Re: probable gtk_window_present and pango help

> On Fri, May 18, 2012 at 09:12:45PM +0530, Rudra Banerjee wrote:
> > Here is a minimal example of a program, where if i click the button, a
> > pop up window appears. I am posting both the call back function and the
> > main routine (table.c).
> > I am facing 2 problem.
>
> Unfortunately, you are facing much more problems.
>
> For start
>
>     gtk_container_add(GTK_CONTAINER(window1), vbox1);
>
> is called with an unitialised variable window1 (i.e. no window1 is ever
> created).  This leads to a CRITICAL message to console and/or crash.
>
> And if window1 existed then vbox1 would be packed into two different
> containers (window1 and window) which is not possible.  So I'm ignoring
> that part altogether.
>
> The callback should look like
>
> void
> callback_it(GtkWidget *button, gpointer user_data)
> {
>    ...
> }
>
> where in user_data the callback receives the last argument you passed to
> g_signal_connect().  It is rarely useful to pass a constant such as
> "Call" there.
>
> The callback is *not* another main() function; it should *not* call
> gtk_init() again, etc.  Please read the signals section in the Gtk+
> tutorial
>
>     http://developer.gnome.org/gtk-tutorial/2.90/x159.html
>
> There are several other highly suspicious things:
> - redeclaration of global variables (such as window) inside a function;
>   are you aware this creates a new local variable window that has nothing
>   to do with the global one?
> - inclusion of .c files instead of separate compilation + linking them
>   together
> - calling gtk_widget_show() on individual widgets and then again showing
>   everything using gtk_widget_show_all()
> - not terminating the Gtk+ main loop when the main window is destroyed;
>   this is usually the first thing to set up in a Gtk+ program, see
>
>     http://developer.gnome.org/gtk-tutorial/2.90/c39.html#SEC-HELLOWORLD
>
> etc.
>
> > 1) The problem is evry time I click the button "main", a new window
> > appears(obviously). What I want to achive is, if the window is already
> > present, it should not open again; rather it should focus that window. I
> > believe, this can be achived by gtk_window_present(may be I am wrong).
> > But I don't know how to use it.
>
> You use it just by calling gtk_window_present() on the window object.
> To that meaningfully you need not only to keep the window object around
> but also get notified when the window is destroyed.  Either by
> connecting to the "destroy" signal or, if you just want to set a pointer
> to NULL once it is gone, by using g_object_add_weak_pointer().
>
> > 2) In the callback function, I have C_1 and C_2. What I want to achive
> > is C₁ etc via pango(or any other).
>
> For simple things you can sometimes just use UTF-8.  But generally, you
> need to use Pango markup.  If the widget does not have function to set
> the markup it has a function to obtain the label widget so that you can
> use gtk_label_set_markup() on that.
>
> See the attached code with main problems fixed (and merged to one file).
> Please go through the Gtk+ tutorial farther that you perhaps have done.
>
> Yeti
>