Re: Text properties and FTGL

[Abdelrazak Younes]

On 31/10/2008 18:09, John Swensen wrote:
> On Oct 31, 2008, at 2:25 AM, Abdelrazak Younes wrote:
>
> > Hello,
> >
> > On 31/10/2008 03:02, John Swensen wrote:
> > > So I have done a few tests, probably in a very naive way, about
> > > rendering LaTeX strings to OpenGL. I think it is going to be
> > > prohibitively slow. Using the following code, even a simple equation
> > > took about 0.6 seconds. Maybe there is a faster way of doing this. I
> > > searched around and couldn't find a way to link against a library for
> > > rendering LaTeX code.
> >
> > Did you have a look at latexpreview?
> >
> > http://preview-latex.sourceforge.net/manual/
> >
> > This is IMHO the perfect solution for embedded LateX snippets. You 
> > can see how we are using that within LyX:
> >
> > http://wiki.lyx.org/LyX/InstantPreview
> >
> > Hope this helps,
> > Abdel.
>
> This is essentially what my most recent test does.  It generates a 
> very simple .tex file with the equation included, runs it through 
> pdflatex, runs it through pdfcrop (which is a script calling 
> ghostscript) to cut it down to just the equation bounding box, and 
> then use poppler to render it to an in-memory bitmap.  I then draw it 
> to OpenGL.  From everything I have read and a quick glance at 
> preview-latex sources, this appears to be essentially the same process.
>
> Any suggestions on getting the steps of running pdflatex and pdfcrop 
> to go faster?

Not from me sorry.

>   Currently it seems to be taking too long for this to be a feasible 
> solution if there are more than 1 or 2 equations in text on a given 
> figure.

In LyX we cache the generated graphics in png format so that we don't 
have to generate them again if the equations are unchanged (you can crc 
the LaTeX snippets). But if you want something scalable I suggest that 
you cache the generated pdf graphics instead (after pdfcrop). I think it 
is acceptable to wait a tiny bit the first time the equation is rendered.

Abdel.