c@119: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
c@119: /*
c@119:     Constant-Q library
c@119:     Copyright (c) 2013-2014 Queen Mary, University of London
c@119: 
c@119:     Permission is hereby granted, free of charge, to any person
c@119:     obtaining a copy of this software and associated documentation
c@119:     files (the "Software"), to deal in the Software without
c@119:     restriction, including without limitation the rights to use, copy,
c@119:     modify, merge, publish, distribute, sublicense, and/or sell copies
c@119:     of the Software, and to permit persons to whom the Software is
c@119:     furnished to do so, subject to the following conditions:
c@119: 
c@119:     The above copyright notice and this permission notice shall be
c@119:     included in all copies or substantial portions of the Software.
c@119: 
c@119:     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
c@119:     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
c@119:     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
c@119:     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
c@119:     CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
c@119:     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
c@119:     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
c@119: 
c@119:     Except as contained in this notice, the names of the Centre for
c@119:     Digital Music; Queen Mary, University of London; and Chris Cannam
c@119:     shall not be used in advertising or otherwise to promote the sale,
c@119:     use or other dealings in this Software without prior written
c@119:     authorization.
c@119: */
c@119: 
c@119: #ifndef KAISER_WINDOW_H
c@119: #define KAISER_WINDOW_H
c@119: 
c@119: #include <vector>
c@119: #include <cmath>
c@119: 
c@179: #include "pi.h"
c@179: 
c@119: /**
c@119:  * Kaiser window: A windower whose bandwidth and sidelobe height
c@119:  * (signal-noise ratio) can be specified. These parameters are traded
c@119:  * off against the window length.
c@119:  */
c@119: class KaiserWindow
c@119: {
c@119: public:
c@119:     struct Parameters {
c@119: 	int length;
c@119: 	double beta;
c@119:     };
c@119: 
c@119:     /**
c@119:      * Construct a Kaiser windower with the given length and beta
c@119:      * parameter.
c@119:      */
c@119:     KaiserWindow(Parameters p) : m_length(p.length), m_beta(p.beta) { init(); }
c@119: 
c@119:     /**
c@119:      * Construct a Kaiser windower with the given attenuation in dB
c@119:      * and transition width in samples.
c@119:      */
c@119:     static KaiserWindow byTransitionWidth(double attenuation,
c@119: 					  double transition) {
c@119: 	return KaiserWindow
c@119: 	    (parametersForTransitionWidth(attenuation, transition));
c@119:     }
c@119: 
c@119:     /**
c@119:      * Construct a Kaiser windower with the given attenuation in dB
c@119:      * and transition bandwidth in Hz for the given samplerate.
c@119:      */
c@119:     static KaiserWindow byBandwidth(double attenuation,
c@119: 				    double bandwidth,
c@119: 				    double samplerate) {
c@119: 	return KaiserWindow
c@119: 	    (parametersForBandwidth(attenuation, bandwidth, samplerate));
c@119:     }
c@119: 
c@119:     /**
c@119:      * Obtain the parameters necessary for a Kaiser window of the
c@119:      * given attenuation in dB and transition width in samples.
c@119:      */
c@119:     static Parameters parametersForTransitionWidth(double attenuation,
c@119: 						   double transition);
c@119: 
c@119:     /**
c@119:      * Obtain the parameters necessary for a Kaiser window of the
c@119:      * given attenuation in dB and transition bandwidth in Hz for the
c@119:      * given samplerate.
c@119:      */
c@119:     static Parameters parametersForBandwidth(double attenuation,
c@119: 					     double bandwidth,
c@119: 					     double samplerate) {
c@119: 	return parametersForTransitionWidth
c@119: 	    (attenuation, (bandwidth * 2 * M_PI) / samplerate);
c@119:     } 
c@119: 
c@119:     int getLength() const {
c@119: 	return m_length;
c@119:     }
c@119: 
c@119:     const double *getWindow() const { 
c@119: 	return m_window.data();
c@119:     }
c@119: 
c@119:     void cut(double *src) const { 
c@119: 	cut(src, src); 
c@119:     }
c@119: 
c@119:     void cut(const double *src, double *dst) const {
c@119: 	for (int i = 0; i < m_length; ++i) {
c@119: 	    dst[i] = src[i] * m_window[i];
c@119: 	}
c@119:     }
c@119: 
c@119: private:
c@119:     int m_length;
c@119:     double m_beta;
c@119:     std::vector<double> m_window;
c@119: 
c@119:     void init();
c@119: };
c@119: 
c@119: #endif