view base/Window.h @ 141:4f26f623a8bc

* Finish preferences dialog (as far as it's going at the moment) and connect it up
* Fix Parzen window shape (was triangular!)
* Various fixes to spectrogram draw coordinates in smoothing mode etc
* Draw C keys in grey on the piano

/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*-  vi:set ts=8 sts=4 sw=4: */

/*
    Sonic Visualiser
    An audio file viewer and annotation editor.
    Centre for Digital Music, Queen Mary, University of London.
    This file copyright 2006 Chris Cannam.
    
    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.  See the file
    COPYING included with this distribution for more information.
*/

#ifndef _WINDOW_H_
#define _WINDOW_H_

#include <cmath>
#include <iostream>
#include <map>

enum WindowType {
    RectangularWindow,
    BartlettWindow,
    HammingWindow,
    HanningWindow,
    BlackmanWindow,
    GaussianWindow,
    ParzenWindow
};

template <typename T>
class Window
{
public:
    /**
     * Construct a windower of the given type.
     */
    Window(WindowType type, size_t size) : m_type(type), m_size(size) { encache(); }
    Window(const Window &w) : m_type(w.m_type), m_size(w.m_size) { encache(); }
    Window &operator=(const Window &w) {
	if (&w == this) return *this;
	m_type = w.m_type;
	m_size = w.m_size;
	encache();
	return *this;
    }
    virtual ~Window() { delete m_cache; }
    
    void cut(T *src) const { cut(src, src); }
    void cut(T *src, T *dst) const {
	for (size_t i = 0; i < m_size; ++i) dst[i] = src[i] * m_cache[i];
    }

    T getValue(size_t i) { return m_cache[i]; }

    WindowType getType() const { return m_type; }
    size_t getSize() const { return m_size; }

protected:
    WindowType m_type;
    size_t m_size;
    T *m_cache;
    
    void encache();
};

template <typename T>
void Window<T>::encache()
{
    int n = int(m_size);
    T *mult = new T[n];
    int i;
    for (i = 0; i < n; ++i) mult[i] = 1.0;

    switch (m_type) {
		
    case RectangularWindow:
	for (i = 0; i < n; ++i) {
	    mult[i] *= 0.5;
	}
	break;
	    
    case BartlettWindow:
	for (i = 0; i < n/2; ++i) {
	    mult[i] *= (i / T(n/2));
	    mult[i + n/2] *= (1.0 - (i / T(n/2)));
	}
	break;
	    
    case HammingWindow:
	for (i = 0; i < n; ++i) {
	    mult[i] *= (0.54 - 0.46 * cos(2 * M_PI * i / n));
	}
	break;
	    
    case HanningWindow:
	for (i = 0; i < n; ++i) {
	    mult[i] *= (0.50 - 0.50 * cos(2 * M_PI * i / n));
	}
	break;
	    
    case BlackmanWindow:
	for (i = 0; i < n; ++i) {
	    mult[i] *= (0.42 - 0.50 * cos(2 * M_PI * i / n)
				 + 0.08 * cos(4 * M_PI * i / n));
	}
	break;
	    
    case GaussianWindow:
	for (i = 0; i < n; ++i) {
            mult[i] *= exp(-(pow(i - (n-1)/2.0, 2) /
                                      (2 * pow(0.25 * n, 2)))); // sd = 0.25
	}
	break;
	    
    case ParzenWindow:
    {
        int N = n-1;
        for (i = 0; i < N/4; ++i) {
            T m = 2 * pow(1.0 - (T(N)/2 - i) / (T(N)/2), 3);
            mult[i] *= m;
            mult[N-i] *= m;
        }
        for (i = N/4; i <= N/2; ++i) {
            int wn = i - N/2;
            T m = 1.0 - 6 * pow(wn / (T(N)/2), 2) * (1.0 - abs(wn) / (T(N)/2));
            mult[i] *= m;
            mult[N-i] *= m;
        }            
    }            
	break;
    }
	
    m_cache = mult;
}

#endif