annotate view/View.cpp @ 1127:9fb8dfd7ce4c spectrogram-minor-refactor

Fix threshold in spectrogram -- it wasn't working in the last release.
There is a new protocol for this. Formerly the threshold parameter had a
range from -50dB to 0 with the default at -50, and -50 treated internally
as "no threshold". However, there was a hardcoded, hidden internal threshold
for spectrogram colour mapping at -80dB with anything below this being rounded
to zero. Now the threshold parameter has range -81 to -1 with the default
at -80, -81 is treated internally as "no threshold", and there is no hidden
internal threshold. So the default behaviour is the same as before, an
effective -80dB threshold, but it is now possible to change this in both
directions. Sessions reloaded from prior versions may look slightly different
because, if the session says there should be no threshold, there will now
actually be no threshold instead of having the hidden internal one.

Still need to do something in the UI to make it apparent that the -81dB
setting removes the threshold entirely. This is at least no worse than the
previous, also obscured, magic -50dB setting.

/* -*- 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 "ViewProxy.h"

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

#include "data/model/PowerOfSqrtTwoZoomConstraint.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 <iostream>
#include <cassert>
#include <cmath>

#include <unistd.h>

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

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

View::~View()
{
//    cerr << "View::~View(" << this << ")" << endl;

    m_deleting = true;
    delete m_propertyContainer;
}

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[getObjectExportId(*i)] = *i;
        }
    }

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

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

    delete m_cache;
    m_cache = 0;

    Layer *selectedLayer = 0;

    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()
{
    delete m_cache;
    m_cache = 0;
    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 + m_zoomLevel * (width() / 2));
}

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

    if (m_centreFrame != f) {

	int formerPixel = int(m_centreFrame / m_zoomLevel);

	m_centreFrame = f;

	int newPixel = int(m_centreFrame / m_zoomLevel);
	
	if (newPixel != formerPixel) {

#ifdef DEBUG_VIEW_WIDGET_PAINT
	    cout << "View(" << this << ")::setCentreFrame: newPixel " << newPixel << ", formerPixel " << formerPixel << endl;
#endif
	    update();

	    changeVisible = true;
	}

	if (e) {
            sv_frame_t rf = alignToReference(f);
#ifdef DEBUG_VIEW
            cerr << "View[" << this << "]::setCentreFrame(" << f
                      << "): emitting centreFrameChanged("
                      << rf << ")" << endl;
#endif
            emit centreFrameChanged(rf, m_followPan, m_followPlay);
        }
    }

    return changeVisible;
}

int
View::getXForFrame(sv_frame_t frame) const
{
    return int((frame - getStartFrame()) / m_zoomLevel);
}

sv_frame_t
View::getFrameForX(int x) const
{
    sv_frame_t z = m_zoomLevel; // nb not just int, or multiplication may overflow
    sv_frame_t frame = m_centreFrame - (width()/2) * z;

    frame = (frame / z) * z; // this is start frame
    frame = frame + x * z;

#ifdef DEBUG_VIEW_WIDGET_PAINT
    cerr << "View::getFrameForX(" << x << "): z = " << z << ", m_centreFrame = " << m_centreFrame << ", width() = " << width() << ", frame = " << frame << endl;
#endif

    return frame;
}

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;
    }
}

int
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(int z)
{
    int dpratio = effectiveDevicePixelRatio();
    if (z < dpratio) return;
    if (z < 1) z = 1;
    if (m_zoomLevel != int(z)) {
	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::ColourAndBackgroundSignificant)) {
        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.light();
        } else {
            return widgetbg.dark();
        }
    }
    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)
{
    delete m_cache;
    m_cache = 0;

    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("fileclose"));
    cancel->setFlat(true);
    cancel->setFixedSize(QSize(20, 20));
    connect(cancel, SIGNAL(clicked()), this, SLOT(cancelClicked()));
    
    ProgressBarRec pbr;
    pbr.cancel = cancel;
    pbr.bar = pb;
    pbr.lastCheck = 0;
    pbr.checkTimer = new QTimer();
    connect(pbr.checkTimer, 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()),
	    this,    SLOT(modelChanged()));
    connect(layer, SIGNAL(modelCompletionChanged()),
	    this,    SLOT(modelCompletionChanged()));
    connect(layer, SIGNAL(modelAlignmentCompletionChanged()),
	    this,    SLOT(modelAlignmentCompletionChanged()));
    connect(layer, SIGNAL(modelChangedWithin(sv_frame_t, sv_frame_t)),
	    this,    SLOT(modelChangedWithin(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;
    }

    delete m_cache;
    m_cache = 0;

    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].checkTimer;
		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()),
               this,    SLOT(modelChanged()));
    disconnect(layer, SIGNAL(modelCompletionChanged()),
               this,    SLOT(modelCompletionChanged()));
    disconnect(layer, SIGNAL(modelAlignmentCompletionChanged()),
               this,    SLOT(modelAlignmentCompletionChanged()));
    disconnect(layer, SIGNAL(modelChangedWithin(sv_frame_t, sv_frame_t)),
               this,    SLOT(modelChangedWithin(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 0;
}

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 0;
    }
}

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 *, int, 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(int, 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 *, int, bool)),
	    this, SLOT(viewZoomLevelChanged(View *, int, 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(int, bool)),
	    m_manager, SLOT(viewZoomLevelChanged(int, 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()
{
    QObject *obj = sender();

#ifdef DEBUG_VIEW_WIDGET_PAINT
    cerr << "View(" << this << ")::modelChanged()" << 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 == obj || (*i)->getModel() == obj) {
	    recreate = true;
	    break;
	}
    }

    if (recreate) {
	delete m_cache;
	m_cache = 0;
    }

    emit layerModelChanged();

    checkProgress(obj);

    update();
}

void
View::modelChangedWithin(sv_frame_t startFrame, sv_frame_t endFrame)
{
    QObject *obj = sender();

    sv_frame_t myStartFrame = getStartFrame();
    sv_frame_t myEndFrame = getEndFrame();

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

    if (myStartFrame > 0 && endFrame < myStartFrame) {
	checkProgress(obj);
	return;
    }
    if (startFrame > myEndFrame) {
	checkProgress(obj);
	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 == obj || (*i)->getModel() == obj) {
	    recreate = true;
	    break;
	}
    }

    if (recreate) {
	delete m_cache;
	m_cache = 0;
    }

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

    checkProgress(obj);

    update();
}    

void
View::modelCompletionChanged()
{
//    cerr << "View(" << this << ")::modelCompletionChanged()" << endl;

    QObject *obj = sender();
    checkProgress(obj);
}

void
View::modelAlignmentCompletionChanged()
{
//    cerr << "View(" << this << ")::modelAlignmentCompletionChanged()" << endl;

    QObject *obj = sender();
    checkProgress(obj);
}

void
View::modelReplaced()
{
#ifdef DEBUG_VIEW_WIDGET_PAINT
    cerr << "View(" << this << ")::modelReplaced()" << endl;
#endif
    delete m_cache;
    m_cache = 0;

    update();
}

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

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

    delete m_cache;
    m_cache = 0;
    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
        cerr << "View[" << this << "]::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        
    cerr << "View::viewManagerPlaybackFrameChanged(" << f << ")" << endl;
#endif

    f = getAlignedPlaybackFrame();

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

    movePlayPointer(f);
}

void
View::movePlayPointer(sv_frame_t newFrame)
{
#ifdef DEBUG_VIEW
    cerr << "View(" << this << ")::movePlayPointer(" << newFrame << ")" << endl;
#endif

    if (m_playPointerFrame == newFrame) return;
    bool visibleChange =
        (getXForFrame(m_playPointerFrame) != getXForFrame(newFrame));
    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 / 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
            cerr << "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
            cerr << "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, int z, bool locked)
{
#ifdef DEBUG_VIEW_WIDGET_PAINT
    cerr  << "View[" << this << "]: viewZoomLevelChanged(" << p << ", " << z << ", " << locked << ")" << endl;
#endif
    if (m_followZoom && p != this && locked) {
        setZoomLevel(z);
    }
}

void
View::selectionChanged()
{
    if (m_selectionCached) {
	delete m_cache;
	m_cache = 0;
	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 (LayerList::const_iterator i = m_layerStack.begin(); i != m_layerStack.end(); ++i) {

	if ((*i)->getModel() && (*i)->getModel()->isOK()) {

	    sv_frame_t thisStartFrame = (*i)->getModel()->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 (LayerList::const_iterator i = m_layerStack.begin(); i != m_layerStack.end(); ++i) {

	if ((*i)->getModel() && (*i)->getModel()->isOK()) {

	    sv_frame_t thisEndFrame = (*i)->getModel()->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 (LayerList::const_iterator i = m_layerStack.begin(); i != m_layerStack.end(); ++i) {
	if ((*i)->getModel() && (*i)->getModel()->isOK()) {
	    return (*i)->getModel()->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()) {
            Model *model = layer->getModel();
            models.insert(model);
        }
    }

    return models;
}

Model *
View::getAligningModel() const
{
    if (!m_manager ||
        !m_manager->getAlignMode() ||
        !m_manager->getPlaybackModel()) {
        return 0;
    }

    Model *anyModel = 0;
    Model *alignedModel = 0;
    Model *goodModel = 0;

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

        Layer *layer = *i;

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

        Model *model = (*i)->getModel();
        if (!model) continue;

        anyModel = model;

        if (model->getAlignmentReference()) {
            alignedModel = model;
            if (layer->isLayerOpaque() ||
                dynamic_cast<RangeSummarisableTimeValueModel *>(model)) {
                goodModel = model;
            }
        }
    }

    if (goodModel) return goodModel;
    else if (alignedModel) return alignedModel;
    else return anyModel;
}

sv_frame_t
View::alignFromReference(sv_frame_t f) const
{
    if (!m_manager || !m_manager->getAlignMode()) return f;
    Model *aligningModel = 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;
    Model *aligningModel = 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;

    Model *aligningModel = 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;
//        cerr << "(name is " << (*i)->objectName() << ")"
//                  << endl;
//        SVDEBUG << "View::getScrollableBackLayers: I am " << this << 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;
}

int
View::getZoomConstraintBlockSize(int blockSize,
				 ZoomConstraint::RoundingDirection dir)
    const
{
    int candidate = blockSize;
    bool haveCandidate = false;

    PowerOfSqrtTwoZoomConstraint defaultZoomConstraint;

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

	const ZoomConstraint *zoomConstraint = (*i)->getZoomConstraint();
	if (!zoomConstraint) zoomConstraint = &defaultZoomConstraint;

	int thisBlockSize =
	    zoomConstraint->getNearestBlockSize(blockSize, dir);

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

    return candidate;
}

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)
{
    int newZoomLevel = m_zoomLevel;

    if (in) {
	newZoomLevel = getZoomConstraintBlockSize(newZoomLevel - 1, 
						  ZoomConstraint::RoundDown);
    } else {
	newZoomLevel = getZoomConstraintBlockSize(newZoomLevel + 1,
						  ZoomConstraint::RoundUp);
    }

    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;

    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;

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

        if (i->second.cancel == cancel) {

            Layer *layer = i->first;
            Model *model = layer->getModel();

            if (model) model->abandon();
        }
    }
}

void
View::checkProgress(void *object)
{
    if (!m_showProgress) return;

    int ph = 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 == object) {

            // 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.checkTimer;

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

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

            Model *model = i->first->getModel();
            RangeSummarisableTimeValueModel *wfm = 
                dynamic_cast<RangeSummarisableTimeValueModel *>(model);

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

            if (completion >= 100) {

                //!!!
                if (wfm ||
                    (model && 
                     (wfm = dynamic_cast<RangeSummarisableTimeValueModel *>
                      (model->getSourceModel())))) {
                    completion = wfm->getAlignmentCompletion();
//                    SVDEBUG << "View::checkProgress: Alignment completion = " << completion << endl;
                    if (completion < 100) {
                        text = tr("Alignment");
                    }
                }

            } else if (wfm) {
                update(); // ensure duration &c gets updated
            }

	    if (completion >= 100) {

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

	    } else {

//                cerr << "progress = " << completion << endl;

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

                cancel->move(0, ph - pb->height()/2 - 10);
                cancel->show();

		pb->setValue(completion);
		pb->move(20, ph - pb->height());

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

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

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.checkTimer == t) {
            int value = i->second.bar->value();
            if (value > 0 && value == i->second.lastCheck) {
                i->second.bar->setMaximum(0); // indeterminate
            }
            i->second.lastCheck = value;
            return;
        }
    }
}

int
View::getProgressBarWidth() const
{
    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);
//    cerr << "View::paintEvent: centre frame is " << m_centreFrame << endl;

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

    // ensure our constraints are met

/*!!! Should we do this only if we have layers that can't support other
  zoom levels?

    m_zoomLevel = getZoomConstraintBlockSize(m_zoomLevel,
					     ZoomConstraint::RoundUp);
*/

    QPainter paint;
    bool repaintCache = false;
    bool paintedCacheRect = false;

    QRect cacheRect(rect());

    if (e) {
	cacheRect &= e->rect();
#ifdef DEBUG_VIEW_WIDGET_PAINT
	cerr << "paint rect " << cacheRect.width() << "x" << cacheRect.height()
		  << ", my rect " << width() << "x" << height() << endl;
#endif
    }

    QRect nonCacheRect(cacheRect);

    int dpratio = effectiveDevicePixelRatio();

    // 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);
    bool selectionCacheable = nonScrollables.empty();
    bool haveSelections = m_manager && !m_manager->getSelections().empty();

    // If all the non-scrollable layers are non-opaque, then we draw
    // the selection rectangle behind them and cache it.  If any are
    // opaque, however, or if our device-pixel ratio is not 1 (so we
    // need to paint direct to the widget), then we can't cache.
    //
    if (dpratio == 1) {

        if (!selectionCacheable) {
            selectionCacheable = true;
            for (LayerList::const_iterator i = nonScrollables.begin();
                 i != nonScrollables.end(); ++i) {
                if ((*i)->isLayerOpaque()) {
                    selectionCacheable = false;
                    break;
                }
            }
        }

        if (selectionCacheable) {
            QPoint localPos;
            bool closeToLeft, closeToRight;
            if (shouldIlluminateLocalSelection
                (localPos, closeToLeft, closeToRight)) {
                selectionCacheable = false;
            }
        }

    } else {

        selectionCacheable = false;
    }

#ifdef DEBUG_VIEW_WIDGET_PAINT
    cerr << "View(" << this << ")::paintEvent: have " << scrollables.size()
	      << " scrollable back layers and " << nonScrollables.size()
	      << " non-scrollable front layers" << endl;
    cerr << "haveSelections " << haveSelections << ", selectionCacheable "
	      << selectionCacheable << ", m_selectionCached " << m_selectionCached << endl;
#endif

    if (layersChanged || scrollables.empty() ||
	(haveSelections && (selectionCacheable != m_selectionCached))) {
	delete m_cache;
	m_cache = 0;
	m_selectionCached = false;
    }

    QSize scaledCacheSize(scaledSize(size(), dpratio));
    QRect scaledCacheRect(scaledRect(cacheRect, dpratio));

    if (!m_buffer || scaledCacheSize != m_buffer->size()) {
        delete m_buffer;
        m_buffer = new QPixmap(scaledCacheSize);
    }
    
    if (!scrollables.empty()) {

#ifdef DEBUG_VIEW_WIDGET_PAINT
        cerr << "View(" << this << "): cache " << m_cache << ", cache zoom "
                  << m_cacheZoomLevel << ", zoom " << m_zoomLevel << endl;
#endif

	if (!m_cache ||
	    m_cacheZoomLevel != m_zoomLevel ||
            scaledCacheSize != m_cache->size()) {

	    // cache is not valid

	    if (cacheRect.width() < width()/10) {
		delete m_cache;
                m_cache = 0;
#ifdef DEBUG_VIEW_WIDGET_PAINT
		cerr << "View(" << this << ")::paintEvent: small repaint, not bothering to recreate cache" << endl;
#endif
	    } else {
		delete m_cache;
		m_cache = new QPixmap(scaledCacheSize);
#ifdef DEBUG_VIEW_WIDGET_PAINT
		cerr << "View(" << this << ")::paintEvent: recreated cache" << endl;
#endif
		cacheRect = rect();
		repaintCache = true;
	    }

	} else if (m_cacheCentreFrame != m_centreFrame) {

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

	    if (dx > -width() && dx < width()) {
		static QPixmap *tmpPixmap = 0;
		if (!tmpPixmap || tmpPixmap->size() != scaledCacheSize) {
		    delete tmpPixmap;
		    tmpPixmap = new QPixmap(scaledCacheSize);
		}
		paint.begin(tmpPixmap);
		paint.drawPixmap(0, 0, *m_cache);
		paint.end();
		paint.begin(m_cache);
		paint.drawPixmap(dx, 0, *tmpPixmap);
		paint.end();
		if (dx < 0) {
		    cacheRect = QRect(width() + dx, 0, -dx, height());
		} else {
		    cacheRect = QRect(0, 0, dx, height());
		}
#ifdef DEBUG_VIEW_WIDGET_PAINT
		cerr << "View(" << this << ")::paintEvent: scrolled cache by " << dx << endl;
#endif
	    } else {
		cacheRect = rect();
#ifdef DEBUG_VIEW_WIDGET_PAINT
		cerr << "View(" << this << ")::paintEvent: scrolling too far" << endl;
#endif
	    }
	    repaintCache = true;

	} else {
#ifdef DEBUG_VIEW_WIDGET_PAINT
	    cerr << "View(" << this << ")::paintEvent: cache is good" << endl;
#endif
	    paint.begin(m_buffer);
	    paint.drawPixmap(scaledCacheRect, *m_cache, scaledCacheRect);
	    paint.end();
	    QFrame::paintEvent(e);
	    paintedCacheRect = true;
	}

	m_cacheCentreFrame = m_centreFrame;
	m_cacheZoomLevel = m_zoomLevel;
    }

#ifdef DEBUG_VIEW_WIDGET_PAINT
//    cerr << "View(" << this << ")::paintEvent: cacheRect " << cacheRect << ", nonCacheRect " << (nonCacheRect | cacheRect) << ", repaintCache " << repaintCache << ", paintedCacheRect " << paintedCacheRect << endl;
#endif

    // Scrollable (cacheable) items first

    ViewProxy proxy(this, dpratio);
    
    if (!paintedCacheRect) {

        QRect rectToPaint;

	if (repaintCache) {
            paint.begin(m_cache);
            rectToPaint = scaledCacheRect;
        } else {
            paint.begin(m_buffer);
            rectToPaint = scaledCacheRect;
        }

        setPaintFont(paint);
	paint.setClipRect(rectToPaint);

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

	paint.setPen(getForeground());
	paint.setBrush(Qt::NoBrush);
	
	for (LayerList::iterator i = scrollables.begin(); i != scrollables.end(); ++i) {
	    paint.setRenderHint(QPainter::Antialiasing, false);
	    paint.save();
#ifdef DEBUG_VIEW_WIDGET_PAINT
            cerr << "Painting scrollable layer " << *i << " using proxy with repaintCache = " << repaintCache << ", dpratio = " << dpratio << ", rectToPaint = " << rectToPaint.x() << "," << rectToPaint.y() << " " << rectToPaint.width() << "x" << rectToPaint.height() << endl;
#endif
            (*i)->paint(&proxy, paint, rectToPaint);
	    paint.restore();
	}

	if (haveSelections && selectionCacheable) {
	    drawSelections(paint);
	    m_selectionCached = repaintCache;
	}
	
	paint.end();

	if (repaintCache) {
	    cacheRect |= (e ? e->rect() : rect());
            scaledCacheRect = scaledRect(cacheRect, dpratio);
	    paint.begin(m_buffer);
	    paint.drawPixmap(scaledCacheRect, *m_cache, scaledCacheRect);
	    paint.end();
	}
    }

    // Now non-cacheable items.  We always need to redraw the
    // non-cacheable items across at least the area we drew of the
    // cacheable items.

    nonCacheRect |= cacheRect;

    QRect scaledNonCacheRect = scaledRect(nonCacheRect, dpratio);
    
    paint.begin(m_buffer);
    paint.setClipRect(scaledNonCacheRect);
    setPaintFont(paint);
    if (scrollables.empty()) {
        paint.setPen(getBackground());
        paint.setBrush(getBackground());
	paint.drawRect(scaledNonCacheRect);
    }
	
    paint.setPen(getForeground());
    paint.setBrush(Qt::NoBrush);
	
    for (LayerList::iterator i = nonScrollables.begin(); i != nonScrollables.end(); ++i) {
//        Profiler profiler2("View::paintEvent non-cacheable");
#ifdef DEBUG_VIEW_WIDGET_PAINT
        cerr << "Painting non-scrollable layer " << *i << " without proxy with repaintCache = " << repaintCache << ", dpratio = " << dpratio << ", rectToPaint = " << nonCacheRect.x() << "," << nonCacheRect.y() << " " << nonCacheRect.width() << "x" << nonCacheRect.height() << endl;
#endif
	(*i)->paint(&proxy, paint, scaledNonCacheRect);
    }
	
    paint.end();
    
    paint.begin(this);
    QRect finalPaintRect = e ? e->rect() : rect();
    paint.drawPixmap(finalPaintRect, *m_buffer, scaledRect(finalPaintRect, dpratio));
    paint.end();

    paint.begin(this);
    setPaintFont(paint);
    if (e) paint.setClipRect(e->rect());
    if (!m_selectionCached) {
	drawSelections(paint);
    }
    paint.end();

    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) {

	paint.begin(this);

        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);

	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));

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

        if (translucent && shouldLabelSelections()) {
            paint.drawRect(p0, -1, p1 - p0, height() + 1);
        } 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(p0, 0, p1 - p0, height() - 1);
        }

	if (illuminateThis) {
	    paint.save();
            paint.setPen(QPen(getForeground(), 2));
	    if (closeToLeft) {
		paint.drawLine(p0, 1, p1, 1);
		paint.drawLine(p0, 0, p0, height());
		paint.drawLine(p0, height() - 1, p1, height() - 1);
	    } else if (closeToRight) {
		paint.drawLine(p0, 1, p1, 1);
		paint.drawLine(p1, 0, p1, height());
		paint.drawLine(p0, height() - 1, p1, height() - 1);
	    } else {
		paint.setBrush(Qt::NoBrush);
		paint.drawRect(p0, 1, p1 - p0, height() - 2);
	    }
	    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());

	    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;
	    }

	    paint.drawText(sx, sy, startText);
	    paint.drawText(ex, ey, endText);
	    paint.drawText(dx, dy, durationText);
            if (durationBothEnds) {
                paint.drawText(sx, dy, durationText);
            }
	}
    }

    paint.restore();
}

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(f0 / m_zoomLevel);
    int x1 = int(f1 / m_zoomLevel);

    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 + (x + width()/2) * m_zoomLevel;
        
        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);

                cerr << "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::toNewImage()
{
    sv_frame_t f0 = getModelsStartFrame();
    sv_frame_t f1 = getModelsEndFrame();

    return toNewImage(f0, f1);
}

QImage *
View::toNewImage(sv_frame_t f0, sv_frame_t f1)
{
    int x0 = int(f0 / getZoomLevel());
    int x1 = int(f1 / getZoomLevel());
    
    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 0;
    } else {
        delete paint;
        return image;
    }
}

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

    return getImageSize(f0, f1);
}
    
QSize
View::getImageSize(sv_frame_t f0, sv_frame_t f1)
{
    int x0 = int(f0 / getZoomLevel());
    int x1 = int(f1 / getZoomLevel());

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

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

    stream << QString("<view "
                      "centre=\"%1\" "
                      "zoom=\"%2\" "
                      "followPan=\"%3\" "
                      "followZoom=\"%4\" "
                      "tracking=\"%5\" "
                      " %6>\n")
	.arg(m_centreFrame)
	.arg(m_zoomLevel)
	.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)
{
//    cerr << "ViewPropertyContainer: " << this << " is owned by View " << v << endl;
    connect(m_v, SIGNAL(propertyChanged(PropertyContainer::PropertyName)),
	    this, SIGNAL(propertyChanged(PropertyContainer::PropertyName)));
}

ViewPropertyContainer::~ViewPropertyContainer()
{
}