annotate view/View.cpp @ 1534:bfd8b22fd67c

Fix #1904 Scrolling colour 3d plot does not always work when in View normalisation mode. We shouldn't imagine we've just invalidated the cache if the truth is that we've only just created the renderer

/* -*- 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.
*/

#include "View.h"
#include "layer/Layer.h"
#include "data/model/Model.h"
#include "base/ZoomConstraint.h"
#include "base/Profiler.h"
#include "base/Pitch.h"
#include "base/Preferences.h"
#include "base/HitCount.h"
#include "ViewProxy.h"

#include "layer/TimeRulerLayer.h"
#include "layer/SingleColourLayer.h"
#include "layer/PaintAssistant.h"

#include "data/model/RelativelyFineZoomConstraint.h"
#include "data/model/RangeSummarisableTimeValueModel.h"

#include "widgets/IconLoader.h"

#include <QPainter>
#include <QPaintEvent>
#include <QRect>
#include <QApplication>
#include <QProgressDialog>
#include <QTextStream>
#include <QFont>
#include <QMessageBox>
#include <QPushButton>
#include <QSettings>
#include <QSvgGenerator>

#include <iostream>
#include <cassert>
#include <cmath>

//#define DEBUG_VIEW 1
//#define DEBUG_VIEW_WIDGET_PAINT 1
//#define DEBUG_PROGRESS_STUFF 1

View::View(QWidget *w, bool showProgress) :
    QFrame(w),
    m_id(getNextId()),
    m_centreFrame(0),
    m_zoomLevel(ZoomLevel::FramesPerPixel, 1024),
    m_followPan(true),
    m_followZoom(true),
    m_followPlay(PlaybackScrollPageWithCentre),
    m_followPlayIsDetached(false),
    m_playPointerFrame(0),
    m_showProgress(showProgress),
    m_cache(nullptr),
    m_buffer(nullptr),
    m_cacheValid(false),
    m_cacheCentreFrame(0),
    m_cacheZoomLevel(ZoomLevel::FramesPerPixel, 1024),
    m_selectionCached(false),
    m_deleting(false),
    m_haveSelectedLayer(false),
    m_useAligningProxy(false),
    m_alignmentProgressBar({ {}, nullptr }),
    m_manager(nullptr),
    m_propertyContainer(new ViewPropertyContainer(this))
{
//    SVCERR << "View::View[" << getId() << "]" << endl;
}

View::~View()
{
//    SVCERR << "View::~View[" << getId() << "]" << endl;

    m_deleting = true;
    delete m_propertyContainer;
    delete m_cache;
    delete m_buffer;
}

PropertyContainer::PropertyList
View::getProperties() const
{
    PropertyContainer::PropertyList list;
    list.push_back("Global Scroll");
    list.push_back("Global Zoom");
    list.push_back("Follow Playback");
    return list;
}

QString
View::getPropertyLabel(const PropertyName &pn) const
{
    if (pn == "Global Scroll") return tr("Global Scroll");
    if (pn == "Global Zoom") return tr("Global Zoom");
    if (pn == "Follow Playback") return tr("Follow Playback");
    return "";
}

PropertyContainer::PropertyType
View::getPropertyType(const PropertyContainer::PropertyName &name) const
{
    if (name == "Global Scroll") return PropertyContainer::ToggleProperty;
    if (name == "Global Zoom") return PropertyContainer::ToggleProperty;
    if (name == "Follow Playback") return PropertyContainer::ValueProperty;
    return PropertyContainer::InvalidProperty;
}

int
View::getPropertyRangeAndValue(const PropertyContainer::PropertyName &name,
                               int *min, int *max, int *deflt) const
{
    if (deflt) *deflt = 1;
    if (name == "Global Scroll") return m_followPan;
    if (name == "Global Zoom") return m_followZoom;
    if (name == "Follow Playback") {
        if (min) *min = 0;
        if (max) *max = 2;
        if (deflt) *deflt = int(PlaybackScrollPageWithCentre);
        switch (m_followPlay) {
        case PlaybackScrollContinuous: return 0;
        case PlaybackScrollPageWithCentre: case PlaybackScrollPage: return 1;
        case PlaybackIgnore: return 2;
        }
    }
    if (min) *min = 0;
    if (max) *max = 0;
    if (deflt) *deflt = 0;
    return 0;
}

QString
View::getPropertyValueLabel(const PropertyContainer::PropertyName &name,
                            int value) const
{
    if (name == "Follow Playback") {
        switch (value) {
        default:
        case 0: return tr("Scroll");
        case 1: return tr("Page");
        case 2: return tr("Off");
        }
    }
    return tr("<unknown>");
}

void
View::setProperty(const PropertyContainer::PropertyName &name, int value)
{
    if (name == "Global Scroll") {
        setFollowGlobalPan(value != 0);
    } else if (name == "Global Zoom") {
        setFollowGlobalZoom(value != 0);
    } else if (name == "Follow Playback") {
        switch (value) {
        default:
        case 0: setPlaybackFollow(PlaybackScrollContinuous); break;
        case 1: setPlaybackFollow(PlaybackScrollPageWithCentre); break;
        case 2: setPlaybackFollow(PlaybackIgnore); break;
        }
    }
}

int
View::getPropertyContainerCount() const
{
    return int(m_fixedOrderLayers.size()) + 1; // the 1 is for me
}

const PropertyContainer *
View::getPropertyContainer(int i) const
{
    return (const PropertyContainer *)(((View *)this)->
                                       getPropertyContainer(i));
}

PropertyContainer *
View::getPropertyContainer(int i)
{
    if (i == 0) return m_propertyContainer;
    return m_fixedOrderLayers[i-1];
}

bool
View::getValueExtents(QString unit, double &min, double &max, bool &log) const
{
    bool have = false;

    for (LayerList::const_iterator i = m_layerStack.begin();
         i != m_layerStack.end(); ++i) { 

        QString layerUnit;
        double layerMin = 0.0, layerMax = 0.0;
        double displayMin = 0.0, displayMax = 0.0;
        bool layerLog = false;

        if ((*i)->getValueExtents(layerMin, layerMax, layerLog, layerUnit) &&
            layerUnit.toLower() == unit.toLower()) {

            if ((*i)->getDisplayExtents(displayMin, displayMax)) {

                min = displayMin;
                max = displayMax;
                log = layerLog;
                have = true;
                break;

            } else {

                if (!have || layerMin < min) min = layerMin;
                if (!have || layerMax > max) max = layerMax;
                if (layerLog) log = true;
                have = true;
            }
        }
    }

    return have;
}

int
View::getTextLabelHeight(const Layer *layer, QPainter &paint) const
{
    std::map<int, Layer *> sortedLayers;

    for (LayerList::const_iterator i = m_layerStack.begin();
         i != m_layerStack.end(); ++i) { 
        if ((*i)->needsTextLabelHeight()) {
            sortedLayers[(*i)->getExportId()] = *i;
        }
    }

    int y = scalePixelSize(15) + paint.fontMetrics().ascent();

    for (std::map<int, Layer *>::const_iterator i = sortedLayers.begin();
         i != sortedLayers.end(); ++i) {
        if (i->second == layer) break;
        y += paint.fontMetrics().height();
    }

    return y;
}

void
View::propertyContainerSelected(View *client, PropertyContainer *pc)
{
    if (client != this) return;
    
    if (pc == m_propertyContainer) {
        if (m_haveSelectedLayer) {
            m_haveSelectedLayer = false;
            update();
        }
        return;
    }

    m_cacheValid = false;

    Layer *selectedLayer = nullptr;

    for (LayerList::iterator i = m_layerStack.begin(); i != m_layerStack.end(); ++i) {
        if (*i == pc) {
            selectedLayer = *i;
            m_layerStack.erase(i);
            break;
        }
    }

    if (selectedLayer) {
        m_haveSelectedLayer = true;
        m_layerStack.push_back(selectedLayer);
        update();
    } else {
        m_haveSelectedLayer = false;
    }

    emit propertyContainerSelected(pc);
}

void
View::toolModeChanged()
{
//    SVDEBUG << "View::toolModeChanged(" << m_manager->getToolMode() << ")" << endl;
}

void
View::overlayModeChanged()
{
    m_cacheValid = false;
    update();
}

void
View::zoomWheelsEnabledChanged()
{
    // subclass might override this
}

sv_frame_t
View::getStartFrame() const
{
    return getFrameForX(0);
}

sv_frame_t
View::getEndFrame() const
{
    return getFrameForX(width()) - 1;
}

void
View::setStartFrame(sv_frame_t f)
{
    setCentreFrame(f + sv_frame_t(round
                                  (m_zoomLevel.pixelsToFrames(width() / 2))));
}

bool
View::setCentreFrame(sv_frame_t f, bool e)
{
    bool changeVisible = false;

#ifdef DEBUG_VIEW
    SVCERR << "View[" << getId() << "]::setCentreFrame: from " << m_centreFrame
           << " to " << f << endl;
#endif

    if (m_centreFrame != f) {

        sv_frame_t formerCentre = m_centreFrame;
        m_centreFrame = f;
        
        if (m_zoomLevel.zone == ZoomLevel::PixelsPerFrame) {

#ifdef DEBUG_VIEW
            SVCERR << "View[" << getId() << "]::setCentreFrame: in PixelsPerFrame zone, so change must be visible" << endl;
#endif
            update();
            changeVisible = true;

        } else {
        
            int formerPixel = int(formerCentre / m_zoomLevel.level);
            int newPixel = int(m_centreFrame / m_zoomLevel.level);
        
            if (newPixel != formerPixel) {

#ifdef DEBUG_VIEW
                SVCERR << "View[" << getId() << "]::setCentreFrame: newPixel " << newPixel << ", formerPixel " << formerPixel << endl;
#endif
                // ensure the centre frame is a multiple of the zoom level
                m_centreFrame = sv_frame_t(newPixel) * m_zoomLevel.level;

#ifdef DEBUG_VIEW
                SVCERR << "View[" << getId()
                       << "]::setCentreFrame: centre frame rounded to "
                       << m_centreFrame << " (zoom level is "
                       << m_zoomLevel.level << ")" << endl;
#endif
                
                update();
                changeVisible = true;
            }
        }

        if (e) {
            sv_frame_t rf = alignToReference(m_centreFrame);
#ifdef DEBUG_VIEW
            SVCERR << "View[" << getId() << "]::setCentreFrame(" << f
                 << "): m_centreFrame = " << m_centreFrame
                 << ", emitting centreFrameChanged with aligned frame "
                 << rf << endl;
#endif
            emit centreFrameChanged(rf, m_followPan, m_followPlay);
        }
    }

    return changeVisible;
}

int
View::getXForFrame(sv_frame_t frame) const
{
    // In FramesPerPixel mode, the pixel should be the one "covering"
    // the given frame, i.e. to the "left" of it - not necessarily the
    // nearest boundary.
    
    sv_frame_t level = m_zoomLevel.level;
    sv_frame_t fdiff = frame - m_centreFrame;
    int result = 0;

    bool inRange = false;
    if (m_zoomLevel.zone == ZoomLevel::FramesPerPixel) {
        inRange = ((fdiff / level) < sv_frame_t(INT_MAX) &&
                   (fdiff / level) > sv_frame_t(INT_MIN));
    } else {
        inRange = (fdiff < sv_frame_t(INT_MAX) / level &&
                   fdiff > sv_frame_t(INT_MIN) / level);
    }

    if (inRange) {
        
        sv_frame_t adjusted;

        if (m_zoomLevel.zone == ZoomLevel::FramesPerPixel) {
            sv_frame_t roundedCentreFrame = (m_centreFrame / level) * level;
            fdiff = frame - roundedCentreFrame;
            adjusted = fdiff / level;
            if ((fdiff < 0) && ((fdiff % level) != 0)) {
                --adjusted; // round to the left
            }
        } else {
            adjusted = fdiff * level;
        }

        adjusted = adjusted + (width()/2);

        if (adjusted > INT_MAX || adjusted < INT_MIN) {
            inRange = false;
        } else {
            result = int(adjusted);
        }
    }

    if (!inRange) {
        SVCERR << "ERROR: Frame " << frame
               << " is out of range in View::getXForFrame" << endl;
        SVCERR << "ERROR: (centre frame = " << getCentreFrame() << ", fdiff = "
               << fdiff << ", zoom level = " << m_zoomLevel << ")" << endl;
        SVCERR << "ERROR: This is a logic error: getXForFrame should not be "
               << "called for locations unadjacent to the current view"
               << endl;
        return 0;
    }

#ifdef DEBUG_VIEW
    if (m_zoomLevel.zone == ZoomLevel::PixelsPerFrame) {
        sv_frame_t reversed = getFrameForX(result);
        if (reversed != frame) {
            SVCERR << "View[" << getId() << "]::getXForFrame: WARNING: Converted frame " << frame << " to x " << result << " in PixelsPerFrame zone, but the reverse conversion gives frame " << reversed << " (error = " << reversed - frame << ")" << endl;
            SVCERR << "(centre frame = " << getCentreFrame() << ", fdiff = "
                   << fdiff << ", level = " << level << ", centre % level = "
                   << (getCentreFrame() % level) << ", fdiff % level = "
                   << (fdiff % level) << ", frame % level = "
                   << (frame % level) << ", reversed % level = "
                   << (reversed % level) << ")" << endl;
        }
    }
#endif

    return result;
}

sv_frame_t
View::getFrameForX(int x) const
{
    // Note, this must always return a value that is on a zoom-level
    // boundary - regardless of whether the nominal centre frame is on
    // such a boundary or not. (It is legitimate for the centre frame
    // not to be on a zoom-level boundary, because the centre frame
    // may be shared with other views having different zoom levels.)

    // In FramesPerPixel mode, the frame returned for a given x should
    // be the first for which getXForFrame(frame) == x; a corollary is
    // that if the centre frame is not on a zoom-level boundary, then
    // getFrameForX(x) should not return the centre frame for any x.
    
    // In PixelsPerFrame mode, the frame returned should be the one
    // immediately left of the given pixel, not necessarily the
    // nearest.

    int diff = x - (width()/2);
    sv_frame_t level = m_zoomLevel.level;
    sv_frame_t fdiff, result;
    
    if (m_zoomLevel.zone == ZoomLevel::FramesPerPixel) {
        sv_frame_t roundedCentreFrame = (m_centreFrame / level) * level;
        fdiff = diff * level;
        result = fdiff + roundedCentreFrame;
    } else {
        fdiff = diff / level;
        if ((diff < 0) && ((diff % level) != 0)) {
            --fdiff; // round to the left
        }
        result = fdiff + m_centreFrame;
    }

#ifdef DEBUG_VIEW_WIDGET_PAINT
/*
    if (x == 0) {
        SVCERR << "getFrameForX(" << x << "): diff = " << diff << ", fdiff = "
               << fdiff << ", m_centreFrame = " << m_centreFrame
               << ", level = " << m_zoomLevel.level
               << ", diff % level = " << (diff % m_zoomLevel.level)
               << ", nominal " << fdiff + m_centreFrame
               << ", will return " << result
               << endl;
    }
*/    
#endif
    
#ifdef DEBUG_VIEW
    if (m_zoomLevel.zone == ZoomLevel::FramesPerPixel) {
        int reversed = getXForFrame(result);
        if (reversed != x) {
            SVCERR << "View[" << getId() << "]::getFrameForX: WARNING: Converted pixel " << x << " to frame " << result << " in FramesPerPixel zone, but the reverse conversion gives pixel " << reversed << " (error = " << reversed - x << ")" << endl;
            SVCERR << "(centre frame = " << getCentreFrame()
                   << ", width/2 = " << width()/2 << ", diff = " << diff
                   << ", fdiff = " << fdiff << ", level = " << level
                   << ", centre % level = " << (getCentreFrame() % level)
                   << ", fdiff % level = " << (fdiff % level)
                   << ", frame % level = " << (result % level) << ")" << endl;
        }
    }
#endif
    
    return result;
}

double
View::getYForFrequency(double frequency,
                       double minf,
                       double maxf, 
                       bool logarithmic) const
{
    Profiler profiler("View::getYForFrequency");

    int h = height();

    if (logarithmic) {

        static double lastminf = 0.0, lastmaxf = 0.0;
        static double logminf = 0.0, logmaxf = 0.0;

        if (lastminf != minf) {
            lastminf = (minf == 0.0 ? 1.0 : minf);
            logminf = log10(minf);
        }
        if (lastmaxf != maxf) {
            lastmaxf = (maxf < lastminf ? lastminf : maxf);
            logmaxf = log10(maxf);
        }

        if (logminf == logmaxf) return 0;
        return h - (h * (log10(frequency) - logminf)) / (logmaxf - logminf);

    } else {
        
        if (minf == maxf) return 0;
        return h - (h * (frequency - minf)) / (maxf - minf);
    }
}

double
View::getFrequencyForY(double y,
                       double minf,
                       double maxf,
                       bool logarithmic) const
{
    double h = height();

    if (logarithmic) {

        static double lastminf = 0.0, lastmaxf = 0.0;
        static double logminf = 0.0, logmaxf = 0.0;

        if (lastminf != minf) {
            lastminf = (minf == 0.0 ? 1.0 : minf);
            logminf = log10(minf);
        }
        if (lastmaxf != maxf) {
            lastmaxf = (maxf < lastminf ? lastminf : maxf);
            logmaxf = log10(maxf);
        }

        if (logminf == logmaxf) return 0;
        return pow(10.0, logminf + ((logmaxf - logminf) * (h - y)) / h);

    } else {

        if (minf == maxf) return 0;
        return minf + ((h - y) * (maxf - minf)) / h;
    }
}

ZoomLevel
View::getZoomLevel() const
{
#ifdef DEBUG_VIEW_WIDGET_PAINT
//        cout << "zoom level: " << m_zoomLevel << endl;
#endif
    return m_zoomLevel;
}

int
View::effectiveDevicePixelRatio() const
{
#ifdef Q_OS_MAC
    int dpratio = devicePixelRatio();
    if (dpratio > 1) {
        QSettings settings;
        settings.beginGroup("Preferences");
        if (!settings.value("scaledHiDpi", true).toBool()) {
            dpratio = 1;
        }
        settings.endGroup();
    }
    return dpratio;
#else
    return 1;
#endif
}

void
View::setZoomLevel(ZoomLevel z)
{
//!!!    int dpratio = effectiveDevicePixelRatio();
//    if (z < dpratio) return;
//    if (z < 1) z = 1;
    if (m_zoomLevel == z) {
        return;
    }
    m_zoomLevel = z;
    emit zoomLevelChanged(z, m_followZoom);
    update();
}

bool
View::hasLightBackground() const
{
    bool darkPalette = false;
    if (m_manager) darkPalette = m_manager->getGlobalDarkBackground();

    Layer::ColourSignificance maxSignificance = Layer::ColourAbsent;
    bool mostSignificantHasDarkBackground = false;
    
    for (LayerList::const_iterator i = m_layerStack.begin();
         i != m_layerStack.end(); ++i) {

        Layer::ColourSignificance s = (*i)->getLayerColourSignificance();
        bool light = (*i)->hasLightBackground();

        if (int(s) > int(maxSignificance)) {
            maxSignificance = s;
            mostSignificantHasDarkBackground = !light;
        } else if (s == maxSignificance && !light) {
            mostSignificantHasDarkBackground = true;
        }
    }

    if (int(maxSignificance) >= int(Layer::ColourDistinguishes)) {
        return !mostSignificantHasDarkBackground;
    } else {
        return !darkPalette;
    }
}

QColor
View::getBackground() const
{
    bool light = hasLightBackground();

    QColor widgetbg = palette().window().color();
    bool widgetLight =
        (widgetbg.red() + widgetbg.green() + widgetbg.blue()) > 384;

    if (widgetLight == light) {
        if (widgetLight) {
            return widgetbg.lighter();
        } else {
            return widgetbg.darker();
        }
    }
    else if (light) return Qt::white;
    else return Qt::black;
}

QColor
View::getForeground() const
{
    bool light = hasLightBackground();

    QColor widgetfg = palette().text().color();
    bool widgetLight =
        (widgetfg.red() + widgetfg.green() + widgetfg.blue()) > 384;

    if (widgetLight != light) return widgetfg;
    else if (light) return Qt::black;
    else return Qt::white;
}

void
View::addLayer(Layer *layer)
{
    m_cacheValid = false;

    SingleColourLayer *scl = dynamic_cast<SingleColourLayer *>(layer);
    if (scl) scl->setDefaultColourFor(this);

    m_fixedOrderLayers.push_back(layer);
    m_layerStack.push_back(layer);

    QProgressBar *pb = new QProgressBar(this);
    pb->setMinimum(0);
    pb->setMaximum(0);
    pb->setFixedWidth(80);
    pb->setTextVisible(false);

    QPushButton *cancel = new QPushButton(this);
    cancel->setIcon(IconLoader().load("cancel"));
    cancel->setFlat(true);
    int scaled20 = scalePixelSize(20);
    cancel->setFixedSize(QSize(scaled20, scaled20));
    connect(cancel, SIGNAL(clicked()), this, SLOT(cancelClicked()));
    
    ProgressBarRec pbr;
    pbr.cancel = cancel;
    pbr.bar = pb;
    pbr.lastStallCheckValue = 0;
    pbr.stallCheckTimer = new QTimer();
    connect(pbr.stallCheckTimer, SIGNAL(timeout()), this,
            SLOT(progressCheckStalledTimerElapsed()));

    m_progressBars[layer] = pbr;

    QFont f(pb->font());
    int fs = Preferences::getInstance()->getViewFontSize();
    f.setPointSize(std::min(fs, int(ceil(fs * 0.85))));

    cancel->hide();

    pb->setFont(f);
    pb->hide();
    
    connect(layer, SIGNAL(layerParametersChanged()),
            this,    SLOT(layerParametersChanged()));
    connect(layer, SIGNAL(layerParameterRangesChanged()),
            this,    SLOT(layerParameterRangesChanged()));
    connect(layer, SIGNAL(layerMeasurementRectsChanged()),
            this,    SLOT(layerMeasurementRectsChanged()));
    connect(layer, SIGNAL(layerNameChanged()),
            this,    SLOT(layerNameChanged()));
    connect(layer, SIGNAL(modelChanged(ModelId)),
            this,    SLOT(modelChanged(ModelId)));
    connect(layer, SIGNAL(modelCompletionChanged(ModelId)),
            this,    SLOT(modelCompletionChanged(ModelId)));
    connect(layer, SIGNAL(modelAlignmentCompletionChanged(ModelId)),
            this,    SLOT(modelAlignmentCompletionChanged(ModelId)));
    connect(layer, SIGNAL(modelChangedWithin(ModelId, sv_frame_t, sv_frame_t)),
            this,    SLOT(modelChangedWithin(ModelId, sv_frame_t, sv_frame_t)));
    connect(layer, SIGNAL(modelReplaced()),
            this,    SLOT(modelReplaced()));

    update();

    emit propertyContainerAdded(layer);
}

void
View::removeLayer(Layer *layer)
{
    if (m_deleting) {
        return;
    }

    m_cacheValid = false;

    for (LayerList::iterator i = m_fixedOrderLayers.begin();
         i != m_fixedOrderLayers.end();
         ++i) {
        if (*i == layer) {
            m_fixedOrderLayers.erase(i);
            break;
        }
    }

    for (LayerList::iterator i = m_layerStack.begin(); 
         i != m_layerStack.end();
         ++i) {
        if (*i == layer) {
            m_layerStack.erase(i);
            if (m_progressBars.find(layer) != m_progressBars.end()) {
                delete m_progressBars[layer].bar;
                delete m_progressBars[layer].cancel;
                delete m_progressBars[layer].stallCheckTimer;
                m_progressBars.erase(layer);
            }
            break;
        }
    }
    
    disconnect(layer, SIGNAL(layerParametersChanged()),
               this,    SLOT(layerParametersChanged()));
    disconnect(layer, SIGNAL(layerParameterRangesChanged()),
               this,    SLOT(layerParameterRangesChanged()));
    disconnect(layer, SIGNAL(layerNameChanged()),
               this,    SLOT(layerNameChanged()));
    disconnect(layer, SIGNAL(modelChanged(ModelId)),
               this,    SLOT(modelChanged(ModelId)));
    disconnect(layer, SIGNAL(modelCompletionChanged(ModelId)),
               this,    SLOT(modelCompletionChanged(ModelId)));
    disconnect(layer, SIGNAL(modelAlignmentCompletionChanged(ModelId)),
               this,    SLOT(modelAlignmentCompletionChanged(ModelId)));
    disconnect(layer, SIGNAL(modelChangedWithin(ModelId, sv_frame_t, sv_frame_t)),
               this,    SLOT(modelChangedWithin(ModelId, sv_frame_t, sv_frame_t)));
    disconnect(layer, SIGNAL(modelReplaced()),
               this,    SLOT(modelReplaced()));

    update();

    emit propertyContainerRemoved(layer);
}

Layer *
View::getInteractionLayer()
{
    Layer *sl = getSelectedLayer();
    if (sl && !(sl->isLayerDormant(this))) {
        return sl;
    }
    if (!m_layerStack.empty()) {
        int n = getLayerCount();
        while (n > 0) {
            --n;
            Layer *layer = getLayer(n);
            if (!(layer->isLayerDormant(this))) {
                return layer;
            }
        }
    }
    return nullptr;
}

const Layer *
View::getInteractionLayer() const
{
    return const_cast<const Layer *>(const_cast<View *>(this)->getInteractionLayer());
}

Layer *
View::getSelectedLayer()
{
    if (m_haveSelectedLayer && !m_layerStack.empty()) {
        return getLayer(getLayerCount() - 1);
    } else {
        return nullptr;
    }
}

const Layer *
View::getSelectedLayer() const
{
    return const_cast<const Layer *>(const_cast<View *>(this)->getSelectedLayer());
}

void
View::setViewManager(ViewManager *manager)
{
    if (m_manager) {
        m_manager->disconnect(this, SLOT(globalCentreFrameChanged(sv_frame_t)));
        m_manager->disconnect(this, SLOT(viewCentreFrameChanged(View *, sv_frame_t)));
        m_manager->disconnect(this, SLOT(viewManagerPlaybackFrameChanged(sv_frame_t)));
        m_manager->disconnect(this, SLOT(viewZoomLevelChanged(View *, ZoomLevel, bool)));
        m_manager->disconnect(this, SLOT(toolModeChanged()));
        m_manager->disconnect(this, SLOT(selectionChanged()));
        m_manager->disconnect(this, SLOT(overlayModeChanged()));
        m_manager->disconnect(this, SLOT(zoomWheelsEnabledChanged()));
        disconnect(m_manager, SLOT(viewCentreFrameChanged(sv_frame_t, bool, PlaybackFollowMode)));
        disconnect(m_manager, SLOT(zoomLevelChanged(ZoomLevel, bool)));
    }

    m_manager = manager;

    connect(m_manager, SIGNAL(globalCentreFrameChanged(sv_frame_t)),
            this, SLOT(globalCentreFrameChanged(sv_frame_t)));
    connect(m_manager, SIGNAL(viewCentreFrameChanged(View *, sv_frame_t)),
            this, SLOT(viewCentreFrameChanged(View *, sv_frame_t)));
    connect(m_manager, SIGNAL(playbackFrameChanged(sv_frame_t)),
            this, SLOT(viewManagerPlaybackFrameChanged(sv_frame_t)));

    connect(m_manager, SIGNAL(viewZoomLevelChanged(View *, ZoomLevel, bool)),
            this, SLOT(viewZoomLevelChanged(View *, ZoomLevel, bool)));

    connect(m_manager, SIGNAL(toolModeChanged()),
            this, SLOT(toolModeChanged()));
    connect(m_manager, SIGNAL(selectionChanged()),
            this, SLOT(selectionChanged()));
    connect(m_manager, SIGNAL(inProgressSelectionChanged()),
            this, SLOT(selectionChanged()));
    connect(m_manager, SIGNAL(overlayModeChanged()),
            this, SLOT(overlayModeChanged()));
    connect(m_manager, SIGNAL(showCentreLineChanged()),
            this, SLOT(overlayModeChanged()));
    connect(m_manager, SIGNAL(zoomWheelsEnabledChanged()),
            this, SLOT(zoomWheelsEnabledChanged()));

    connect(this, SIGNAL(centreFrameChanged(sv_frame_t, bool,
                                            PlaybackFollowMode)),
            m_manager, SLOT(viewCentreFrameChanged(sv_frame_t, bool,
                                                   PlaybackFollowMode)));

    connect(this, SIGNAL(zoomLevelChanged(ZoomLevel, bool)),
            m_manager, SLOT(viewZoomLevelChanged(ZoomLevel, bool)));

    switch (m_followPlay) {
        
    case PlaybackScrollPage:
    case PlaybackScrollPageWithCentre:
        setCentreFrame(m_manager->getGlobalCentreFrame(), false);
        break;

    case PlaybackScrollContinuous:
        setCentreFrame(m_manager->getPlaybackFrame(), false);
        break;

    case PlaybackIgnore:
        if (m_followPan) {
            setCentreFrame(m_manager->getGlobalCentreFrame(), false);
        }
        break;
    }

    if (m_followZoom) setZoomLevel(m_manager->getGlobalZoom());

    movePlayPointer(getAlignedPlaybackFrame());

    toolModeChanged();
}

void
View::setViewManager(ViewManager *vm, sv_frame_t initialCentreFrame)
{
    setViewManager(vm);
    setCentreFrame(initialCentreFrame, false);
}

void
View::setFollowGlobalPan(bool f)
{
    m_followPan = f;
    emit propertyContainerPropertyChanged(m_propertyContainer);
}

void
View::setFollowGlobalZoom(bool f)
{
    m_followZoom = f;
    emit propertyContainerPropertyChanged(m_propertyContainer);
}

void
View::setPlaybackFollow(PlaybackFollowMode m)
{
    m_followPlay = m;
    emit propertyContainerPropertyChanged(m_propertyContainer);
}

void
View::modelChanged(ModelId modelId)
{
#if defined(DEBUG_VIEW_WIDGET_PAINT) || defined(DEBUG_PROGRESS_STUFF)
    SVCERR << "View[" << getId() << "]::modelChanged(" << modelId << ")" << endl;
#endif

    // If the model that has changed is not used by any of the cached
    // layers, we won't need to recreate the cache
    
    bool recreate = false;

    bool discard;
    LayerList scrollables = getScrollableBackLayers(false, discard);
    for (LayerList::const_iterator i = scrollables.begin();
         i != scrollables.end(); ++i) {
        if ((*i)->getModel() == modelId) {
            recreate = true;
            break;
        }
    }

    if (recreate) {
        m_cacheValid = false;
    }

    emit layerModelChanged();

    checkProgress(modelId);

    update();
}

void
View::modelChangedWithin(ModelId modelId,
                         sv_frame_t startFrame, sv_frame_t endFrame)
{
    sv_frame_t myStartFrame = getStartFrame();
    sv_frame_t myEndFrame = getEndFrame();

#ifdef DEBUG_VIEW_WIDGET_PAINT
    SVCERR << "View[" << getId() << "]::modelChangedWithin(" << startFrame << "," << endFrame << ") [me " << myStartFrame << "," << myEndFrame << "]" << endl;
#endif

    if (myStartFrame > 0 && endFrame < myStartFrame) {
        checkProgress(modelId);
        return;
    }
    if (startFrame > myEndFrame) {
        checkProgress(modelId);
        return;
    }

    // If the model that has changed is not used by any of the cached
    // layers, we won't need to recreate the cache
    
    bool recreate = false;

    bool discard;
    LayerList scrollables = getScrollableBackLayers(false, discard);
    for (LayerList::const_iterator i = scrollables.begin();
         i != scrollables.end(); ++i) {
        if ((*i)->getModel() == modelId) {
            recreate = true;
            break;
        }
    }

    if (recreate) {
        m_cacheValid = false;
    }

    if (startFrame < myStartFrame) startFrame = myStartFrame;
    if (endFrame > myEndFrame) endFrame = myEndFrame;

    checkProgress(modelId);

    update();
}    

void
View::modelCompletionChanged(ModelId modelId)
{
#ifdef DEBUG_PROGRESS_STUFF
    SVCERR << "View[" << getId() << "]::modelCompletionChanged(" << modelId << ")" << endl;
#endif
    checkProgress(modelId);
}

void
View::modelAlignmentCompletionChanged(ModelId modelId)
{
#ifdef DEBUG_PROGRESS_STUFF
    SVCERR << "View[" << getId() << "]::modelAlignmentCompletionChanged(" << modelId << ")" << endl;
#endif
    checkAlignmentProgress(modelId);
}

void
View::modelReplaced()
{
#ifdef DEBUG_VIEW_WIDGET_PAINT
    SVCERR << "View[" << getId() << "]::modelReplaced()" << endl;
#endif
    m_cacheValid = false;
    update();
}

void
View::layerParametersChanged()
{
    Layer *layer = dynamic_cast<Layer *>(sender());

#ifdef DEBUG_VIEW_WIDGET_PAINT
    SVDEBUG << "View::layerParametersChanged()" << endl;
#endif

    m_cacheValid = false;
    update();

    if (layer) {
        emit propertyContainerPropertyChanged(layer);
    }
}

void
View::layerParameterRangesChanged()
{
    Layer *layer = dynamic_cast<Layer *>(sender());
    if (layer) emit propertyContainerPropertyRangeChanged(layer);
}

void
View::layerMeasurementRectsChanged()
{
    Layer *layer = dynamic_cast<Layer *>(sender());
    if (layer) update();
}

void
View::layerNameChanged()
{
    Layer *layer = dynamic_cast<Layer *>(sender());
    if (layer) emit propertyContainerNameChanged(layer);
}

void
View::globalCentreFrameChanged(sv_frame_t rf)
{
    if (m_followPan) {
        sv_frame_t f = alignFromReference(rf);
#ifdef DEBUG_VIEW
        SVCERR << "View[" << getId() << "]::globalCentreFrameChanged(" << rf
                  << "): setting centre frame to " << f << endl;
#endif
        setCentreFrame(f, false);
    }
}

void
View::viewCentreFrameChanged(View *, sv_frame_t )
{
    // We do nothing with this, but a subclass might
}

void
View::viewManagerPlaybackFrameChanged(sv_frame_t f)
{
    if (m_manager) {
        if (sender() != m_manager) return;
    }

#ifdef DEBUG_VIEW        
    SVCERR << "View[" << getId() << "]::viewManagerPlaybackFrameChanged(" << f << ")" << endl;
#endif

    f = getAlignedPlaybackFrame();

#ifdef DEBUG_VIEW
    SVCERR << " -> aligned frame = " << f << endl;
#endif

    movePlayPointer(f);
}

void
View::movePlayPointer(sv_frame_t newFrame)
{
#ifdef DEBUG_VIEW
    SVCERR << "View[" << getId() << "]::movePlayPointer(" << newFrame << ")" << endl;
#endif

    if (m_playPointerFrame == newFrame) return;
    bool visibleChange =
        (getXForFrame(m_playPointerFrame) != getXForFrame(newFrame));

#ifdef DEBUG_VIEW_WIDGET_PAINT
    SVCERR << "View[" << getId() << "]::movePlayPointer: moving from "
           << m_playPointerFrame << " to " << newFrame << ", visible = "
           << visibleChange << endl;
#endif
    
    sv_frame_t oldPlayPointerFrame = m_playPointerFrame;
    m_playPointerFrame = newFrame;
    if (!visibleChange) return;

    bool somethingGoingOn =
        ((QApplication::mouseButtons() != Qt::NoButton) ||
         (QApplication::keyboardModifiers() & Qt::AltModifier));

    bool pointerInVisibleArea =
        long(m_playPointerFrame) >= getStartFrame() &&
        (m_playPointerFrame < getEndFrame() ||
         // include old pointer location so we know to refresh when moving out
         oldPlayPointerFrame < getEndFrame());

    switch (m_followPlay) {

    case PlaybackScrollContinuous:
        if (!somethingGoingOn) {
            setCentreFrame(m_playPointerFrame, false);
        }
        break;

    case PlaybackScrollPage:
    case PlaybackScrollPageWithCentre:

        if (!pointerInVisibleArea && somethingGoingOn) {

            m_followPlayIsDetached = true;

        } else if (!pointerInVisibleArea && m_followPlayIsDetached) {

            // do nothing; we aren't tracking until the pointer comes back in

        } else {

            int xold = getXForFrame(oldPlayPointerFrame);
            update(xold - 4, 0, 9, height());

            sv_frame_t w = getEndFrame() - getStartFrame();
            w -= w/5;
            sv_frame_t sf = m_playPointerFrame;
            if (w > 0) {
                sf = (sf / w) * w - w/8;
            }

            if (m_manager &&
                m_manager->isPlaying() &&
                m_manager->getPlaySelectionMode()) {
                MultiSelection::SelectionList selections = m_manager->getSelections();
                if (!selections.empty()) {
                    sv_frame_t selectionStart = selections.begin()->getStartFrame();
                    if (sf < selectionStart - w / 10) {
                        sf = selectionStart - w / 10;
                    }
                }
            }

#ifdef DEBUG_VIEW_WIDGET_PAINT
            SVCERR << "PlaybackScrollPage: f = " << m_playPointerFrame << ", sf = " << sf << ", start frame "
                 << getStartFrame() << endl;
#endif

            // We don't consider scrolling unless the pointer is outside
            // the central visible range already

            int xnew = getXForFrame(m_playPointerFrame);

#ifdef DEBUG_VIEW_WIDGET_PAINT
            SVCERR << "xnew = " << xnew << ", width = " << width() << endl;
#endif

            bool shouldScroll = (xnew > (width() * 7) / 8);

            if (!m_followPlayIsDetached && (xnew < width() / 8)) {
                shouldScroll = true;
            }

            if (xnew > width() / 8) {
                m_followPlayIsDetached = false;
            } else if (somethingGoingOn) {
                m_followPlayIsDetached = true;
            }

            if (!somethingGoingOn && shouldScroll) {
                sv_frame_t offset = getFrameForX(width()/2) - getStartFrame();
                sv_frame_t newCentre = sf + offset;
                bool changed = setCentreFrame(newCentre, false);
                if (changed) {
                    xold = getXForFrame(oldPlayPointerFrame);
                    update(xold - 4, 0, 9, height());
                }
            }

            update(xnew - 4, 0, 9, height());
        }
        break;

    case PlaybackIgnore:
        if (m_playPointerFrame >= getStartFrame() &&
            m_playPointerFrame < getEndFrame()) {
            update();
        }
        break;
    }
}

void
View::viewZoomLevelChanged(View *p, ZoomLevel z, bool locked)
{
#ifdef DEBUG_VIEW_WIDGET_PAINT
    SVCERR  << "View[" << getId() << "]: viewZoomLevelChanged(" << p << ", " << z << ", " << locked << ")" << endl;
#endif
    if (m_followZoom && p != this && locked) {
        setZoomLevel(z);
    }
}

void
View::selectionChanged()
{
    if (m_selectionCached) {
        m_cacheValid = false;
        m_selectionCached = false;
    }
    update();
}

sv_frame_t
View::getFirstVisibleFrame() const
{
    sv_frame_t f0 = getStartFrame();
    sv_frame_t f = getModelsStartFrame();
    if (f0 < 0 || f0 < f) return f;
    return f0;
}

sv_frame_t 
View::getLastVisibleFrame() const
{
    sv_frame_t f0 = getEndFrame();
    sv_frame_t f = getModelsEndFrame();
    if (f0 > f) return f;
    return f0;
}

sv_frame_t
View::getModelsStartFrame() const
{
    bool first = true;
    sv_frame_t startFrame = 0;

    for (Layer *layer: m_layerStack) {

        auto model = ModelById::get(layer->getModel());

        if (model && model->isOK()) {

            sv_frame_t thisStartFrame = model->getStartFrame();

            if (first || thisStartFrame < startFrame) {
                startFrame = thisStartFrame;
            }
            first = false;
        }
    }
    
    return startFrame;
}

sv_frame_t
View::getModelsEndFrame() const
{
    bool first = true;
    sv_frame_t endFrame = 0;

    for (Layer *layer: m_layerStack) {

        auto model = ModelById::get(layer->getModel());

        if (model && model->isOK()) {

            sv_frame_t thisEndFrame = model->getEndFrame();

            if (first || thisEndFrame > endFrame) {
                endFrame = thisEndFrame;
            }
            first = false;
        }
    }

    if (first) return getModelsStartFrame();
    return endFrame;
}

sv_samplerate_t
View::getModelsSampleRate() const
{
    //!!! Just go for the first, for now.  If we were supporting
    // multiple samplerates, we'd probably want to do frame/time
    // conversion in the model

    //!!! nah, this wants to always return the sr of the main model!

    for (Layer *layer: m_layerStack) {

        auto model = ModelById::get(layer->getModel());

        if (model && model->isOK()) {
            return model->getSampleRate();
        }
    }

    return 0;
}

View::ModelSet
View::getModels()
{
    ModelSet models;

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

        Layer *layer = getLayer(i);

        if (dynamic_cast<TimeRulerLayer *>(layer)) {
            continue;
        }

        if (layer && !layer->getModel().isNone()) {
            models.insert(layer->getModel());
        }
    }

    return models;
}

ModelId
View::getAligningModel() const
{
    ModelId aligning, reference;
    getAligningAndReferenceModels(aligning, reference);
    return aligning;
}

void
View::getAligningAndReferenceModels(ModelId &aligning,
                                    ModelId &reference) const
{
    if (!m_manager ||
        !m_manager->getAlignMode() ||
        m_manager->getPlaybackModel().isNone()) {
        return;
    }

    ModelId anyModel;

    for (auto layer: m_layerStack) {

        if (!layer) continue;
        if (dynamic_cast<TimeRulerLayer *>(layer)) continue;

        ModelId thisId = layer->getModel();
        auto model = ModelById::get(thisId);
        if (!model) continue;

        anyModel = thisId;

        if (!model->getAlignmentReference().isNone()) {

            if (layer->isLayerOpaque() ||
                std::dynamic_pointer_cast
                <RangeSummarisableTimeValueModel>(model)) {

                aligning = thisId;
                reference = model->getAlignmentReference();
                return;

            } else if (aligning.isNone()) {
                
                aligning = thisId;
                reference = model->getAlignmentReference();
            }
        }
    }

    if (aligning.isNone()) {
        aligning = anyModel;
        reference = {};
    }
}

sv_frame_t
View::alignFromReference(sv_frame_t f) const
{
    if (!m_manager || !m_manager->getAlignMode()) return f;
    auto aligningModel = ModelById::get(getAligningModel());
    if (!aligningModel) return f;
    return aligningModel->alignFromReference(f);
}

sv_frame_t
View::alignToReference(sv_frame_t f) const
{
    if (!m_manager->getAlignMode()) return f;
    auto aligningModel = ModelById::get(getAligningModel());
    if (!aligningModel) return f;
    return aligningModel->alignToReference(f);
}

sv_frame_t
View::getAlignedPlaybackFrame() const
{
    if (!m_manager) return 0;
    sv_frame_t pf = m_manager->getPlaybackFrame();
    if (!m_manager->getAlignMode()) return pf;

    auto aligningModel = ModelById::get(getAligningModel());
    if (!aligningModel) return pf;

    sv_frame_t af = aligningModel->alignFromReference(pf);

    return af;
}

bool
View::areLayersScrollable() const
{
    // True iff all views are scrollable
    for (LayerList::const_iterator i = m_layerStack.begin(); i != m_layerStack.end(); ++i) {
        if (!(*i)->isLayerScrollable(this)) return false;
    }
    return true;
}

View::LayerList
View::getScrollableBackLayers(bool testChanged, bool &changed) const
{
    changed = false;

    // We want a list of all the scrollable layers that are behind the
    // backmost non-scrollable layer.

    LayerList scrollables;
    bool metUnscrollable = false;

    for (LayerList::const_iterator i = m_layerStack.begin(); i != m_layerStack.end(); ++i) {
//        SVDEBUG << "View::getScrollableBackLayers: calling isLayerDormant on layer " << *i << endl;
//        SVCERR << "(name is " << (*i)->objectName() << ")"
//                  << endl;
//        SVDEBUG << "View::getScrollableBackLayers: I am " << getId() << endl;
        if ((*i)->isLayerDormant(this)) continue;
        if ((*i)->isLayerOpaque()) {
            // You can't see anything behind an opaque layer!
            scrollables.clear();
            if (metUnscrollable) break;
        }
        if (!metUnscrollable && (*i)->isLayerScrollable(this)) {
            scrollables.push_back(*i);
        } else {
            metUnscrollable = true;
        }
    }

    if (testChanged && scrollables != m_lastScrollableBackLayers) {
        m_lastScrollableBackLayers = scrollables;
        changed = true;
    }
    return scrollables;
}

View::LayerList
View::getNonScrollableFrontLayers(bool testChanged, bool &changed) const
{
    changed = false;
    LayerList nonScrollables;

    // Everything in front of the first non-scrollable from the back
    // should also be considered non-scrollable

    bool started = false;

    for (LayerList::const_iterator i = m_layerStack.begin(); i != m_layerStack.end(); ++i) {
        if ((*i)->isLayerDormant(this)) continue;
        if (!started && (*i)->isLayerScrollable(this)) {
            continue;
        }
        started = true;
        if ((*i)->isLayerOpaque()) {
            // You can't see anything behind an opaque layer!
            nonScrollables.clear();
        }
        nonScrollables.push_back(*i);
    }

    if (testChanged && nonScrollables != m_lastNonScrollableBackLayers) {
        m_lastNonScrollableBackLayers = nonScrollables;
        changed = true;
    }

    return nonScrollables;
}

ZoomLevel
View::getZoomConstraintLevel(ZoomLevel zoomLevel,
                             ZoomConstraint::RoundingDirection dir)
    const
{
    using namespace std::rel_ops;
    
    ZoomLevel candidate =
        RelativelyFineZoomConstraint().getNearestZoomLevel(zoomLevel, dir);

    for (auto i : m_layerStack) {

        if (i->supportsOtherZoomLevels() || !(i->getZoomConstraint())) {
            continue;
        }
        
        ZoomLevel thisLevel =
            i->getZoomConstraint()->getNearestZoomLevel(zoomLevel, dir);

        // Go for the block size that's furthest from the one
        // passed in.  Most of the time, that's what we want.
        if ((thisLevel > zoomLevel && thisLevel > candidate) ||
            (thisLevel < zoomLevel && thisLevel < candidate)) {
            candidate = thisLevel;
        }
    }

    return candidate;
}

int
View::countZoomLevels() const
{
    int n = 0;
    ZoomLevel min = ZoomConstraint().getMinZoomLevel();
    ZoomLevel max = ZoomConstraint().getMaxZoomLevel();
    ZoomLevel level = min;
    while (true) {
        ++n;
        if (level == max) {
            break;
        }
        level = getZoomConstraintLevel
            (level.incremented(), ZoomConstraint::RoundUp);
    }
//    SVCERR << "View::countZoomLevels: " << n << endl;
    return n;
}

ZoomLevel
View::getZoomLevelByIndex(int ix) const
{
    int n = 0;
    ZoomLevel min = ZoomConstraint().getMinZoomLevel();
    ZoomLevel max = ZoomConstraint().getMaxZoomLevel();
    ZoomLevel level = min;
    while (true) {
        if (n == ix) {
//            SVCERR << "View::getZoomLevelByIndex: " << ix << " -> " << level
//                 << endl;
            return level;
        }
        ++n;
        if (level == max) {
            break;
        }
        level = getZoomConstraintLevel
            (level.incremented(), ZoomConstraint::RoundUp);
    }
//    SVCERR << "View::getZoomLevelByIndex: " << ix << " -> " << max << " (max)"
//         << endl;
    return max;
}

int
View::getZoomLevelIndex(ZoomLevel z) const
{
    int n = 0;
    ZoomLevel min = ZoomConstraint().getMinZoomLevel();
    ZoomLevel max = ZoomConstraint().getMaxZoomLevel();
    ZoomLevel level = min;
    while (true) {
        if (z == level) {
//            SVCERR << "View::getZoomLevelIndex: " << z << " -> " << n
//                 << endl;
            return n;
        }
        ++n;
        if (level == max) {
            break;
        }
        level = getZoomConstraintLevel
            (level.incremented(), ZoomConstraint::RoundUp);
    }
//    SVCERR << "View::getZoomLevelIndex: " << z << " -> " << n << " (max)"
//         << endl;
    return n;
}

double
View::scaleSize(double size) const
{
    static double ratio = 0.0;

    if (ratio == 0.0) {
        double baseEm;
#ifdef Q_OS_MAC
        baseEm = 17.0;
#else
        baseEm = 15.0;
#endif
        double em = QFontMetrics(QFont()).height();
        ratio = em / baseEm;

        SVDEBUG << "View::scaleSize: ratio is " << ratio
                << " (em = " << em << ")" << endl;

        if (ratio < 1.0) {
            SVDEBUG << "View::scaleSize: rounding ratio up to 1.0" << endl;
            ratio = 1.0;
        }
    }

    return size * ratio;
}

int
View::scalePixelSize(int size) const
{
    double d = scaleSize(size);
    int i = int(d + 0.5);
    if (size != 0 && i == 0) i = 1;
    return i;
}

double
View::scalePenWidth(double width) const 
{
    if (width <= 0) { // zero-width pen, produce a scaled one-pixel pen
        width = 1;
    }
    double ratio = scaleSize(1.0);
    return width * sqrt(ratio);
}

QPen
View::scalePen(QPen pen) const 
{
    return QPen(pen.color(), scalePenWidth(pen.width()));
}

bool
View::areLayerColoursSignificant() const
{
    for (LayerList::const_iterator i = m_layerStack.begin(); i != m_layerStack.end(); ++i) {
        if ((*i)->getLayerColourSignificance() ==
            Layer::ColourHasMeaningfulValue) return true;
        if ((*i)->isLayerOpaque()) break;
    }
    return false;
}

bool
View::hasTopLayerTimeXAxis() const
{
    LayerList::const_iterator i = m_layerStack.end();
    if (i == m_layerStack.begin()) return false;
    --i;
    return (*i)->hasTimeXAxis();
}

void
View::zoom(bool in)
{
    ZoomLevel newZoomLevel = m_zoomLevel;

    if (in) {
        newZoomLevel = getZoomConstraintLevel(m_zoomLevel.decremented(),
                                              ZoomConstraint::RoundDown);
    } else {
        newZoomLevel = getZoomConstraintLevel(m_zoomLevel.incremented(),
                                              ZoomConstraint::RoundUp);
    }

    using namespace std::rel_ops;
    
    if (newZoomLevel != m_zoomLevel) {
        setZoomLevel(newZoomLevel);
    }
}

void
View::scroll(bool right, bool lots, bool e)
{
    sv_frame_t delta;
    if (lots) {
        delta = (getEndFrame() - getStartFrame()) / 2;
    } else {
        delta = (getEndFrame() - getStartFrame()) / 20;
    }
    if (right) delta = -delta;

#ifdef DEBUG_VIEW
    SVCERR << "View::scroll(" << right << ", " << lots << ", " << e << "): "
           << "delta = " << delta << ", m_centreFrame = " << m_centreFrame
           << endl;
#endif
    
    if (m_centreFrame < delta) {
        setCentreFrame(0, e);
    } else if (m_centreFrame - delta >= getModelsEndFrame()) {
        setCentreFrame(getModelsEndFrame(), e);
    } else {
        setCentreFrame(m_centreFrame - delta, e);
    }
}

void
View::cancelClicked()
{
    QPushButton *cancel = qobject_cast<QPushButton *>(sender());
    if (!cancel) return;

    Layer *layer = nullptr;
    
    for (ProgressMap::iterator i = m_progressBars.begin();
         i != m_progressBars.end(); ++i) {
        if (i->second.cancel == cancel) {
            layer = i->first;
            break;
        }
    }

    if (layer) {
        emit cancelButtonPressed(layer);
    }
}

void
View::checkProgress(ModelId modelId)
{
    if (!m_showProgress) {
#ifdef DEBUG_PROGRESS_STUFF
        SVCERR << "View[" << getId() << "]::checkProgress(" << modelId << "): "
               << "m_showProgress is off" << endl;
#endif
        return;
    }

#ifdef DEBUG_PROGRESS_STUFF
    SVCERR << "View[" << getId() << "]::checkProgress(" << modelId << ")" << endl;
#endif

    QSettings settings;
    settings.beginGroup("View");
    bool showCancelButton = settings.value("showcancelbuttons", true).toBool();
    settings.endGroup();
    
    int ph = height();
    bool found = false;

    if (m_alignmentProgressBar.bar) {
        ph -= m_alignmentProgressBar.bar->height();
    }

    for (ProgressMap::iterator i = m_progressBars.begin();
         i != m_progressBars.end(); ++i) {

        QProgressBar *pb = i->second.bar;
        QPushButton *cancel = i->second.cancel;

        if (i->first && i->first->getModel() == modelId) {

            found = true;
            
            // The timer is used to test for stalls.  If the progress
            // bar does not get updated for some length of time, the
            // timer prompts it to go back into "indeterminate" mode
            QTimer *timer = i->second.stallCheckTimer;

            int completion = i->first->getCompletion(this);
            QString error = i->first->getError(this);

#ifdef DEBUG_PROGRESS_STUFF
            SVCERR << "View[" << getId() << "]::checkProgress(" << modelId << "): "
                   << "found progress bar " << pb << " for layer at height " << ph
                   << ": completion = " << completion << endl;
#endif

            if (error != "" && error != m_lastError) {
                QMessageBox::critical(this, tr("Layer rendering error"), error);
                m_lastError = error;
            }

            if (completion > 0) {
                pb->setMaximum(100); // was 0, for indeterminate start
            }

            if (completion < 100 &&
                ModelById::isa<RangeSummarisableTimeValueModel>(modelId)) {
                update(); // ensure duration &c gets updated
            }

            if (completion >= 100) {

                pb->hide();
                cancel->hide();
                timer->stop();

            } else if (i->first->isLayerDormant(this)) {

                // A dormant (invisible) layer can still be busy
                // generating, but we don't usually want to indicate
                // it because it probably means it's a duplicate of a
                // visible layer
#ifdef DEBUG_PROGRESS_STUFF
                SVCERR << "View[" << getId() << "]::checkProgress("
                       << modelId << "): layer is dormant" << endl;
#endif
                pb->hide();
                cancel->hide();
                timer->stop();
                
            } else {

                if (!pb->isVisible()) {
                    i->second.lastStallCheckValue = 0;
                    timer->setInterval(2000);
                    timer->start();
                }

                if (showCancelButton) {
                
                    int scaled20 = scalePixelSize(20);

                    cancel->move(0, ph - pb->height()/2 - scaled20/2);
                    cancel->show();

                    pb->setValue(completion);
                    pb->move(scaled20, ph - pb->height());

                } else {

                    cancel->hide();

                    pb->setValue(completion);
                    pb->move(0, ph - pb->height());
                }

                pb->show();
                pb->update();

                if (pb->isVisible()) {
                    ph -= pb->height();
                }
            }
        } else {
            if (pb->isVisible()) {
                ph -= pb->height();
            }
        }
    }

    if (!found) {
#ifdef DEBUG_PROGRESS_STUFF
        SVCERR << "View[" << getId() << "]::checkProgress(" << modelId << "): "
               << "failed to find layer for model in progress map"
               << endl;
#endif
    }
}

void
View::checkAlignmentProgress(ModelId modelId)
{
    if (!m_showProgress) {
#ifdef DEBUG_PROGRESS_STUFF
        SVCERR << "View[" << getId() << "]::checkAlignmentProgress(" << modelId << "): "
               << "m_showProgress is off" << endl;
#endif
        return;
    }

#ifdef DEBUG_PROGRESS_STUFF
    SVCERR << "View[" << getId() << "]::checkAlignmentProgress(" << modelId << ")" << endl;
#endif

    if (!m_alignmentProgressBar.alignedModel.isNone() &&
        modelId != m_alignmentProgressBar.alignedModel) {
#ifdef DEBUG_PROGRESS_STUFF
        SVCERR << "View[" << getId() << "]::checkAlignmentProgress(" << modelId << "): Different model (we're currently showing alignment progress for " << modelId << ", ignoring" << endl;
#endif
        return;
    }
    
    auto model = ModelById::get(modelId);
    if (!model) {
#ifdef DEBUG_PROGRESS_STUFF
        SVCERR << "View[" << getId() << "]::checkAlignmentProgress(" << modelId << "): Model gone" << endl;
#endif
        m_alignmentProgressBar.alignedModel = {};
        delete m_alignmentProgressBar.bar;
        m_alignmentProgressBar.bar = nullptr;
        return;
    }

    int completion = model->getAlignmentCompletion();

#ifdef DEBUG_PROGRESS_STUFF
    SVCERR << "View[" << getId() << "]::checkAlignmentProgress(" << modelId << "): Completion is " << completion << endl;
#endif

    int ph = height();

    if (completion >= 100) {
        m_alignmentProgressBar.alignedModel = {};
        delete m_alignmentProgressBar.bar;
        m_alignmentProgressBar.bar = nullptr;
        return;
    }

    QProgressBar *pb = m_alignmentProgressBar.bar;
    if (!pb) {
        pb = new QProgressBar(this);
        pb->setMinimum(0);
        pb->setMaximum(100);
        pb->setFixedWidth(80);
        pb->setTextVisible(false);
        m_alignmentProgressBar.alignedModel = modelId;
        m_alignmentProgressBar.bar = pb;
    }
        
    pb->setValue(completion);
    pb->move(0, ph - pb->height());
    pb->show();
    pb->update();
}

void
View::progressCheckStalledTimerElapsed()
{
    QObject *s = sender();
    QTimer *t = qobject_cast<QTimer *>(s);
    if (!t) return;

    for (ProgressMap::iterator i =  m_progressBars.begin();
         i != m_progressBars.end(); ++i) {

        if (i->second.stallCheckTimer == t) {

            int value = i->second.bar->value();

#ifdef DEBUG_PROGRESS_STUFF
            SVCERR << "View[" << getId() << "]::progressCheckStalledTimerElapsed for layer " << i->first << ": value is " << value << endl;
#endif
    
            if (value > 0 && value == i->second.lastStallCheckValue) {
                i->second.bar->setMaximum(0); // indeterminate
            }
            i->second.lastStallCheckValue = value;
            return;
        }
    }
}

int
View::getProgressBarWidth() const
{
    if (m_alignmentProgressBar.bar) {
        return m_alignmentProgressBar.bar->width();
    }
    
    for (ProgressMap::const_iterator i = m_progressBars.begin();
         i != m_progressBars.end(); ++i) {
        if (i->second.bar && i->second.bar->isVisible()) {
            return i->second.bar->width();
        }
    }

    return 0;
}

void
View::setPaintFont(QPainter &paint)
{
    int scaleFactor = 1;
    int dpratio = effectiveDevicePixelRatio();
    if (dpratio > 1) {
        QPaintDevice *dev = paint.device();
        if (dynamic_cast<QPixmap *>(dev) || dynamic_cast<QImage *>(dev)) {
            scaleFactor = dpratio;
        }
    }

    QFont font(paint.font());
    font.setPointSize(Preferences::getInstance()->getViewFontSize()
                      * scaleFactor);
    paint.setFont(font);
}

QRect
View::getPaintRect() const
{
    return rect();
}

void
View::paintEvent(QPaintEvent *e)
{
//    Profiler prof("View::paintEvent", false);

#ifdef DEBUG_VIEW_WIDGET_PAINT
    {
        sv_frame_t startFrame = getStartFrame();
        SVCERR << "View[" << getId() << "]::paintEvent: centre frame is " << m_centreFrame << " (start frame " << startFrame << ", height " << height() << ")" << endl;
    }
#endif

    if (m_layerStack.empty()) {
        QFrame::paintEvent(e);
        return;
    }

    // ensure our constraints are met
    m_zoomLevel = getZoomConstraintLevel
        (m_zoomLevel, ZoomConstraint::RoundNearest);

    // We have a cache, which retains the state of scrollable (back)
    // layers from one paint to the next, and a buffer, which we paint
    // onto before copying directly to the widget. Both are at scaled
    // resolution (e.g. 2x on a pixel-doubled display), whereas the
    // paint event always comes in at formal (1x) resolution.

    // If we touch the cache, we always leave it in a valid state
    // across its whole extent. When another method invalidates the
    // cache, it does so by setting m_cacheValid false, so if that
    // flag is true on entry, then the cache is valid across its whole
    // extent - although it may be valid for a different centre frame,
    // zoom level, or view size from those now in effect.

    // Our process goes:
    // 
    // 1. Check whether we have any scrollable (cacheable) layers.  If
    //    we don't, then invalidate and ignore the cache and go to
    //    step 5.  Otherwise:
    // 
    // 2. Check the cache, scroll as necessary, identify any area that
    //    needs to be refreshed (this might be the whole cache).
    //
    // 3. Paint to cache the area that needs to be refreshed, from the
    //    stack of scrollable layers.
    //
    // 4. Paint to buffer from cache: if there are no non-cached areas
    //    or selections and the cache has not scrolled, then paint the
    //    union of the area of cache that has changed and the area
    //    that the paint event reported as exposed; otherwise paint
    //    the whole.
    //
    // 5. Paint the exposed area to the buffer from the cache plus all
    //    the layers that haven't been cached, plus selections etc.
    //
    // 6. Paint the exposed rect from the buffer.
    //
    // Note that all rects except the target for the final step are at
    // cache (scaled, 2x as applicable) resolution.

    int dpratio = effectiveDevicePixelRatio();

    QRect requestedPaintArea(scaledRect(rect(), dpratio));
    if (e) {
        // cut down to only the area actually exposed
        requestedPaintArea &= scaledRect(e->rect(), dpratio);
    }

    // If not all layers are scrollable, but some of the back layers
    // are, we should store only those in the cache.

    bool layersChanged = false;
    LayerList scrollables = getScrollableBackLayers(true, layersChanged);
    LayerList nonScrollables = getNonScrollableFrontLayers(true, layersChanged);

#ifdef DEBUG_VIEW_WIDGET_PAINT
    SVCERR << "View[" << getId() << "]::paintEvent: have " << scrollables.size()
              << " scrollable back layers and " << nonScrollables.size()
              << " non-scrollable front layers" << endl;
#endif

    if (layersChanged || scrollables.empty()) {
        m_cacheValid = false;
    }

    QRect wholeArea(scaledRect(rect(), dpratio));
    QSize wholeSize(scaledSize(size(), dpratio));

    if (!m_buffer || wholeSize != m_buffer->size()) {
        delete m_buffer;
        m_buffer = new QPixmap(wholeSize);
    }

    bool shouldUseCache = false;
    bool shouldRepaintCache = false;
    QRect cacheAreaToRepaint;
    
    static HitCount count("View cache");

    if (!scrollables.empty()) {

        shouldUseCache = true;
        shouldRepaintCache = true;
        cacheAreaToRepaint = wholeArea;

#ifdef DEBUG_VIEW_WIDGET_PAINT
        SVCERR << "View[" << getId() << "]: cache " << m_cache << ", cache zoom "
                  << m_cacheZoomLevel << ", zoom " << m_zoomLevel << endl;
#endif

        using namespace std::rel_ops;
    
        if (!m_cacheValid ||
            !m_cache ||
            m_cacheZoomLevel != m_zoomLevel ||
            m_cache->size() != wholeSize) {

            // cache is not valid at all

            if (requestedPaintArea.width() < wholeSize.width() / 10) {

                m_cacheValid = false;
                shouldUseCache = false;
                shouldRepaintCache = false;

#ifdef DEBUG_VIEW_WIDGET_PAINT
                SVCERR << "View[" << getId() << "]::paintEvent: cache is invalid but only small area requested, will repaint directly instead" << endl;
#endif
            } else {

                if (!m_cache ||
                    m_cache->size() != wholeSize) {
                    delete m_cache;
                    m_cache = new QPixmap(wholeSize);
                }

#ifdef DEBUG_VIEW_WIDGET_PAINT
                SVCERR << "View[" << getId() << "]::paintEvent: cache is invalid, will repaint whole" << endl;
#endif
            }

            count.miss();
            
        } else if (m_cacheCentreFrame != m_centreFrame) {

#ifdef DEBUG_VIEW_WIDGET_PAINT
            SVCERR << "View[" << getId() << "]::paintEvent: cache centre frame is " << m_cacheCentreFrame << endl;
#endif

            int dx = dpratio * (getXForFrame(m_cacheCentreFrame) -
                                getXForFrame(m_centreFrame));

            if (dx > -m_cache->width() && dx < m_cache->width()) {

                m_cache->scroll(dx, 0, m_cache->rect(), nullptr);

                if (dx < 0) {
                    cacheAreaToRepaint = 
                        QRect(m_cache->width() + dx, 0, -dx, m_cache->height());
                } else {
                    cacheAreaToRepaint = 
                        QRect(0, 0, dx, m_cache->height());
                }

                count.partial();

#ifdef DEBUG_VIEW_WIDGET_PAINT
                SVCERR << "View[" << getId() << "]::paintEvent: scrolled cache by " << dx << endl;
#endif
            } else {
                count.miss();
#ifdef DEBUG_VIEW_WIDGET_PAINT
                SVCERR << "View[" << getId() << "]::paintEvent: scrolling too far" << endl;
#endif
            }

        } else {
#ifdef DEBUG_VIEW_WIDGET_PAINT
            SVCERR << "View[" << getId() << "]::paintEvent: cache is good" << endl;
#endif
            count.hit();
            shouldRepaintCache = false;
        }
    }

#ifdef DEBUG_VIEW_WIDGET_PAINT
    SVCERR << "View[" << getId() << "]::paintEvent: m_cacheValid = " << m_cacheValid << ", shouldUseCache = " << shouldUseCache << ", shouldRepaintCache = " << shouldRepaintCache << ", cacheAreaToRepaint = " << cacheAreaToRepaint.x() << "," << cacheAreaToRepaint.y() << " " << cacheAreaToRepaint.width() << "x" << cacheAreaToRepaint.height() << endl;
#endif

    if (shouldRepaintCache && !shouldUseCache) {
        // If we are repainting the cache, then we paint the
        // scrollables only to the cache, not to the buffer. So if
        // shouldUseCache is also false, then the scrollables can't
        // appear because they will only be on the cache
        throw std::logic_error("ERROR: shouldRepaintCache is true, but shouldUseCache is false: this can't lead to the correct result");
    }

    // Create the ViewProxy for geometry provision, using the
    // device-pixel ratio for pixel-doubled hi-dpi rendering as
    // appropriate.

    ViewProxy proxy(this, dpratio);

    // Some layers may need an aligning proxy. If a layer's model has
    // a source model that is the reference model for the aligning
    // model, and the layer is tagged as to be aligned, then we might
    // use an aligning proxy. Note this is actually made use of only
    // if m_useAligningProxy is true further down.
    
    ModelId alignmentModelId;
    ModelId alignmentReferenceId;
    auto aligningModel = ModelById::get(getAligningModel());
    if (aligningModel) {
        alignmentModelId = aligningModel->getAlignment();
        alignmentReferenceId = aligningModel->getAlignmentReference();
#ifdef DEBUG_VIEW_WIDGET_PAINT
        SVCERR << "alignmentModelId = " << alignmentModelId << " (reference = " << alignmentReferenceId << ")" << endl;
#endif
    } else {
#ifdef DEBUG_VIEW_WIDGET_PAINT
        SVCERR << "no aligningModel" << endl;
#endif
    }
    ViewProxy aligningProxy(this, dpratio, alignmentModelId);
    
    // Scrollable (cacheable) items first. If we are repainting the
    // cache, then we paint these to the cache; otherwise straight to
    // the buffer.
    QRect areaToPaint;
    QPainter paint;

    if (shouldRepaintCache) {
        paint.begin(m_cache);
        areaToPaint = cacheAreaToRepaint;
    } else {
        paint.begin(m_buffer);
        areaToPaint = requestedPaintArea;
    }

    setPaintFont(paint);
    paint.setClipRect(areaToPaint);

    paint.setPen(getBackground());
    paint.setBrush(getBackground());
    paint.drawRect(areaToPaint);

    paint.setPen(getForeground());
    paint.setBrush(Qt::NoBrush);
        
    for (LayerList::iterator i = scrollables.begin();
         i != scrollables.end(); ++i) {

        paint.setRenderHint(QPainter::Antialiasing, false);
        paint.save();

        Layer *layer = *i;
        
        bool useAligningProxy = false;
        if (m_useAligningProxy) {
            if (layer->getModel() == alignmentReferenceId ||
                layer->getSourceModel() == alignmentReferenceId) {
                useAligningProxy = true;
            }
        }

#ifdef DEBUG_VIEW_WIDGET_PAINT
        SVCERR << "Painting scrollable layer " << layer << " (model " << layer->getModel() << ", source model " << layer->getSourceModel() << ") with shouldRepaintCache = " << shouldRepaintCache << ", useAligningProxy = " << useAligningProxy << ", dpratio = " << dpratio << ", areaToPaint = " << areaToPaint.x() << "," << areaToPaint.y() << " " << areaToPaint.width() << "x" << areaToPaint.height() << endl;
#endif
        
        layer->paint(useAligningProxy ? &aligningProxy : &proxy,
                     paint, areaToPaint);

        paint.restore();
    }

    paint.end();

    if (shouldRepaintCache) {
        // and now we have
        m_cacheValid = true;
        m_cacheCentreFrame = m_centreFrame;
        m_cacheZoomLevel = m_zoomLevel;
    }

    if (shouldUseCache) {
        paint.begin(m_buffer);
        paint.drawPixmap(requestedPaintArea, *m_cache, requestedPaintArea);
        paint.end();
    }

    // Now non-cacheable items.

    paint.begin(m_buffer);
    paint.setClipRect(requestedPaintArea);
    setPaintFont(paint);
    if (scrollables.empty()) {
        paint.setPen(getBackground());
        paint.setBrush(getBackground());
        paint.drawRect(requestedPaintArea);
    }
        
    paint.setPen(getForeground());
    paint.setBrush(Qt::NoBrush);
        
    for (LayerList::iterator i = nonScrollables.begin(); 
         i != nonScrollables.end(); ++i) {
        
        Layer *layer = *i;
        
        bool useAligningProxy = false;
        if (m_useAligningProxy) {
            if (layer->getModel() == alignmentReferenceId ||
                layer->getSourceModel() == alignmentReferenceId) {
                useAligningProxy = true;
            }
        }

#ifdef DEBUG_VIEW_WIDGET_PAINT
        SVCERR << "Painting non-scrollable layer " << layer << " (model " << layer->getModel() << ", source model " << layer->getSourceModel() << ") with shouldRepaintCache = " << shouldRepaintCache << ", useAligningProxy = " << useAligningProxy << ", dpratio = " << dpratio << ", requestedPaintArea = " << requestedPaintArea.x() << "," << requestedPaintArea.y() << " " << requestedPaintArea.width() << "x" << requestedPaintArea.height() << endl;
#endif

        layer->paint(useAligningProxy ? &aligningProxy : &proxy,
                     paint, requestedPaintArea);
    }
        
    paint.end();

    // Now paint to widget from buffer: target rects from here on,
    // unlike all the preceding, are at formal (1x) resolution

    paint.begin(this);
    setPaintFont(paint);
    if (e) paint.setClipRect(e->rect());

    QRect finalPaintRect = e ? e->rect() : rect();
    paint.drawPixmap(finalPaintRect, *m_buffer, 
                     scaledRect(finalPaintRect, dpratio));

    drawSelections(paint);
    drawPlayPointer(paint);

    paint.end();

    QFrame::paintEvent(e);
}

void
View::drawSelections(QPainter &paint)
{
    if (!hasTopLayerTimeXAxis()) return;

    MultiSelection::SelectionList selections;

    if (m_manager) {
        selections = m_manager->getSelections();
        if (m_manager->haveInProgressSelection()) {
            bool exclusive;
            Selection inProgressSelection =
                m_manager->getInProgressSelection(exclusive);
            if (exclusive) selections.clear();
            selections.insert(inProgressSelection);
        }
    }

    paint.save();

    bool translucent = !areLayerColoursSignificant();

    if (translucent) {
        paint.setBrush(QColor(150, 150, 255, 80));
    } else {
        paint.setBrush(Qt::NoBrush);
    }

    sv_samplerate_t sampleRate = getModelsSampleRate();

    QPoint localPos;
    sv_frame_t illuminateFrame = -1;
    bool closeToLeft, closeToRight;

    if (shouldIlluminateLocalSelection(localPos, closeToLeft, closeToRight)) {
        illuminateFrame = getFrameForX(localPos.x());
    }

    const QFontMetrics &metrics = paint.fontMetrics();

    for (MultiSelection::SelectionList::iterator i = selections.begin();
         i != selections.end(); ++i) {

        int p0 = getXForFrame(alignFromReference(i->getStartFrame()));
        int p1 = getXForFrame(alignFromReference(i->getEndFrame()));

        if (p1 < 0 || p0 > width()) continue;

#ifdef DEBUG_VIEW_WIDGET_PAINT
        SVDEBUG << "View::drawSelections: " << p0 << ",-1 [" << (p1-p0) << "x" << (height()+1) << "]" << endl;
#endif

        bool illuminateThis =
            (illuminateFrame >= 0 && i->contains(illuminateFrame));

        double h = height();
        double penWidth = scalePenWidth(1.0);
        double half = penWidth/2.0;

        paint.setPen(QPen(QColor(150, 150, 255), penWidth));

        if (translucent && shouldLabelSelections()) {
            paint.drawRect(QRectF(p0, -penWidth, p1 - p0, h + 2*penWidth));
        } else {
            // Make the top & bottom lines of the box visible if we
            // are lacking some of the other visual cues.  There's no
            // particular logic to this, it's just a question of what
            // I happen to think looks nice.
            paint.drawRect(QRectF(p0, half, p1 - p0, h - penWidth));
        }

        if (illuminateThis) {
            paint.save();
            penWidth = scalePenWidth(2.0);
            half = penWidth/2.0;
            paint.setPen(QPen(getForeground(), penWidth));
            if (closeToLeft) {
                paint.drawLine(QLineF(p0, half, p1, half));
                paint.drawLine(QLineF(p0, half, p0, h - half));
                paint.drawLine(QLineF(p0, h - half, p1, h - half));
            } else if (closeToRight) {
                paint.drawLine(QLineF(p0, half, p1, half));
                paint.drawLine(QLineF(p1, half, p1, h - half));
                paint.drawLine(QLineF(p0, h - half, p1, h - half));
            } else {
                paint.setBrush(Qt::NoBrush);
                paint.drawRect(QRectF(p0, half, p1 - p0, h - penWidth));
            }
            paint.restore();
        }

        if (sampleRate && shouldLabelSelections() && m_manager &&
            m_manager->shouldShowSelectionExtents()) {
            
            QString startText = QString("%1 / %2")
                .arg(QString::fromStdString
                     (RealTime::frame2RealTime
                      (i->getStartFrame(), sampleRate).toText(true)))
                .arg(i->getStartFrame());
            
            QString endText = QString(" %1 / %2")
                .arg(QString::fromStdString
                     (RealTime::frame2RealTime
                      (i->getEndFrame(), sampleRate).toText(true)))
                .arg(i->getEndFrame());
            
            QString durationText = QString("(%1 / %2) ")
                .arg(QString::fromStdString
                     (RealTime::frame2RealTime
                      (i->getEndFrame() - i->getStartFrame(), sampleRate)
                      .toText(true)))
                .arg(i->getEndFrame() - i->getStartFrame());
            
    // Qt 5.13 deprecates QFontMetrics::width(), but its suggested
    // replacement (horizontalAdvance) was only added in Qt 5.11
    // which is too new for us
#pragma GCC diagnostic ignored "-Wdeprecated-declarations"

            int sw = metrics.width(startText),
                ew = metrics.width(endText),
                dw = metrics.width(durationText);

            int sy = metrics.ascent() + metrics.height() + 4;
            int ey = sy;
            int dy = sy + metrics.height();

            int sx = p0 + 2;
            int ex = sx;
            int dx = sx;

            bool durationBothEnds = true;

            if (sw + ew > (p1 - p0)) {
                ey += metrics.height();
                dy += metrics.height();
                durationBothEnds = false;
            }

            if (ew < (p1 - p0)) {
                ex = p1 - 2 - ew;
            }

            if (dw < (p1 - p0)) {
                dx = p1 - 2 - dw;
            }

            PaintAssistant::drawVisibleText(this, paint, sx, sy, startText,
                                            PaintAssistant::OutlinedText);
            PaintAssistant::drawVisibleText(this, paint, ex, ey, endText,
                                            PaintAssistant::OutlinedText);
            PaintAssistant::drawVisibleText(this, paint, dx, dy, durationText,
                                            PaintAssistant::OutlinedText);
            if (durationBothEnds) {
                PaintAssistant::drawVisibleText(this, paint, sx, dy, durationText,
                                                PaintAssistant::OutlinedText);
            }
        }
    }

    paint.restore();
}

void
View::drawPlayPointer(QPainter &paint)
{
    bool showPlayPointer = true;

    if (m_followPlay == PlaybackScrollContinuous) {
        showPlayPointer = false;
    } else if (m_playPointerFrame <= getStartFrame() ||
               m_playPointerFrame >= getEndFrame()) {
        showPlayPointer = false;
    } else if (m_manager && !m_manager->isPlaying()) {
        if (m_playPointerFrame == getCentreFrame() &&
            m_manager->shouldShowCentreLine() &&
            m_followPlay != PlaybackIgnore) {
            // Don't show the play pointer when it is redundant with
            // the centre line
            showPlayPointer = false;
        }
    }
    
    if (showPlayPointer) {

        int playx = getXForFrame(m_playPointerFrame);
        
        paint.setPen(getForeground());
        paint.drawLine(playx - 1, 0, playx - 1, height() - 1);
        paint.drawLine(playx + 1, 0, playx + 1, height() - 1);
        paint.drawPoint(playx, 0);
        paint.drawPoint(playx, height() - 1);
        paint.setPen(getBackground());
        paint.drawLine(playx, 1, playx, height() - 2);
    }
}

void
View::drawMeasurementRect(QPainter &paint, const Layer *topLayer, QRect r,
                          bool focus) const
{
//    SVDEBUG << "View::drawMeasurementRect(" << r.x() << "," << r.y() << " "
//              << r.width() << "x" << r.height() << ")" << endl;

    if (r.x() + r.width() < 0 || r.x() >= width()) return;

    if (r.width() != 0 || r.height() != 0) {
        paint.save();
        if (focus) {
            paint.setPen(Qt::NoPen);
            QColor brushColour(Qt::black);
            brushColour.setAlpha(hasLightBackground() ? 15 : 40);
            paint.setBrush(brushColour);
            if (r.x() > 0) {
                paint.drawRect(0, 0, r.x(), height());
            }
            if (r.x() + r.width() < width()) {
                paint.drawRect(r.x() + r.width(), 0, width()-r.x()-r.width(), height());
            }
            if (r.y() > 0) {
                paint.drawRect(r.x(), 0, r.width(), r.y());
            }
            if (r.y() + r.height() < height()) {
                paint.drawRect(r.x(), r.y() + r.height(), r.width(), height()-r.y()-r.height());
            }
            paint.setBrush(Qt::NoBrush);
        }
        paint.setPen(Qt::green);
        paint.drawRect(r);
        paint.restore();
    } else {
        paint.save();
        paint.setPen(Qt::green);
        paint.drawPoint(r.x(), r.y());
        paint.restore();
    }

    if (!focus) return;

    paint.save();
    QFont fn = paint.font();
    if (fn.pointSize() > 8) {
        fn.setPointSize(fn.pointSize() - 1);
        paint.setFont(fn);
    }

    int fontHeight = paint.fontMetrics().height();
    int fontAscent = paint.fontMetrics().ascent();

    double v0, v1;
    QString u0, u1;
    bool b0 = false, b1 = false;

    QString axs, ays, bxs, bys, dxs, dys;

    int axx, axy, bxx, bxy, dxx, dxy;
    int aw = 0, bw = 0, dw = 0;
    
    int labelCount = 0;

    // top-left point, x-coord

    if ((b0 = topLayer->getXScaleValue(this, r.x(), v0, u0))) {
        axs = QString("%1 %2").arg(v0).arg(u0);
        if (u0 == "Hz" && Pitch::isFrequencyInMidiRange(v0)) {
            axs = QString("%1 (%2)").arg(axs)
                .arg(Pitch::getPitchLabelForFrequency(v0));
        }
        aw = paint.fontMetrics().width(axs);
        ++labelCount;
    }

    // bottom-right point, x-coord
        
    if (r.width() > 0) {
        if ((b1 = topLayer->getXScaleValue(this, r.x() + r.width(), v1, u1))) {
            bxs = QString("%1 %2").arg(v1).arg(u1);
            if (u1 == "Hz" && Pitch::isFrequencyInMidiRange(v1)) {
                bxs = QString("%1 (%2)").arg(bxs)
                    .arg(Pitch::getPitchLabelForFrequency(v1));
            }
            bw = paint.fontMetrics().width(bxs);
        }
    }

    // dimension, width
        
    if (b0 && b1 && v1 != v0 && u0 == u1) {
        dxs = QString("[%1 %2]").arg(fabs(v1 - v0)).arg(u1);
        dw = paint.fontMetrics().width(dxs);
    }
    
    b0 = false;
    b1 = false;

    // top-left point, y-coord

    if ((b0 = topLayer->getYScaleValue(this, r.y(), v0, u0))) {
        ays = QString("%1 %2").arg(v0).arg(u0);
        if (u0 == "Hz" && Pitch::isFrequencyInMidiRange(v0)) {
            ays = QString("%1 (%2)").arg(ays)
                .arg(Pitch::getPitchLabelForFrequency(v0));
        }
        aw = std::max(aw, paint.fontMetrics().width(ays));
        ++labelCount;
    }

    // bottom-right point, y-coord

    if (r.height() > 0) {
        if ((b1 = topLayer->getYScaleValue(this, r.y() + r.height(), v1, u1))) {
            bys = QString("%1 %2").arg(v1).arg(u1);
            if (u1 == "Hz" && Pitch::isFrequencyInMidiRange(v1)) {
                bys = QString("%1 (%2)").arg(bys)
                    .arg(Pitch::getPitchLabelForFrequency(v1));
            }
            bw = std::max(bw, paint.fontMetrics().width(bys));
        }
    }

    bool bd = false;
    double dy = 0.f;
    QString du;

    // dimension, height
        
    if ((bd = topLayer->getYScaleDifference(this, r.y(), r.y() + r.height(),
                                            dy, du)) &&
        dy != 0) {
        if (du != "") {
            if (du == "Hz") {
                int semis;
                double cents;
                semis = Pitch::getPitchForFrequencyDifference(v0, v1, &cents);
                dys = QString("[%1 %2 (%3)]")
                    .arg(dy).arg(du)
                    .arg(Pitch::getLabelForPitchRange(semis, cents));
            } else {
                dys = QString("[%1 %2]").arg(dy).arg(du);
            }
        } else {
            dys = QString("[%1]").arg(dy);
        }
        dw = std::max(dw, paint.fontMetrics().width(dys));
    }

    int mw = r.width();
    int mh = r.height();

    bool edgeLabelsInside = false;
    bool sizeLabelsInside = false;

    if (mw < std::max(aw, std::max(bw, dw)) + 4) {
        // defaults stand
    } else if (mw < aw + bw + 4) {
        if (mh > fontHeight * labelCount * 3 + 4) {
            edgeLabelsInside = true;
            sizeLabelsInside = true;
        } else if (mh > fontHeight * labelCount * 2 + 4) {
            edgeLabelsInside = true;
        }
    } else if (mw < aw + bw + dw + 4) {
        if (mh > fontHeight * labelCount * 3 + 4) {
            edgeLabelsInside = true;
            sizeLabelsInside = true;
        } else if (mh > fontHeight * labelCount + 4) {
            edgeLabelsInside = true;
        }
    } else {
        if (mh > fontHeight * labelCount + 4) {
            edgeLabelsInside = true;
            sizeLabelsInside = true;
        }
    }

    if (edgeLabelsInside) {

        axx = r.x() + 2;
        axy = r.y() + fontAscent + 2;

        bxx = r.x() + r.width() - bw - 2;
        bxy = r.y() + r.height() - (labelCount-1) * fontHeight - 2;

    } else {

        axx = r.x() - aw - 2;
        axy = r.y() + fontAscent;
        
        bxx = r.x() + r.width() + 2;
        bxy = r.y() + r.height() - (labelCount-1) * fontHeight;
    }

    dxx = r.width()/2 + r.x() - dw/2;

    if (sizeLabelsInside) {

        dxy = r.height()/2 + r.y() - (labelCount * fontHeight)/2 + fontAscent;

    } else {

        dxy = r.y() + r.height() + fontAscent + 2;
    }
    
    if (axs != "") {
        PaintAssistant::drawVisibleText(this, paint, axx, axy, axs, PaintAssistant::OutlinedText);
        axy += fontHeight;
    }
    
    if (ays != "") {
        PaintAssistant::drawVisibleText(this, paint, axx, axy, ays, PaintAssistant::OutlinedText);
        axy += fontHeight;
    }

    if (bxs != "") {
        PaintAssistant::drawVisibleText(this, paint, bxx, bxy, bxs, PaintAssistant::OutlinedText);
        bxy += fontHeight;
    }

    if (bys != "") {
        PaintAssistant::drawVisibleText(this, paint, bxx, bxy, bys, PaintAssistant::OutlinedText);
        bxy += fontHeight;
    }

    if (dxs != "") {
        PaintAssistant::drawVisibleText(this, paint, dxx, dxy, dxs, PaintAssistant::OutlinedText);
        dxy += fontHeight;
    }

    if (dys != "") {
        PaintAssistant::drawVisibleText(this, paint, dxx, dxy, dys, PaintAssistant::OutlinedText);
        dxy += fontHeight;
    }

    paint.restore();
}

bool
View::render(QPainter &paint, int xorigin, sv_frame_t f0, sv_frame_t f1)
{
    int x0 = int(round(m_zoomLevel.framesToPixels(double(f0))));
    int x1 = int(round(m_zoomLevel.framesToPixels(double(f1))));

    int w = x1 - x0;

    sv_frame_t origCentreFrame = m_centreFrame;

    bool someLayersIncomplete = false;

    for (LayerList::iterator i = m_layerStack.begin();
         i != m_layerStack.end(); ++i) {

        int c = (*i)->getCompletion(this);
        if (c < 100) {
            someLayersIncomplete = true;
            break;
        }
    }

    if (someLayersIncomplete) {

        QProgressDialog progress(tr("Waiting for layers to be ready..."),
                                 tr("Cancel"), 0, 100, this);
        
        int layerCompletion = 0;

        while (layerCompletion < 100) {

            for (LayerList::iterator i = m_layerStack.begin();
                 i != m_layerStack.end(); ++i) {

                int c = (*i)->getCompletion(this);
                if (i == m_layerStack.begin() || c < layerCompletion) {
                    layerCompletion = c;
                }
            }

            if (layerCompletion >= 100) break;

            progress.setValue(layerCompletion);
            qApp->processEvents();
            if (progress.wasCanceled()) {
                update();
                return false;
            }

            usleep(50000);
        }
    }

    QProgressDialog progress(tr("Rendering image..."),
                             tr("Cancel"), 0, w / width(), this);

    for (int x = 0; x < w; x += width()) {

        progress.setValue(x / width());
        qApp->processEvents();
        if (progress.wasCanceled()) {
            m_centreFrame = origCentreFrame;
            update();
            return false;
        }

        m_centreFrame = f0 + sv_frame_t(round(m_zoomLevel.pixelsToFrames
                                              (x + width()/2)));
        
        QRect chunk(0, 0, width(), height());

        paint.setPen(getBackground());
        paint.setBrush(getBackground());

        paint.drawRect(QRect(xorigin + x, 0, width(), height()));

        paint.setPen(getForeground());
        paint.setBrush(Qt::NoBrush);

        for (LayerList::iterator i = m_layerStack.begin();
             i != m_layerStack.end(); ++i) {
            if (!((*i)->isLayerDormant(this))){

                paint.setRenderHint(QPainter::Antialiasing, false);

                paint.save();
                paint.translate(xorigin + x, 0);

                SVCERR << "Centre frame now: " << m_centreFrame << " drawing to " << chunk.x() + x + xorigin << ", " << chunk.width() << endl;

                (*i)->setSynchronousPainting(true);

                (*i)->paint(this, paint, chunk);

                (*i)->setSynchronousPainting(false);

                paint.restore();
            }
        }
    }

    m_centreFrame = origCentreFrame;
    update();
    return true;
}

QImage *
View::renderToNewImage()
{
    sv_frame_t f0 = getModelsStartFrame();
    sv_frame_t f1 = getModelsEndFrame();

    return renderPartToNewImage(f0, f1);
}

QImage *
View::renderPartToNewImage(sv_frame_t f0, sv_frame_t f1)
{
    int x0 = int(round(getZoomLevel().framesToPixels(double(f0))));
    int x1 = int(round(getZoomLevel().framesToPixels(double(f1))));
    
    QImage *image = new QImage(x1 - x0, height(), QImage::Format_RGB32);

    QPainter *paint = new QPainter(image);
    if (!render(*paint, 0, f0, f1)) {
        delete paint;
        delete image;
        return nullptr;
    } else {
        delete paint;
        return image;
    }
}

QSize
View::getRenderedImageSize()
{
    sv_frame_t f0 = getModelsStartFrame();
    sv_frame_t f1 = getModelsEndFrame();

    return getRenderedPartImageSize(f0, f1);
}
    
QSize
View::getRenderedPartImageSize(sv_frame_t f0, sv_frame_t f1)
{
    int x0 = int(round(getZoomLevel().framesToPixels(double(f0))));
    int x1 = int(round(getZoomLevel().framesToPixels(double(f1))));

    return QSize(x1 - x0, height());
}

bool
View::renderToSvgFile(QString filename)
{
    sv_frame_t f0 = getModelsStartFrame();
    sv_frame_t f1 = getModelsEndFrame();

    return renderPartToSvgFile(filename, f0, f1);
}

bool
View::renderPartToSvgFile(QString filename, sv_frame_t f0, sv_frame_t f1)
{
    int x0 = int(round(getZoomLevel().framesToPixels(double(f0))));
    int x1 = int(round(getZoomLevel().framesToPixels(double(f1))));

    QSvgGenerator generator;
    generator.setFileName(filename);
    generator.setSize(QSize(x1 - x0, height()));
    generator.setViewBox(QRect(0, 0, x1 - x0, height()));
    generator.setTitle(tr("Exported image from %1")
                       .arg(QApplication::applicationName()));
    
    QPainter paint;
    paint.begin(&generator);
    bool result = render(paint, 0, f0, f1);
    paint.end();
    return result;
}

void
View::toXml(QTextStream &stream,
            QString indent, QString extraAttributes) const
{
    stream << indent;

    int classicZoomValue, deepZoomValue;

    if (m_zoomLevel.zone == ZoomLevel::FramesPerPixel) {
        classicZoomValue = m_zoomLevel.level;
        deepZoomValue = 1;
    } else {
        classicZoomValue = 1;
        deepZoomValue = m_zoomLevel.level;
    }

    stream << QString("<view "
                      "centre=\"%1\" "
                      "zoom=\"%2\" "
                      "deepZoom=\"%3\" "
                      "followPan=\"%4\" "
                      "followZoom=\"%5\" "
                      "tracking=\"%6\" "
                      " %7>\n")
        .arg(m_centreFrame)
        .arg(classicZoomValue)
        .arg(deepZoomValue)
        .arg(m_followPan)
        .arg(m_followZoom)
        .arg(m_followPlay == PlaybackScrollContinuous ? "scroll" :
             m_followPlay == PlaybackScrollPageWithCentre ? "page" :
             m_followPlay == PlaybackScrollPage ? "daw" :
             "ignore")
        .arg(extraAttributes);

    for (int i = 0; i < (int)m_fixedOrderLayers.size(); ++i) {
        bool visible = !m_fixedOrderLayers[i]->isLayerDormant(this);
        m_fixedOrderLayers[i]->toBriefXml(stream, indent + "  ",
                                          QString("visible=\"%1\"")
                                          .arg(visible ? "true" : "false"));
    }

    stream << indent + "</view>\n";
}

ViewPropertyContainer::ViewPropertyContainer(View *v) :
    m_v(v)
{
//    SVCERR << "ViewPropertyContainer: " << getId() << " is owned by View " << v << endl;
    connect(m_v, SIGNAL(propertyChanged(PropertyContainer::PropertyName)),
            this, SIGNAL(propertyChanged(PropertyContainer::PropertyName)));
}

ViewPropertyContainer::~ViewPropertyContainer()
{
}