/***************************************************************************
    FrequencyResponseWidget.h  -  displays a frequency response
			     -------------------
    begin                : Mar 09 2003
    copyright            : (C) 2003 by Thomas Eschenbacher
    email                : Thomas Eschenbacher <thomas.eschenbacher@gmx.de>
 ***************************************************************************/

/***************************************************************************
 *                                                                         *
 *   This program is free software; you can redistribute it and/or modify  *
 *   it under the terms of the GNU General Public License as published by  *
 *   the Free Software Foundation; either version 2 of the License, or     *
 *   (at your option) any later version.                                   *
 *                                                                         *
 ***************************************************************************/

#ifndef _FREQUENCY_RESPONSE_WIDGET_H_
#define _FREQUENCY_RESPONSE_WIDGET_H_

#include "config.h"
#include <qobject.h>
#include <qpixmap.h>
#include <qwidget.h>

class QPaintEvent;
class TransmissionFunction;

/**
 * displays a frequency response
 */
class FrequencyResponseWidget: public QWidget
{
    Q_OBJECT

public:

    /** Constructor */
    FrequencyResponseWidget(QWidget *parent, const char *name);

    /** Destructor */
    virtual ~FrequencyResponseWidget();

    /**
     * Initialize the widget dimensions.
     * @param freq highest frequency, will be internally rounded
     *             up to the next decade if necessary
     * @param db_min lowest amplitude in decibel
     * @param db_max highest amplitude in decibel
     */
    virtual void init(double freq, int db_min, int db_max);

    /** Set a new transmission function and update the display */
    virtual void setFilter(TransmissionFunction *func);

    /** @see QWidget::paintEvent() */
    virtual void paintEvent(QPaintEvent *);

private:

    /** highest frequency, rounded up to the next decade */
    double m_f_max;

    /** lowest amplitude in decibel */
    int m_db_min;

    /** highest amplitude in decibel */
    int m_db_max;

    /** number of decades, calculated from m_f_max */
    int m_decades;

    /**
     * Pointer to a transmission function object, used for
     * painting the frequency response.
     */
    TransmissionFunction *m_function;

    /** QPixmap to be blitted to screen (avoiding flicker) */
    QPixmap *m_pixmap;

};

#endif /* _FREQUENCY_RESPONSE_WIDGET_H_ */
