text: /****************************************************************************
  **                                MIT License
  **
  ** Copyright (C) 2020 Klarälvdalens Datakonsult AB, a KDAB Group company, info@kdab.com
  ** Author: Nicolas Arnaud-Cormos <nicolas.arnaud-cormos@kdab.com>
  **
  ** This file is part of KDToolBox (https://github.com/KDAB/KDToolBox).
  **
  ** Permission is hereby granted, free of charge, to any person obtaining a copy
  ** of this software and associated documentation files (the "Software"), to deal
  ** in the Software without restriction, including without limitation the rights
  ** to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
  ** copies of the Software, ** and to permit persons to whom the Software is
  ** furnished to do so, subject to the following conditions:
  **
  ** The above copyright notice and this permission notice (including the next paragraph)
  ** shall be included in all copies or substantial portions of the Software.
  **
  ** THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  ** IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  ** FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
  ** AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  ** LIABILITY, WHETHER IN AN ACTION OF ** CONTRACT, TORT OR OTHERWISE,
  ** ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
  ** DEALINGS IN THE SOFTWARE.
  ****************************************************************************/
  
  #ifndef TABWINDOW_H
  #define TABWINDOW_H
  
  #include <QTabWidget>
  #include <QCursor>
  
  QT_BEGIN_NAMESPACE
  class QWindow;
  QT_END_NAMESPACE
  class TabWindow;
  
  class TabWindowManager : public QObject
  {
      Q_OBJECT
  
  public:
      static TabWindowManager *instance();
  
      QList<TabWindow*> windows() const;
  
      TabWindow *currentWindow() const;
      QWidget *currentWidget() const;
  
  Q_SIGNALS:
      void tabCloseRequested(QWidget *widget, TabWindow *window);
  
  protected:
      void addWindow(TabWindow *window);
      void removeWindow(TabWindow *window);
  
      TabWindow *possibleWindow(TabWindow *currentWindow, const QPoint &globalPos = QCursor::pos());
  
  private:
      void activateWindow(QWindow *window);
      void requestCloseTab(int index);
  
  private:
      explicit TabWindowManager();
  
      friend class TabWindow;
      QList<TabWindow*> m_windows;
  };
  
  class TabWindow : public QTabWidget
  {
      Q_OBJECT
  public:
      explicit TabWindow(QWidget *parent = 0);
      ~TabWindow();
  
      bool eventFilter(QObject *object, QEvent *event) override;
  
  private:
      bool m_isMoving = false;
      bool m_ignoreMouseEvent = false;
      TabWindow *m_movingWindow = nullptr;
      QPoint m_mouseDelta;
  };
  
  #endif // TABWINDOW_H
  