Re: Text properties and FTGL

[John Swensen]

On Oct 29, 2008, at 12:18 AM, Shai Ayal wrote:

> > 1) balhtexml - This is the library used by MediaWiki (same as used by
> > Wikipedia) to allow people to use LaTeX code inline with the web  
> > pages.
> > They also have a command line tool and a library that could easily be
> > linked against directly.
>
> I could not find this library on google. Could you provide a line?
Sorry, that is blahtexml (http://gva.noekeon.org/blahtexml/ and 
http://www.mediawiki.org/wiki/Extension:Blahtex)


> > 2) gtkmathviewer - Despite having dependencies on GTK, the "core" of
> > gtkmathviewer does not depend on GTK and could be ripped out and a  
> > simple
> > render to a bitmap/pixmap could be done for inclusion into the  
> > OpenGL plots.
>
> This looks nice but renders MathML, not LaTeX
Right, that is why I proposed the two step process of LaTeX to MathML,  
then MathML to something that can be rendered to the OpenGL plot.

> > I think in the long run this will look less pretty than the LaTeX  
> > output,
> > but seems simpler and dependent on less stuff.
>
> I don't think we really need to be as pretty as LaTeX - I really think
> having a small subset (greek, sub, super) is enough. It seems a wasted
> effort to try and re-write LaTeX. If you really need very complex
> LaTeX text on your plot, you can always use some ps+TeX trick:
> I think we will use gl2ps to get postscript output from our OpenGL
> code, and it supports combined ps+latex:
>
> http://www.geuz.org/gl2ps/#tthFtNtAAB
>
> i.e. you get 2 output files files -- a ps file with all the graphics
> and a latex file which \includes the graphics and adds the text. This
> way, on your hardcopy (but not on-screen) you can have true LaTeX
> capabilities.
>
> Shai

I think that small subset should also have \dot, \ddot, \hat, \tilde,  
and maybe a couple others, since these get used quite frequently.

Would you be averse to having the two options available at compile  
time?  That way, for those with systems where LaTeX and libpoppler are  
available (whether gtk or QT), we could compile in the support for the  
full interpreter?

My latest test involved the following process, and while I haven't got  
it to draw in the Octave OpenGL plot yet, I do have it drawing in an  
OpenGL window as a texture on the cube
1) Run pdflatex on an equation: e.g.   \dot{x}(t) = Ax(t) + bu(t)
2) Run pdfcrop on the file to cut it down from a full page to just the  
bounding box
3) Load the resulting PDF with libpoppler and put it into a pixel buffer
4) Transfer the pixel buffer to an OpenGL texture
5) Apply the texture to the side of a cube (I'm assuming I could apply  
this to a transparent plane also?)

I haven't timed this yet because I am still doing (1)-(2) manually  
from the command line, but (1)-(2) really only need to be done once.   
Even (3) only needs to be done once unless some sort of zooming or  
resizing of the text takes place.  Also, libpoppler does the scaling  
and such before it converts it to a pixmap, so the text looks good  
even at large and small scales.  This process actually seems quite  
simple and doable to me, and is even a fairly simple process given  
these libraries are readily available on your platform.  I know that  
all of these are readily available on Linux and OSX, but have no clue  
about windows.


John