gnuplot-beta

%%BoundingBox and %%Orientation in *.ps and *.eps files

[Ethan M. <merritt@u.washington.edu>]

Harald (and everyone else):

You mention in your patch comments

>Date: 2005-01-26 16:44
>Sender: harders
>
>- Remove the '%%Orientation: ...' line from all kinds of eps
>  graphics since it confuses ghostscript 8.5. In normal
>  postscript (landscape, portrait) this statement remains existing.

It is true that %%Orientation should not appear in an *eps file.

But in looking this up in the PostScript Reference Manual I also
notice that there is a distinction between

%%BoundingBox and %%PageBoundingBox

An *eps file should use only %%BoundingBox.  So we're OK there.

But the existence of %%PageBoundingBox seems directly relevant
to recent discussion on the use of "set size" before and
after "set term".  

I believe that the sequence
  set size <x>,<y>
  set term post
should alter the contents of %%BoundingBox

But the sequence
  set term post
  set size <x>,<y>
  plot "foo"
  set size <x2>,<y2>
  plot "baz"
should in principle be setting %%PageBoundingBox each time
the size is changed. At the end of the file, %%BoundingBox
is set to the maximum values ever used for individual pages.

Is it worth making this change?


-- 
Ethan A Merritt       merritt@u.washington.edu
Biomolecular Structure Center
Mailstop 357742
University of Washington, Seattle, WA 98195

Re: %%BoundingBox and %%Orientation in *.ps and *.eps files

[Harald H. <h.h...@tu...>]

On Thu, 27 Jan 2005, Ethan Merritt wrote:

> But in looking this up in the PostScript Reference Manual I also
> notice that there is a distinction between
>
> %%BoundingBox and %%PageBoundingBox
>
> An *eps file should use only %%BoundingBox.  So we're OK there.
>
> But the existence of %%PageBoundingBox seems directly relevant
> to recent discussion on the use of "set size" before and
> after "set term".
>
> I believe that the sequence
>   set size <x>,<y>
>   set term post
> should alter the contents of %%BoundingBox
>
> But the sequence
>   set term post
>   set size <x>,<y>
>   plot "foo"
>   set size <x2>,<y2>
>   plot "baz"
> should in principle be setting %%PageBoundingBox each time
> the size is changed. At the end of the file, %%BoundingBox
> is set to the maximum values ever used for individual pages.
>
> Is it worth making this change?

How do you want to programme that? The BoundingBox has to be in the header
of the Postscript file. It is not allowed to use (atend) here. You have to
know what the BoundingBox of the plot will be before you do the first
plot. Or do you want to hold the whole Postscript file in memory until the
terminal is resetted or output is changed?  I am curious.

Regards
Harald

-- 
Harald Harders
h.h...@tu...
http://www.harald-harders.de

Re: %%BoundingBox and %%Orientation in *.ps and *.eps files

[Ethan M. <merritt@u.washington.edu>]

On Friday 28 January 2005 01:53 pm, Harald Harders wrote:
> 
> How do you want to programme that? The BoundingBox has to be in the header
> of the Postscript file. It is not allowed to use (atend) here.

Yes it is.  This is explicitly stated in Appendix G of the PostScript
Language Reference.  It's also pretty common, for obvious reasons.


-- 
Ethan A Merritt       merritt@u.washington.edu
Biomolecular Structure Center
Mailstop 357742
University of Washington, Seattle, WA 98195

Re: %%BoundingBox and %%Orientation in *.ps and *.eps files

[Harald H. <h.h...@tu...>]

On Fri, 28 Jan 2005, Ethan Merritt wrote:

> On Friday 28 January 2005 01:53 pm, Harald Harders wrote:
> >
> > How do you want to programme that? The BoundingBox has to be in the header
> > of the Postscript file. It is not allowed to use (atend) here.
>
> Yes it is.  This is explicitly stated in Appendix G of the PostScript
> Language Reference.  It's also pretty common, for obvious reasons.

Oh, sorry, I did not know that. But I am pretty sure that many programmes
will not be able to work with a Postscript file that does not have the
BoundingBox at the beginning of the file. I believe I remember that LaTeX,
for example, only reads the first few lines. I recommend not to use this
feature, although it is allowed.

Mmmh, I do not understand why you say that it's common to use it. Yes, of
course it is handy to write such files; but I cannot remember that I have
ever seen such a file.

Regards
Harald

-- 
Harald Harders
h.h...@tu...
http://www.harald-harders.de

Re: %%BoundingBox and %%Orientation in *.ps and *.eps files

[Hans-Bernhard B. <br...@ph...>]

Ethan Merritt wrote:
[...]
> But the sequence
>   set term post
>   set size <x>,<y>
>   plot "foo"
>   set size <x2>,<y2>
>   plot "baz"
> should in principle be setting %%PageBoundingBox each time
> the size is changed.

Not everytime the 'set size' changes, though.  Just everytime a new page 
is started with a different 'set size' in effect.  The difference 
becomes important if 'multiplot' is in use, where 'set size' doesn't 
actually control the page size if used between 'set multiplot' and 
'unset multiplot'.

Re: %%BoundingBox and %%Orientation in *.ps and *.eps files

[Ethan M. <merritt@u.washington.edu>]

On Sunday 30 January 2005 11:59 am, Hans-Bernhard Broeker wrote:
>
> Not everytime the 'set size' changes, though.  Just everytime a new page
> is started with a different 'set size' in effect.  The difference
> becomes important if 'multiplot' is in use, where 'set size' doesn't
> actually control the page size if used between 'set multiplot' and
> 'unset multiplot'.

Of course you are correct.

-- 
Ethan A Merritt
Biomolecular Structure Center
University of Washington 98195-7742