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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 SV_LOG_RANGE_H
#define SV_LOG_RANGE_H
#include <vector>
#include "Debug.h"
namespace sv {
class LogRange
{
public:
/**
* Map a value onto a logarithmic range. This just means taking
* the base-10 log of the absolute value, or using the threshold
* value if the absolute value is zero.
*/
static double map(double value, double thresh = -10);
/**
* Map a value from the logarithmic range back again. This just
* means taking the value'th power of ten.
*/
static double unmap(double value);
/**
* Map a linear range onto a logarithmic range. min and max are
* passed as the extents of the linear range and returned as the
* extents of the logarithmic range. thresh is the minimum value
* for the log range, to be used if the linear range spans zero.
*/
static void mapRange(double &min, double &max, double thresh = -10);
/**
* Estimate whether a set of values would be more properly shown
* using a logarithmic than a linear scale. This is only ever
* going to be a rough guess.
*/
static bool shouldUseLogScale(std::vector<double> values);
};
} // end namespace sv
#endif
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