qwt_dyngrid_layout.cpp

QWT5.01用于Qt开发的二维图形库程序

/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/

#include <qwidget.h>
#include "qwt_dyngrid_layout.h"
#include "qwt_math.h"

#if QT_VERSION < 0x040000
#include <qvaluelist.h>
#else
#include <qlist.h>
#endif

class QwtDynGridLayout::PrivateData
{
public:

#if QT_VERSION < 0x040000
    class LayoutIterator: public QGLayoutIterator
    {
    public:
        LayoutIterator(PrivateData *data):
            d_data(data)  
        {
            d_iterator = d_data->itemList.begin();
        }

        virtual QLayoutItem *current()
        { 
            if (d_iterator == d_data->itemList.end())
               return NULL;

            return *d_iterator;
        }

        virtual QLayoutItem *next()
        { 
            if (d_iterator == d_data->itemList.end())
               return NULL;

            d_iterator++;
            if (d_iterator == d_data->itemList.end())
               return NULL;

            return *d_iterator;
        }

        virtual QLayoutItem *takeCurrent()
        { 
            if ( d_iterator == d_data->itemList.end() )
                return NULL;

            QLayoutItem *item = *d_iterator;

            d_data->isDirty = true;
            d_iterator = d_data->itemList.remove(d_iterator);
            return item;
        }

    private:
        
        QValueListIterator<QLayoutItem*> d_iterator;
        QwtDynGridLayout::PrivateData *d_data;
    };
#endif

    PrivateData():
        isDirty(true)
    {
    }

#if QT_VERSION < 0x040000
    typedef QValueList<QLayoutItem*> LayoutItemList;
#else
    typedef QList<QLayoutItem*> LayoutItemList;
#endif

    mutable LayoutItemList itemList;

    uint maxCols;
    uint numRows;
    uint numCols;

#if QT_VERSION < 0x040000
    QSizePolicy::ExpandData expanding;
#else
    Qt::Orientations expanding;
#endif

    bool isDirty;
    QwtArray<QSize> itemSizeHints;
};


/*!
  \param parent Parent widget
  \param margin Margin
  \param spacing Spacing
*/

QwtDynGridLayout::QwtDynGridLayout(QWidget *parent, 
        int margin, int spacing):
    QLayout(parent)
{
    init();

    setSpacing(spacing);
    setMargin(margin);
}

#if QT_VERSION < 0x040000
/*!
  \param parent Parent widget
  \param spacing Spacing
*/
QwtDynGridLayout::QwtDynGridLayout(QLayout *parent, int spacing):
    QLayout(parent, spacing)
{
    init();
}
#endif

/*!
  \param spacing Spacing
*/

QwtDynGridLayout::QwtDynGridLayout(int spacing)
{
    init();
    setSpacing(spacing);
}

/*!
  Initialize the layout with default values.
*/
void QwtDynGridLayout::init()
{
    d_data = new QwtDynGridLayout::PrivateData;
    d_data->maxCols = d_data->numRows 
        = d_data->numCols = 0;

#if QT_VERSION < 0x040000
    d_data->expanding = QSizePolicy::NoDirection;
    setSupportsMargin(true);
#else
    d_data->expanding = 0;
#endif
}

//! Destructor

QwtDynGridLayout::~QwtDynGridLayout()
{
#if QT_VERSION < 0x040000
    deleteAllItems(); 
#endif

    delete d_data;
}

void QwtDynGridLayout::invalidate()
{
    d_data->isDirty = true;
    QLayout::invalidate();
}

void QwtDynGridLayout::updateLayoutCache()
{
    d_data->itemSizeHints.resize(itemCount());

    int index = 0;

    for (PrivateData::LayoutItemList::iterator it = d_data->itemList.begin();
        it != d_data->itemList.end(); ++it, index++)
    {
        d_data->itemSizeHints[int(index)] = (*it)->sizeHint();
    }

    d_data->isDirty = false;
}

/*!
  Limit the number of columns.
  \param maxCols upper limit, 0 means unlimited
  \sa QwtDynGridLayout::maxCols()
*/
  
void QwtDynGridLayout::setMaxCols(uint maxCols)
{
    d_data->maxCols = maxCols;
}

/*!
  Return the upper limit for the number of columns.
  0 means unlimited, what is the default.
  \sa QwtDynGridLayout::setMaxCols()
*/

uint QwtDynGridLayout::maxCols() const 
{ 
    return d_data->maxCols; 
}

//! Adds item to the next free position.

void QwtDynGridLayout::addItem(QLayoutItem *item)
{
    d_data->itemList.append(item);
    invalidate();
}

/*! 
  \return true if this layout is empty. 
*/

bool QwtDynGridLayout::isEmpty() const
{
    return d_data->itemList.isEmpty();
}

/*! 
  \return number of layout items
*/

uint QwtDynGridLayout::itemCount() const
{
    return d_data->itemList.count();
}

#if  QT_VERSION < 0x040000
/*! 
  \return An iterator over the children of this layout.
*/

QLayoutIterator QwtDynGridLayout::iterator()
{       
    return QLayoutIterator( 
        new QwtDynGridLayout::PrivateData::LayoutIterator(d_data) );
}

/*!
  Set whether this layout can make use of more space than sizeHint(). 
  A value of Vertical or Horizontal means that it wants to grow in only 
  one dimension, while BothDirections means that it wants to grow in 
  both dimensions. The default value is NoDirection. 
  \sa QwtDynGridLayout::expanding()
*/

void QwtDynGridLayout::setExpanding(QSizePolicy::ExpandData expanding)
{
    d_data->expanding = expanding;
}

/*!
  Returns whether this layout can make use of more space than sizeHint(). 
  A value of Vertical or Horizontal means that it wants to grow in only 
  one dimension, while BothDirections means that it wants to grow in 
  both dimensions. 
  \sa QwtDynGridLayout::setExpanding()
*/

QSizePolicy::ExpandData QwtDynGridLayout::expanding() const
{
    return d_data->expanding;
}

#else // QT_VERSION >= 0x040000

QLayoutItem *QwtDynGridLayout::itemAt( int index ) const
{
    if ( index < 0 || index >= d_data->itemList.count() )
        return NULL;

    return d_data->itemList.at(index);
}
    
QLayoutItem *QwtDynGridLayout::takeAt( int index )
{
    if ( index < 0 || index >= d_data->itemList.count() )
        return NULL;
  
    d_data->isDirty = true;
    return d_data->itemList.takeAt(index);
}

int QwtDynGridLayout::count() const
{
    return d_data->itemList.count();
}

void QwtDynGridLayout::setExpandingDirections(Qt::Orientations expanding)
{
    d_data->expanding = expanding;
}

Qt::Orientations QwtDynGridLayout::expandingDirections() const
{
    return d_data->expanding;
}

#endif

/*!
  Reorganizes columns and rows and resizes managed widgets within 
  the rectangle rect. 
*/

void QwtDynGridLayout::setGeometry(const QRect &rect)
{
    QLayout::setGeometry(rect);

    if ( isEmpty() )
        return;

    d_data->numCols = columnsForWidth(rect.width());
    d_data->numRows = itemCount() / d_data->numCols;
    if ( itemCount() % d_data->numCols )
        d_data->numRows++;

#if QT_VERSION < 0x040000
    QValueList<QRect> itemGeometries = layoutItems(rect, d_data->numCols);
#else
    QList<QRect> itemGeometries = layoutItems(rect, d_data->numCols);
#endif

    int index = 0;
    for (PrivateData::LayoutItemList::iterator it = d_data->itemList.begin();
        it != d_data->itemList.end(); ++it)
    {
        QWidget *w = (*it)->widget();
        if ( w )
        {
            w->setGeometry(itemGeometries[index]);
            index++;
        }
    }
}

/*! 
  Calculate the number of columns for a given width. It tries to