Mercurial > hg > svgui
view layer/NoteLayer.cpp @ 128:33929e0c3c6b
* Reorganising code base. This revision probably should compile once more.
author | Chris Cannam |
---|---|
date | Mon, 31 Jul 2006 14:05:22 +0000 |
parents | 999ae0f7d10c |
children | 6b023411087b |
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/* -*- c-basic-offset: 4 indent-tabs-mode: nil -*- vi:set ts=8 sts=4 sw=4: */ /* Sonic Visualiser An audio file viewer and annotation editor. Centre for Digital Music, Queen Mary, University of London. This file copyright 2006 Chris Cannam. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; either version 2 of the License, or (at your option) any later version. See the file COPYING included with this distribution for more information. */ #include "NoteLayer.h" #include "data/model/Model.h" #include "base/RealTime.h" #include "base/Profiler.h" #include "base/Pitch.h" #include "view/View.h" #include "data/model/NoteModel.h" #include "widgets/ItemEditDialog.h" #include "SpectrogramLayer.h" // for optional frequency alignment #include <QPainter> #include <QPainterPath> #include <QMouseEvent> #include <iostream> #include <cmath> NoteLayer::NoteLayer() : Layer(), m_model(0), m_editing(false), m_originalPoint(0, 0.0, 0, tr("New Point")), m_editingPoint(0, 0.0, 0, tr("New Point")), m_editingCommand(0), m_colour(Qt::black), m_verticalScale(AutoAlignScale) { } void NoteLayer::setModel(NoteModel *model) { if (m_model == model) return; m_model = model; connect(m_model, SIGNAL(modelChanged()), this, SIGNAL(modelChanged())); connect(m_model, SIGNAL(modelChanged(size_t, size_t)), this, SIGNAL(modelChanged(size_t, size_t))); connect(m_model, SIGNAL(completionChanged()), this, SIGNAL(modelCompletionChanged())); // std::cerr << "NoteLayer::setModel(" << model << ")" << std::endl; emit modelReplaced(); } Layer::PropertyList NoteLayer::getProperties() const { PropertyList list; list.push_back("Colour"); list.push_back("Vertical Scale"); list.push_back("Scale Units"); return list; } QString NoteLayer::getPropertyLabel(const PropertyName &name) const { if (name == "Colour") return tr("Colour"); if (name == "Vertical Scale") return tr("Vertical Scale"); if (name == "Scale Units") return tr("Scale Units"); return ""; } Layer::PropertyType NoteLayer::getPropertyType(const PropertyName &name) const { if (name == "Scale Units") return UnitsProperty; return ValueProperty; } int NoteLayer::getPropertyRangeAndValue(const PropertyName &name, int *min, int *max) const { //!!! factor this colour handling stuff out into a colour manager class int deft = 0; if (name == "Colour") { if (min) *min = 0; if (max) *max = 5; if (m_colour == Qt::black) deft = 0; else if (m_colour == Qt::darkRed) deft = 1; else if (m_colour == Qt::darkBlue) deft = 2; else if (m_colour == Qt::darkGreen) deft = 3; else if (m_colour == QColor(200, 50, 255)) deft = 4; else if (m_colour == QColor(255, 150, 50)) deft = 5; } else if (name == "Vertical Scale") { if (min) *min = 0; if (max) *max = 3; deft = int(m_verticalScale); } else if (name == "Scale Units") { if (m_model) { deft = UnitDatabase::getInstance()->getUnitId (m_model->getScaleUnits()); } } else { deft = Layer::getPropertyRangeAndValue(name, min, max); } return deft; } QString NoteLayer::getPropertyValueLabel(const PropertyName &name, int value) const { if (name == "Colour") { switch (value) { default: case 0: return tr("Black"); case 1: return tr("Red"); case 2: return tr("Blue"); case 3: return tr("Green"); case 4: return tr("Purple"); case 5: return tr("Orange"); } } else if (name == "Vertical Scale") { switch (value) { default: case 0: return tr("Auto-Align"); case 1: return tr("Linear Scale"); case 2: return tr("Log Scale"); case 3: return tr("MIDI Note Range"); } } return tr("<unknown>"); } void NoteLayer::setProperty(const PropertyName &name, int value) { if (name == "Colour") { switch (value) { default: case 0: setBaseColour(Qt::black); break; case 1: setBaseColour(Qt::darkRed); break; case 2: setBaseColour(Qt::darkBlue); break; case 3: setBaseColour(Qt::darkGreen); break; case 4: setBaseColour(QColor(200, 50, 255)); break; case 5: setBaseColour(QColor(255, 150, 50)); break; } } else if (name == "Vertical Scale") { setVerticalScale(VerticalScale(value)); } else if (name == "Scale Units") { if (m_model) { m_model->setScaleUnits (UnitDatabase::getInstance()->getUnitById(value)); emit modelChanged(); } } } void NoteLayer::setBaseColour(QColor colour) { if (m_colour == colour) return; m_colour = colour; emit layerParametersChanged(); } void NoteLayer::setVerticalScale(VerticalScale scale) { if (m_verticalScale == scale) return; m_verticalScale = scale; emit layerParametersChanged(); } bool NoteLayer::isLayerScrollable(const View *v) const { QPoint discard; return !v->shouldIlluminateLocalFeatures(this, discard); } bool NoteLayer::shouldConvertMIDIToHz() const { QString unit = m_model->getScaleUnits(); return (unit != "Hz"); // if (unit == "" || // unit.startsWith("MIDI") || // unit.startsWith("midi")) return true; // return false; } bool NoteLayer::getValueExtents(float &min, float &max, bool &logarithmic, QString &unit) const { if (!m_model) return false; min = m_model->getValueMinimum(); max = m_model->getValueMaximum(); if (shouldConvertMIDIToHz()) { unit = "Hz"; min = Pitch::getFrequencyForPitch(lrintf(min)); max = Pitch::getFrequencyForPitch(lrintf(max + 1)); } else unit = m_model->getScaleUnits(); if (m_verticalScale == MIDIRangeScale || m_verticalScale == LogScale) logarithmic = true; return true; } bool NoteLayer::getDisplayExtents(float &min, float &max) const { if (!m_model || m_verticalScale == AutoAlignScale) return false; if (m_verticalScale == MIDIRangeScale) { min = Pitch::getFrequencyForPitch(0); max = Pitch::getFrequencyForPitch(127); return true; } min = m_model->getValueMinimum(); max = m_model->getValueMaximum(); if (shouldConvertMIDIToHz()) { min = Pitch::getFrequencyForPitch(lrintf(min)); max = Pitch::getFrequencyForPitch(lrintf(max + 1)); } return true; } NoteModel::PointList NoteLayer::getLocalPoints(View *v, int x) const { if (!m_model) return NoteModel::PointList(); long frame = v->getFrameForX(x); NoteModel::PointList onPoints = m_model->getPoints(frame); if (!onPoints.empty()) { return onPoints; } NoteModel::PointList prevPoints = m_model->getPreviousPoints(frame); NoteModel::PointList nextPoints = m_model->getNextPoints(frame); NoteModel::PointList usePoints = prevPoints; if (prevPoints.empty()) { usePoints = nextPoints; } else if (prevPoints.begin()->frame < v->getStartFrame() && !(nextPoints.begin()->frame > v->getEndFrame())) { usePoints = nextPoints; } else if (nextPoints.begin()->frame - frame < frame - prevPoints.begin()->frame) { usePoints = nextPoints; } if (!usePoints.empty()) { int fuzz = 2; int px = v->getXForFrame(usePoints.begin()->frame); if ((px > x && px - x > fuzz) || (px < x && x - px > fuzz + 1)) { usePoints.clear(); } } return usePoints; } QString NoteLayer::getFeatureDescription(View *v, QPoint &pos) const { int x = pos.x(); if (!m_model || !m_model->getSampleRate()) return ""; NoteModel::PointList points = getLocalPoints(v, x); if (points.empty()) { if (!m_model->isReady()) { return tr("In progress"); } else { return tr("No local points"); } } Note note(0); NoteModel::PointList::iterator i; for (i = points.begin(); i != points.end(); ++i) { int y = getYForValue(v, i->value); int h = 3; if (m_model->getValueQuantization() != 0.0) { h = y - getYForValue(v, i->value + m_model->getValueQuantization()); if (h < 3) h = 3; } if (pos.y() >= y - h && pos.y() <= y) { note = *i; break; } } if (i == points.end()) return tr("No local points"); RealTime rt = RealTime::frame2RealTime(note.frame, m_model->getSampleRate()); RealTime rd = RealTime::frame2RealTime(note.duration, m_model->getSampleRate()); QString pitchText; if (shouldConvertMIDIToHz()) { int mnote = lrintf(note.value); int cents = lrintf((note.value - mnote) * 100); float freq = Pitch::getFrequencyForPitch(mnote, cents); pitchText = QString("%1 (%2 Hz)") .arg(Pitch::getPitchLabel(mnote, cents)).arg(freq); } else if (m_model->getScaleUnits() == "Hz") { pitchText = QString("%1 Hz (%2)") .arg(note.value) .arg(Pitch::getPitchLabelForFrequency(note.value)); } else { pitchText = QString("%1 %2") .arg(note.value).arg(m_model->getScaleUnits()); } QString text; if (note.label == "") { text = QString(tr("Time:\t%1\nPitch:\t%2\nDuration:\t%3\nNo label")) .arg(rt.toText(true).c_str()) .arg(pitchText) .arg(rd.toText(true).c_str()); } else { text = QString(tr("Time:\t%1\nPitch:\t%2\nDuration:\t%3\nLabel:\t%4")) .arg(rt.toText(true).c_str()) .arg(pitchText) .arg(rd.toText(true).c_str()) .arg(note.label); } pos = QPoint(v->getXForFrame(note.frame), getYForValue(v, note.value)); return text; } bool NoteLayer::snapToFeatureFrame(View *v, int &frame, size_t &resolution, SnapType snap) const { if (!m_model) { return Layer::snapToFeatureFrame(v, frame, resolution, snap); } resolution = m_model->getResolution(); NoteModel::PointList points; if (snap == SnapNeighbouring) { points = getLocalPoints(v, v->getXForFrame(frame)); if (points.empty()) return false; frame = points.begin()->frame; return true; } points = m_model->getPoints(frame, frame); int snapped = frame; bool found = false; for (NoteModel::PointList::const_iterator i = points.begin(); i != points.end(); ++i) { if (snap == SnapRight) { if (i->frame > frame) { snapped = i->frame; found = true; break; } } else if (snap == SnapLeft) { if (i->frame <= frame) { snapped = i->frame; found = true; // don't break, as the next may be better } else { break; } } else { // nearest NoteModel::PointList::const_iterator j = i; ++j; if (j == points.end()) { snapped = i->frame; found = true; break; } else if (j->frame >= frame) { if (j->frame - frame < frame - i->frame) { snapped = j->frame; } else { snapped = i->frame; } found = true; break; } } } frame = snapped; return found; } void NoteLayer::getScaleExtents(View *v, float &min, float &max, bool &log) const { min = 0.0; max = 0.0; log = false; QString queryUnits; if (shouldConvertMIDIToHz()) queryUnits = "Hz"; else queryUnits = m_model->getScaleUnits(); if (m_verticalScale == AutoAlignScale) { if (!v->getValueExtents(queryUnits, min, max, log)) { min = m_model->getValueMinimum(); max = m_model->getValueMaximum(); if (shouldConvertMIDIToHz()) { min = Pitch::getFrequencyForPitch(lrintf(min)); max = Pitch::getFrequencyForPitch(lrintf(max + 1)); } std::cerr << "NoteLayer[" << this << "]::getScaleExtents: min = " << min << ", max = " << max << ", log = " << log << std::endl; } else if (log) { min = (min < 0.0) ? -log10(-min) : (min == 0.0) ? 0.0 : log10(min); max = (max < 0.0) ? -log10(-max) : (max == 0.0) ? 0.0 : log10(max); std::cerr << "NoteLayer[" << this << "]::getScaleExtents: min = " << min << ", max = " << max << ", log = " << log << std::endl; } } else { min = m_model->getValueMinimum(); max = m_model->getValueMaximum(); if (m_verticalScale == MIDIRangeScale) { min = Pitch::getFrequencyForPitch(0); max = Pitch::getFrequencyForPitch(127); } else if (shouldConvertMIDIToHz()) { min = Pitch::getFrequencyForPitch(lrintf(min)); max = Pitch::getFrequencyForPitch(lrintf(max + 1)); } if (m_verticalScale == LogScale || m_verticalScale == MIDIRangeScale) { min = (min < 0.0) ? -log10(-min) : (min == 0.0) ? 0.0 : log10(min); max = (max < 0.0) ? -log10(-max) : (max == 0.0) ? 0.0 : log10(max); log = true; } } if (max == min) max = min + 1.0; } int NoteLayer::getYForValue(View *v, float val) const { float min = 0.0, max = 0.0; bool logarithmic = false; int h = v->height(); getScaleExtents(v, min, max, logarithmic); // std::cerr << "NoteLayer[" << this << "]::getYForValue(" << val << "): min = " << min << ", max = " << max << ", log = " << logarithmic << std::endl; if (shouldConvertMIDIToHz()) { val = Pitch::getFrequencyForPitch(lrintf(val), lrintf((val - lrintf(val)) * 100)); // std::cerr << "shouldConvertMIDIToHz true, val now = " << val << std::endl; } if (logarithmic) { val = (val < 0.0) ? -log10(-val) : (val == 0.0) ? 0.0 : log10(val); // std::cerr << "logarithmic true, val now = " << val << std::endl; } int y = int(h - ((val - min) * h) / (max - min)) - 1; // std::cerr << "y = " << y << std::endl; return y; } float NoteLayer::getValueForY(View *v, int y) const { float min = 0.0, max = 0.0; bool logarithmic = false; int h = v->height(); getScaleExtents(v, min, max, logarithmic); float val = min + (float(h - y) * float(max - min)) / h; if (logarithmic) { val = pow(10, val); } if (shouldConvertMIDIToHz()) { val = Pitch::getPitchForFrequency(val); } return val; } void NoteLayer::paint(View *v, QPainter &paint, QRect rect) const { if (!m_model || !m_model->isOK()) return; int sampleRate = m_model->getSampleRate(); if (!sampleRate) return; // Profiler profiler("NoteLayer::paint", true); int x0 = rect.left(), x1 = rect.right(); long frame0 = v->getFrameForX(x0); long frame1 = v->getFrameForX(x1); NoteModel::PointList points(m_model->getPoints(frame0, frame1)); if (points.empty()) return; paint.setPen(m_colour); QColor brushColour(m_colour); brushColour.setAlpha(80); // std::cerr << "NoteLayer::paint: resolution is " // << m_model->getResolution() << " frames" << std::endl; float min = m_model->getValueMinimum(); float max = m_model->getValueMaximum(); if (max == min) max = min + 1.0; int origin = int(nearbyint(v->height() - (-min * v->height()) / (max - min))); QPoint localPos; long illuminateFrame = -1; if (v->shouldIlluminateLocalFeatures(this, localPos)) { NoteModel::PointList localPoints = getLocalPoints(v, localPos.x()); if (!localPoints.empty()) illuminateFrame = localPoints.begin()->frame; } paint.save(); paint.setRenderHint(QPainter::Antialiasing, false); for (NoteModel::PointList::const_iterator i = points.begin(); i != points.end(); ++i) { const NoteModel::Point &p(*i); int x = v->getXForFrame(p.frame); int y = getYForValue(v, p.value); int w = v->getXForFrame(p.frame + p.duration) - x; int h = 3; if (m_model->getValueQuantization() != 0.0) { h = y - getYForValue(v, p.value + m_model->getValueQuantization()); if (h < 3) h = 3; } if (w < 1) w = 1; paint.setPen(m_colour); paint.setBrush(brushColour); if (illuminateFrame == p.frame) { if (localPos.y() >= y - h && localPos.y() < y) { paint.setPen(Qt::black);//!!! paint.setBrush(Qt::black);//!!! } } paint.drawRect(x, y - h/2, w, h); /// if (p.label != "") { /// paint.drawText(x + 5, y - paint.fontMetrics().height() + paint.fontMetrics().ascent(), p.label); /// } } paint.restore(); } void NoteLayer::drawStart(View *v, QMouseEvent *e) { // std::cerr << "NoteLayer::drawStart(" << e->x() << "," << e->y() << ")" << std::endl; if (!m_model) return; long frame = v->getFrameForX(e->x()); if (frame < 0) frame = 0; frame = frame / m_model->getResolution() * m_model->getResolution(); float value = getValueForY(v, e->y()); m_editingPoint = NoteModel::Point(frame, value, 0, tr("New Point")); m_originalPoint = m_editingPoint; if (m_editingCommand) m_editingCommand->finish(); m_editingCommand = new NoteModel::EditCommand(m_model, tr("Draw Point")); m_editingCommand->addPoint(m_editingPoint); m_editing = true; } void NoteLayer::drawDrag(View *v, QMouseEvent *e) { // std::cerr << "NoteLayer::drawDrag(" << e->x() << "," << e->y() << ")" << std::endl; if (!m_model || !m_editing) return; long frame = v->getFrameForX(e->x()); if (frame < 0) frame = 0; frame = frame / m_model->getResolution() * m_model->getResolution(); float newValue = getValueForY(v, e->y()); long newFrame = m_editingPoint.frame; long newDuration = frame - newFrame; if (newDuration < 0) { newFrame = frame; newDuration = -newDuration; } else if (newDuration == 0) { newDuration = 1; } m_editingCommand->deletePoint(m_editingPoint); m_editingPoint.frame = newFrame; m_editingPoint.value = newValue; m_editingPoint.duration = newDuration; m_editingCommand->addPoint(m_editingPoint); } void NoteLayer::drawEnd(View *v, QMouseEvent *e) { // std::cerr << "NoteLayer::drawEnd(" << e->x() << "," << e->y() << ")" << std::endl; if (!m_model || !m_editing) return; m_editingCommand->finish(); m_editingCommand = 0; m_editing = false; } void NoteLayer::editStart(View *v, QMouseEvent *e) { // std::cerr << "NoteLayer::editStart(" << e->x() << "," << e->y() << ")" << std::endl; if (!m_model) return; NoteModel::PointList points = getLocalPoints(v, e->x()); if (points.empty()) return; m_editingPoint = *points.begin(); m_originalPoint = m_editingPoint; if (m_editingCommand) { m_editingCommand->finish(); m_editingCommand = 0; } m_editing = true; } void NoteLayer::editDrag(View *v, QMouseEvent *e) { // std::cerr << "NoteLayer::editDrag(" << e->x() << "," << e->y() << ")" << std::endl; if (!m_model || !m_editing) return; long frame = v->getFrameForX(e->x()); if (frame < 0) frame = 0; frame = frame / m_model->getResolution() * m_model->getResolution(); float value = getValueForY(v, e->y()); if (!m_editingCommand) { m_editingCommand = new NoteModel::EditCommand(m_model, tr("Drag Point")); } m_editingCommand->deletePoint(m_editingPoint); m_editingPoint.frame = frame; m_editingPoint.value = value; m_editingCommand->addPoint(m_editingPoint); } void NoteLayer::editEnd(View *v, QMouseEvent *e) { // std::cerr << "NoteLayer::editEnd(" << e->x() << "," << e->y() << ")" << std::endl; if (!m_model || !m_editing) return; if (m_editingCommand) { QString newName = m_editingCommand->getName(); if (m_editingPoint.frame != m_originalPoint.frame) { if (m_editingPoint.value != m_originalPoint.value) { newName = tr("Edit Point"); } else { newName = tr("Relocate Point"); } } else { newName = tr("Change Point Value"); } m_editingCommand->setName(newName); m_editingCommand->finish(); } m_editingCommand = 0; m_editing = false; } void NoteLayer::editOpen(View *v, QMouseEvent *e) { if (!m_model) return; NoteModel::PointList points = getLocalPoints(v, e->x()); if (points.empty()) return; NoteModel::Point note = *points.begin(); ItemEditDialog *dialog = new ItemEditDialog (m_model->getSampleRate(), ItemEditDialog::ShowTime | ItemEditDialog::ShowDuration | ItemEditDialog::ShowValue | ItemEditDialog::ShowText, m_model->getScaleUnits()); dialog->setFrameTime(note.frame); dialog->setValue(note.value); dialog->setFrameDuration(note.duration); dialog->setText(note.label); if (dialog->exec() == QDialog::Accepted) { NoteModel::Point newNote = note; newNote.frame = dialog->getFrameTime(); newNote.value = dialog->getValue(); newNote.duration = dialog->getFrameDuration(); newNote.label = dialog->getText(); NoteModel::EditCommand *command = new NoteModel::EditCommand (m_model, tr("Edit Point")); command->deletePoint(note); command->addPoint(newNote); command->finish(); } delete dialog; } void NoteLayer::moveSelection(Selection s, size_t newStartFrame) { if (!m_model) return; NoteModel::EditCommand *command = new NoteModel::EditCommand(m_model, tr("Drag Selection")); NoteModel::PointList points = m_model->getPoints(s.getStartFrame(), s.getEndFrame()); for (NoteModel::PointList::iterator i = points.begin(); i != points.end(); ++i) { if (s.contains(i->frame)) { NoteModel::Point newPoint(*i); newPoint.frame = i->frame + newStartFrame - s.getStartFrame(); command->deletePoint(*i); command->addPoint(newPoint); } } command->finish(); } void NoteLayer::resizeSelection(Selection s, Selection newSize) { if (!m_model) return; NoteModel::EditCommand *command = new NoteModel::EditCommand(m_model, tr("Resize Selection")); NoteModel::PointList points = m_model->getPoints(s.getStartFrame(), s.getEndFrame()); double ratio = double(newSize.getEndFrame() - newSize.getStartFrame()) / double(s.getEndFrame() - s.getStartFrame()); for (NoteModel::PointList::iterator i = points.begin(); i != points.end(); ++i) { if (s.contains(i->frame)) { double targetStart = i->frame; targetStart = newSize.getStartFrame() + double(targetStart - s.getStartFrame()) * ratio; double targetEnd = i->frame + i->duration; targetEnd = newSize.getStartFrame() + double(targetEnd - s.getStartFrame()) * ratio; NoteModel::Point newPoint(*i); newPoint.frame = lrint(targetStart); newPoint.duration = lrint(targetEnd - targetStart); command->deletePoint(*i); command->addPoint(newPoint); } } command->finish(); } void NoteLayer::deleteSelection(Selection s) { if (!m_model) return; NoteModel::EditCommand *command = new NoteModel::EditCommand(m_model, tr("Delete Selected Points")); NoteModel::PointList points = m_model->getPoints(s.getStartFrame(), s.getEndFrame()); for (NoteModel::PointList::iterator i = points.begin(); i != points.end(); ++i) { if (s.contains(i->frame)) { command->deletePoint(*i); } } command->finish(); } void NoteLayer::copy(Selection s, Clipboard &to) { if (!m_model) return; NoteModel::PointList points = m_model->getPoints(s.getStartFrame(), s.getEndFrame()); for (NoteModel::PointList::iterator i = points.begin(); i != points.end(); ++i) { if (s.contains(i->frame)) { Clipboard::Point point(i->frame, i->value, i->duration, i->label); to.addPoint(point); } } } bool NoteLayer::paste(const Clipboard &from, int frameOffset, bool interactive) { if (!m_model) return false; const Clipboard::PointList &points = from.getPoints(); NoteModel::EditCommand *command = new NoteModel::EditCommand(m_model, tr("Paste")); for (Clipboard::PointList::const_iterator i = points.begin(); i != points.end(); ++i) { if (!i->haveFrame()) continue; size_t frame = 0; if (frameOffset > 0 || -frameOffset < i->getFrame()) { frame = i->getFrame() + frameOffset; } NoteModel::Point newPoint(frame); if (i->haveLabel()) newPoint.label = i->getLabel(); if (i->haveValue()) newPoint.value = i->getValue(); else newPoint.value = (m_model->getValueMinimum() + m_model->getValueMaximum()) / 2; if (i->haveDuration()) newPoint.duration = i->getDuration(); else { size_t nextFrame = frame; Clipboard::PointList::const_iterator j = i; for (; j != points.end(); ++j) { if (!j->haveFrame()) continue; if (j != i) break; } if (j != points.end()) { nextFrame = j->getFrame(); } if (nextFrame == frame) { newPoint.duration = m_model->getResolution(); } else { newPoint.duration = nextFrame - frame; } } command->addPoint(newPoint); } command->finish(); return true; } QString NoteLayer::toXmlString(QString indent, QString extraAttributes) const { return Layer::toXmlString(indent, extraAttributes + QString(" colour=\"%1\" verticalScale=\"%2\"") .arg(encodeColour(m_colour)).arg(m_verticalScale)); } void NoteLayer::setProperties(const QXmlAttributes &attributes) { QString colourSpec = attributes.value("colour"); if (colourSpec != "") { QColor colour(colourSpec); if (colour.isValid()) { setBaseColour(QColor(colourSpec)); } } bool ok; VerticalScale scale = (VerticalScale) attributes.value("verticalScale").toInt(&ok); if (ok) setVerticalScale(scale); }