
> > pdftex mailing list
> > pdftex at tug.org
> > http://tug.org/mailman/listinfo/pdftex
> >
> 
> 
> -----Original Message-----
> From: The Thanh Han <hanthethanh at gmx.net>
> Date: Thu, 14 Apr 2005 16:49:07
> To:Igor Khomyakov <ikh at tmo.blackberry.net>
> Subject: Re: [pdftex] XObject name
> 
> can you please resend the relevent mails? I forgot about that. Sorry.
> 
> Thanh
> 
> 
> 

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