Re: [libcvd-members] GUI/GVars readline code

[Georg Klein]

On Tue, 15 Jan 2008, Gerhard Reitmayr wrote:

> I'm fine about the gl part, more interested in the text rendering. I
> have been using fltk2 fine, but switched to CVD::glwindow alone to avoid
> the dependency on fltk2. now I only have it through gvars3. I'd be happy
> to just make CVD::glwindow work on different platforms. If X is ok, then
> Unix and OSX already work fine. A windows or Carbon implementation
> shouldn't be too hard.

GLX on X on OSX is crippled; to a lesser extent than GLX on Cygwin/X, but 
it's not good enough, so yes, you'd need a carbon implementation. 
Re-implementing a GL window class for many OS may seem a nice programming 
exercise but it's ultimately just re-doing what other people (GLUT, FLTK) 
have already done; plus it means you have to design yet another input 
abstraction layer which again, has already been done.

The real annoyance is that on anything other than X, you need some form of 
window event manager. A nice property of X is that each window can have 
its own connection to the X server, and therefore the event code for each 
window is independent. Not so on MacOS, and not so (I believe) on 
Windows: all windows' events get piped to one central manager. This means
you need some sort of messy event dispatching system too. Again, all this 
has been done (sort of) by other people (FLTK.) This unfortunate fact 
makes FLTK's irritating single-global-instance trait somewhat forgiveable.

> If some simple, independent text rendering could be had (or someone can
> design a nice line font, mine are dreadful :). I looked at various nice
> gl wrappers of freetype but it just adds lots of dependencies...
>
> a pure gl GUI implementation could be added to gvars3 (replacing the
> current toolkit bindings) or just used by myself...

I think a GL window with associated user interface should be its own 
project, which may depend on GVars, but should not be part of it. It's too 
big a task IMO.