/******************************************************************** Implementation CannonField class, Qt tutorial 8******************************************************************/#include "cannon.h"#include <qpainter.h>CannonField::CannonField( QWidget *parent, const char *name )        : QWidget( parent, name ){    ang = 45;    setPalette( QPalette( QColor( 250, 250, 200) ) );}void CannonField::setAngle( int degrees ){    if ( degrees < 5 )	degrees = 5;    if ( degrees > 70 )	degrees = 70;    if ( ang == degrees )	return;    ang = degrees;    repaint();    emit angleChanged( ang );}void CannonField::paintEvent( QPaintEvent * ){    QString s = "Angle = " + QString::number( ang );    QPainter p( this );    p.drawText( 100, 100, s );}QSizePolicy CannonField::sizePolicy() const{    return QSizePolicy( QSizePolicy::Expanding, QSizePolicy::Expanding );}