Kwave::WindowFunction Class Reference

#include <WindowFunction.h>

Collaboration diagram for Kwave::WindowFunction:

Classes
class	InitializedTypesMap

Public Member Functions
	WindowFunction (window_function_t type)
virtual	~WindowFunction ()
QVector< double >	points (unsigned int len) const

Static Public Member Functions
static window_function_t	findFromIndex (unsigned int index)
static window_function_t	findFromName (const QString &name)
static unsigned int	index (window_function_t type)
static const QString	name (window_function_t type)
static QString	description (window_function_t type, bool localized)
static unsigned int	count ()

Private Attributes
window_function_t	m_type

Static Private Attributes
static InitializedTypesMap	m_types_map

Detailed Description

Handles window functions for signal processing. Also holds a static map of known window functions.

Definition at line 47 of file WindowFunction.h.

Constructor & Destructor Documentation

WindowFunction()

Kwave::WindowFunction::WindowFunction ( Kwave::window_function_t  type )

explicit

Constructor

Parameters

type	initial window function type.

Definition at line 49 of file WindowFunction.cpp.

    :m_type(type)
{
}

~WindowFunction()

Kwave::WindowFunction::~WindowFunction ( )

virtual

Destructor

Definition at line 55 of file WindowFunction.cpp.

{
}

Member Function Documentation

count()

static unsigned int Kwave::WindowFunction::count ( )

inlinestatic

returns the number of available window functions

Definition at line 115 of file WindowFunction.h.

Referenced by Kwave::SonagramDialog::SonagramDialog().

                                    {
            return m_types_map.count();
        }

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description()

static QString Kwave::WindowFunction::description ( window_function_t  type, bool  localized  )

inlinestatic

Returns the description of a window function.

Parameters

type	the type of the window function
localized	if true, the localized description will be returned instead of the non-localized one

Definition at line 108 of file WindowFunction.h.

Referenced by Kwave::SonagramDialog::SonagramDialog().

        {
            return m_types_map.description(type, localized);
        }

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findFromIndex()

static window_function_t Kwave::WindowFunction::findFromIndex ( unsigned int  index )

inlinestatic

Returns the window function id through it's numeric index. If the index is out of range, the return value will be "WINDOW_FUNC_NONE".

Parameters

index

numeric index to be searched [0...count-1]

Definition at line 71 of file WindowFunction.h.

Referenced by Kwave::SonagramDialog::parameters().

                                                                   {
            return m_types_map.findFromData(index);
        }

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findFromName()

static window_function_t Kwave::WindowFunction::findFromName ( const QString &  name )

inlinestatic

Returns the window function id through it's name. If the name is unknown the return value will be "WINDOW_FUNC_NONE".

Parameters

name	the name to be searched

Definition at line 80 of file WindowFunction.h.

Referenced by Kwave::SonagramPlugin::interpreteParameters().

                                                                   {
            return m_types_map.findFromName(name);
        }

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index()

static unsigned int Kwave::WindowFunction::index ( window_function_t  type )

inlinestatic

Returns the numeric index of a window function [0...count-1].

Parameters

type	the type of the window function

Definition at line 88 of file WindowFunction.h.

Referenced by Kwave::SonagramDialog::setWindowFunction().

        {
            return m_types_map.data(type);
        }

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name()

static const QString Kwave::WindowFunction::name ( window_function_t  type )

inlinestatic

Returns the name of a window function.

Parameters

type	the type of the window function

Definition at line 97 of file WindowFunction.h.

Referenced by Kwave::SonagramDialog::parameters().

        {
            return m_types_map.name(type);
        }

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points()

QVector< double > Kwave::WindowFunction::points

(

unsigned int

len

)

const

Returns the coefficients of a window function with the given number of points. This is similar to Kwave's Interpolation class.

Definition at line 60 of file WindowFunction.cpp.

References m_type, Kwave::toInt(), Kwave::WINDOW_FUNC_BLACKMAN, Kwave::WINDOW_FUNC_HAMMING, Kwave::WINDOW_FUNC_HANNING, Kwave::WINDOW_FUNC_NONE, and Kwave::WINDOW_FUNC_TRIANGULAR.

Referenced by Kwave::SonagramPlugin::makeAllValid().

{
    QVector<double> out(len);
    Q_ASSERT(out.count() == Kwave::toInt(len));
    if (out.count() != Kwave::toInt(len)) {
        out.resize(0);
        return out;
    }

    // Hanning, Hamming, Blackman window functions as proposed
    // in Oppenheim, Schafer, p.241 ff
    switch (m_type) {
        case WINDOW_FUNC_NONE:   //rectangular window
            for (unsigned int i = 0; i < len; i++)
                out[i] = 1;
            break;
        case WINDOW_FUNC_HANNING:
            for (unsigned int i = 0; i < len; i++)
                out[i] = 0.5 * (1 - cos(i * 2 * M_PI / (len - 1)));
            break;
        case WINDOW_FUNC_HAMMING:
            for (unsigned int i = 0; i < len; i++)
                out[i] = 0.54-(0.46 * cos(static_cast<double>(i) * 2 * M_PI /
                         (len - 1)));
            break;
        case WINDOW_FUNC_BLACKMAN:
            for (unsigned int i = 0; i < len; i++)
                out[i] = 0.42-(0.50 * cos(static_cast<double>(i) * 2 * M_PI /
                         (len - 1))) +
                         (0.08 * cos(static_cast<double>(i) * 4 * M_PI /
                         (len - 1)));
            break;
        case WINDOW_FUNC_TRIANGULAR:
            for (unsigned int i = 0; i < len / 2; i++)
                out[i] = static_cast<double>(i) / (len / 2 - 1);

            for (unsigned int i = len / 2; i < len; i++)
                out[i] = 1 - (static_cast<double>(i) - len / 2) / (len / 2 - 1);
            break;
    }

    return out;
}

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Member Data Documentation

m_type

window_function_t Kwave::WindowFunction::m_type

private

id of the window function

Definition at line 140 of file WindowFunction.h.

Referenced by points().

m_types_map

Kwave::WindowFunction::InitializedTypesMap Kwave::WindowFunction::m_types_map

staticprivate

Static map of window function types.

Definition at line 143 of file WindowFunction.h.

Referenced by Kwave::WindowFunction::InitializedTypesMap::fill().

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The documentation for this class was generated from the following files:

• libkwave/WindowFunction.h
• libkwave/WindowFunction.cpp