File indexing completed on 2024-04-14 03:57:13

 /*
     This file is part of the KDE project
     SPDX-FileCopyrightText: 2021 Felix Ernst <fe.a.ernst@gmail.com>
 
     SPDX-License-Identifier: LGPL-2.1-or-later OR BSD-2-Clause
 */
 
 #ifndef KTOOLTIPHELPER_H
 #define KTOOLTIPHELPER_H
 
 #include <kxmlgui_export.h>
 
 #include <QObject>
 
 #include <memory>
 
 class KToolTipHelperPrivate;
 
 /**
  * @class KToolTipHelper ktooltiphelper.h KToolTipHelper
  *
  * @short An event filter used to enhance tooltips
  *
  * Example:
  * Without this class, a tooltip of a QToolButton of a "New" action will read something like
  * "New File". Using this class, the tooltip can be enhanced to read something like
  * "New File (Ctrl+N)" and in the next line smaller "Press Shift for help.".
  * Pressing Shift will open the "What's This" context help for that widget. If a hyperlink in
  * that help is clicked, the corresponding event will also be filtered by this class and open
  * the linked location.
  *
  * The extra text added to tooltips is only shown when available and where it makes sense. If a
  * QToolButton has no associated shortcut and an empty QWidget::whatsThis(), this class won't
  * tamper with the requested tooltip at all.
  *
  * This class also activates tooltips for actions in QMenus but only when it makes sense like when
  * the tooltip isn't equal to the already displayed text.
  *
  * If you want the "Press Shift for help." line to be displayed for a widget that has whatsThis()
  * but no toolTip() take a look at KToolTipHelper::whatsThisHintOnly().
  *
  * The enhanced tooltips can be enabled at any time after the QApplication was constructed with
  * \code
  * qApp->installEventFilter(KToolTipHelper::instance());
  * \endcode
  * Therefore, to de-activate them you can call
  * \code
  * qApp->removeEventFilter(KToolTipHelper::instance());
  * \endcode
  * any time later.
  *
  * If you want KToolTipHelper to not tamper with certain QEvents, e.g. you want to handle some
  * tooltips differently or you want to change what happens when a QWhatsThisClickedEvent is
  * processed, first remove KToolTipHelper as an event filter just like in the line of code above.
  * Then create your own custom EventFilter that handles those QEvents differently and for all
  * cases that you don't want to handle differently call
  * \code
  * return KToolTipHelper::instance()->eventFilter(watched, event);
  * \endcode
  *
  * KMainWindow will have this EventFilter installed by default from framework version 5.84 onward
  * so if you want to opt out of that, remove the EventFilter in the constructor of your MainWindow
  * class inheriting from KMainWindow.
  *
  * @see QToolTip
  * @since 5.84
  */
 class KXMLGUI_EXPORT KToolTipHelper : public QObject
 {
     Q_OBJECT
     Q_DISABLE_COPY(KToolTipHelper)
 
 public:
     static KToolTipHelper *instance();
 
     /**
      * Filters QEvent::ToolTip if an enhanced tooltip is available for the widget.
      * Filters the QEvent::KeyPress that is used to expand an expandable tooltip.
      * Filters QEvent::WhatsThisClicked so hyperlinks in whatsThis() texts work.
      *
      * @see QObject::eventFilter()
      * @see QHelpEvent
      */
     virtual bool eventFilter(QObject *watched, QEvent *event) override;
 
     /**
      * Use this to have a widget show "Press Shift for help." as its tooltip.
      * \code
      * widget->setToolTip(KToolTipHelper::whatsThisHintOnly());
      * \endcode
      * KToolTipHelper won't show that tooltip if the widget's whatsThis() is empty.
      *
      * @return a QString that is interpreted by this class to show the expected tooltip.
      */
     static const QString whatsThisHintOnly();
 
 private:
     KXMLGUI_NO_EXPORT explicit KToolTipHelper(QObject *parent);
 
     KXMLGUI_NO_EXPORT ~KToolTipHelper() override;
 
 private:
     std::unique_ptr<KToolTipHelperPrivate> const d;
 
     friend class KToolTipHelperPrivate;
 };
 
 #endif // KTOOLTIPHELPER_H