I'm looking for some general advice on the code design of a form which has to generate an image when submitted. I'm new to this, and the data communication from the form to the image generator has me stumped. Any advice appreciated (I've got lots of C experience, a bit of JavaScript, no php).
Problem: a user has to fill in a form (in Joomla). The user sets a number of parameters, and hits submit. When I see the submission, I have to call a C program, passing it the form parameters. The C program then outputs JavaScript (which codes for an SVG image). This image must then appear (preferably in a modal) at the client's browser.
I haven't been able to find an existing Joomla extension which does anything like this, or which I can modify to do this.
I can write php to call the C code, but how do I get the form data to the php, and arrange for display inside the popup? I've got a general idea of how I can use jQuery to respond to a form submission and to generate a popup using data from a form (along the lines of http://www.sohtanaka.com/web-design/inline-modal-window-w-css-and-jquery/). However, I can't see that this is relevant. The main problem is that I have to generate the SVG JavaScript on the server, and I can't influence this from the client jQuery code (I think). The client code can't, I think, do much more than style the popup.
Any pointers appreciated.