notepad_gtk_source.h

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#ifndef GTK_SOURCE_H_
#define GTK_SOURCE_H_

/*
 * File Name: notepad_gtk_source.h
 */

/*
 * This file is part of notepad.
 *
 * notepad is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * notepad is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */

/**
 * Copyright (C) 2010 IREX Technologies B.V.
 * All rights reserved.
 */
 
#include <gtk/gtk.h>

namespace gtk
{
    /// @brief Enable caller to handle GTK events without inheriting from any class.
    /// One-one connection. It's better to use template based technology. 
    /// By GtkEventSource caller is able to handle multiple widgets' events.
    template <class T>
    class GtkEventSource 
    {
    public:
        enum EventType 
        {
            EVENT_EXPOSE = 0,       // signal expose_event
            EVENT_VISIBILITY_NOTIFY,// signal visibility_notify_event
            EVENT_CONFIG,           // signal configure_event
            EVENT_BUTTON_PRESS,     // signal button_press_event
            EVENT_BUTTON_RELEASE,   // signal button_release_event
            EVENT_MOTION_NOTIFY,    // signal motion_notify_event
            EVENT_KEY_PRESS,        // signal key_press_event
            EVENT_KEY_RELEASE,      // signal key_release_event
            EVENT_DELETE,           // signal delete_event
            EVENT_MAX,          // number of events
        };

    public:
        GtkEventSource(T* r)
            : receiver(r)
        {
            memset(&callbacks[0], 0, sizeof(callbacks));
        }

        ~GtkEventSource()
        {
        }

        /// Disconnect all connected signal handlers.
        void disconnect_event_handlers(GtkWidget* widget)
        {
            for(int i = 0; i < EVENT_MAX; i++)
            {
                if ( handler_ids[i] )
                    g_signal_handler_disconnect(GTK_OBJECT (widget), handler_ids[i]);
            }

            receiver = 0;
            memset(&callbacks[0], 0, sizeof(callbacks));
        }

        /// @brief Connect the event handler(slot) with the gtk event(signal)
        void connect_event_handlers(GtkWidget* widget)
        {
            // events 
            gtk_widget_set_events (widget,
                GDK_EXPOSURE_MASK | GDK_BUTTON_MOTION_MASK |
                GDK_BUTTON_PRESS_MASK | GDK_BUTTON_RELEASE_MASK |
                GDK_KEY_PRESS_MASK | GDK_KEY_RELEASE_MASK | GDK_VISIBILITY_NOTIFY_MASK);

            // install event handlers.
            handler_ids[EVENT_EXPOSE] = 
                g_signal_connect( GTK_OBJECT(widget), "expose_event",
                G_CALLBACK(widget_event_handler), this);

            handler_ids[EVENT_VISIBILITY_NOTIFY] = 
                g_signal_connect( GTK_OBJECT(widget), "visibility_notify_event",
                G_CALLBACK(widget_event_handler), this);

            handler_ids[EVENT_CONFIG] =
                g_signal_connect( GTK_OBJECT(widget), "configure_event",
                G_CALLBACK(widget_event_handler), this);

            handler_ids[EVENT_BUTTON_PRESS] =
                g_signal_connect( GTK_OBJECT(widget), "button_press_event",
                G_CALLBACK(widget_event_handler), this);

            handler_ids[EVENT_BUTTON_RELEASE] = 
                g_signal_connect( GTK_OBJECT(widget), "button_release_event",
                G_CALLBACK(widget_event_handler), this);

            handler_ids[EVENT_MOTION_NOTIFY] =
                g_signal_connect( GTK_OBJECT(widget), "motion_notify_event",
                G_CALLBACK(widget_event_handler), this);

            handler_ids[EVENT_KEY_PRESS] =
                g_signal_connect( GTK_OBJECT(widget), "key_press_event",
                G_CALLBACK(widget_event_handler), this);

            handler_ids[EVENT_KEY_RELEASE] =
                g_signal_connect( GTK_OBJECT(widget), "key_release_event",
                G_CALLBACK(widget_event_handler), this);

            handler_ids[EVENT_DELETE] =
                g_signal_connect( GTK_OBJECT(widget), "delete_event",
                G_CALLBACK(widget_event_handler), this);
        }


        /// @brief Set event handler of gtk event (from event loop)
        inline void set_event_handler(EventType type, 
                                      void (T::*func)(GdkEvent* event) )
        {
            callbacks[type] = func;
        }
        
    private:
        /// static: wraps from GTK to C++ 
        static void widget_event_handler(GtkWidget*, GdkEvent* event, gpointer user_data)
        {
            GtkEventSource* pThis = static_cast<GtkEventSource*> (user_data);
            if ((event == 0) || (pThis == 0))
            {
                return;
            }

            pThis->invoke_callback(event);
        }

        // invoker, translates GDK event type to enum EventType
        void invoke_callback(GdkEvent* event)
        {
            if (receiver)
            {
                switch (event->type)
                {
                    case GDK_EXPOSE:
                        if ( callbacks[EVENT_EXPOSE] )
                            (receiver->*callbacks[EVENT_EXPOSE]) (event);
                        break;
                    case GDK_VISIBILITY_NOTIFY:
                        if ( callbacks[EVENT_VISIBILITY_NOTIFY] )
                            (receiver->*callbacks[EVENT_VISIBILITY_NOTIFY]) (event);
                        break;
                    case GDK_CONFIGURE:
                        if ( callbacks[EVENT_CONFIG] )
                            (receiver->*callbacks[EVENT_CONFIG]) (event);
                        break;
                    case GDK_BUTTON_PRESS:
                        if ( callbacks[EVENT_BUTTON_PRESS] )
                            (receiver->*callbacks[EVENT_BUTTON_PRESS]) (event);
                        break;
                    case GDK_BUTTON_RELEASE:
                        if ( callbacks[EVENT_BUTTON_RELEASE] )
                            (receiver->*callbacks[EVENT_BUTTON_RELEASE]) (event);
                        break;
                    case GDK_MOTION_NOTIFY:
                        if ( callbacks[EVENT_MOTION_NOTIFY] )
                            (receiver->*callbacks[EVENT_MOTION_NOTIFY]) (event);
                        break;
                    case GDK_KEY_PRESS:
                        if ( callbacks[EVENT_KEY_PRESS] )
                            (receiver->*callbacks[EVENT_KEY_PRESS]) (event);
                        break;
                    case GDK_KEY_RELEASE:
                        if ( callbacks[EVENT_KEY_RELEASE] )
                            (receiver->*callbacks[EVENT_KEY_RELEASE]) (event);
                        break;
                    case GDK_DELETE:
                        if ( callbacks[EVENT_DELETE] )
                            (receiver->*callbacks[EVENT_DELETE]) (event);
                        break;
                    default:
                        break;
                }
            }
        }

    private:
        T* receiver; // receiver object
        void (T::*callbacks[EVENT_MAX])(GdkEvent* event); // list of callback member functionpointers

        gulong handler_ids[EVENT_MAX]; // used to disconnect events
    };

}; //namespace gtk

#endif