Finally got some more time to work on this. The workaround I have found to
this problem is to add this somewhere in the main loop:
gui.mOutput->throw_focus();
the fltk::Output will steal key events for Delete, Backspace, Ctrl, and a few
others. I'm not sure why this should happen. I can understand why
fltk::Output should take the Tab key event if you are tabbing through widgets,
but I don't know why it needs some of these other events. Perhaps
Output::handle() should return 0 for some of these keys instead of letting them
fall through to Input::handle().
- Terry
> > On 30/11/11 08:20, Terry Welsh wrote:
> > > Hi,
> > > I'm using FLTK 2, and I have a class derived from GlWindow. My handle()
> > > function gets called for almost every key on the keyboard, but not when I
> > > press backspace or delete. Is this expected behavior? Is there a way to
> > > get events for these keys?
> >
> > Urgh, I'm not even sure. So in theory, the answer to "Is this expected?"
> > is no, while "is there a way to get events for these keys?" is yes.
> > However:
> > OpenGL compatibility with FLTK2 (especially with keyboards and whatnot)
> > is achieved by emulating certain bits of OGL functionality, to make it
> > work properly with fltk. As such, there are a few really dirty hacks
> > going on to (try to) make things work as they should. Occasionally,
> > however, things stop working.
> >
> > However, in saying that this doesn't automagically make fltk the
> > problem; there could be a whole raft of issues to do with your platform,
> > or code, or etc.
> > If you could post a minimal, compilable example of your current code
> > that shows the problem, this would be fantastic. I'll take a look if I
> > get the time, though at the moment that's a rather large if.
> > In the meantime, I'd suggest using fltk1.3 -- this is far far more
> > stable than 2.0 and is less likely to have as many bugs. If you really
> > desperately need 2.0 compatibility, you'll probably want to wait until
> > fltk3 comes out (and I get the 2.0 compatibility layer in, too, though
> > like I said I'm struggling for time at the moment).
> >
> > HTH,
> > Ben
> >
>
> Hi Ben,
> Thanks for the reply. BTW, my platform is Suse 11.3 and Gnome 2.x. Below is
> the minimal test case you asked for. It appears the problem is introduced by
> having an fltk::Output beside the GlWindow. If you comment out the creation
> of the fltk::Output, then the Backspace and Delete keys will work. Changing
> the GlWindow to a regular Window does not help. I found other keys that fail
> in the presence of the fltk::Output: Esc Tab, Shift, Ctrl, Home, and End.
>
> That's as far as I've gotten. I'll try other Linux distros and desktop
> enviroments and dig into the fltk code when I get a little more time to work
> on this. Any suggestions would be great.
>
> We started this project years ago when 2.0 was supposed to be the future.
> Switching to 1.3 sounds more difficult than they'll give me time for. You're
> probably right that 3.0 is the way to go eventually. (Funny how people here
> talk about 2.0 as unstable, since it's still the most stable open source
> project I've ever used.)
>
>
> #include <fltk/GlWindow.h>
> #include <fltk/Output.h>
> #include <fltk/events.h>
> #include <fltk/run.h>
> #include <iostream>
>
>
> using namespace std;
> using namespace fltk;
>
>
> class MyView : public fltk::GlWindow{
> public:
> MyView(int x, int y, int w, int h, const char *l)
> : GlWindow(x, y, w, h, l) {}
> ~MyView(){}
>
> void draw(){}
>
> int handle(int e){
> switch(e){
> case fltk::SHORTCUT:
> cout << fltk::event_key() << endl;
> break;
> }
>
> return (GlWindow::handle(e));
> }
> };
>
>
> class MyGui{
> public:
> Window* mMainWindow;
> MyView* mMyView;
> Output* mOutput;
>
> MyGui(){
> Window* o = mMainWindow = new Window(400, 400, "FLTK delete key
> test");
> o->shortcut(0xff1b);
> o->user_data((void*)(this));
> o->begin();
>
> mMyView = new MyView(0, 0, 400, 375, "");
> Group::current()->resizable(mMyView);
>
> mOutput = new fltk::Output(0, 375, 400, 25);
>
> o->end();
> }
>
> ~MyGui(){}
>
> void show(){
> mMainWindow->show();
> }
> };
>
>
> int main(int argc, char* argv[]){
> MyGui gui;
> gui.show();
>
> while(1){
> fltk::check();
> }
>
> return 0;
> }
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