Re: How to "extend" a widget?

[jjacky <i am jack mail gmail com>]

Thanks. I will have a look into Vala, although for projects I have 
planned, I really want/need to be using C.

And while GTK is oriented-object, it is written in C and, AFAIK, there 
are no such things as classes in C?
I believe the way to create a widget based on/extending another one is 
how I have done so far (based on the docs /tutorials I read), only I'm 
not sure how to properly do things like "overriding" functions to change 
behaviors or add features.

If Vala allows to do that easily and does produce C code though, I might 
try and see how it does/what code it produces, but I'm not sure learning 
a new language is something I wanna get into right now...

-jacky


On 12/16/2011 07:05 PM, Michael Torrie wrote:
> On 12/16/2011 08:16 AM, jacky wrote:
> > As I said, I'm not sure this is the right way to do such a thing, so I
> > would appreciate any help/information on how one would do this
> > properly.
>
> Since GTK is object oriented, you could just create a new class that
> inherits from GtkCalender.  However this is C we're using, so it's not
> quite as simple as in C++, Java, or Python.  If I recall correctly,
> you'll end up with 3 files.  2 .C files and 1 .H  One C file will
> contain the klass and vtable initialization stuff, one .C file of your
> implementation, and one .H file with your public interfaces, cast
> macros, and so forth.  At one time GTK people were using a tool called
> "gob" to compile a single file of some object-oriented C-like syntax
> into these files.
>
> Seems to me, though, that you'd be well-served in doing this in Vala.
> Vala itself defines a C-like (more C#-like) language that compiles into
> C and GObject code.  You can take the output of Vala and use it in your
> normal C development.  In fact the job you describe is just what Vala
> was originally designed for, though Vala has gone far beyond just being
> a GObject compiler.
>
> Michael.
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