view base/Window.h @ 117:c30728d5625c sv1-v0.9rc1

* Make vertical scale alignment modes work in note layer as well as time-value layer, and several significant fixes to it * Make it possible to draw notes properly on the note layer * Show units (and frequencies etc in note layer's case) in the time-value and note layer description boxes * Minor fix to item edit dialog layout * Some minor menu rearrangement * Comment out a lot of debug output * Add SV website and reference URLs to Help menu, and add code to (attempt to) open them in the user's preferred browser
author Chris Cannam
date Fri, 12 May 2006 14:40:43 +0000
parents 534373d65f39
children a35098a9c814
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/* -*- 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];
    }

    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()
{
    size_t n = m_size;
    T *mult = new T[n];
    size_t i;
    for (i = 0; i < n; ++i) mult[i] = 1.0;

    switch (m_type) {
		
    case RectangularWindow:
	for (i = 0; i < n; ++i) {
	    mult[i] = mult[i] * 0.5;
	}
	break;
	    
    case BartlettWindow:
	for (i = 0; i < n/2; ++i) {
	    mult[i] = mult[i] * (i / T(n/2));
	    mult[i + n/2] = mult[i + n/2] * (1.0 - (i / T(n/2)));
	}
	break;
	    
    case HammingWindow:
	for (i = 0; i < n; ++i) {
	    mult[i] = mult[i] * (0.54 - 0.46 * cos(2 * M_PI * i / n));
	}
	break;
	    
    case HanningWindow:
	for (i = 0; i < n; ++i) {
	    mult[i] = mult[i] * (0.50 - 0.50 * cos(2 * M_PI * i / n));
	}
	break;
	    
    case BlackmanWindow:
	for (i = 0; i < n; ++i) {
	    mult[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] = mult[i] * exp(-(pow(i - (n-1)/2.0, 2) /
                                      (2 * pow(0.25 * n, 2)))); // sd = 0.25
	}
	break;
	    
    case ParzenWindow:
	for (i = 0; i < n; ++i) {
	    mult[i] = mult[i] * (1.0 - fabs((T(2*i) - n) / T(n + 1)));
	}
	break;
    }
	
    m_cache = mult;
}

#endif