qcustomplot添加图例_qchart显示点数据

【实例简介】QCustomPlot动态绘图，解决CPU占用内存高问题

【实例截图】Qt动态实时绘图

【核心代码】

LXTracer::LXTracer(QCustomPlot *_plot, TracerType _type, QObject *parent)

: QObject(parent),

m_plot(_plot),

m_type(_type)

{

m_visible = true;

m_tracer = Q_NULLPTR;// 跟踪的点

m_label = Q_NULLPTR;// 显示的数值

m_arrow = Q_NULLPTR;// 箭头

if (m_plot)

{

QColor clrDefault(Qt::red);

QBrush brushDefault(Qt::NoBrush);

QPen penDefault(clrDefault);

// penDefault.setBrush(brushDefault);

penDefault.setWidthF(0.5);

m_tracer = new QCPItemTracer(m_plot);

m_tracer->setStyle(QCPItemTracer::tsCircle);

m_tracer->setPen(penDefault);

m_tracer->setBrush(brushDefault);

m_label = new QCPItemText(m_plot);

m_label->setLayer(“overlay”);

m_label->setClipToAxisRect(false);

m_label->setPadding(QMargins(5, 5, 5, 5));

m_label->setBrush(brushDefault);

m_label->setPen(penDefault);

m_label->position->setParentAnchor(m_tracer->position);

// m_label->setFont(QFont(“宋体”, 8));

m_label->setFont(QFont(“Arial”, 8));

m_label->setColor(clrDefault);

m_label->setText(“”);

m_arrow = new QCPItemLine(m_plot);

QPen arrowPen(clrDefault, 1);

m_arrow->setPen(penDefault);

m_arrow->setLayer(“overlay”);

m_arrow->setClipToAxisRect(false);

m_arrow->setHead(QCPLineEnding::esSpikeArrow);//设置头部为箭头形状

switch (m_type)

{

case XAxisTracer:

{

m_tracer->position->setTypeX(QCPItemPosition::ptPlotCoords);

m_tracer->position->setTypeY(QCPItemPosition::ptAxisRectRatio);

m_tracer->setSize(7);

m_label->setPositionAlignment(Qt::AlignTop | Qt::AlignHCenter);

m_arrow->end->setParentAnchor(m_tracer->position);

m_arrow->start->setParentAnchor(m_arrow->end);

m_arrow->start->setCoords(0, 20);//偏移量

break;

}

case YAxisTracer:

{

m_tracer->position->setTypeX(QCPItemPosition::ptAxisRectRatio);

m_tracer->position->setTypeY(QCPItemPosition::ptPlotCoords);

m_tracer->setSize(7);

m_label->setPositionAlignment(Qt::AlignRight | Qt::AlignHCenter);

m_arrow->end->setParentAnchor(m_tracer->position);

m_arrow->start->setParentAnchor(m_label->position);

m_arrow->start->setCoords(-20, 0);//偏移量

break;

}

case DataTracer:

{

m_tracer->position->setTypeX(QCPItemPosition::ptPlotCoords);

m_tracer->position->setTypeY(QCPItemPosition::ptPlotCoords);

m_tracer->setSize(5);

m_label->setPositionAlignment(Qt::AlignLeft | Qt::AlignVCenter);

m_arrow->end->setParentAnchor(m_tracer->position);

m_arrow->start->setParentAnchor(m_arrow->end);

m_arrow->start->setCoords(20, 0);

break;

}

default:

break;

}

setVisible(false);

}

}

LXTracer::~LXTracer()

{

if(m_plot)

{

if (m_tracer)

{

m_plot->removeItem(m_tracer);

}

if (m_label)

{

m_plot->removeItem(m_label);

}

if (m_arrow)

{

m_plot->removeItem(m_arrow);

}

}

}

void LXTracer::setPen(const QPen &pen)

{

if(m_tracer)

{

m_tracer->setPen(pen);

}

if(m_arrow)

{

m_arrow->setPen(pen);

}

}

void LXTracer::setBrush(const QBrush &brush)

{

if(m_tracer)

{

m_tracer->setBrush(brush);

}

}

void LXTracer::setLabelPen(const QPen &pen)

{

if(m_label)

{

m_label->setPen(pen);

m_label->setBrush(Qt::NoBrush);

m_label->setColor(pen.color());

}

}

void LXTracer::setText(const QString &text)

{

if(m_label)

{

m_label->setText(text);

}

}

void LXTracer::setVisible(bool vis)

{

m_visible = vis;

if(m_tracer)

{

m_tracer->setVisible(m_visible);

}

if(m_label)

{

m_label->setVisible(m_visible);

}

if(m_arrow)

{

m_arrow->setVisible(m_visible);

}

}

void LXTracer::updatePosition(double xValue, double yValue)

{

if (!m_visible)

{

setVisible(true);

m_visible = true;

}

if (yValue > m_plot->yAxis->range().upper)

{

yValue = m_plot->yAxis->range().upper;

}

switch (m_type)

{

case XAxisTracer:

{

m_tracer->position->setCoords(xValue, 1);

m_label->position->setCoords(0, 15);

m_arrow->start->setCoords(0, 15);

m_arrow->end->setCoords(0, 0);

setText(QString::number(xValue));

break;

}

case YAxisTracer:

{

m_tracer->position->setCoords(0, yValue);

m_label->position->setCoords(-20, 0);

// m_arrow->start->setCoords(20, 0);

// m_arrow->end->setCoords(0, 0);

setText(QString::number(yValue));

break;

}

case DataTracer:

{

m_tracer->position->setCoords(xValue, yValue);

m_label->position->setCoords(20, 0);

setText(QString(“x:%1,y:%2”).arg(xValue).arg(yValue));

break;

}

default:

break;

}

}

LXTraceLine::LXTraceLine(QCustomPlot *_plot, LineType _type, QObject *parent)

: QObject(parent),

m_type(_type),

m_plot(_plot)

{

m_lineV = Q_NULLPTR;

m_lineH = Q_NULLPTR;

initLine();

}

LXTraceLine::~LXTraceLine()

{

if(m_plot)

{

if (m_lineV)

{

m_plot->removeItem(m_lineV);

}

if (m_lineH)

{

m_plot->removeItem(m_lineH);

}

}

}

void LXTraceLine::initLine()

{

if(m_plot)

{

QPen linesPen(Qt::red, 1, Qt::SolidLine);

if(VerticalLine == m_type || Both == m_type)

{

m_lineV = new QCPItemStraightLine(m_plot);//垂直线

m_lineV->setLayer(“overlay”);

m_lineV->setPen(linesPen);

m_lineV->setClipToAxisRect(true);

m_lineV->point1->setCoords(0, 0);

m_lineV->point2->setCoords(0, 0);

}

if(HorizonLine == m_type || Both == m_type)

{

m_lineH = new QCPItemStraightLine(m_plot);//水平线

m_lineH->setLayer(“overlay”);

m_lineH->setPen(linesPen);

m_lineH->setClipToAxisRect(true);

m_lineH->point1->setCoords(0, 0);

m_lineH->point2->setCoords(0, 0);

}

}

}

void LXTraceLine::updatePosition(double xValue, double yValue)

{

if(VerticalLine == m_type || Both == m_type)

{

if(m_lineV)

{

m_lineV->point1->setCoords(xValue, m_plot->yAxis->range().lower);

m_lineV->point2->setCoords(xValue, m_plot->yAxis->range().upper);

}

}

if(HorizonLine == m_type || Both == m_type)

{

if(m_lineH)

{

m_lineH->point1->setCoords(m_plot->xAxis->range().lower, yValue);

m_lineH->point2->setCoords(m_plot->xAxis->range().upper, yValue);

}

}

}