Re: locana, SVG, cross-platform GUI meanderings...

"Tom Sawyer" <[e-mail]> wrote in message
news:[e-mail]...
>
>
> so i'm polling here. i am working on a Ruby GUI, and it is in the very
early
> stages. right now i am planning to use the GGI api for graphics rendering.
> what are the merits of SVG compared to something like GGI? what would be
the
> draw in using one over the other? can SVG reasonably accomadate a GUI
> toolkit? could both SVG and GGI be used together seemlessly? by the way,
GGI
> dosn't do font rendering and i was looking at using FreeType2 for that.

I just took a second look at FLTK - I'm not through looking at it so this is
preliminary.
Up to this point I have considered Fox the best crossplatform choice, but I
have been wondering a lot about developing GUI natively in OpenGL. All the
toolkits I have looked at have not really been any serious option, except
perhaps GLGooy, but it is intended for Game development and spends all the
CPU on creating frames. GLGooey apparently uses the best FreeType (FTGL)and
OpenGL helper frameworks available (GLFW) - so with respect to FreeType it
may be worth a look. An OpenGL GUI can be be rendered like any normal 2D API
without redrawing the entire frame over and over (but this is not the GLGooy
way, unfortunately).

FTGL http://homepages.paradise.net.nz/henryj/code/
GLFW http://hem.passagen.se/opengl/glfw/
GLGooy http://nwaldren.bei.t-online.de/glgooey.htm

Then I became aware the FLTK preferably renders to OpenGL. I no longer
remember my objections againts FLTK and I need more research - but there is
new FLTK 2.0 in the pipeline with multiple theme support (or potential for
it). Apparently IME (asian input) and UTF-8 is supported or at least in the
planning.

NVDIA drives OpenGL development and releases drivers to Linux and FreeBSD.
OpenGL should be as good as any 2D drawing API with 3D as a bonus to the
extend the CPU and GPU are fast enough.
Therefore it makes sense to develop GUI in OpenGL rather than stuffing
OpenGL into the GUI as a special case.
With the future 3D graphics adapters even on the average laptop, OpenGL is
indeed interesting. Of course Direct-X is also relevant, but not exactly
cross-platform.

When developing GUI applications you often end up needing a userinterface
that looks like other known GUI's: a tree control, tool bars, dockable
windows. And inevitable these are not natively available so you either need
to purchase extremely buggy third party tools doing something similar, or
implement it youself, which is faster because you don't need to fight the
bugs you didn't write. And whatever is considered native OS widgets are
outdated anyway. Just look at how many different drawing styles Windows
provides in Microsoft products. Only starting with .Net do you actually get
access to a fairly updated GUI toolkit.

In consequence, you might as well use a powerful graphics API for drawing
the controls you need to draw anyway.
The major problem with OpenGL is that it does not come with an event model
or font support. Font can be handled using FTGL but the event model can be
more tricky.

Perhaps FLTK adds a layer on OpenGL that handle events and allows you to
extend with you own widgets without bogging down the CPU and without crappy
updates - or perhaps not - but then I'd rather draw manually.

SVG is nice and has improved a lot lately - but it's still to sluggish to be
real GUI platform, although for client server alternative SVG or Flash are
interesting.

I have a vision of a thin OpenGL client with a socket to the server
application. Basically like HTML, but with a permanent socket connection and
none of the HTML DOM ambiguities. I guess not unlike how Flash works, except
using OpenGL.
Given all the crap time spend and making hopeless GUI's in browsers, one
might as well spend the time writing a client server GUI architecture that
actually works and which compiles and all platforms supporting OpenGL.

So purely based on FLTK rendering OpenGL I think I'll give it a second look.
That said, I have nothing against Fox if it just fixes minor drawing
problems and solves the internationalization issue - it just doesn't allow
me to extend widgets in OpenGL.

And face it - we can either go native 3D GUI now or wait until Microsoft and
Apple does it and the do it. I'm not saying everything should be 3D, but I
wouldn't mind reading my mails like starwars intro when logging into the
system ;-)
What I'm saying is that staying with 2D API's has limited life expectancy.

Mikkel