kdelibs/kdeui/util/kcursor.h

/* This file is part of the KDE libraries
   Copyright (C) 1998 Kurt Granroth (granroth@kde.org)
                 2000 Carsten Pfeiffer <pfeiffer@kde.org>

   This library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Library General Public
   License version 2 as published by the Free Software Foundation.

   This library 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
   Library General Public License for more details.

   You should have received a copy of the GNU Library General Public License
   along with this library; see the file COPYING.LIB.  If not, write to
   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
   Boston, MA 02110-1301, USA.
*/

#ifndef KCURSOR_H
#define KCURSOR_H

#include <kdeui_export.h>
#include <QtGui/QCursor>

#include <QEvent>
#include <QWidget>

/**
 * The KCursor class extends QCursor with the ability to create an arbitrary
 * named cursor from the cursor theme, and provides a set of static
 * convenience methods for auto-hiding cursors on widgets.
 *
 * @author Kurt Granroth <granroth@kde.org>
 */
class KDEUI_EXPORT KCursor : public QCursor
{
public:
    /**
     * Attempts to load the requested @p name cursor from the current theme.
     * 
     * This allows one to access cursors that may be in a theme but not in
     * the Qt::CursorShape enum.
     *
     * If the specified cursor doesn't exist in the theme, or if KDE was
     * built without Xcursor support, the cursor will be loaded from the X11
     * cursor font instead. If the cursor doesn't exist in the cursor font,
     * it falls back to the Qt::CursorShape provided as the second parameter.
     *
     * On platforms other than X11, the fallback shape is always used.
     *
     * @param name the name of the cursor to try and load
     * @param fallback the cursor to load if @p name cursor can not be loaded
     */
    explicit KCursor( const QString & name, Qt::CursorShape fallback = Qt::ArrowCursor );

    /**
     * Creates a copy of @p cursor.
     */
    KCursor( const QCursor & cursor );

    /**
     * Assigns @p cursor to this cursor, and returns a reference to this
     * cursor.
     */
    KCursor & operator = ( const KCursor & cursor );

    /**
     * Sets auto-hiding the cursor for widget @p w. Enabling it will result in
     * the cursor being hidden when
     * @li a key-event happens
     * @li there are no key-events for a configured time-frame (see
     * setHideCursorDelay())
     *
     * The cursor will be shown again when the focus is lost or a mouse-event
     * happens.
     *
     * Side effect: when enabling auto-hide, mouseTracking is enabled for the
     * specified widget, because it's needed to get mouse-move-events. So
     * don't disable mouseTracking for a widget while using auto-hide for it.
     *
     * When disabling auto-hide, mouseTracking will be disabled, so if you need
     * mouseTracking after disabling auto-hide, you have to reenable
     * mouseTracking.
     *
     * If you want to use auto-hiding for widgets that don't take focus, e.g.
     * a QCanvasView, then you have to pass all key-events that should trigger
     * auto-hiding to autoHideEventFilter().
     */
    static void setAutoHideCursor( QWidget *w, bool enable,
                                   bool customEventFilter = false );

    /**
     * Sets the delay time in milliseconds for auto-hiding. When no keyboard
     * events arrive for that time-frame, the cursor will be hidden.
     *
     * Default is 5000, i.e. 5 seconds.
     */
    static void setHideCursorDelay( int ms );

    /**
     * @returns the current auto-hide delay time.
     *
     * Default is 5000, i.e. 5 seconds.
     */
    static int hideCursorDelay();

    /**
     * KCursor has to install an eventFilter over the widget you want to
     * auto-hide. If you have an own eventFilter() on that widget and stop
     * some events by returning true, you might break auto-hiding, because
     * KCursor doesn't get those events.
     *
     * In this case, you need to call setAutoHideCursor( widget, true, true );
     * to tell KCursor not to install an eventFilter. Then you call this method
     * from the beginning of your eventFilter, for example:
     * \code
     * edit = new KEdit( this, "some edit widget" );
     * edit->installEventFilter( this );
     * KCursor::setAutoHideCursor( edit, true, true );
     *
     * [...]
     *
     * bool YourClass::eventFilter( QObject *o, QEvent *e )
     * {
     *     if ( o == edit ) // only that widget where you enabled auto-hide!
     *         KCursor::autoHideEventFilter( o, e );
     *
     *     // now you can do your own event-processing
     *     [...]
     * }
     * \endcode
     *
     * Note that you must not call KCursor::autoHideEventFilter() when you
     * didn't enable or after disabling auto-hiding.
     */
    static void autoHideEventFilter( QObject *, QEvent * );

private:
    class Private;
    Private* const d;
};


#endif // _KCURSOR_H