c@121: /* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */
c@121: /*
c@121:     Constant-Q library
c@121:     Copyright (c) 2013-2014 Queen Mary, University of London
c@121: 
c@121:     Permission is hereby granted, free of charge, to any person
c@121:     obtaining a copy of this software and associated documentation
c@121:     files (the "Software"), to deal in the Software without
c@121:     restriction, including without limitation the rights to use, copy,
c@121:     modify, merge, publish, distribute, sublicense, and/or sell copies
c@121:     of the Software, and to permit persons to whom the Software is
c@121:     furnished to do so, subject to the following conditions:
c@121: 
c@121:     The above copyright notice and this permission notice shall be
c@121:     included in all copies or substantial portions of the Software.
c@121: 
c@121:     THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
c@121:     EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
c@121:     MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
c@121:     NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
c@121:     CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF
c@121:     CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
c@121:     WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
c@121: 
c@121:     Except as contained in this notice, the names of the Centre for
c@121:     Digital Music; Queen Mary, University of London; and Chris Cannam
c@121:     shall not be used in advertising or otherwise to promote the sale,
c@121:     use or other dealings in this Software without prior written
c@121:     authorization.
c@121: */
c@121: 
c@179: #ifndef WINDOW_H
c@179: #define WINDOW_H
c@121: 
c@121: #include <cmath>
c@121: #include <iostream>
c@121: #include <map>
c@121: #include <vector>
c@121: 
c@179: #include "pi.h"
c@179: 
c@121: enum WindowType {
c@121:     RectangularWindow,
c@121:     BartlettWindow,
c@121:     HammingWindow,
c@121:     HanningWindow,
c@121:     BlackmanWindow,
c@121:     BlackmanHarrisWindow,
c@121: 
c@121:     FirstWindow = RectangularWindow,
c@121:     LastWindow = BlackmanHarrisWindow
c@121: };
c@121: 
c@121: /**
c@121:  * Various shaped windows for sample frame conditioning, including
c@121:  * cosine windows (Hann etc) and triangular and rectangular windows.
c@121:  */
c@121: template <typename T>
c@121: class Window
c@121: {
c@121: public:
c@121:     /**
c@121:      * Construct a windower of the given type and size. 
c@121:      *
c@121:      * Note that the cosine windows are periodic by design, rather
c@121:      * than symmetrical. (A window of size N is equivalent to a
c@121:      * symmetrical window of size N+1 with the final element missing.)
c@121:      */
c@121:     Window(WindowType type, int size) : m_type(type), m_size(size) { encache(); }
c@121:     Window(const Window &w) : m_type(w.m_type), m_size(w.m_size) { encache(); }
c@121:     Window &operator=(const Window &w) {
c@121: 	if (&w == this) return *this;
c@121: 	m_type = w.m_type;
c@121: 	m_size = w.m_size;
c@121: 	encache();
c@121: 	return *this;
c@121:     }
c@121:     virtual ~Window() { delete[] m_cache; }
c@121:     
c@121:     void cut(T *src) const { cut(src, src); }
c@121:     void cut(const T *src, T *dst) const {
c@121: 	for (int i = 0; i < m_size; ++i) dst[i] = src[i] * m_cache[i];
c@121:     }
c@121: 
c@121:     WindowType getType() const { return m_type; }
c@121:     int getSize() const { return m_size; }
c@121: 
c@121:     std::vector<T> getWindowData() const {
c@121:         std::vector<T> d;
c@121:         for (int i = 0; i < m_size; ++i) {
c@121:             d.push_back(m_cache[i]);
c@121:         }
c@121:         return d;
c@121:     }
c@121: 
c@121: protected:
c@121:     WindowType m_type;
c@121:     int m_size;
c@121:     T *m_cache;
c@121:     
c@121:     void encache();
c@121: };
c@121: 
c@121: template <typename T>
c@121: void Window<T>::encache()
c@121: {
c@121:     int n = m_size;
c@121:     T *mult = new T[n];
c@121:     int i;
c@121:     for (i = 0; i < n; ++i) mult[i] = 1.0;
c@121: 
c@121:     switch (m_type) {
c@121: 		
c@121:     case RectangularWindow:
c@121:         for (i = 0; i < n; ++i) {
c@121:             mult[i] = mult[i] * 0.5;
c@121: 	}
c@121: 	break;
c@121: 	    
c@121:     case BartlettWindow:
c@121:         if (n == 2) {
c@121:             mult[0] = mult[1] = 0; // "matlab compatible"
c@121:         } else if (n == 3) {
c@121:             mult[0] = 0;
c@121:             mult[1] = mult[2] = 2./3.;
c@121:         } else if (n > 3) {
c@121:             for (i = 0; i < n/2; ++i) {
c@121:                 mult[i] = mult[i] * (i / T(n/2));
c@121:                 mult[i + n - n/2] = mult[i + n - n/2] * (1.0 - (i / T(n/2)));
c@121:             }
c@121: 	}
c@121: 	break;
c@121: 	    
c@121:     case HammingWindow:
c@121:         if (n > 1) {
c@121:             for (i = 0; i < n; ++i) {
c@121:                 mult[i] = mult[i] * (0.54 - 0.46 * cos(2 * M_PI * i / n));
c@121:             }
c@121: 	}
c@121: 	break;
c@121: 	    
c@121:     case HanningWindow:
c@121:         if (n > 1) {
c@121:             for (i = 0; i < n; ++i) {
c@121:                 mult[i] = mult[i] * (0.50 - 0.50 * cos(2 * M_PI * i / n));
c@121:             }
c@121: 	}
c@121: 	break;
c@121: 	    
c@121:     case BlackmanWindow:
c@121:         if (n > 1) {
c@121:             for (i = 0; i < n; ++i) {
c@121:                 mult[i] = mult[i] * (0.42 - 0.50 * cos(2 * M_PI * i / n)
c@121:                                      + 0.08 * cos(4 * M_PI * i / n));
c@121:             }
c@121: 	}
c@121: 	break;
c@121: 	    
c@121:     case BlackmanHarrisWindow:
c@121:         if (n > 1) {
c@121:             for (i = 0; i < n; ++i) {
c@121:                 mult[i] = mult[i] * (0.35875
c@121:                                      - 0.48829 * cos(2 * M_PI * i / n)
c@121:                                      + 0.14128 * cos(4 * M_PI * i / n)
c@121:                                      - 0.01168 * cos(6 * M_PI * i / n));
c@121:             }
c@121: 	}
c@121: 	break;
c@121:     }
c@121: 	   
c@121:     m_cache = mult;
c@121: }
c@121: 
c@121: #endif