Re: [gtkmm] Another Events problem

[Phillip Neiswanger <sigsegv prodigy net>]

On Sat, 14 Feb 2004 13:20:18 -0700, Phillip Neiswanger 
<sigsegv prodigy net> wrote:

> In this program the main working widget is a drawingarea.  It is 
> contained in a frame.  At certain points it makes sense to allow the 
> user to split this widget.  I wrote some code that would remove the 
> drawingarea from the frame, construct 2 new drawingarea widgets and 
> place them in a vertical or horizontal paned widget, then add the paned 
> widget to the frame and delete the original drawingarea.  That code 
> works and when I split the original drawingarea it generates the 2 paned 
> drawingareas.  Unfortunately, the new drawingareas no longer get any 
> events even though the code to set up the events is the same.  I tried 
> setting the events and focus parameters in the paned widget, but that 
> doesn't help.  Then it occured to me that the paned widget might be a 
> windowless widget, so I created an EventBox and stuffed the paned widget 
> in it and added the eventbox to the frame instead of the paned widget.  
> So far I can't get that code to work.  It just hangs the program.  I 
> don't really care about that because what I really want to know is the 
> following.
>
> What am I missing?  Why don't the drawingareas get events when I put 
> them in a paned widget?  Is there some parameter I need to set in the 
> paned widget, or do I simple need to get the eventbox code working?

Please excuse me if I'm being very dense.  The following is some example 
code that readily exercises the problem.

#include <libgnomemm/main.h>
#include <libgnomeuimm/init.h>
#include <libgnomeuimm/app.h>
#include <gtkmm/frame.h>
#include <gtkmm/paned.h>
#include <gtkmm/drawingarea.h>
#include <gdkmm/color.h>

const char *name = "example";

class DerivedDrawingArea : public Gtk::DrawingArea
{
  public:
        typedef SigC::Signal1<void, DerivedDrawingArea*> SplitJoinSignal;

        DerivedDrawingArea();
        virtual ~DerivedDrawingArea();

        SplitJoinSignal split() { return _split; }
        SplitJoinSignal join() { return _join; }

  protected:
        virtual bool on_expose_event(GdkEventExpose*);
        virtual bool on_configure_event(GdkEventConfigure*);
        virtual bool on_key_press_event(GdkEventKey*);

  private:
        SplitJoinSignal _split,
                                        _join;
};

class DerivedFrame : public Gtk::Frame
{
  public:
        DerivedFrame();
        virtual ~DerivedFrame();

        void split(DerivedDrawingArea*);
        void join(DerivedDrawingArea*);

  private:
        SigC::Connection _split;
        Gtk::Widget *_w;
};

class DerivedHPaned : public Gtk::HPaned
{
  public:
        DerivedHPaned(DerivedFrame*, DerivedDrawingArea*);
        virtual ~DerivedHPaned();

  private:
        DerivedDrawingArea      *dda1,
                                                *dda2;
};

class DerivedApp : public Gnome::UI::App
{
  public:
        DerivedApp();
        virtual ~DerivedApp();
};

DerivedDrawingArea::DerivedDrawingArea()
{
        set_flags(get_flags()|Gtk::CAN_FOCUS);
        add_events(Gdk::KEY_PRESS_MASK);
}

DerivedDrawingArea::~DerivedDrawingArea()
{
}

bool
DerivedDrawingArea::on_expose_event(GdkEventExpose*)
{
        get_window()->clear();
        return true;
}

bool
DerivedDrawingArea::on_configure_event(GdkEventConfigure*)
{
        get_window()->set_background(Gdk::Color("black"));
        return true;
}

bool
DerivedDrawingArea::on_key_press_event(GdkEventKey* e)
{
        bool rV = Gtk::DrawingArea::on_key_press_event(e);

        if (rV == false)
        {
                if (   (e->keyval == GDK_S || e->keyval == GDK_s)
                        && (e->state & GDK_CONTROL_MASK))
                {
                        _split(this);
                }
                else if (   (e->keyval == GDK_J || e->keyval == GDK_j)
                                 && (e->state & GDK_CONTROL_MASK))
                {
                        _join(this);
                }
                else
                        std::cerr << "key: " << char(e->keyval) << '\n';
        }

        return rV;
}

DerivedHPaned::DerivedHPaned(DerivedFrame* df, DerivedDrawingArea*)
{
        dda1 = new DerivedDrawingArea;
        dda2 = new DerivedDrawingArea;
        pack1(*dda1, true, true);
        pack2(*dda2, true, true);
        dda1->join().connect(SigC::slot(*df, &DerivedFrame::join));
        dda2->join().connect(SigC::slot(*df, &DerivedFrame::join));
}

DerivedHPaned::~DerivedHPaned()
{
}

DerivedFrame::DerivedFrame()
{
        set_border_width(0);
        set_shadow_type(Gtk::SHADOW_NONE);

        DerivedDrawingArea *dda = new DerivedDrawingArea;

        _split = dda->split().connect(SigC::slot(*this, 
&DerivedFrame::split));

        _w = dda;
        add(*_w);
        show_all();
}

DerivedFrame::~DerivedFrame()
{
}

void
DerivedFrame::split(DerivedDrawingArea* dda)
{
        _split.disconnect();
        DerivedHPaned *dhp = new DerivedHPaned(this, dda);
        remove();
        delete _w;
        add(*dhp);
        _w = dhp;
        show_all_children();
}

void
DerivedFrame::join(DerivedDrawingArea*)
{
        std::cerr << "DerivedFrame::join()\n";
}

DerivedApp::DerivedApp() : Gnome::UI::App(name, name)
{
        set_resizable();
        set_default_size(640, 480);
        set_wmclass(name, name);

        set_contents(*Gtk::manage(new DerivedFrame));

        show_all();
}

DerivedApp::~DerivedApp()
{
}

int
main(int argc, char *argv[])
{
        Gnome::Main main(name, name, Gnome::UI::module_info_get(), argc, 
argv);

        DerivedApp derivedApp;

        main.run(derivedApp);

        return 0;
}

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