Russian Qt Forum

C++ (Qt)
#include <QApplication>
#include <QGraphicsScene>
#include <QGraphicsView>
#include <QGraphicsRectItem>
#include <QMouseEvent>
 
class RubberItem : public QGraphicsRectItem
{
public:
	RubberItem( const QRectF& r, QGraphicsItem* parent = 0 )
	: QGraphicsRectItem( r, parent )
	{
		QColor clr( Qt::blue );
		setPen( clr );
		clr.setAlphaF( .1 );
		setBrush( clr );
	}
	virtual ~RubberItem() {}
	QRectF boundingRect() const
	{
		qreal es = grip_size_ / 2;
		return rect().adjusted( -es, -es, es, es );
	}
	void paint( QPainter* painter, const QStyleOptionGraphicsItem* option, QWidget* widget = 0 )
	{
		QGraphicsRectItem::paint( painter, option, widget );
 
		QMatrix m = painter->matrix();
		QRectF irect( QRectF( QPointF( 0, 0 ), m.mapRect( rect() ).size() ) );
 
		qreal gs = grip_size_;
		QRectF r( -gs / 2, -gs / 2, gs, gs );
		r.translate( m.map( QPointF( 0, 0 ) ) );
 
		QColor clr( painter->brush().color() );
		clr.setAlphaF( 1 );
		painter->setBrush( clr );
 
		painter->resetTransform();
 
		painter->drawRect( r.translated( irect.topLeft() ) );
		painter->drawRect( r.translated( QPointF( irect.width() / 2, 0 ) ) );
		painter->drawRect( r.translated( irect.topRight() ) );
		painter->drawRect( r.translated( QPointF( 0, irect.height() / 2 ) ) );
		painter->drawRect( r.translated( irect.bottomLeft() ) );
		painter->drawRect( r.translated( QPointF( irect.width(), irect.height() / 2 ) ) );
		painter->drawRect( r.translated( irect.bottomRight() ) );
		painter->drawRect( r.translated( QPointF( irect.width() / 2, irect.height() ) ) );
	}
	Qt::WindowFrameSection frameSectionAt( const QPointF& p ) const
	{
		QRectF irect( rect() );
 
		qreal gs = grip_size_;
		QRectF r( -gs / 2, -gs / 2, gs, gs );
		r.translate( pos() );
 
		Qt::WindowFrameSection section = Qt::NoSection;
		if( r.translated( irect.topLeft() ).contains( p ) )
			section = Qt::TopLeftSection;
		else if( r.translated( QPointF( irect.width() / 2, 0 ) ).contains( p ) )
			section = Qt::TopSection;
		else if( r.translated( irect.topRight() ).contains( p ) )
			section = Qt::TopRightSection;
		else if( r.translated( QPointF( irect.width(), irect.height() / 2 ) ).contains( p ) )
			section = Qt::RightSection;
		else if( r.translated( irect.bottomRight() ).contains( p ) )
			section = Qt::BottomRightSection;
		else if( r.translated( QPointF( irect.width() / 2, irect.height() ) ).contains( p ) )
			section = Qt::BottomSection;
		else if( r.translated( irect.bottomLeft() ).contains( p ) )
			section = Qt::BottomLeftSection;
		else if( r.translated( QPointF( 0, irect.height() / 2 ) ).contains( p ) )
			section = Qt::LeftSection;
		return section;
	}
 
	static qreal gripSize() { return grip_size_; }
 
private:
	static const qreal grip_size_ = 5;
};
 
class GraphicsView : public QGraphicsView
{
public:
	GraphicsView( QWidget* p = 0 ) : QGraphicsView( p )
	{
		viewport()->setMouseTracking( true );
	}
	void resizeEvent( QResizeEvent* e )
	{
		fitInView( scene()->sceneRect() );
	}
	void mouseMoveEvent( QMouseEvent* e )
	{
		QGraphicsView::mouseMoveEvent( e );
		QList< QGraphicsItem* > il = items(
				e->pos().x(), e->pos().y(), 1, 1, Qt::IntersectsItemBoundingRect );
		RubberItem* ri;
		if( !il.isEmpty() &&
			( ri = dynamic_cast< RubberItem* >( il.first() ) ) )
			updateRubberItemCursor( ri, e->pos() );
		else
			viewport()->unsetCursor();
	}
	void updateRubberItemCursor( RubberItem* ri, const QPoint& cpos )
	{
		switch( ri->frameSectionAt( mapToScene( cpos ) ) )
		{
			case Qt::TopLeftSection:
			case Qt::BottomRightSection:
				viewport()->setCursor( Qt::SizeFDiagCursor );
				break;
			case Qt::TopRightSection:
			case Qt::BottomLeftSection:
				viewport()->setCursor( Qt::SizeBDiagCursor );
				break;
			case Qt::TopSection:
			case Qt::BottomSection:
				viewport()->setCursor( Qt::SizeVerCursor );
				break;
			case Qt::LeftSection:
			case Qt::RightSection:
				viewport()->setCursor( Qt::SizeHorCursor );
				break;
			default:
				viewport()->unsetCursor();
				break;
		}
	}
};
 
int main( int argc, char** argv )
{
	QApplication app( argc, argv );
 
	GraphicsView	gv;
	QGraphicsScene	scene;
 
	gv.setScene( &scene );
 
	scene.setSceneRect( 0, 0, 300, 300 );
	RubberItem item( QRectF( 0, 0, 200, 200 ) );
	scene.addItem( &item );
	item.setPos( 50, 50 );
 
	gv.show();
 
	return app.exec();
}
 

C++ (Qt)
void QPen::setCosmetic ( bool cosmetic )