Plot Screenshots: Item Demo
Setup function:
customPlot->setInteractions(QCP::iRangeDrag | QCP::iRangeZoom);
QCPGraph *graph = customPlot->addGraph();
int n = 500;
double phase = 0;
double k = 3;
QVector<double> x(n), y(n);
for (int i=0; i<n; ++i)
{
x[i] = i/(double)(n-1)*34 - 17;
y[i] = qExp(-x[i]*x[i]/20.0)*qSin(k*x[i]+phase);
}
graph->setData(x, y);
graph->setPen(QPen(Qt::blue));
graph->rescaleKeyAxis();
customPlot->yAxis->setRange(-1.45, 1.65);
customPlot->xAxis->grid()->setZeroLinePen(Qt::NoPen);
// add the bracket at the top:
QCPItemBracket *bracket = new QCPItemBracket(customPlot);
bracket->left->setCoords(-8, 1.1);
bracket->right->setCoords(8, 1.1);
bracket->setLength(13);
// add the text label at the top:
QCPItemText *wavePacketText = new QCPItemText(customPlot);
wavePacketText->position->setParentAnchor(bracket->center);
wavePacketText->position->setCoords(0, -10); // move 10 pixels to the top from bracket center anchor
wavePacketText->setPositionAlignment(Qt::AlignBottom|Qt::AlignHCenter);
wavePacketText->setText("Wavepacket");
wavePacketText->setFont(QFont(font().family(), 10));
// add the phase tracer (red circle) which sticks to the graph data (and gets updated in bracketDataSlot by timer event):
QCPItemTracer *phaseTracer = new QCPItemTracer(customPlot);
itemDemoPhaseTracer = phaseTracer; // so we can access it later in the bracketDataSlot for animation
phaseTracer->setGraph(graph);
phaseTracer->setGraphKey((M_PI*1.5-phase)/k);
phaseTracer->setInterpolating(true);
phaseTracer->setStyle(QCPItemTracer::tsCircle);
phaseTracer->setPen(QPen(Qt::red));
phaseTracer->setBrush(Qt::red);
phaseTracer->setSize(7);
// add label for phase tracer:
QCPItemText *phaseTracerText = new QCPItemText(customPlot);
phaseTracerText->position->setType(QCPItemPosition::ptAxisRectRatio);
phaseTracerText->setPositionAlignment(Qt::AlignRight|Qt::AlignBottom);
phaseTracerText->position->setCoords(1.0, 0.95); // lower right corner of axis rect
phaseTracerText->setText("Points of fixed\nphase define\nphase velocity vp");
phaseTracerText->setTextAlignment(Qt::AlignLeft);
phaseTracerText->setFont(QFont(font().family(), 9));
phaseTracerText->setPadding(QMargins(8, 0, 0, 0));
// add arrow pointing at phase tracer, coming from label:
QCPItemCurve *phaseTracerArrow = new QCPItemCurve(customPlot);
phaseTracerArrow->start->setParentAnchor(phaseTracerText->left);
phaseTracerArrow->startDir->setParentAnchor(phaseTracerArrow->start);
phaseTracerArrow->startDir->setCoords(-40, 0); // direction 30 pixels to the left of parent anchor (tracerArrow->start)
phaseTracerArrow->end->setParentAnchor(phaseTracer->position);
phaseTracerArrow->end->setCoords(10, 10);
phaseTracerArrow->endDir->setParentAnchor(phaseTracerArrow->end);
phaseTracerArrow->endDir->setCoords(30, 30);
phaseTracerArrow->setHead(QCPLineEnding::esSpikeArrow);
phaseTracerArrow->setTail(QCPLineEnding(QCPLineEnding::esBar, (phaseTracerText->bottom->pixelPosition().y()-phaseTracerText->top->pixelPosition().y())*0.85));
// add the group velocity tracer (green circle):
QCPItemTracer *groupTracer = new QCPItemTracer(customPlot);
groupTracer->setGraph(graph);
groupTracer->setGraphKey(5.5);
groupTracer->setInterpolating(true);
groupTracer->setStyle(QCPItemTracer::tsCircle);
groupTracer->setPen(QPen(Qt::green));
groupTracer->setBrush(Qt::green);
groupTracer->setSize(7);
// add label for group tracer:
QCPItemText *groupTracerText = new QCPItemText(customPlot);
groupTracerText->position->setType(QCPItemPosition::ptAxisRectRatio);
groupTracerText->setPositionAlignment(Qt::AlignRight|Qt::AlignTop);
groupTracerText->position->setCoords(1.0, 0.20); // lower right corner of axis rect
groupTracerText->setText("Fixed positions in\nwave packet define\ngroup velocity vg");
groupTracerText->setTextAlignment(Qt::AlignLeft);
groupTracerText->setFont(QFont(font().family(), 9));
groupTracerText->setPadding(QMargins(8, 0, 0, 0));
// add arrow pointing at group tracer, coming from label:
QCPItemCurve *groupTracerArrow = new QCPItemCurve(customPlot);
groupTracerArrow->start->setParentAnchor(groupTracerText->left);
groupTracerArrow->startDir->setParentAnchor(groupTracerArrow->start);
groupTracerArrow->startDir->setCoords(-40, 0); // direction 30 pixels to the left of parent anchor (tracerArrow->start)
groupTracerArrow->end->setCoords(5.5, 0.4);
groupTracerArrow->endDir->setParentAnchor(groupTracerArrow->end);
groupTracerArrow->endDir->setCoords(0, -40);
groupTracerArrow->setHead(QCPLineEnding::esSpikeArrow);
groupTracerArrow->setTail(QCPLineEnding(QCPLineEnding::esBar, (groupTracerText->bottom->pixelPosition().y()-groupTracerText->top->pixelPosition().y())*0.85));
// add dispersion arrow:
QCPItemCurve *arrow = new QCPItemCurve(customPlot);
arrow->start->setCoords(1, -1.1);
arrow->startDir->setCoords(-1, -1.3);
arrow->endDir->setCoords(-5, -0.3);
arrow->end->setCoords(-10, -0.2);
arrow->setHead(QCPLineEnding::esSpikeArrow);
// add the dispersion arrow label:
QCPItemText *dispersionText = new QCPItemText(customPlot);
dispersionText->position->setCoords(-6, -0.9);
dispersionText->setRotation(40);
dispersionText->setText("Dispersion with\nvp < vg");
dispersionText->setFont(QFont(font().family(), 10));
// setup a timer that repeatedly calls MainWindow::bracketDataSlot:
connect(&dataTimer, SIGNAL(timeout()), this, SLOT(bracketDataSlot()));
dataTimer.start(0); // Interval 0 means to refresh as fast as possible
bracketDataSlot, called by timer:
double secs = QCPAxisTickerDateTime::dateTimeToKey(QDateTime::currentDateTime());
// update data to make phase move:
int n = 500;
double phase = secs*5;
double k = 3;
QVector<double> x(n), y(n);
for (int i=0; i<n; ++i)
{
x[i] = i/(double)(n-1)*34 - 17;
y[i] = qExp(-x[i]*x[i]/20.0)*qSin(k*x[i]+phase);
}
ui->customPlot->graph()->setData(x, y);
itemDemoPhaseTracer->setGraphKey((8*M_PI+fmod(M_PI*1.5-phase, 6*M_PI))/k);
ui->customPlot->replot();
// calculate frames per second:
double key = secs;
static double lastFpsKey;
static int frameCount;
++frameCount;
if (key-lastFpsKey > 2) // average fps over 2 seconds
{
ui->statusBar->showMessage(
QString("%1 FPS, Total Data points: %2")
.arg(frameCount/(key-lastFpsKey), 0, 'f', 0)
.arg(ui->customPlot->graph(0)->data()->size())
, 0);
lastFpsKey = key;
frameCount = 0;
}