[Tioga-users] Using the new pdf preview features in 1.2

[Bill Paxton]

On Oct 24, 2006, at 4:02 PM, Ivars Finvers wrote:

> I saw a message saying the Tioga 1.2.x has the ability to directly
> produce a "final" version of a figure's pdf. A quick browse of the
> documentation didn't reveal how to do this (or even, exactly what the
> new commands are).
>
> For those of us who aren't intimate with the details of Tioga, would
> it be possible to provide an example of using the new pdf mode?


Hi Ivars,

Thanks for the email.  It seems that the releases have gotten out in  
front of the documentation again!

Before going into details of commands, please allow me to take  
another shot at explaining this talk about "final" versions of a  
figure's pdf means.  For me, there's been a change of view not unlike  
the famous visual illusion (is it a vase or is it a reflected profile?):


In the "old days", I thought of Tioga as producing intermediate files  
(the *_figure.tex and *_figure.txt files) that would at some later  
time be combined by TeX to create a figure in a TeX document.  So, in  
that view, the "final" figure PDF was created by TeX as part of  
typesetting a document.  However, I naturally wanted to see what the  
figure looked like while I was debugging it, and so there was a  
"preview" ability in Tioga as well.  And before long it became clear  
that I was looking at things in the "wrong" way.

So there was a reversal in my image, and now I think of the process  
as Tioga producing the final PDF for the figure and, as part of that,  
calling TeX as a subroutine to get the job done.  Then the figure PDF  
can be used however you wish -- as part of a TeX document of course,  
but for anything else as well.  There is no longer any need for a  
"preview" and the *_figure files can be deleted immediately since  
they're now just temporaries created to drive TeX.

There wasn't too much needed to provide better support for this new  
view of things.  Mainly, you need to be able to specify exact sizes  
for figure and fonts.

Now for specifics.  Please take a quick look at tioga samples/plots/ 
plots.rb that is part of the download.   At the end of the initialize  
routine, at line 63, there is a new addition:

         t.def_enter_page_function { enter_page }

This tells tioga that whenever it is about to create a new PDF page,  
it should call the 'enter_page' method which is defined in the next  
few lines of the file:

     def enter_page
         t.page_setup(11*72/2,8.5*72/2)
         t.set_frame_sides(0.15,0.85,0.85,0.15) # left, right, top,  
bottom in page coords
     end

The page_setup routine takes the desired width and height in "big  
points" (72 per inch).   So in this case, the PDF will be 5.5 inches  
wide and 4.25 inches high.  The set_frame_sides routine takes  
fractional positions on the page (i.e., page coordinates).  If you  
wanted to change the fonts, you could do that in the enter_page  
routine as well by adding a line like this:

         t.set_default_font_size(14)


I hope this helps to clarify things.

Cheers,
Bill


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