text: /****************************************************************************
  **
  ** Copyright (C) 2015 The Qt Company Ltd.
  ** Contact: http://www.qt.io/licensing/
  **
  ** This file is part of the QtWidgets module of the Qt Toolkit.
  **
  ** $QT_BEGIN_LICENSE:LGPL21$
  ** Commercial License Usage
  ** Licensees holding valid commercial Qt licenses may use this file in
  ** accordance with the commercial license agreement provided with the
  ** Software or, alternatively, in accordance with the terms contained in
  ** a written agreement between you and The Qt Company. For licensing terms
  ** and conditions see http://www.qt.io/terms-conditions. For further
  ** information use the contact form at http://www.qt.io/contact-us.
  **
  ** GNU Lesser General Public License Usage
  ** Alternatively, this file may be used under the terms of the GNU Lesser
  ** General Public License version 2.1 or version 3 as published by the Free
  ** Software Foundation and appearing in the file LICENSE.LGPLv21 and
  ** LICENSE.LGPLv3 included in the packaging of this file. Please review the
  ** following information to ensure the GNU Lesser General Public License
  ** requirements will be met: https://www.gnu.org/licenses/lgpl.html and
  ** http://www.gnu.org/licenses/old-licenses/lgpl-2.1.html.
  **
  ** As a special exception, The Qt Company gives you certain additional
  ** rights. These rights are described in The Qt Company LGPL Exception
  ** version 1.1, included in the file LGPL_EXCEPTION.txt in this package.
  **
  ** $QT_END_LICENSE$
  **
  ****************************************************************************/
  
  #ifndef QLAYOUTITEM_H
  #define QLAYOUTITEM_H
  
  #include <QtWidgets/qsizepolicy.h>
  #include <QtCore/qrect.h>
  
  #include <limits.h>
  
  QT_BEGIN_NAMESPACE
  
  
  static const Q_DECL_UNUSED int QLAYOUTSIZE_MAX = INT_MAX/256/16;
  
  class QLayout;
  class QLayoutItem;
  class QSpacerItem;
  class QWidget;
  class QSize;
  
  class Q_WIDGETS_EXPORT QLayoutItem
  {
  public:
      inline explicit QLayoutItem(Qt::Alignment alignment = Qt::Alignment());
      virtual ~QLayoutItem();
      virtual QSize sizeHint() const = 0;
      virtual QSize minimumSize() const = 0;
      virtual QSize maximumSize() const = 0;
      virtual Qt::Orientations expandingDirections() const = 0;
      virtual void setGeometry(const QRect&) = 0;
      virtual QRect geometry() const = 0;
      virtual bool isEmpty() const = 0;
      virtual bool hasHeightForWidth() const;
      virtual int heightForWidth(int) const;
      virtual int minimumHeightForWidth(int) const;
      virtual void invalidate();
  
      virtual QWidget *widget();
      virtual QLayout *layout();
      virtual QSpacerItem *spacerItem();
  
      Qt::Alignment alignment() const { return align; }
      void setAlignment(Qt::Alignment a);
      virtual QSizePolicy::ControlTypes controlTypes() const;
  
  protected:
      Qt::Alignment align;
  };
  
  inline QLayoutItem::QLayoutItem(Qt::Alignment aalignment)
      : align(aalignment) { }
  
  class Q_WIDGETS_EXPORT QSpacerItem : public QLayoutItem
  {
  public:
      QSpacerItem(int w, int h,
                   QSizePolicy::Policy hData = QSizePolicy::Minimum,
                   QSizePolicy::Policy vData = QSizePolicy::Minimum)
          : width(w), height(h), sizeP(hData, vData) { }
      ~QSpacerItem();
  
      void changeSize(int w, int h,
                       QSizePolicy::Policy hData = QSizePolicy::Minimum,
                       QSizePolicy::Policy vData = QSizePolicy::Minimum);
      QSize sizeHint() const;
      QSize minimumSize() const;
      QSize maximumSize() const;
      Qt::Orientations expandingDirections() const;
      bool isEmpty() const;
      void setGeometry(const QRect&);
      QRect geometry() const;
      QSpacerItem *spacerItem();
      QSizePolicy sizePolicy() const { return sizeP; }
  
  private:
      int width;
      int height;
      QSizePolicy sizeP;
      QRect rect;
  };
  
  class Q_WIDGETS_EXPORT QWidgetItem : public QLayoutItem
  {
      Q_DISABLE_COPY(QWidgetItem)
  
  public:
      explicit QWidgetItem(QWidget *w) : wid(w) { }
      ~QWidgetItem();
  
      QSize sizeHint() const;
      QSize minimumSize() const;
      QSize maximumSize() const;
      Qt::Orientations expandingDirections() const;
      bool isEmpty() const;
      void setGeometry(const QRect&);
      QRect geometry() const;
      virtual QWidget *widget();
  
      bool hasHeightForWidth() const;
      int heightForWidth(int) const;
      QSizePolicy::ControlTypes controlTypes() const;
  protected:
      QWidget *wid;
  };
  
  class Q_WIDGETS_EXPORT QWidgetItemV2 : public QWidgetItem
  {
  public:
      explicit QWidgetItemV2(QWidget *widget);
      ~QWidgetItemV2();
  
      QSize sizeHint() const;
      QSize minimumSize() const;
      QSize maximumSize() const;
      int heightForWidth(int width) const;
  
  private:
      enum { Dirty = -123, HfwCacheMaxSize = 3 };
  
      inline bool useSizeCache() const;
      void updateCacheIfNecessary() const;
      inline void invalidateSizeCache() {
          q_cachedMinimumSize.setWidth(Dirty);
          q_hfwCacheSize = 0;
      }
  
      mutable QSize q_cachedMinimumSize;
      mutable QSize q_cachedSizeHint;
      mutable QSize q_cachedMaximumSize;
      mutable QSize q_cachedHfws[HfwCacheMaxSize];
      mutable short q_firstCachedHfw;
      mutable short q_hfwCacheSize;
      void *d;
  
      friend class QWidgetPrivate;
  
      Q_DISABLE_COPY(QWidgetItemV2)
  };
  
  QT_END_NAMESPACE
  
  #endif // QLAYOUTITEM_H
  