/* -*- mode: C++ ; c-file-style: "stroustrup" -*- *****************************
 * Qwt Widget Library
 * Copyright (C) 1997   Josef Wilgen
 * Copyright (C) 2002   Uwe Rathmann
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the Qwt License, Version 1.0
 *****************************************************************************/

#ifndef QWT_KNOB_H
#define QWT_KNOB_H

#include "qwt_global.h"
#include "qwt_abstract_slider.h"
#include "qwt_abstract_scale.h"

class QwtRoundScaleDraw;

/*!
  \brief The Knob Widget

  The QwtKnob widget imitates look and behaviour of a volume knob on a radio.
  It contains a scale around the knob which is set up automatically or can
  be configured manually (see QwtAbstractScale).
  Automatic scrolling is enabled when the user presses a mouse
  button on the scale. For a description of signals, slots and other
  members, see QwtAbstractSlider.

  \image html knob.png
  \sa   QwtAbstractSlider and QwtAbstractScale for the descriptions
    of the inherited members.
*/

class QWT_EXPORT QwtKnob : public QwtAbstractSlider, public QwtAbstractScale
{
    Q_OBJECT
    Q_ENUMS ( Symbol )
    Q_PROPERTY( int knobWidth READ knobWidth WRITE setKnobWidth )
    Q_PROPERTY( int borderWidth READ borderWidth WRITE setBorderWidth )
    Q_PROPERTY( double totalAngle READ totalAngle WRITE setTotalAngle )
    Q_PROPERTY( Symbol symbol READ symbol WRITE setSymbol )

public:
    /*!
        Symbol
        \sa setSymbol()
    */
    enum Symbol 
    { 
        Line, 
        Dot 
    };

    explicit QwtKnob( QWidget* parent = NULL );
    virtual ~QwtKnob();

    void setKnobWidth( int w );
    int knobWidth() const;

    void setTotalAngle ( double angle );
    double totalAngle() const;

    void setBorderWidth( int bw );
    int borderWidth() const;

    void setSymbol( Symbol );
    Symbol symbol() const;

    virtual QSize sizeHint() const;
    virtual QSize minimumSizeHint() const;

    void setScaleDraw( QwtRoundScaleDraw * );
    const QwtRoundScaleDraw *scaleDraw() const;
    QwtRoundScaleDraw *scaleDraw();

protected:
    virtual void paintEvent( QPaintEvent *e );
    virtual void resizeEvent( QResizeEvent *e );

    void draw( QPainter *p, const QRect& ur );
    void drawKnob( QPainter *p, const QRect &r );
    void drawMarker( QPainter *p, double arc, const QColor &c );

private:
    void initKnob();
    void layoutKnob( bool update = true );
    double getValue( const QPoint &p );
    void getScrollMode( const QPoint &p, int &scrollMode, int &direction );
    void recalcAngle();

    virtual void valueChange();
    virtual void rangeChange();
    virtual void scaleChange();
    virtual void fontChange( const QFont &oldFont );

    class PrivateData;
    PrivateData *d_data;
};

#endif