How to resize a layout item?

**lni** · 21st February 2009, 20:31

Hi,

I am trying to force a specific size on a layout item as shown (400x400), but it doesn't work. Is there a way for it?

Thanks

Qt Code:

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#include <QtGui>
 
class LayoutItem : public QGraphicsWidget {
public:
  LayoutItem(QGraphicsItem *parent = 0) : QGraphicsWidget( parent ) {}
  void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
             QWidget *widget = 0) {
 
    qDebug() << "LayoutItem::paint, size = " << size();
    QRectF frame(QPointF(0,0), geometry().size());
    painter->drawRect( frame );
  }
 
};
 
class Window : public QGraphicsWidget {
public:
  Window(QGraphicsWidget *parent = 0) {
 
    QGraphicsGridLayout *grid = new QGraphicsGridLayout( this );
    LayoutItem* item = new LayoutItem;
    grid->addItem(item, 0, 0, 1, 1);
    item->resize( 400, 400 );
  }
};
 
int main(int argc, char **argv)
{
  QApplication app(argc, argv);
 
  QGraphicsScene scene;
 
  Window *window = new Window;
  scene.addItem(window);
  QGraphicsView view(&scene);
  view.resize(500, 500);
  view.show();
 
  return app.exec();
}

#include <QtGui>

class LayoutItem : public QGraphicsWidget {
public:
  LayoutItem(QGraphicsItem *parent = 0) : QGraphicsWidget( parent ) {}
  void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
             QWidget *widget = 0) {

    qDebug() << "LayoutItem::paint, size = " << size();
    QRectF frame(QPointF(0,0), geometry().size());
    painter->drawRect( frame );
  }

};

class Window : public QGraphicsWidget {
public:
  Window(QGraphicsWidget *parent = 0) {

    QGraphicsGridLayout *grid = new QGraphicsGridLayout( this );
    LayoutItem* item = new LayoutItem;
    grid->addItem(item, 0, 0, 1, 1);
    item->resize( 400, 400 );
  }
};

int main(int argc, char **argv)
{
  QApplication app(argc, argv);

  QGraphicsScene scene;

  Window *window = new Window;
  scene.addItem(window);
  QGraphicsView view(&scene);
  view.resize(500, 500);
  view.show();

  return app.exec();
}

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**talk2amulya** · 21st February 2009, 21:26

try resizing the item before you add it to the layout

**lni** · 21st February 2009, 22:12

Originally Posted by talk2amulya

try resizing the item before you add it to the layout

It doesn't work either...

**Lykurg** · 22nd February 2009, 08:53

Hi,

you have to use option->rect and implement the pure virtual function boundingRect()!

Qt Code:

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class LayoutItem : public QGraphicsWidget {
public:
  LayoutItem(QGraphicsItem *parent = 0) : QGraphicsWidget( parent ) {}
  void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
             QWidget *widget = 0) {
 
    qDebug() << "LayoutItem::paint, size = " << option->rect;
    painter->drawRect( option->rect );
  }
 QRectF boundingRect() const
 {
     return QRectF(0,0,400.0,400.0);
 }
 
};
 
class Window : public QGraphicsWidget {
public:
  Window(QGraphicsWidget *parent = 0) 
  {
    QGraphicsGridLayout *grid = new QGraphicsGridLayout( this );
    LayoutItem* item = new LayoutItem;
    grid->addItem(item, 0, 0, 1, 1);
  }
};

class LayoutItem : public QGraphicsWidget {
public:
  LayoutItem(QGraphicsItem *parent = 0) : QGraphicsWidget( parent ) {}
  void paint(QPainter *painter, const QStyleOptionGraphicsItem *option,
             QWidget *widget = 0) {
 
    qDebug() << "LayoutItem::paint, size = " << option->rect;
    painter->drawRect( option->rect );
  }
 QRectF boundingRect() const
 {
     return QRectF(0,0,400.0,400.0);
 }
 
};
 
class Window : public QGraphicsWidget {
public:
  Window(QGraphicsWidget *parent = 0) 
  {
    QGraphicsGridLayout *grid = new QGraphicsGridLayout( this );
    LayoutItem* item = new LayoutItem;
    grid->addItem(item, 0, 0, 1, 1);
  }
};

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