view layer/ColourScale.cpp @ 1386:fc3d89f88690 spectrogramparam

Use log-frequency rather than log-bin for calculating x coord in spectrum. This has the advantage that frequency positions don't move when we change the window size or oversampling ratio, but it does give us an unhelpfully large amount of space for very low frequencies - to be considered

/* -*- 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 2006-2016 Chris Cannam and QMUL.
    
    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.
*/

#include "ColourScale.h"

#include "base/AudioLevel.h"
#include "base/LogRange.h"

#include <cmath>
#include <iostream>

using namespace std;

int ColourScale::m_maxPixel = 255;

ColourScale::ColourScale(Parameters parameters) :
    m_params(parameters),
    m_mapper(m_params.colourMap, m_params.inverted, 1.f, double(m_maxPixel))
{
    if (m_params.minValue >= m_params.maxValue) {
        SVCERR << "ERROR: ColourScale::ColourScale: minValue = "
             << m_params.minValue << ", maxValue = " << m_params.maxValue << endl;
        throw std::logic_error("maxValue must be greater than minValue");
    }

    m_mappedMin = m_params.minValue;
    m_mappedMax = m_params.maxValue;

    if (m_mappedMin < m_params.threshold) {
        m_mappedMin = m_params.threshold;
    }
    
    if (m_params.scaleType == ColourScaleType::Log) {

        // When used in e.g. spectrogram, we have a range with a min
        // value of zero. The LogRange converts that to a threshold
        // value of -10, so for a range of e.g. (0,1) we end up with
        // (-10,0) as the mapped range.
        // 
        // But in other contexts we could end up with a mapped range
        // much larger than that if we have a small non-zero minimum
        // value (less than 1e-10), or a particularly large
        // maximum. That's unlikely to give us good results, so let's
        // insist that the mapped log range has no more than 10
        // difference between min and max, to match the behaviour when
        // min == 0 at the input.
        //
        double threshold = -10.0;
        LogRange::mapRange(m_mappedMin, m_mappedMax, threshold);
        if (m_mappedMin < m_mappedMax + threshold) {
            m_mappedMin = m_mappedMax + threshold;
        }
        
    } else if (m_params.scaleType == ColourScaleType::PlusMinusOne) {
        
        m_mappedMin = -1.0;
        m_mappedMax =  1.0;

    } else if (m_params.scaleType == ColourScaleType::Absolute) {

        m_mappedMin = fabs(m_mappedMin);
        m_mappedMax = fabs(m_mappedMax);
        if (m_mappedMin >= m_mappedMax) {
            std::swap(m_mappedMin, m_mappedMax);
        }
    }

    if (m_mappedMin >= m_mappedMax) {
        SVCERR << "ERROR: ColourScale::ColourScale: minValue = " << m_params.minValue
             << ", maxValue = " << m_params.maxValue
             << ", threshold = " << m_params.threshold
             << ", scale = " << int(m_params.scaleType)
             << " resulting in mapped minValue = " << m_mappedMin
             << ", mapped maxValue = " << m_mappedMax << endl;
        throw std::logic_error("maxValue must be greater than minValue [after mapping]");
    }
}

ColourScale::~ColourScale()
{
}

ColourScaleType
ColourScale::getScale() const
{
    return m_params.scaleType;
}

int
ColourScale::getPixel(double value) const
{
    double maxPixF = m_maxPixel;

    if (m_params.scaleType == ColourScaleType::Phase) {
        double half = (maxPixF - 1.f) / 2.f;
        int pixel = 1 + int((value * half) / M_PI + half);
//        SVCERR << "phase = " << value << " pixel = " << pixel << endl;
        return pixel;
    }
    
    value *= m_params.gain;
    
    if (value < m_params.threshold) return 0;

    double mapped = value;

    if (m_params.scaleType == ColourScaleType::Log) {
        mapped = LogRange::map(value);
    } else if (m_params.scaleType == ColourScaleType::PlusMinusOne) {
        if (mapped < -1.f) mapped = -1.f;
        if (mapped > 1.f) mapped = 1.f;
    } else if (m_params.scaleType == ColourScaleType::Absolute) {
        if (mapped < 0.f) mapped = -mapped;
    }

    mapped *= m_params.multiple;
    
    if (mapped < m_mappedMin) {
        mapped = m_mappedMin;
    }
    if (mapped > m_mappedMax) {
        mapped = m_mappedMax;
    }

    double proportion = (mapped - m_mappedMin) / (m_mappedMax - m_mappedMin);

    int pixel = 0;

    if (m_params.scaleType == ColourScaleType::Meter) {
        pixel = AudioLevel::multiplier_to_preview(proportion, m_maxPixel-1) + 1;
    } else {
        pixel = int(proportion * maxPixF) + 1;
    }

    if (pixel < 0) {
        pixel = 0;
    }
    if (pixel > m_maxPixel) {
        pixel = m_maxPixel;
    }
    return pixel;
}

QColor
ColourScale::getColourForPixel(int pixel, int rotation) const
{
    if (pixel < 0) {
        pixel = 0;
    }
    if (pixel > m_maxPixel) {
        pixel = m_maxPixel;
    }
    if (pixel == 0) {
        if (m_mapper.hasLightBackground()) {
            return Qt::white;
        } else {
            return Qt::black;
        }
    } else {
        int target = int(pixel) + rotation;
        while (target < 1) target += m_maxPixel;
        while (target > m_maxPixel) target -= m_maxPixel;
        return m_mapper.map(double(target));
    }
}