annotate layer/WaveformLayer.cpp @ 287:cd2492c5fe45

* Add SingleColourLayer to manage colours for layers that have a single
  predominant colour (i.e. most of them).

/* -*- 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 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 "WaveformLayer.h"

#include "base/AudioLevel.h"
#include "view/View.h"
#include "base/Profiler.h"
#include "base/RangeMapper.h"
#include "base/ColourDatabase.h"

#include <QPainter>
#include <QPixmap>

#include <iostream>
#include <cmath>

//#define DEBUG_WAVEFORM_PAINT 1

using std::cerr;
using std::endl;

WaveformLayer::WaveformLayer() :
    SingleColourLayer(),
    m_model(0),
    m_gain(1.0f),
    m_autoNormalize(false),
    m_showMeans(true),
    m_greyscale(true),
    m_channelMode(SeparateChannels),
    m_channel(-1),
    m_scale(LinearScale),
    m_aggressive(false),
    m_cache(0),
    m_cacheValid(false)
{
    
}

WaveformLayer::~WaveformLayer()
{
    delete m_cache;
}

void
WaveformLayer::setModel(const RangeSummarisableTimeValueModel *model)
{
    bool channelsChanged = false;
    if (m_channel == -1) {
        if (!m_model) {
            if (model) {
                channelsChanged = true;
            }
        } else {
            if (model &&
                m_model->getChannelCount() != model->getChannelCount()) {
                channelsChanged = true;
            }
        }
    }

    m_model = model;
    m_cacheValid = false;
    if (!m_model || !m_model->isOK()) return;

    connect(m_model, SIGNAL(modelChanged()), this, SIGNAL(modelChanged()));
    connect(m_model, SIGNAL(modelChanged(size_t, size_t)),
	    this, SIGNAL(modelChanged(size_t, size_t)));

    connect(m_model, SIGNAL(completionChanged()),
	    this, SIGNAL(modelCompletionChanged()));

    emit modelReplaced();

    if (channelsChanged) emit layerParametersChanged();
}

Layer::PropertyList
WaveformLayer::getProperties() const
{
    PropertyList list = SingleColourLayer::getProperties();
    list.push_back("Scale");
    list.push_back("Gain");
    list.push_back("Normalize Visible Area");

    if (m_model && m_model->getChannelCount() > 1 && m_channel == -1) {
        list.push_back("Channels");
    }

    return list;
}

QString
WaveformLayer::getPropertyLabel(const PropertyName &name) const
{
    if (name == "Scale") return tr("Scale");
    if (name == "Gain") return tr("Gain");
    if (name == "Normalize Visible Area") return tr("Normalize Visible Area");
    if (name == "Channels") return tr("Channels");
    return SingleColourLayer::getPropertyLabel(name);
}

Layer::PropertyType
WaveformLayer::getPropertyType(const PropertyName &name) const
{
    if (name == "Gain") return RangeProperty;
    if (name == "Normalize Visible Area") return ToggleProperty;
    if (name == "Channels") return ValueProperty;
    if (name == "Scale") return ValueProperty;
    return SingleColourLayer::getPropertyType(name);
}

QString
WaveformLayer::getPropertyGroupName(const PropertyName &name) const
{
    if (name == "Gain" ||
        name == "Normalize Visible Area" ||
	name == "Scale") return tr("Scale");
    return QString();
}

int
WaveformLayer::getPropertyRangeAndValue(const PropertyName &name,
                                        int *min, int *max, int *deflt) const
{
    int val = 0;

    int garbage0, garbage1, garbage2;
    if (!min) min = &garbage0;
    if (!max) max = &garbage1;
    if (!deflt) deflt = &garbage2;

    if (name == "Gain") {

	*min = -50;
	*max = 50;
        *deflt = 0;

	val = lrint(log10(m_gain) * 20.0);
	if (val < *min) val = *min;
	if (val > *max) val = *max;

    } else if (name == "Normalize Visible Area") {

        val = (m_autoNormalize ? 1 : 0);
        *deflt = 0;

    } else if (name == "Channels") {

        *min = 0;
        *max = 2;
        *deflt = 0;
        if (m_channelMode == MixChannels) val = 1;
        else if (m_channelMode == MergeChannels) val = 2;
        else val = 0;

    } else if (name == "Scale") {

	*min = 0;
	*max = 2;
        *deflt = 0;

	val = (int)m_scale;

    } else {
	val = SingleColourLayer::getPropertyRangeAndValue(name, min, max, deflt);
    }

    return val;
}

QString
WaveformLayer::getPropertyValueLabel(const PropertyName &name,
				    int value) const
{
    if (name == "Scale") {
	switch (value) {
	default:
	case 0: return tr("Linear");
	case 1: return tr("Meter");
	case 2: return tr("dB");
	}
    }
    if (name == "Channels") {
        switch (value) {
        default:
        case 0: return tr("Separate");
        case 1: return tr("Mean");
        case 2: return tr("Butterfly");
        }
    }
    return SingleColourLayer::getPropertyValueLabel(name, value);
}

RangeMapper *
WaveformLayer::getNewPropertyRangeMapper(const PropertyName &name) const
{
    if (name == "Gain") {
        return new LinearRangeMapper(-50, 50, -25, 25, tr("dB"));
    }
    return 0;
}

void
WaveformLayer::setProperty(const PropertyName &name, int value)
{
    if (name == "Gain") {
	setGain(pow(10, float(value)/20.0));
    } else if (name == "Normalize Visible Area") {
        setAutoNormalize(value ? true : false);
    } else if (name == "Channels") {
        if (value == 1) setChannelMode(MixChannels);
        else if (value == 2) setChannelMode(MergeChannels);
        else setChannelMode(SeparateChannels);
    } else if (name == "Scale") {
	switch (value) {
	default:
	case 0: setScale(LinearScale); break;
	case 1: setScale(MeterScale); break;
	case 2: setScale(dBScale); break;
	}
    } else {
        SingleColourLayer::setProperty(name, value);
    }
}

void
WaveformLayer::setGain(float gain)
{
    if (m_gain == gain) return;
    m_gain = gain;
    m_cacheValid = false;
    emit layerParametersChanged();
    emit verticalZoomChanged();
}

void
WaveformLayer::setAutoNormalize(bool autoNormalize)
{
    if (m_autoNormalize == autoNormalize) return;
    m_autoNormalize = autoNormalize;
    m_cacheValid = false;
    emit layerParametersChanged();
}

void
WaveformLayer::setShowMeans(bool showMeans)
{
    if (m_showMeans == showMeans) return;
    m_showMeans = showMeans;
    m_cacheValid = false;
    emit layerParametersChanged();
}

void
WaveformLayer::setUseGreyscale(bool useGreyscale)
{
    if (m_greyscale == useGreyscale) return;
    m_greyscale = useGreyscale;
    m_cacheValid = false;
    emit layerParametersChanged();
}

void
WaveformLayer::setChannelMode(ChannelMode channelMode)
{
    if (m_channelMode == channelMode) return;
    m_channelMode = channelMode;
    m_cacheValid = false;
    emit layerParametersChanged();
}

void
WaveformLayer::setChannel(int channel)
{
//    std::cerr << "WaveformLayer::setChannel(" << channel << ")" << std::endl;

    if (m_channel == channel) return;
    m_channel = channel;
    m_cacheValid = false;
    emit layerParametersChanged();
}

void
WaveformLayer::setScale(Scale scale)
{
    if (m_scale == scale) return;
    m_scale = scale;
    m_cacheValid = false;
    emit layerParametersChanged();
}

void
WaveformLayer::setAggressiveCacheing(bool aggressive)
{
    if (m_aggressive == aggressive) return;
    m_aggressive = aggressive;
    m_cacheValid = false;
    emit layerParametersChanged();
}

int
WaveformLayer::getCompletion(View *) const
{
    int completion = 100;
    if (!m_model || !m_model->isOK()) return completion;
    if (m_model->isReady(&completion)) return 100;
    return completion;
}

bool
WaveformLayer::getValueExtents(float &min, float &max,
                               bool &, QString &unit) const
{
    if (m_scale == LinearScale) {
        min = 0.0;
        max = 1.0;
        unit = "V";
    } else if (m_scale == MeterScale) {
        return false; //!!!
    } else {
        min = AudioLevel::multiplier_to_dB(0.0);
        max = AudioLevel::multiplier_to_dB(1.0);
        unit = "dB";
    }
    return true;
}

int
WaveformLayer::dBscale(float sample, int m) const
{
    if (sample < 0.0) return dBscale(-sample, m);
    float dB = AudioLevel::multiplier_to_dB(sample);
    if (dB < -50.0) return 0;
    if (dB > 0.0) return m;
    return int(((dB + 50.0) * m) / 50.0 + 0.1);
}

size_t
WaveformLayer::getChannelArrangement(size_t &min, size_t &max,
                                     bool &merging, bool &mixing)
    const
{
    if (!m_model || !m_model->isOK()) return 0;

    size_t channels = m_model->getChannelCount();
    if (channels == 0) return 0;

    size_t rawChannels = channels;

    if (m_channel == -1) {
	min = 0;
	if (m_channelMode == MergeChannels ||
            m_channelMode == MixChannels) {
	    max = 0;
	    channels = 1;
	} else {
	    max = channels - 1;
	}
    } else {
	min = m_channel;
	max = m_channel;
	rawChannels = 1;
	channels = 1;
    }

    merging = (m_channelMode == MergeChannels && rawChannels > 1);
    mixing = (m_channelMode == MixChannels && rawChannels > 1);

//    std::cerr << "WaveformLayer::getChannelArrangement: min " << min << ", max " << max << ", merging " << merging << ", channels " << channels << std::endl;

    return channels;
}    

bool
WaveformLayer::isLayerScrollable(const View *) const
{
    return !m_autoNormalize;
}

static float meterdbs[] = { -40, -30, -20, -15, -10,
                            -5, -3, -2, -1, -0.5, 0 };

void
WaveformLayer::paint(View *v, QPainter &viewPainter, QRect rect) const
{
    if (!m_model || !m_model->isOK()) {
	return;
    }
  
    long startFrame = v->getStartFrame();
    int zoomLevel = v->getZoomLevel();

#ifdef DEBUG_WAVEFORM_PAINT
    Profiler profiler("WaveformLayer::paint", true);
    std::cerr << "WaveformLayer::paint (" << rect.x() << "," << rect.y()
	      << ") [" << rect.width() << "x" << rect.height() << "]: zoom " << zoomLevel << ", start " << startFrame << std::endl;
#endif

    size_t channels = 0, minChannel = 0, maxChannel = 0;
    bool mergingChannels = false, mixingChannels = false;

    channels = getChannelArrangement(minChannel, maxChannel,
                                     mergingChannels, mixingChannels);
    if (channels == 0) return;

    int w = v->width();
    int h = v->height();

    bool ready = m_model->isReady();
    QPainter *paint;

    if (m_aggressive) {

#ifdef DEBUG_WAVEFORM_PAINT
        std::cerr << "WaveformLayer::paint: aggressive is true" << std::endl;
#endif

	if (m_cacheValid && (zoomLevel != m_cacheZoomLevel)) {
	    m_cacheValid = false;
	}

	if (!m_cache || m_cache->width() != w || m_cache->height() != h) {
#ifdef DEBUG_WAVEFORM_PAINT
            if (m_cache) {
                std::cerr << "WaveformLayer::paint: cache size " << m_cache->width() << "x" << m_cache->height() << " differs from view size " << w << "x" << h << ": regenerating aggressive cache" << std::endl;
            }
#endif
	    delete m_cache;
	    m_cache = new QPixmap(w, h);
            m_cacheValid = false;
	}

	if (m_cacheValid) {
	    viewPainter.drawPixmap(rect, *m_cache, rect);
	    return;
	}

	paint = new QPainter(m_cache);

	paint->setPen(Qt::NoPen);
	paint->setBrush(getBackgroundQColor(v));
	paint->drawRect(rect);

	paint->setPen(getForegroundQColor(v));
	paint->setBrush(Qt::NoBrush);

    } else {
	paint = &viewPainter;
    }

    paint->setRenderHint(QPainter::Antialiasing, false);

    int x0 = 0, x1 = w - 1;
    int y0 = 0, y1 = h - 1;

    x0 = rect.left();
    x1 = rect.right();
    y0 = rect.top();
    y1 = rect.bottom();

    if (x0 > 0) --x0;
    if (x1 < v->width()) ++x1;

    long frame0 = v->getFrameForX(x0);
    long frame1 = v->getFrameForX(x1 + 1);
     
#ifdef DEBUG_WAVEFORM_PAINT
    std::cerr << "Painting waveform from " << frame0 << " to " << frame1 << " (" << (x1-x0+1) << " pixels at zoom " << zoomLevel << ")" <<  std::endl;
#endif

    RangeSummarisableTimeValueModel::RangeBlock *ranges = 
        new RangeSummarisableTimeValueModel::RangeBlock;

    RangeSummarisableTimeValueModel::RangeBlock *otherChannelRanges = 0;
    RangeSummarisableTimeValueModel::Range range;

    QColor baseColour = getBaseQColor();
    std::vector<QColor> greys = getPartialShades(v);
        
    QColor midColour = baseColour;
    if (midColour == Qt::black) {
	midColour = Qt::gray;
    } else if (v->hasLightBackground()) {
	midColour = midColour.light(150);
    } else {
	midColour = midColour.light(50);
    }

    while (m_effectiveGains.size() <= maxChannel) {
        m_effectiveGains.push_back(m_gain);
    }

    for (size_t ch = minChannel; ch <= maxChannel; ++ch) {

	int prevRangeBottom = -1, prevRangeTop = -1;
	QColor prevRangeBottomColour = baseColour, prevRangeTopColour = baseColour;

        m_effectiveGains[ch] = m_gain;

        if (m_autoNormalize) {
            RangeSummarisableTimeValueModel::Range range =
                m_model->getRange(ch, startFrame < 0 ? 0 : startFrame,
                                  v->getEndFrame());
            if (mergingChannels || mixingChannels) {
                RangeSummarisableTimeValueModel::Range otherRange =
                    m_model->getRange(1, startFrame < 0 ? 0 : startFrame,
                                      v->getEndFrame());
                range.max = std::max(range.max, otherRange.max);
                range.min = std::min(range.min, otherRange.min);
                range.absmean = std::min(range.absmean, otherRange.absmean);
            }
            m_effectiveGains[ch] = 1.0 / std::max(fabsf(range.max),
                                                  fabsf(range.min));
        }

        float gain = m_effectiveGains[ch];

	int m = (h / channels) / 2;
	int my = m + (((ch - minChannel) * h) / channels);
	
//	std::cerr << "ch = " << ch << ", channels = " << channels << ", m = " << m << ", my = " << my << ", h = " << h << std::endl;

	if (my - m > y1 || my + m < y0) continue;

        if ((m_scale == dBScale || m_scale == MeterScale) &&
            m_channelMode != MergeChannels) {
            m = (h / channels);
            my = m + (((ch - minChannel) * h) / channels);
        }

	paint->setPen(greys[0]);
	paint->drawLine(x0, my, x1, my);

        int n = 10;
        int py = -1;
        
        if (v->hasLightBackground() &&
            v->getViewManager() &&
            v->getViewManager()->shouldShowScaleGuides()) {

            paint->setPen(QColor(240, 240, 240));

            for (int i = 1; i < n; ++i) {
                
                float val = 0.0, nval = 0.0;

                switch (m_scale) {

                case LinearScale:
                    val = (i * gain) / n;
                    if (i > 0) nval = -val;
                    break;

                case MeterScale:
                    val = AudioLevel::dB_to_multiplier(meterdbs[i]) * gain;
                    break;

                case dBScale:
                    val = AudioLevel::dB_to_multiplier(-(10*n) + i * 10) * gain;
                    break;
                }

                if (val < -1.0 || val > 1.0) continue;

                int y = getYForValue(v, val, ch);

                if (py >= 0 && abs(y - py) < 10) continue;
                else py = y;

                int ny = y;
                if (nval != 0.0) {
                    ny = getYForValue(v, nval, ch);
                }

                paint->drawLine(x0, y, x1, y);
                if (ny != y) {
                    paint->drawLine(x0, ny, x1, ny);
                }
            }
        }

	if (frame1 <= 0) continue;

	size_t modelZoomLevel = zoomLevel;

	m_model->getRanges
	    (ch, frame0 < 0 ? 0 : frame0, frame1, *ranges, modelZoomLevel);
        
	if (mergingChannels || mixingChannels) {
            if (m_model->getChannelCount() > 1) {
                if (!otherChannelRanges) {
                    otherChannelRanges =
                        new RangeSummarisableTimeValueModel::RangeBlock;
                }
                m_model->getRanges
                    (1, frame0 < 0 ? 0 : frame0, frame1, *otherChannelRanges,
                     modelZoomLevel);
            } else {
                if (otherChannelRanges != ranges) delete otherChannelRanges;
                otherChannelRanges = ranges;
            }
	}

	for (int x = x0; x <= x1; ++x) {

	    range = RangeSummarisableTimeValueModel::Range();
	    size_t index = x - x0;
	    size_t maxIndex = index;

	    if (frame0 < 0) {
		if (index < size_t(-frame0 / zoomLevel)) {
		    continue;
		} else {
		    index -= -frame0 / zoomLevel;
		    maxIndex = index;
		}
	    }
            
	    if (int(modelZoomLevel) != zoomLevel) {

		index = size_t((double(index) * zoomLevel) / modelZoomLevel);

		if (int(modelZoomLevel) < zoomLevel) {
		    // Peaks may be missed!  The model should avoid
		    // this by rounding zoom levels up rather than
		    // down, but we'd better cope in case it doesn't
		    maxIndex = index;
		} else {
		    maxIndex = size_t((double(index + 1) * zoomLevel)
				      / modelZoomLevel) - 1;
		}
	    }

	    if (ranges && index < ranges->size()) {

		range = (*ranges)[index];

		if (maxIndex > index && maxIndex < ranges->size()) {
		    range.max = std::max(range.max, (*ranges)[maxIndex].max);
		    range.min = std::min(range.min, (*ranges)[maxIndex].min);
		    range.absmean = (range.absmean +
				     (*ranges)[maxIndex].absmean) / 2;
		}

	    } else {
		continue;
	    }

	    int rangeBottom = 0, rangeTop = 0, meanBottom = 0, meanTop = 0;

	    if (mergingChannels) {

		if (otherChannelRanges && index < otherChannelRanges->size()) {

		    range.max = fabsf(range.max);
		    range.min = -fabsf((*otherChannelRanges)[index].max);
		    range.absmean = (range.absmean +
				     (*otherChannelRanges)[index].absmean) / 2;

		    if (maxIndex > index && maxIndex < otherChannelRanges->size()) {
			// let's not concern ourselves about the mean
			range.min = std::min
			    (range.min,
			     -fabsf((*otherChannelRanges)[maxIndex].max));
		    }
		}

	    } else if (mixingChannels) {

		if (otherChannelRanges && index < otherChannelRanges->size()) {

                    range.max = (range.max + (*otherChannelRanges)[index].max) / 2;
                    range.min = (range.min + (*otherChannelRanges)[index].min) / 2;
                    range.absmean = (range.absmean + (*otherChannelRanges)[index].absmean) / 2;
                }
            }

	    int greyLevels = 1;
	    if (m_greyscale && (m_scale == LinearScale)) greyLevels = 4;

	    switch (m_scale) {

	    case LinearScale:
		rangeBottom = int( m * greyLevels * range.min * gain);
		rangeTop    = int( m * greyLevels * range.max * gain);
		meanBottom  = int(-m * range.absmean * gain);
		meanTop     = int( m * range.absmean * gain);
		break;

	    case dBScale:
                if (!mergingChannels) {
                    int db0 = dBscale(range.min * gain, m);
                    int db1 = dBscale(range.max * gain, m);
                    rangeTop    = std::max(db0, db1);
                    meanTop     = std::min(db0, db1);
                    if (mixingChannels) rangeBottom = meanTop;
                    else rangeBottom = dBscale(range.absmean * gain, m);
                    meanBottom  = rangeBottom;
                } else {
                    rangeBottom = -dBscale(range.min * gain, m * greyLevels);
                    rangeTop    =  dBscale(range.max * gain, m * greyLevels);
                    meanBottom  = -dBscale(range.absmean * gain, m);
                    meanTop     =  dBscale(range.absmean * gain, m);
                }
		break;

	    case MeterScale:
                if (!mergingChannels) {
                    int r0 = abs(AudioLevel::multiplier_to_preview(range.min * gain, m));
                    int r1 = abs(AudioLevel::multiplier_to_preview(range.max * gain, m));
                    rangeTop    = std::max(r0, r1);
                    meanTop     = std::min(r0, r1);
                    if (mixingChannels) rangeBottom = meanTop;
                    else rangeBottom = AudioLevel::multiplier_to_preview(range.absmean * gain, m);
                    meanBottom  = rangeBottom;
                } else {
                    rangeBottom =  AudioLevel::multiplier_to_preview(range.min * gain, m * greyLevels);
                    rangeTop    =  AudioLevel::multiplier_to_preview(range.max * gain, m * greyLevels);
                    meanBottom  = -AudioLevel::multiplier_to_preview(range.absmean * gain, m);
                    meanTop     =  AudioLevel::multiplier_to_preview(range.absmean * gain, m);
                }
                break;
	    }

	    rangeBottom = my * greyLevels - rangeBottom;
	    rangeTop    = my * greyLevels - rangeTop;
	    meanBottom  = my - meanBottom;
	    meanTop     = my - meanTop;

	    int topFill = (rangeTop % greyLevels);
	    if (topFill > 0) topFill = greyLevels - topFill;

	    int bottomFill = (rangeBottom % greyLevels);

	    rangeTop = rangeTop / greyLevels;
	    rangeBottom = rangeBottom / greyLevels;

	    bool clipped = false;

	    if (rangeTop < my - m) { rangeTop = my - m; }
	    if (rangeTop > my + m) { rangeTop = my + m; }
	    if (rangeBottom < my - m) { rangeBottom = my - m; }
	    if (rangeBottom > my + m) { rangeBottom = my + m; }

	    if (range.max <= -1.0 ||
		range.max >= 1.0) clipped = true;
	    
	    if (meanBottom > rangeBottom) meanBottom = rangeBottom;
	    if (meanTop < rangeTop) meanTop = rangeTop;

	    bool drawMean = m_showMeans;
	    if (meanTop == rangeTop) {
		if (meanTop < meanBottom) ++meanTop;
		else drawMean = false;
	    }
	    if (meanBottom == rangeBottom && m_scale == LinearScale) {
		if (meanBottom > meanTop) --meanBottom;
		else drawMean = false;
	    }

	    if (x != x0 && prevRangeBottom != -1) {
		if (prevRangeBottom > rangeBottom &&
		    prevRangeTop    > rangeBottom) {
//		    paint->setPen(midColour);
		    paint->setPen(baseColour);
		    paint->drawLine(x-1, prevRangeTop, x, rangeBottom);
		    paint->setPen(prevRangeTopColour);
		    paint->drawPoint(x-1, prevRangeTop);
		} else if (prevRangeBottom < rangeTop &&
			   prevRangeTop    < rangeTop) {
//		    paint->setPen(midColour);
		    paint->setPen(baseColour);
		    paint->drawLine(x-1, prevRangeBottom, x, rangeTop);
		    paint->setPen(prevRangeBottomColour);
		    paint->drawPoint(x-1, prevRangeBottom);
		}
	    }

	    if (ready) {
		if (clipped /*!!! ||
		    range.min * gain <= -1.0 ||
		    range.max * gain >=  1.0 */) {
		    paint->setPen(Qt::red); //!!! getContrastingColour
		} else {
		    paint->setPen(baseColour);
		}
	    } else {
		paint->setPen(midColour);
	    }

	    paint->drawLine(x, rangeBottom, x, rangeTop);

	    prevRangeTopColour = baseColour;
	    prevRangeBottomColour = baseColour;

	    if (m_greyscale && (m_scale == LinearScale) && ready) {
		if (!clipped) {
		    if (rangeTop < rangeBottom) {
			if (topFill > 0 &&
			    (!drawMean || (rangeTop < meanTop - 1))) {
			    paint->setPen(greys[topFill - 1]);
			    paint->drawPoint(x, rangeTop);
			    prevRangeTopColour = greys[topFill - 1];
			}
			if (bottomFill > 0 && 
			    (!drawMean || (rangeBottom > meanBottom + 1))) {
			    paint->setPen(greys[bottomFill - 1]);
			    paint->drawPoint(x, rangeBottom);
			    prevRangeBottomColour = greys[bottomFill - 1];
			}
		    }
		}
	    }
        
	    if (drawMean) {
		paint->setPen(midColour);
		paint->drawLine(x, meanBottom, x, meanTop);
	    }
        
	    prevRangeBottom = rangeBottom;
	    prevRangeTop = rangeTop;
	}
    }

    if (m_aggressive) {

	if (ready && rect == v->rect()) {
	    m_cacheValid = true;
	    m_cacheZoomLevel = zoomLevel;
	}
	paint->end();
	delete paint;
	viewPainter.drawPixmap(rect, *m_cache, rect);
    }

    if (otherChannelRanges != ranges) delete otherChannelRanges;
    delete ranges;
}

QString
WaveformLayer::getFeatureDescription(View *v, QPoint &pos) const
{
    int x = pos.x();

    if (!m_model || !m_model->isOK()) return "";

    long f0 = v->getFrameForX(x);
    long f1 = v->getFrameForX(x + 1);

    if (f0 < 0) f0 = 0;
    if (f1 <= f0) return "";
    
    QString text;

    RealTime rt0 = RealTime::frame2RealTime(f0, m_model->getSampleRate());
    RealTime rt1 = RealTime::frame2RealTime(f1, m_model->getSampleRate());

    if (f1 != f0 + 1 && (rt0.sec != rt1.sec || rt0.msec() != rt1.msec())) {
	text += tr("Time:\t%1 - %2")
	    .arg(rt0.toText(true).c_str())
	    .arg(rt1.toText(true).c_str());
    } else {
	text += tr("Time:\t%1")
	    .arg(rt0.toText(true).c_str());
    }

    size_t channels = 0, minChannel = 0, maxChannel = 0;
    bool mergingChannels = false, mixingChannels = false;

    channels = getChannelArrangement(minChannel, maxChannel,
                                     mergingChannels, mixingChannels);
    if (channels == 0) return "";

    for (size_t ch = minChannel; ch <= maxChannel; ++ch) {

	size_t blockSize = v->getZoomLevel();
	RangeSummarisableTimeValueModel::RangeBlock ranges;
        m_model->getRanges(ch, f0, f1, ranges, blockSize);

	if (ranges.empty()) continue;
	
	RangeSummarisableTimeValueModel::Range range = ranges[0];
	
	QString label = tr("Level:");
	if (minChannel != maxChannel) {
	    if (ch == 0) label = tr("Left:");
	    else if (ch == 1) label = tr("Right:");
	    else label = tr("Channel %1").arg(ch + 1);
	}

        bool singleValue = false;
        float min, max;

        if (fabs(range.min) < 0.01) {
            min = range.min;
            max = range.max;
            singleValue = (min == max);
        } else {
            int imin = int(range.min * 1000);
            int imax = int(range.max * 1000);
            singleValue = (imin == imax);
            min = float(imin)/1000;
            max = float(imax)/1000;
        }

	int db = int(AudioLevel::multiplier_to_dB(std::max(fabsf(range.min),
							   fabsf(range.max)))
		     * 100);

	if (!singleValue) {
	    text += tr("\n%1\t%2 - %3 (%4 dB peak)")
		.arg(label).arg(min).arg(max).arg(float(db)/100);
	} else {
	    text += tr("\n%1\t%2 (%3 dB peak)")
		.arg(label).arg(min).arg(float(db)/100);
	}
    }

    return text;
}

int
WaveformLayer::getYForValue(const View *v, float value, size_t channel) const
{
    size_t channels = 0, minChannel = 0, maxChannel = 0;
    bool mergingChannels = false, mixingChannels = false;

    channels = getChannelArrangement(minChannel, maxChannel,
                                     mergingChannels, mixingChannels);

    if (maxChannel < minChannel || channel < minChannel) return 0;

    int h = v->height();
    int m = (h / channels) / 2;
	
    if ((m_scale == dBScale || m_scale == MeterScale) &&
        m_channelMode != MergeChannels) {
        m = (h / channels);
    }

    int my = m + (((channel - minChannel) * h) / channels);

    int vy = 0;

    switch (m_scale) {

    case LinearScale:
        vy = int(m * value);
        break;

    case MeterScale:
        vy = AudioLevel::multiplier_to_preview(value, m);
        break;

    case dBScale:
        vy = dBscale(value, m);
        break;
    }

    return my - vy;
}

float
WaveformLayer::getValueForY(const View *v, int y, size_t &channel) const
{
    size_t channels = 0, minChannel = 0, maxChannel = 0;
    bool mergingChannels = false, mixingChannels = false;

    channels = getChannelArrangement(minChannel, maxChannel,
                                     mergingChannels, mixingChannels);

    if (maxChannel < minChannel) return 0;

    int h = v->height();
    int m = (h / channels) / 2;

    if ((m_scale == dBScale || m_scale == MeterScale) &&
        m_channelMode != MergeChannels) {
        m = (h / channels);
    }
  
    channel = (y * channels) / h + minChannel;

    int my = m + (((channel - minChannel) * h) / channels);

    int vy = my - y;
    float value = 0;
    float thresh = -50.f;

    switch (m_scale) {

    case LinearScale:
        value = float(vy) / m;
        break;

    case MeterScale:
        value = AudioLevel::preview_to_multiplier(vy, m);
        break;

    case dBScale:
        value = (-thresh * float(vy)) / m + thresh;
        value = AudioLevel::dB_to_multiplier(value);
        break;
    }

    return value / m_gain;
}

bool
WaveformLayer::getYScaleValue(const View *v, int y,
                              float &value, QString &unit) const
{
    size_t channel;

    value = getValueForY(v, y, channel);

    if (m_scale == dBScale || m_scale == MeterScale) {

        float thresh = -50.f;
        
        if (value > 0.f) {
            value = 10.f * log10f(value);
            if (value < thresh) value = thresh;
        } else value = thresh;

        unit = "dBV";

    } else {
        unit = "V";
    }

    return true;
}

bool
WaveformLayer::getYScaleDifference(const View *v, int y0, int y1,
                                   float &diff, QString &unit) const
{
    size_t c0, c1;
    float v0 = getValueForY(v, y0, c0);
    float v1 = getValueForY(v, y1, c1);

    if (c0 != c1) {
        // different channels, not comparable
        diff = 0.f;
        unit = "";
        return false;
    }

    if (m_scale == dBScale || m_scale == MeterScale) {

        float thresh = -50.f;

        if (v1 == v0) diff = thresh;
        else {
            if (v1 > v0) diff = v0 / v1;
            else diff = v1 / v0;

            diff = 10.f * log10f(diff);
            if (diff < thresh) diff = thresh;
        }

        unit = "dBV";

    } else {
        diff = fabsf(v1 - v0);
        unit = "V";
    }

    return true;
}

int
WaveformLayer::getVerticalScaleWidth(View *, QPainter &paint) const
{
    if (m_scale == LinearScale) {
	return paint.fontMetrics().width("0.0") + 13;
    } else {
	return std::max(paint.fontMetrics().width(tr("0dB")),
			paint.fontMetrics().width(tr("-Inf"))) + 13;
    }
}

void
WaveformLayer::paintVerticalScale(View *v, QPainter &paint, QRect rect) const
{
    if (!m_model || !m_model->isOK()) {
	return;
    }

    size_t channels = 0, minChannel = 0, maxChannel = 0;
    bool mergingChannels = false, mixingChannels = false;

    channels = getChannelArrangement(minChannel, maxChannel,
                                     mergingChannels, mixingChannels);
    if (channels == 0) return;

    int h = rect.height(), w = rect.width();
    int textHeight = paint.fontMetrics().height();
    int toff = -textHeight/2 + paint.fontMetrics().ascent() + 1;

    float gain = m_gain;

    for (size_t ch = minChannel; ch <= maxChannel; ++ch) {

	int lastLabelledY = -1;

        if (ch < m_effectiveGains.size()) gain = m_effectiveGains[ch];

        int n = 10;

	for (int i = 0; i <= n; ++i) {

            float val = 0.0, nval = 0.0;
	    QString text = "";

            switch (m_scale) {
                
            case LinearScale:
                val = (i * gain) / n;
		text = QString("%1").arg(float(i) / n);
		if (i == 0) text = "0.0";
                else {
                    nval = -val;
                    if (i == n) text = "1.0";
                }
                break;

            case MeterScale:
                val = AudioLevel::dB_to_multiplier(meterdbs[i]) * gain;
		text = QString("%1").arg(meterdbs[i]);
		if (i == n) text = tr("0dB");
		if (i == 0) {
                    text = tr("-Inf");
                    val = 0.0;
		}
                break;

            case dBScale:
                val = AudioLevel::dB_to_multiplier(-(10*n) + i * 10) * gain;
		text = QString("%1").arg(-(10*n) + i * 10);
		if (i == n) text = tr("0dB");
		if (i == 0) {
                    text = tr("-Inf");
                    val = 0.0;
		}
                break;
            }

            if (val < -1.0 || val > 1.0) continue;

            int y = getYForValue(v, val, ch);

            int ny = y;
            if (nval != 0.0) {
                ny = getYForValue(v, nval, ch);
            }

            bool spaceForLabel = (i == 0 ||
                                  abs(y - lastLabelledY) >= textHeight - 1);

            if (spaceForLabel) {

                int tx = 3;
                if (m_scale != LinearScale) {
                    tx = w - 10 - paint.fontMetrics().width(text);
                }
                  
                int ty = y;
                if (ty < paint.fontMetrics().ascent()) {
                    ty = paint.fontMetrics().ascent();
                } else if (ty > h - paint.fontMetrics().descent()) {
                    ty = h - paint.fontMetrics().descent();
                } else {
                    ty += toff;
                }
                paint.drawText(tx, ty, text);

                lastLabelledY = ty - toff;

                if (ny != y) {
                    ty = ny;
                    if (ty < paint.fontMetrics().ascent()) {
                        ty = paint.fontMetrics().ascent();
                    } else if (ty > h - paint.fontMetrics().descent()) {
                        ty = h - paint.fontMetrics().descent();
                    } else {
                        ty += toff;
                    }
                    paint.drawText(tx, ty, text);
                }

                paint.drawLine(w - 7, y, w, y);
                if (ny != y) paint.drawLine(w - 7, ny, w, ny);

            } else {

                paint.drawLine(w - 4, y, w, y);
                if (ny != y) paint.drawLine(w - 4, ny, w, ny);
            }
	}
    }
}

QString
WaveformLayer::toXmlString(QString indent, QString extraAttributes) const
{
    QString s;
    
    QString colourName, colourSpec, darkbg;
    ColourDatabase::getInstance()->getStringValues
        (m_colour, colourName, colourSpec, darkbg);

    s += QString("gain=\"%1\" "
		 "showMeans=\"%2\" "
		 "greyscale=\"%3\" "
		 "channelMode=\"%4\" "
		 "channel=\"%5\" "
                 "scale=\"%6\" "
		 "aggressive=\"%7\" "
                 "autoNormalize=\"%8\"")
	.arg(m_gain)
	.arg(m_showMeans)
	.arg(m_greyscale)
	.arg(m_channelMode)
	.arg(m_channel)
	.arg(m_scale)
	.arg(m_aggressive)
        .arg(m_autoNormalize);

    return SingleColourLayer::toXmlString(indent, extraAttributes + " " + s);
}

void
WaveformLayer::setProperties(const QXmlAttributes &attributes)
{
    bool ok = false;

    SingleColourLayer::setProperties(attributes);

    float gain = attributes.value("gain").toFloat(&ok);
    if (ok) setGain(gain);

    bool showMeans = (attributes.value("showMeans") == "1" ||
		      attributes.value("showMeans") == "true");
    setShowMeans(showMeans);

    bool greyscale = (attributes.value("greyscale") == "1" ||
		      attributes.value("greyscale") == "true");
    setUseGreyscale(greyscale);

    ChannelMode channelMode = (ChannelMode)
	attributes.value("channelMode").toInt(&ok);
    if (ok) setChannelMode(channelMode);

    int channel = attributes.value("channel").toInt(&ok);
    if (ok) setChannel(channel);

    Scale scale = (Scale)
	attributes.value("scale").toInt(&ok);
    if (ok) setScale(scale);

    bool aggressive = (attributes.value("aggressive") == "1" ||
		       attributes.value("aggressive") == "true");
    setUseGreyscale(aggressive);

    bool autoNormalize = (attributes.value("autoNormalize") == "1" ||
                          attributes.value("autoNormalize") == "true");
    setAutoNormalize(autoNormalize);
}

int
WaveformLayer::getVerticalZoomSteps(int &defaultStep) const
{
    defaultStep = 50;
    return 100;
}

int
WaveformLayer::getCurrentVerticalZoomStep() const
{
    int val = lrint(log10(m_gain) * 20.0) + 50;
    if (val < 0) val = 0;
    if (val > 100) val = 100;
    return val;
}

void
WaveformLayer::setVerticalZoomStep(int step)
{
    setGain(pow(10, float(step - 50) / 20.0));
}