qwt_dyngrid_layout.cpp

/* -*- 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;
};


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

    setSpacing(spacing);
    setMargin(margin);
}

#if QT_VERSION < 0x040000

QwtDynGridLayout::QwtDynGridLayout(QLayout *parent, int spacing):
    QLayout(parent, spacing)
{
    init();
}
#endif

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

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
}


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;
}

void QwtDynGridLayout::setMaxCols(uint maxCols)
{
    d_data->maxCols = maxCols;
}

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


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

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

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

#if  QT_VERSION < 0x040000

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

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

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

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++;
        }
    }
}

uint QwtDynGridLayout::columnsForWidth(int width) const
{
    if ( isEmpty() )
        return 0;

    const int maxCols = (d_data->maxCols > 0) ? d_data->maxCols : itemCount();
    if ( maxRowWidth(maxCols) <= width )
        return maxCols;

    for (int numCols = 2; numCols <= maxCols; numCols++ )
    {
        const int rowWidth = maxRowWidth(numCols);
        if ( rowWidth > width )
            return numCols - 1;
    }

    return 1; // At least 1 column
}

int QwtDynGridLayout::maxRowWidth(int numCols) const
{
    int col;

    QwtArray<int> colWidth(numCols);
    for ( col = 0; col < (int)numCols; col++ )
        colWidth[col] = 0;

    if ( d_data->isDirty )
        ((QwtDynGridLayout*)this)->updateLayoutCache();

    for ( uint index = 0; 
        index < (uint)d_data->itemSizeHints.count(); index++ )
    {
        col = index % numCols;
        colWidth[col] = qwtMax(colWidth[col], 
            d_data->itemSizeHints[int(index)].width());
    }

    int rowWidth = 2 * margin() + (numCols - 1) * spacing();
    for ( col = 0; col < (int)numCols; col++ )
        rowWidth += colWidth[col];

    return rowWidth;
}

int QwtDynGridLayout::maxItemWidth() const
{
    if ( isEmpty() )
        return 0;

    if ( d_data->isDirty )
        ((QwtDynGridLayout*)this)->updateLayoutCache();

    int w = 0;
    for ( uint i = 0; i < (uint)d_data->itemSizeHints.count(); i++ )
    {
        const int itemW = d_data->itemSizeHints[int(i)].width();
        if ( itemW > w )
            w = itemW;
    }

    return w;
}

#if QT_VERSION < 0x040000
QValueList<QRect> QwtDynGridLayout::layoutItems(const QRect &rect,
    uint numCols) const
#else
QList<QRect> QwtDynGridLayout::layoutItems(const QRect &rect,
    uint numCols) const
#endif
{
#if QT_VERSION < 0x040000
    QValueList<QRect> itemGeometries;
#else
    QList<QRect> itemGeometries;
#endif
    if ( numCols == 0 || isEmpty() )
        return itemGeometries;

    uint numRows = itemCount() / numCols;
    if ( numRows % itemCount() )
        numRows++;
 
    QwtArray<int> rowHeight(numRows);
    QwtArray<int> colWidth(numCols);
 
    layoutGrid(numCols, rowHeight, colWidth);

    bool expandH, expandV;
#if QT_VERSION >= 0x040000
    expandH = expandingDirections() & Qt::Horizontal;
    expandV = expandingDirections() & Qt::Vertical;
#else
    expandH = expanding() & QSizePolicy::Horizontally;
    expandV = expanding() & QSizePolicy::Vertically;
#endif

    if ( expandH || expandV )
        stretchGrid(rect, numCols, rowHeight, colWidth);

    QwtDynGridLayout *that = (QwtDynGridLayout *)this;
    const int maxCols = d_data->maxCols;
    that->d_data->maxCols = numCols;
    const QRect alignedRect = alignmentRect(rect);
    that->d_data->maxCols = maxCols;

    const int xOffset = expandH ? 0 : alignedRect.x();
    const int yOffset = expandV ? 0 : alignedRect.y();

    QwtArray<int> colX(numCols);
    QwtArray<int> rowY(numRows);

    const int xySpace = spacing();

    rowY[0] = yOffset + margin();
    for ( int r = 1; r < (int)numRows; r++ )
        rowY[r] = rowY[r-1] + rowHeight[r-1] + xySpace;

    colX[0] = xOffset + margin();
    for ( int c = 1; c < (int)numCols; c++ )
        colX[c] = colX[c-1] + colWidth[c-1] + xySpace;
    
    const int itemCount = d_data->itemList.size();
    for ( int i = 0; i < itemCount; i++ )
    {
        const int row = i / numCols;
        const int col = i % numCols;

        QRect itemGeometry(colX[col], rowY[row], 
            colWidth[col], rowHeight[row]);
        itemGeometries.append(itemGeometry);
    }

    return itemGeometries;
}


void QwtDynGridLayout::layoutGrid(uint numCols, 
    QwtArray<int>& rowHeight, QwtArray<int>& colWidth) const
{
    if ( numCols <= 0 )
        return;

    if ( d_data->isDirty )
        ((QwtDynGridLayout*)this)->updateLayoutCache();

    for ( uint index = 0; 
        index < (uint)d_data->itemSizeHints.count(); index++ )
    {
        const int row = index / numCols;
        const int col = index % numCols;

        const QSize &size = d_data->itemSizeHints[int(index)];

        rowHeight[row] = (col == 0) 
            ? size.height() : qwtMax(rowHeight[row], size.height());
        colWidth[col] = (row == 0) 
            ? size.width() : qwtMax(colWidth[col], size.width());
    }
}

bool QwtDynGridLayout::hasHeightForWidth() const
{
    return true;
}

int QwtDynGridLayout::heightForWidth(int width) const
{
    if ( isEmpty() )
        return 0;

    const uint numCols = columnsForWidth(width);
    uint numRows = itemCount() / numCols;
    if ( itemCount() % numCols )
        numRows++;

    QwtArray<int> rowHeight(numRows);
    QwtArray<int> colWidth(numCols);

    layoutGrid(numCols, rowHeight, colWidth);

    int h = 2 * margin() + (numRows - 1) * spacing();
    for ( int row = 0; row < (int)numRows; row++ )
        h += rowHeight[row];

    return h;
}

void QwtDynGridLayout::stretchGrid(const QRect &rect, 
    uint numCols, QwtArray<int>& rowHeight, QwtArray<int>& colWidth) const
{
    if ( numCols == 0 || isEmpty() )
        return;

    bool expandH, expandV;
#if QT_VERSION >= 0x040000
    expandH = expandingDirections() & Qt::Horizontal;
    expandV = expandingDirections() & Qt::Vertical;
#else
    expandH = expanding() & QSizePolicy::Horizontally;
    expandV = expanding() & QSizePolicy::Vertically;
#endif

    if ( expandH )
    {
        int xDelta = rect.width() - 2 * margin() - (numCols - 1) * spacing();
        for ( int col = 0; col < (int)numCols; col++ )
            xDelta -= colWidth[col];

        if ( xDelta > 0 )
        {
            for ( int col = 0; col < (int)numCols; col++ )
            {
                const int space = xDelta / (numCols - col);
                colWidth[col] += space;
                xDelta -= space;
            }
        }
    }

    if ( expandV )
    {
        uint numRows = itemCount() / numCols;
        if ( itemCount() % numCols )
            numRows++;

        int yDelta = rect.height() - 2 * margin() - (numRows - 1) * spacing();
        for ( int row = 0; row < (int)numRows; row++ )
            yDelta -= rowHeight[row];

        if ( yDelta > 0 )
        {
            for ( int row = 0; row < (int)numRows; row++ )
            {
                const int space = yDelta / (numRows - row);
                rowHeight[row] += space;
                yDelta -= space;
            }
        }
    }
}

QSize QwtDynGridLayout::sizeHint() const
{
    if ( isEmpty() )
        return QSize();

    const uint numCols = (d_data->maxCols > 0 ) ? d_data->maxCols : itemCount();
    uint numRows = itemCount() / numCols;
    if ( itemCount() % numCols )
        numRows++;

    QwtArray<int> rowHeight(numRows);
    QwtArray<int> colWidth(numCols);

    layoutGrid(numCols, rowHeight, colWidth);

    int h = 2 * margin() + (numRows - 1) * spacing();
    for ( int row = 0; row < (int)numRows; row++ )
        h += rowHeight[row];

    int w = 2 * margin() + (numCols - 1) * spacing(); 
    for ( int col = 0; col < (int)numCols; col++ )
        w += colWidth[col];

    return QSize(w, h);
}

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

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

---