A Question On Web Graphics

Gentle People:

    Sorry if this appears off topic but I am not sure where to post the

question. Please do not get mad, just recommend a better venue!

    Currently I am quite experienced with C and learning C++ but I have

never written graphical type applications in either!

    Can you recommend an open source graphics package which would be
called by C/C++ and be fit for drawing complex graphs and charts for Web Applications?

Also I have successfully experimented with Apache and PHP but have not yet identified graphics applications for this venue either! Ideas?

    I am thinking about calling a C/C++ based application called from Apache/PHP,
where the C/C++ Application would call the graphics application as necessary!

Is this the best architecture? Thanks for the help. Thomas Dineen