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# gridlayout.cpp Example File

declarative/cppextensions/qgraphicslayouts/qgraphicsgridlayout/gridlayout.cpp

     /****************************************************************************
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     ** Copyright (C) 2015 The Qt Company Ltd.
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     **
     ** This file is part of the examples of the Qt Toolkit.
     **
     ** $QT_BEGIN_LICENSE:BSD$
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     #include "gridlayout.h"

     #include <QGraphicsWidget>
     #include <QDebug>

     GridLayoutAttached::GridLayoutAttached(QObject *parent)
     : QObject(parent), m_row(-1), m_column(-1), m_rowspan(1), m_colspan(1), m_alignment(-1), m_rowStretch(-1),
         m_colStretch(-1), m_rowSpacing(-1), m_colSpacing(-1), m_rowPrefHeight(-1), m_rowMaxHeight(-1), m_rowMinHeight(-1),
         m_rowFixHeight(-1), m_colPrefwidth(-1), m_colMaxwidth(-1), m_colMinwidth(-1), m_colFixwidth(-1)
     {
     }

     void GridLayoutAttached::setAlignment(Qt::Alignment a)
     {
         if (m_alignment != a) {
             m_alignment = a;
             emit alignmentChanged(reinterpret_cast<QGraphicsLayoutItem*>(parent()), m_alignment);
         }
     }

     QHash<QGraphicsLayoutItem*, GridLayoutAttached*> GraphicsGridLayoutObject::attachedProperties;

     GraphicsGridLayoutObject::GraphicsGridLayoutObject(QObject *parent)
     : QObject(parent)
     {
     }

     GraphicsGridLayoutObject::~GraphicsGridLayoutObject()
     {
     }

     void GraphicsGridLayoutObject::addWidget(QGraphicsWidget *widget)
     {
         //use attached properties
         if (QObject *obj = attachedProperties.value(qobject_cast<QGraphicsLayoutItem*>(widget))) {
             int row = static_cast<GridLayoutAttached *>(obj)->row();
             int column = static_cast<GridLayoutAttached *>(obj)->column();
             int rowSpan = static_cast<GridLayoutAttached *>(obj)->rowSpan();
             int columnSpan = static_cast<GridLayoutAttached *>(obj)->columnSpan();
             if (row == -1 || column == -1) {
                 qWarning() << "Must set row and column for an item in a grid layout";
                 return;
             }
             addItem(widget, row, column, rowSpan, columnSpan);
         }
     }

     void GraphicsGridLayoutObject::addLayoutItem(QGraphicsLayoutItem *item)
     {
         //use attached properties
         if (GridLayoutAttached *obj = attachedProperties.value(item)) {
             int row = obj->row();
             int column = obj->column();
             int rowSpan = obj->rowSpan();
             int columnSpan = obj->columnSpan();
             Qt::Alignment alignment = obj->alignment();

             if (row == -1 || column == -1) {
                 qWarning() << "Must set row and column for an item in a grid layout";
                 return;
             }

             if (obj->rowSpacing() != -1)
                 setRowSpacing(row, obj->rowSpacing());
             if (obj->columnSpacing() != -1)
                 setColumnSpacing(column, obj->columnSpacing());
             if (obj->rowStretchFactor() != -1)
                 setRowStretchFactor(row, obj->rowStretchFactor());
             if (obj->columnStretchFactor() != -1)
                 setColumnStretchFactor(column, obj->columnStretchFactor());
             if (obj->rowPreferredHeight() != -1)
                 setRowPreferredHeight(row, obj->rowPreferredHeight());
             if (obj->rowMaximumHeight() != -1)
                 setRowMaximumHeight(row, obj->rowMaximumHeight());
             if (obj->rowMinimumHeight() != -1)
                 setRowMinimumHeight(row, obj->rowMinimumHeight());
             if (obj->rowFixedHeight() != -1)
                 setRowFixedHeight(row, obj->rowFixedHeight());
             if (obj->columnPreferredWidth() != -1)
                 setColumnPreferredWidth(row, obj->columnPreferredWidth());
             if (obj->columnMaximumWidth() != -1)
                 setColumnMaximumWidth(row, obj->columnMaximumWidth());
             if (obj->columnMinimumWidth() != -1)
                 setColumnMinimumWidth(row, obj->columnMinimumWidth());
             if (obj->columnFixedWidth() != -1)
                 setColumnFixedWidth(row, obj->columnFixedWidth());

             addItem(item, row, column, rowSpan, columnSpan);

             if (alignment != -1)
                 setAlignment(item, alignment);
             QObject::connect(obj, SIGNAL(alignmentChanged(QGraphicsLayoutItem*, Qt::Alignment)),
                              this, SLOT(updateAlignment(QGraphicsLayoutItem*, Qt::Alignment)));
         }
     }

     void GraphicsGridLayoutObject::removeAt(int index)
     {
         QGraphicsLayoutItem *item = itemAt(index);
         if (item) {
             GridLayoutAttached *obj = attachedProperties.value(item);
             obj->disconnect(this);
             attachedProperties.remove(item);
         }
         QGraphicsGridLayout::removeAt(index);
     }

     void GraphicsGridLayoutObject::clearChildren()
     {
         // do not delete the removed items; they will be deleted by the QML engine
         while (count() > 0)
             removeAt(count()-1);
     }

     qreal GraphicsGridLayoutObject::spacing() const
     {
         if (verticalSpacing() == horizontalSpacing())
             return verticalSpacing();
         return -1;
     }

     qreal GraphicsGridLayoutObject::contentsMargin() const
     {
         qreal a, b, c, d;
         getContentsMargins(&a, &b, &c, &d);
         if (a == b && a == c && a == d)
             return a;
         return -1;
     }

     void GraphicsGridLayoutObject::setContentsMargin(qreal m)
     {
         setContentsMargins(m, m, m, m);
     }

     void GraphicsGridLayoutObject::updateAlignment(QGraphicsLayoutItem *item, Qt::Alignment alignment)
     {
         QGraphicsGridLayout::setAlignment(item, alignment);
     }

     GridLayoutAttached *GraphicsGridLayoutObject::qmlAttachedProperties(QObject *obj)
     {
         GridLayoutAttached *rv = new GridLayoutAttached(obj);
         if (qobject_cast<QGraphicsLayoutItem*>(obj))
             attachedProperties.insert(qobject_cast<QGraphicsLayoutItem*>(obj), rv);
         return rv;
     }