Re: Text properties and FTGL

[John Swensen]

On Oct 28, 2008, at 1:44 PM, John W. Eaton wrote:
> You might also look at the way the Emacs preview-latex mode works.
> That doesn't rely on any special toolkit or widget (other than Emacs
> ability to embed images in an Emacs buffer).  So we should be able to
> do this in a reasonably portable way.  I would not want to link it too
> closely to a particular toolkit or widget.
>
> jwe

I downloaded the source code for preview latex and skimmed through  
their documentation and it looks like they do essentially a similar  
thing.  They run the latex code through one of the many TeX variants  
(depending on configuration) and then draw it directly into the  
buffer.  I'm not sure exactly how they draw it into the buffer, but  
that part is really the hangup for us.  Also, theirs also takes a bit  
of time and works in the background.

So, even though I should not be considered an expert on this, I think  
the following might be the way to go:

1) Use tex/latex/pdflatex to convert from an equation string to a dvi/ 
ps/pdf
2) Find a less platform/toolkit specific method of converting from pdf  
to a OpenGL texture
3) Draw the texture as one would expect
Since even poppler isn't dependent on a particular toolkit (it is in  
fact derived from the Xpdf codebase) maybe it will be as simple as  
make a new output device for poppler which renders to OpenGL.  It  
already renders to a GDK pixbuf and a QT QPixMap.  That being said, I  
once again iterate that I know very little about OpenGL and exactly  
how hard that might be.  Can an openGL texture kindof be treated as a  
pixel buffer?  If so, maybe the little extra won't be too hard?

There was an alternate route that I started to go down at the start of  
this and it was
1) .tex to .ps
2) Use pstoedit to convert to an SVG
3) Tried to get a library called svgl (intended for use from python,  
but since it is a C++ compiled extension it might be easy to  
incorporate) to render the output to OpenGL.
I had problems with this method also, as pstoedit didn't seem to  
render equations to SVG properly.

John Swensen