Re: Key presses and releases

[Галымжан Кожаев <kozhayev gmail com>]

Hi, Lyle!
I tested the program on Windows XP and it works great, so you don't
have to study WinAPI. Maybe there are some other ways to do this in
Linux too ? I will test it on Ubuntu 9.10 later, since I don't have
installed Linux right now. Also, if you find a solution, post it here
please, it's interesting.
Good luck!

2009/12/24, Lyle Underwood <lyleunderwood gmail com>:
> So there's no way I can actually use a pressed key as a mode toggle
> without getting down into OS-specific functions like in xlib? I'm build
> a cross-platform application, but I really don't want to get down into
> the win32 api. I've never really done any win32 programming, or xlib for
> that matter, but this functionality would just be so nice to have.
>
> Thanks for confirming my fears though.
>
> On Wed, 2009-12-23 at 21:57 +0100, michi7x7 wrote:
>> This is the automatic key-repeat-function by the OS, Windows does it
>> just like Linux or Mac.
>> If you want to get the real state of the Key, you'll have to use
>> X.org-functions (the xlib)
>> > This must be different between my computer and yours. I'm on Ubuntu
>> > 9.10, are you on a linux system?
>> >
>> > I compiled and ran your test code, but this too is affected by key
>> > repeat. If I hold down the space bar for just a second then I get a
>> > whole bunch of output.
>> >
>> > In this example I only pressed the spacebar one time, and tried to hold
>> > it down for exactly one second:
>> >
>> > $ ./test
>> > Toggled (active)
>> > Toggled (inactive)
>> > Toggled (active)
>> > Toggled (inactive)
>> > Toggled (active)
>> > Toggled (inactive)
>> > Toggled (active)
>> > Toggled (inactive)
>> > Toggled (active)
>> > Toggled (inactive)
>> > Toggled (active)
>> > Toggled (inactive)
>> >
>> > For the first quarter to half a second there was only one
>> > active/inactive pair, and then my key repeat kicked in and I got all the
>> > rest. Is this not what happens for you?
>> >
>> > Thanks for taking the time, by the way.
>> >
>> > On Wed, 2009-12-23 at 16:24 +0600, Галымжан Кожаев wrote:
>> >
>> >> I don't know why your code doesn't work. Look at this, I've written
>> >> and tested this code:
>> >>
>> >> bool hasToggled;
>> >>
>> >> bool keyPressHandler(GdkEventKey* event) {
>> >>   if(event->type == GDK_KEY_PRESS && event->keyval == GDK_space &&
>> >> !hasToggled) {
>> >>     hasToggled = true;
>> >>     cout << "Toggled (active)" << endl;
>> >>   }
>> >>   else if(event->type == GDK_KEY_RELEASE && event->keyval == GDK_space
>> >> && hasToggled) {
>> >>     hasToggled = false;
>> >>     cout << "Toggled (inactive)" << endl;
>> >>   }
>> >>   return false;
>> >> }
>> >>
>> >> gint main(int argc, char *argv[]) {
>> >>   Gtk::Main program(argc, argv);
>> >>   Gtk::Window wnd;
>> >>   hasToggled = false;
>> >>   wnd.signal_key_press_event().connect(sigc::ptr_fun(&keyPressHandler),
>> >> false);
>> >>
>> >> wnd.signal_key_release_event().connect(sigc::ptr_fun(&keyPressHandler),
>> >> false);
>> >>   program.run(wnd);
>> >>   return 0;
>> >> }
>> >>
>> >> Try to compile and run it. Works perfectly, I think it's exactly what
>> >> you need. Write if you have any problems.
>> >>
>> >> 2009/12/23, Lyle Underwood <lyleunderwood gmail com>:
>> >>
>> >>> That's what I'm doing now. The problem is that the signals don't seem
>> >>> to
>> >>> fire in this way. I expected the same behavior you did, I thought it
>> >>> would work like this:
>> >>>
>> >>> pressed event <-- // spacebar held down
>> >>> released event <-- // spacebar let go after a couple seconds
>> >>>
>> >>> pressed event <-- // spacebar held down
>> >>> released event <-- // spacebar let go after a couple seconds
>> >>>
>> >>> pressed event <-- // spacebar held down
>> >>> released event <-- // spacebar let go after a couple seconds
>> >>>
>> >>> But it actually does this:
>> >>>
>> >>> pressed event // <-- spacebar held down
>> >>> released event
>> >>> pressed event
>> >>> released event
>> >>> pressed event
>> >>> released event
>> >>> pressed event
>> >>> released event
>> >>> pressed event
>> >>> released event // <-- spacebar let go after a couple seconds
>> >>>
>> >>> pressed event // <-- spacebar held down
>> >>> released event
>> >>> pressed event
>> >>> released event
>> >>> pressed event
>> >>> released event
>> >>> pressed event
>> >>> released event
>> >>> pressed event
>> >>> released event // <-- spacebar let go after a couple seconds
>> >>>
>> >>> This results in the keyAlreadyPressed bool flipping between true and
>> >>> false over and over in quick succession while the space bar is
>> >>> depressed.
>> >>>
>> >>> On Wed, 2009-12-23 at 12:42 +0600, Галымжан Кожаев wrote:
>> >>>
>> >>>> Hi,
>> >>>>
>> >>>> Maybe you can do like this:
>> >>>>
>> >>>> void onKeyPressed(...) {
>> >>>>   if(!keyAlreadyPressed) {
>> >>>>      // space toggled (now active)
>> >>>>      keyAlreadyPressed = true;
>> >>>>      //... additional handling
>> >>>>   }
>> >>>> }
>> >>>>
>> >>>> void onKeyReleased(...) {
>> >>>>    // space toggled (now inactive)
>> >>>>    keyAlreadyPressed = false;
>> >>>> }
>> >>>>
>> >>>> keyAlreadyPressed is a bool private member or global variable.
>> >>>>
>> >>>> 2009/12/23, Lyle Underwood <lyleunderwood gmail com>:
>> >>>>
>> >>>>> I'm so close to finishing up this application now, I'm just putting
>> >>>>> some
>> >>>>> polish on it.
>> >>>>>
>> >>>>> I have a drawing area in a viewport for scrolling. I want to add the
>> >>>>> ability to pan with the mouse, but since the user is usually drawing
>> >>>>> onto the drawing area I wanted them to use the spacebar to pan. So,
>> >>>>> you
>> >>>>> hold down spacebar and drag around to pan, just like in photoshop,
>> >>>>> gimp,
>> >>>>> etc..
>> >>>>>
>> >>>>> I'm pretty sure I'm not going to have any problem with the actual
>> >>>>> panning, but I can't figure out how to use the spacebar as a toggled
>> >>>>> state. It seems the events are triggered by some kind of key repeat,
>> >>>>> because when I hold down space I get a huge series of press events
>> >>>>> and
>> >>>>> release events. So is there some way that I can tell if the spacebar
>> >>>>> is
>> >>>>> held down constantly? I was looking through the GdkEventKey struct
>> >>>>> and
>> >>>>> couldn't find a solution.
>> >>>>>
>> >>>>> Also, I wanted to ask, what's the easiest way to get the selected
>> >>>>> row in
>> >>>>> a TreeView to redraw?
>> >>>>>
>> >>>>> Thanks.
>> >>>>>
>> >>>>> _______________________________________________
>> >>>>> gtkmm-list mailing list
>> >>>>> gtkmm-list gnome org
>> >>>>> http://mail.gnome.org/mailman/listinfo/gtkmm-list
>> >>>>>
>> >>>>>
>> >>>
>> >>>
>> >
>> >
>> > _______________________________________________
>> > gtkmm-list mailing list
>> > gtkmm-list gnome org
>> > http://mail.gnome.org/mailman/listinfo/gtkmm-list
>> >
>
>
> _______________________________________________
> gtkmm-list mailing list
> gtkmm-list gnome org
> http://mail.gnome.org/mailman/listinfo/gtkmm-list
>