Source: kpanelextension.h

/*****************************************************************

Copyright (c) 2000 Matthias Elter

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******************************************************************/

#ifndef __kpanelextension_h__
#define __kpanelextension_h__

class KConfig;
class KPanelExtensionPrivate;

#include 

/**
 * Implements a panel extension.
 *
 * Panel extensions
 *   @li Are small applications living in the Window Manager dock managed by the panel.
 *   @li Are implemented as DSOs (Dynamic Shared Objects).
 *
 * Note: For security and stability reasons the panel won't load
 * untrusted third party extensions directly into its namespace but via an
 * external wrapper process.
 *
 * The panel locates available extensions by searching for extension desktop
 * files in (ALL_KDEDIRS)/share/apps/kicker/extensions. Every panel extension should
 * install a desktop file there to be recognised by the panel.
 *
 * Besides standard keys like "Name", "Comment" and "Icon" there are
 * two panel extension specific keys:
 *
 * @sect X-KDE-Library
 *
 * Used by the panel to locate the extension DSO (Dynamic Shared Object)
 * Example: X-KDE-Library=libexampleextension
 *
 * @sect X-KDE-UniqueExtension
 *
 * Similar to @ref KApplication and @ref KUniqueApplication there are
 * two types of panel extensions. Use unique extensions when it makes no
 * sence to run more than one instance of an extension in the panel. A
 * good example for unique extensions is the taskbar extension.  Use normal
 * extensions when you need instance specific configuration. An example
 * is a subpanel extension where you might want to run more than one instances.
 * X-KDE-UniqueExtension is a boolean key which defaults
 * to "false".  Example: X-KDE-UniqueExtension=true
 *
 * Back to panel extension DSOs, the following conventions are used for KDE:
 * Name:    libextension.la
 * LDFLAGS: -module -no-undefined
 *
 * To implement a panel extension it is not enough to write a class
 * inheriting from KPanelExtension but you also have to provide a
 * factory function in your DSO.  A sample factory function could look
 * like this:
 *
 * 
 *
 * extern "C"
 * {
 *     KPanelExtension* init(QWidget *parent, const QString& configFile)
 *     {
 *         KGlobal::locale()->insertCatalogue("exampleextension");
 *         return new ExampleExtension(configFile, KPanelExtension::Normal,
 *                       KPanelExtension::About | KPanelExtension::Help | KPanelExtension::Preferences,
 *                       parent, "exampleextension");
 *     }
 * }
 *
 * 
 *
 * Note: Don't change the factory function signature or the panel will
 * fail to load your extension.
 *
 * @author Matthias Elter 
 * @short KDE Panel Extension class
 **/
class KPanelExtension : public QFrame
{
    Q_OBJECT

public:

    enum Type { Normal = 0, Stretch };
    enum Action { About = 1, Help = 2, Preferences = 4, ReportBug = 8 };
    enum Position { Left = 0, Right, Top, Bottom };
    enum Alignment { LeftTop = 0, Center, RightBottom };

    /**
     * Constructs a KPanelExtension just like any other widget.
     *
     * @param configFile The configFile handed over in the factory function.
     * @param Type The extension @ref type().
     * @param actions Standard RMB menu actions supported by the extension (see @ref action() ).
     * @param parent The pointer to the parent widget handed over in the factory function.
     * @param name A Qt object name for your extension.
     **/
    KPanelExtension(const QString& configFile, Type t = Normal,
		 int actions = 0, QWidget *parent = 0, const char *name = 0);

    /**
     * Destructor.
     **/
    ~KPanelExtension();

    /**
     * Returns the prefered size for a given Position.
     *
     * Every extension should reimplement this function.
     *
     * Depending on the panel position the extensions can choose a prefered size for that
     * location in the Window Manager Dock. Please note that the size can not be larger than the
     * maxsize given by the handler.
     **/
    virtual QSize sizeHint(Position /*p*/, QSize maxsize) const { return maxsize; }

    /**
     * Always use this @ref KConfig object to save/load your extensions configuration.
     *
     * For unique extensions this config object will write to a config file called
     * rc in the users local KDE directory.
     *
     * For normal extensions this config object will write to a instance specific config file
     * called rc in the users local KDE directory.
     **/
    KConfig* config() const { return _config; }

    /**
     * @return Type indicating the extensions type.
     * @ref Type
     **/
    Type type() const { return _type; }

    /**
     * @return int indicating the supported RMB menu actions.
     * @ref Action
     **/
    int actions() const { return _actions; }

    /**
     * Generic action dispatcher. Called  when the user selects an item
     * from the extensions RMB menu.
     *
     * Reimplement this function to handle actions.
     *
     * For About, Help, Preferences and ReportBug use the convenience handlers
     * ref about(), help(), preferences(), reportBug()
     *
     **/
    virtual void action( Action a );


    /**
     * Reimplement this function to set a prefered dock position for your extension.
     * The extension manager will try to place new instances of this extension according
     * to this setting.
     * @return Position
     **/
    virtual Position preferedPosition() const { return Bottom; }

    /**
     * @internal
     **/
    void setPosition( Position p );
    /**
     * @internal
     **/
    void setAlignment( Alignment a );

signals:
    /**
     * Emit this signal to make the panel relayout all extensions in the dock, when you want
     * to change the extensions size.
     * The panel is going to relayout all extensions based on their prefered size.
     **/
    void updateLayout();

protected:

    /**
     * Is called when the user selects "About" from the extensions RMB menu.
     * Reimplement this function to launch a about dialog.
     *
     * Note that this is called only when your extension supports the About action.
     * See @ref Action.
     **/
    virtual void about() {}

    /**
     * Is called when the user selects "Help" from the extensions RMB menu.
     * Reimplement this function to launch a manual or help page.
     *
     * Note that this is called only when your extension supports the Help action.
     * See @ref Action.
     **/
    virtual void help() {}

    /**
     * Is called when the user selects "Preferences" from the extensions RMB menu.
     * Reimplement this function to launch a preferences dialog or kcontrol module.
     *
     * Note that this is called only when your extension supports the preferences action.
     * See @ref Action.
     **/
    virtual void preferences() {}
	
    /**
     * Is called when the user selects "Report bug" from the applet's RMB menu.
     * Reimplement this function to launch a bug reporting dialog.
     *
     * Note that this is called only when your applet supports the ReportBug
     * action.
     * See @ref Action.
     **/
    virtual void reportBug() {}

    /**
     * @return the extension's position. (left, right, top, bottom)
     **/
    Position position() const { return _position; }

    /**
     * @return the extension's alignment. (left/top, center, or right/bottom)
     **/
    Alignment alignment() const { return _alignment; }

    /**
     * @return the extensions orientation. (horizontal or vertical)
     **/
    Orientation orientation();

    /**
     * This extension has changed its position.
     * Reimplement this change handler in order to adjust the look of your
     * applet.
     **/
    virtual void positionChange( Position ) {};

    /**
     * This extension has changed its alignment.
     * Reimplement this change handler in order to adjust the look of your
     * applet.
     **/
    virtual void alignmentChange( Alignment ) {};

private:
    Type         		_type;
    Position     		_position;
    Alignment    		_alignment;
    KConfig*     		_config;
    int          		_actions;
protected:
    virtual void virtual_hook( int id, void* data );
private:
    KPanelExtensionPrivate     *d;
};

#endif