Qt tutorial - t9/cannon.cpp

# Source code for tutorial 9: cannon.cpp

    /****************************************************************
    **
    ** Implementation CannonField class, Qt tutorial 9
    **
    ****************************************************************/

    #include "cannon.h"
    #include <qpainter.h>

    CannonField::CannonField( QWidget *parent, const char *name )
            : QWidget( parent, name )
    {
        ang = 45;
    }

    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 * )
    {
        QPainter p;
        QBrush   brush( blue );
        QPen     pen( NoPen );

        p.begin( this );
        p.setBrush( brush );
        p.setPen( pen );

        p.translate( 0, rect().bottom() );
        p.drawPie( QRect(-35, -35, 70, 70), 0, 90*16 );
        p.rotate( -ang );
        p.drawRect( QRect(33, -4, 15, 8) );

        p.end();
    }