/***************************************************************************
        LowPassPlugin.h  -  Plugin for simple lowpass filtering
                             -------------------
    begin                : Fri Mar 07 2003
    copyright            : (C) 2003 by Thomas Eschenbacher
    email                : 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 LOW_PASS_PLUGIN_H
#define LOW_PASS_PLUGIN_H

#include "config.h"

#include <QObject>
#include <QString>
#include <QStringList>

#include "libkwave/Plugin.h"
#include "libkwave/PluginSetupDialog.h"

#include "libgui/FilterPlugin.h"

class QStringList;

namespace Kwave
{

    class KwaveSampleSource;

    class LowPassPlugin: public Kwave::FilterPlugin
    {
	Q_OBJECT

    public:

	/**
	 * Constructor
	 * @param parent reference to our plugin manager
	 * @param args argument list [unused]
	 */
	LowPassPlugin(QObject *parent, const QVariantList &args);

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

	/** Creates the setup dialog and connects it's signals */
	virtual Kwave::PluginSetupDialog *createDialog(QWidget *parent);

	/**
	 * Creates a multi-track filter with the given number of tracks
	 * @param tracks number of tracks that the filter should have
	 * @return pointer to the filter or null if failed
	 */
	virtual Kwave::SampleSource *createFilter(unsigned int tracks);

	/**
	 * Returns true if the parameters have changed during pre-listen.
	 */
	virtual bool paramsChanged();

	/**
	 * Update the filter with new parameters if it has changed
	 * changed during the pre-listen.
	 * @param filter the Kwave::SampleSource to be updated, should be the
	 *               same one as created with createFilter()
	 * @param force if true, even update if no settings have changed
	 */
	virtual void updateFilter(Kwave::SampleSource *filter,
	                          bool force = false);

	/**
	 * Returns a verbose name of the performed action. Used for giving
	 * the undo action a readable name.
	 */
	virtual QString actionName();

    protected:

	/** Reads values from the parameter list */
	virtual int interpreteParameters(QStringList &params);

    protected slots:

	/**
	 * Called when the parameter changed during pre-listen
	 * @param frequency the frequency parameter in Hz
	 */
	void setValue(double frequency);

    private:

	/** cutoff frequency [Hz] */
	double m_frequency;

	/** last value of m_frequency */
	double m_last_freq;
    };
}

#endif /* LOW_PASS_PLUGIN_H */

//***************************************************************************
//***************************************************************************
