Re: [[gnomemm] Key Events]

["Andrew E. Makeev" <andrew solvo ru>]

Murray Cumming wrote:

> Why not use the normal gtkmm or gnomemm accelerator key systems? 
>
> Deepak Chandran <DeepakC dpsl net> wrote:
>  
>
> > Hi!!
> >
> > We are developing an application in gnome-mm.
> > The application needs to allow user to operate it using key combinations.
> > We are providing the user "CTRL" + Key combinations for various operations
> >
> > *****Attached is the code snippet for the same**************
> >
> > bool window::on_key_press(GdkEventKey* key)
> > {
> >    if (( key->keyval == GDK_E || key->keyval == GDK_e)
> >          && ( key->state == GDK_CONTROL_MASK ))
> >    {
> >        /* IF CTLR + e / CTLR + E perform required operation*/
> >    }
> > }
> > **************************************************
> >
> > When we execute the above code, it works fine.
> > But when "Num Lock"  is ON, the above "if" condition fails.
> >
> > We found that when the "Num Lock" is activated, the "key->state" is
> > incremented by a factor of 16. This increment is not consistent for all the
> > keys.
> > This is causing a problem for as we are not able to find if the Num Lock is
> > activated or not.
> > And If activated what is the key->state behaviour for various keys.
> >
> > Is there some way to get the "key->state" irrespective of the Num Lock key
> > state ?
> >
> >    
Guys, it is not GTK question, actually :).
Any mask requires bitwise OR, AND, XOR, NOT operation instead of logical 
EQ, etc.

So, expression like

key->state & GDK_CONTROL_MASK

is going to work for Ctrl+<key> regardless any other STATE-key is 
activated also.

However, I guess, you won't to have your binding activated with 
Ctrl+Alt+<key> (for example). Then you have to build STATE expression 
wisely to filter valid masks (probably, normal key-accelerator system 
does it for you).

Num Lock modifier is mapped to GDK_MOD2_MASK, usually, you could check 
it with 'xmodmap -pm' command in Linux shell.

Regards,
-andrew