qcustomplot库demo和高效实时绘图（底下有扩展网址）
QCustomPlot使用心得四：动态曲线和绘图效率测试(qcustomplot_solution.pro)

基于Qt的频谱分析器，修改于spek

qtcsdr

Spectrum analyzer for multiple SDR platforms(有最大保持等)


gqrx-spectrogram下载

Qt之调用FFTW3实现音频频谱（实现）

Qt之QCustomPlot概述
QCustomPlot使用手册（一）
QCustomPlot使用手册（二）
QCustomPlot使用手册（三）
QCustomPlot使用手册（四）

一、官网下载

https://www.qcustomplot.com/ 　从官网下载 qcustomplot.h 和 qcustomplot.cpp
QCustomPlot官网下载
官网函数手册Reference
2.1版本类图：


一个图包括：坐标轴、图形、标题、题注、文字。
图形类别：

1、QCPGraph主要的画图类型， QCustomPlot::addGraph(), QCustomPlot::graph()
2、QCPCurve是一个key有多个值，与QCPGraph不同，此类型的绘图表可能具有多个具有相同键坐标的点，因此它们的可视表示可以具有循环。这是通过引入第三坐标t来实现的，该坐标定义了其他两个坐标x和y所描述的点的顺序。
3、QCPBars柱状图
4、QCPStaticicalBox统计图
5、QCPColorMap色谱图
6、QCPFinancial K线图

二、加入工程

通过添加现有文件将 qcustomplot.h、qcustomplot.cpp加入工程，并在pro文件中加入printsupport

使用openGL：

QT  += opengl       					#使用opengl
DEFINES += QCUSTOMPLOT_USE_OPENGL  		#使用opengl
INCLUDEPATH += $$PWD/freeglut/include	#依赖freeglut库以及头文件
LIBS += -L -llibfreeglut -lopengl32     #依赖opengl库文件
LIBS += -L$$PWD/freeglut/lib/x64  -lfreeglut

#include <GL/freeglut.h>
setOpenGl(true);
qDebug() << openGl();

三、使用

1、静态生成（QT Designer 中 prompt 插件）

放置widget并提升为QCustomPlot，名称为myplot

点击添加按钮将QCustomPlot加入到提升类列表中，
点击提升按钮将widget提升为QCustomPlot类

2、动态生成

	QWidget *paintArea = new QWidget;
    QCustomPlot *myPlot = new QCustomPlot(paintArea);
    myPlot->setFixedSize(480,300);
    //blue line
    myPlot->addGraph();
    myPlot->graph(0)->setPen(QPen(Qt::blue));
    //xAxis
    myPlot->axisRect()->setupFullAxesBox();
    myPlot->xAxis->setRange(1, 1, Qt::AlignRight);
    myPlot->yAxis->setRange(30, 30, Qt::AlignRight);
    myPlot->xAxis->setLabel("I(A)");
    myPlot->yAxis->setLabel("U(V)");

3、画图

customPlot->xAxis, yAxis, xAxis2, and yAxis2分别是底、左、上、右的轴
设置轴的刻度数目：xAxis->ticker()->setTickCount(6);
   

QCPAxisTicker坐标刻度官方文档
QCustomPlot使用心得五：坐标轴常用属性设置（这个好）
QCustomplot使用分享(六) 坐标轴和网格线
QCPAxisTicker坐标轴类(一)
QCustomPlot 曲线各种属性详细介绍
QCustomPlot 2.0.1类、函数思维导图
15.QCustomPlot数据结构

要在屏幕上显示对绘图的任何更改，调用 customPlot->replot() 。
请注意，replot 函数在当调整widget的大小并触发内置用户交互时，将自动发生重新绘制。比如：用户交互例、用鼠标拖动轴范围、用鼠标滚轮缩放。

// 产生数据
QVector<double> x(101), y(101); // initialize with entries 0..100
for (int i=0; i<101; ++i)
{
  x[i] = i/50.0 - 1; // x goes from -1 to 1
  y[i] = x[i]*x[i]; // let's plot a quadratic function
}
// create graph and assign data to it:
customPlot->addGraph();  //创建新图
customPlot->graph(0)->setData(x, y);//指定数据
// give the axes some labels:
customPlot->xAxis->setLabel("x");
customPlot->yAxis->setLabel("y");
// set axes ranges, so we see all data:
customPlot->xAxis->setRange(-1, 1);
customPlot->yAxis->setRange(0, 1);
customPlot->replot();//重绘，数据变化时调用

// period as decimal separator and comma as thousand separator
customPlot->setLocale(QLocale(QLocale::English, QLocale::UnitedKingdom)); 
customPlot->legend->setVisible(true);
QFont legendFont = font();  // start out with MainWindow's font..
legendFont.setPointSize(9); // and make a bit smaller for legend
customPlot->legend->setFont(legendFont);
customPlot->legend->setBrush(QBrush(QColor(255,255,255,230)));
// by default, the legend is in the inset layout of the main axis rect. 
//So this is how we access it to change legend placement:
customPlot->axisRect()->insetLayout()->setInsetAlignment(0, Qt::AlignBottom|Qt::AlignRight);
 
// setup for graph 0: key axis left, value axis bottom
// will contain left maxwell-like function
customPlot->addGraph(customPlot->yAxis, customPlot->xAxis);
customPlot->graph(0)->setPen(QPen(QColor(255, 100, 0)));
customPlot->graph(0)->setBrush(QBrush(QPixmap("./balboa.jpg"))); // fill with texture of specified image
customPlot->graph(0)->setLineStyle(QCPGraph::lsLine);
customPlot->graph(0)->setScatterStyle(QCPScatterStyle(QCPScatterStyle::ssDisc, 5));
customPlot->graph(0)->setName("Left maxwell function");
 
// setup for graph 1: key axis bottom, value axis left (those are the default axes)
// will contain bottom maxwell-like function with error bars
customPlot->addGraph();
customPlot->graph(1)->setPen(QPen(Qt::red));
customPlot->graph(1)->setBrush(QBrush(QPixmap("./balboa.jpg"))); // same fill as we used for graph 0
customPlot->graph(1)->setLineStyle(QCPGraph::lsStepCenter);
customPlot->graph(1)->setScatterStyle(QCPScatterStyle(QCPScatterStyle::ssCircle, Qt::red, Qt::white, 7));
customPlot->graph(1)->setName("Bottom maxwell function");
QCPErrorBars *errorBars = new QCPErrorBars(customPlot->xAxis, customPlot->yAxis);
errorBars->removeFromLegend();
errorBars->setDataPlottable(customPlot->graph(1));
 
// setup for graph 2: key axis top, value axis right
// will contain high frequency sine with low frequency beating:
customPlot->addGraph(customPlot->xAxis2, customPlot->yAxis2);
customPlot->graph(2)->setPen(QPen(Qt::blue));
customPlot->graph(2)->setName("High frequency sine");
 
// setup for graph 3: same axes as graph 2
// will contain low frequency beating envelope of graph 2
customPlot->addGraph(customPlot->xAxis2, customPlot->yAxis2);
QPen blueDotPen;
blueDotPen.setColor(QColor(30, 40, 255, 150));
blueDotPen.setStyle(Qt::DotLine);
blueDotPen.setWidthF(4);
customPlot->graph(3)->setPen(blueDotPen);
customPlot->graph(3)->setName("Sine envelope");
 
// setup for graph 4: key axis right, value axis top
// will contain parabolically distributed data points with some random perturbance
customPlot->addGraph(customPlot->yAxis2, customPlot->xAxis2);
customPlot->graph(4)->setPen(QColor(50, 50, 50, 255));
customPlot->graph(4)->setLineStyle(QCPGraph::lsNone);
customPlot->graph(4)->setScatterStyle(QCPScatterStyle(QCPScatterStyle::ssCircle, 4));
customPlot->graph(4)->setName("Some random data around\na quadratic function");
 
// generate data, just playing with numbers, not much to learn here:
QVector<double> x0(25), y0(25);
QVector<double> x1(15), y1(15), y1err(15);
QVector<double> x2(250), y2(250);
QVector<double> x3(250), y3(250);
QVector<double> x4(250), y4(250);
for (int i=0; i<25; ++i) // data for graph 0
{
  x0[i] = 3*i/25.0;
  y0[i] = qExp(-x0[i]*x0[i]*0.8)*(x0[i]*x0[i]+x0[i]);
}
for (int i=0; i<15; ++i) // data for graph 1
{
  x1[i] = 3*i/15.0;;
  y1[i] = qExp(-x1[i]*x1[i])*(x1[i]*x1[i])*2.6;
  y1err[i] = y1[i]*0.25;
}
for (int i=0; i<250; ++i) // data for graphs 2, 3 and 4
{
  x2[i] = i/250.0*3*M_PI;
  x3[i] = x2[i];
  x4[i] = i/250.0*100-50;
  y2[i] = qSin(x2[i]*12)*qCos(x2[i])*10;
  y3[i] = qCos(x3[i])*10;
  y4[i] = 0.01*x4[i]*x4[i] + 1.5*(rand()/(double)RAND_MAX-0.5) + 1.5*M_PI;
}
 
// pass data points to graphs:
customPlot->graph(0)->setData(x0, y0);
customPlot->graph(1)->setData(x1, y1);
errorBars->setData(y1err);
customPlot->graph(2)->setData(x2, y2);
customPlot->graph(3)->setData(x3, y3);
customPlot->graph(4)->setData(x4, y4);
// activate top and right axes, which are invisible by default:
customPlot->xAxis2->setVisible(true);
customPlot->yAxis2->setVisible(true);
// set ranges appropriate to show data:
customPlot->xAxis->setRange(0, 2.7);
customPlot->yAxis->setRange(0, 2.6);
customPlot->xAxis2->setRange(0, 3.0*M_PI);
customPlot->yAxis2->setRange(-70, 35);
// set pi ticks on top axis:
customPlot->xAxis2->setTicker(QSharedPointer<QCPAxisTickerPi>(new QCPAxisTickerPi));
// add title layout element:
customPlot->plotLayout()->insertRow(0);
customPlot->plotLayout()->addElement(0, 0, 
		new QCPTextElement(customPlot, "Way too many graphs in one plot", QFont("sans", 12, QFont::Bold)));
// set labels:
customPlot->xAxis->setLabel("Bottom axis with outward ticks");
customPlot->yAxis->setLabel("Left axis label");
customPlot->xAxis2->setLabel("Top axis label");
customPlot->yAxis2->setLabel("Right axis label");
// make ticks on bottom axis go outward:
customPlot->xAxis->setTickLength(0, 5);
customPlot->xAxis->setSubTickLength(0, 3);
// make ticks on right axis go inward and outward:
customPlot->yAxis2->setTickLength(3, 3);
customPlot->yAxis2->setSubTickLength(1, 1);

// set locale to english, so we get english month names:
customPlot->setLocale(QLocale(QLocale::English, QLocale::UnitedKingdom));
// seconds of current time, we'll use it as starting point in time for data:
double now = QDateTime::currentDateTime().toTime_t();
srand(8); // set the random seed, so we always get the same random data
// create multiple graphs:
for (int gi=0; gi<5; ++gi)
{
  customPlot->addGraph();
  QColor color(20+200/4.0*gi,70*(1.6-gi/4.0), 150, 150);
  customPlot->graph()->setLineStyle(QCPGraph::lsLine);
  customPlot->graph()->setPen(QPen(color.lighter(200)));
  customPlot->graph()->setBrush(QBrush(color));
  // generate random walk data:
  QVector<QCPGraphData> timeData(250);
  for (int i=0; i<250; ++i)
  {
    timeData[i].key = now + 24*3600*i;
    if (i == 0)
      timeData[i].value = (i/50.0+1)*(rand()/(double)RAND_MAX-0.5);
    else
      timeData[i].value = qFabs(timeData[i-1].value)*(1+0.02/4.0*(4-gi)) + (i/50.0+1)*(rand()/(double)RAND_MAX-0.5);
  }
  customPlot->graph()->data()->set(timeData);
}
// configure bottom axis to show date instead of number:
QSharedPointer<QCPAxisTickerDateTime> dateTicker(new QCPAxisTickerDateTime);
dateTicker->setDateTimeFormat("d. MMMM\nyyyy");
customPlot->xAxis->setTicker(dateTicker);
// configure left axis text labels:
QSharedPointer<QCPAxisTickerText> textTicker(new QCPAxisTickerText);
textTicker->addTick(10, "a bit\nlow");
textTicker->addTick(50, "quite\nhigh");
customPlot->yAxis->setTicker(textTicker);
// set a more compact font size for bottom and left axis tick labels:
customPlot->xAxis->setTickLabelFont(QFont(QFont().family(), 8));
customPlot->yAxis->setTickLabelFont(QFont(QFont().family(), 8));
// set axis labels:
customPlot->xAxis->setLabel("Date");
customPlot->yAxis->setLabel("Random wobbly lines value");
// make top and right axes visible but without ticks and labels:
customPlot->xAxis2->setVisible(true);
customPlot->yAxis2->setVisible(true);
customPlot->xAxis2->setTicks(false);
customPlot->yAxis2->setTicks(false);
customPlot->xAxis2->setTickLabels(false);
customPlot->yAxis2->setTickLabels(false);
// set axis ranges to show all data:
customPlot->xAxis->setRange(now, now+24*3600*249);
customPlot->yAxis->setRange(0, 60);
// show legend with slightly transparent background brush:
customPlot->legend->setVisible(true);
customPlot->legend->setBrush(QColor(255, 255, 255, 150));

4、清除数据

ui->widget_Svg->clearGraphs();				//清图纸上所有的设置
ui->widget_Svg->clearPlottables();			//清图纸上的所有曲线的设置
ui->customPlot->plotLayout()->clear();
p_show->graph(0)->data().data()->clear();	//只清曲线上的数据
//遍历图上对象
for (int i = ui->customPlot->plotLayout()->elementCount() - 1; i > 0; i--)
{
    ui->customPlot->plotLayout()->removeAt(i);
}
for (int i = ui->customPlot->plottableCount() - 1; i > 0; i--)
{
    ui->customPlot->removePlottable(i);
}
for (int i = ui->customPlot->graphCount() - 1; i >= 0; i--)
{
    ui->customPlot->removeGraph(i);
}

5、背景透明

//两个同时设置才能获得透明背景的效果
customPlot->setBackground(Qt::transparent);
customPlot->setStyleSheet("background: transparent;"); 
//设置背景颜色
customPlot->setBackground(QBrush(Qt::white)); 
customplot->setBackground(QColor(255,255,255,0));	//设置背景颜色(透明)

6、坐标轴同步

//四边安上坐标轴
customPlot->axisRect()->setupFullAxesBox();
//使上下轴、左右轴范围同步
connect(customPlot->xAxis, SIGNAL(rangeChanged(QCPRange)), customPlot->xAxis2, SLOT(setRange(QCPRange)));
connect(customPlot->yAxis, SIGNAL(rangeChanged(QCPRange)), customPlot->yAxis2, SLOT(setRange(QCPRange)));

四、高级应用

QT5使用QCustomplot绘制频谱瀑布图并封快速傅里叶变换fft类(myplot.pro)
QCustomplot绘制实时波形图（频谱图、瀑布图、星座图）并开启opengl支持
QCustomplot系列文章（这个好）
QCustomPlot 绘制多条动态曲线性能测试(LXCustomPlot.pro)
QCustomPlot 使用整理
5.QCustomPlot 创建动态轴标签（有系列文章）
12.QCustomPlot中数据选择机制（有系列文章）
QT应用编程: 使用qcustomplot显示动态曲线、设计心电图显示页面(有动态和数据指针)

4.1 更新大数据(1.0版本)

数据量少时，用setData() 和 addData()给图传数据（内部拷贝效率低）；
数据量大时，用data()接口。

void addToDataBuffer(float x, float y)
{
    QCPData newData;
    newData.key = x;
    newData.value = y;
    
    QCPDataMap *mData = myPlot->graph(0)->data();
//	mData->clear();//根据情况
    mData->insert(x, newData);
}

QCPDataMap 可以看做坐标横纵坐标的组合 （x，y）, 用insert() 添加数据；如果需要key 对应多个值则使用 insertMulti( )往 buffer 里面添加数据。

画新曲线之前，先 clear() 一下 buffer ；更新数据后，replot() 一下。

4.2 更新大数据(2.0版本)

（1）传值法（直接调用无需修改QCustomplot）
下面是源码示例中更新数据方法，画图数据的核心是 mData，是一个 QCPGraphData 类型的 Vector，所以，我们直接构建这样一个 Vector，把内部的替换掉即可。可惜这里不是指针，函数内实现方式是用我们提供的 mData 给内部 mData 赋值，也就是，还是要进行一次拷贝。当然，你也可以去改它的代码把这个指针给放出来。
：

void MainWindow::addNewData()
{
    QSharedPointer< QCPGraphDataContainer > dataContainer;
    dataContainer = customplot->graph(0)->data();
    QVector<QCPGraphData> mData; //warning: it's a local var
    QCPGraphData newPoint; 
    newPoint.key = 123;
    newPoint.value = 456;
    mData.append(newPoint);
    dataContainer->set(mData,true); //if the data has been sorted, set true
}

（2）指针法（需修改QCustomplot.h）
修改如下：

void MainWindow::mDataDirect(QCustomPlot *customPlot)
{
    demoName = "mData";
    customPlot->addGraph();
    QVector<QCPGraphData> *mData;
    mData = customPlot->graph(0)->data()->coreData();//自己添加获得指针的函数
    mData->clear();

    QCPGraphData newPoint;
    for (int i=0; i<101; ++i)
    {
        double tmp = i/50.0 - 1; 
        newPoint.key = tmp;
        newPoint.value = tmp * tmp;  // let's plot a quadratic function
        mData->append(newPoint);
    }
    // give the axes some labels:
    customPlot->xAxis->setLabel("x");
    customPlot->yAxis->setLabel("y");
    // set axes ranges, so we see all data:
    customPlot->xAxis->setRange(-1, 1);
    customPlot->yAxis->setRange(0, 1);
}

在 qcustomplot.h 中加入myMethod这一行

  // setters:
  void setAutoSqueeze(bool enabled);
  
  // myMethod
  QVector<DataType>* coreData() {return &mData;}
  
  // non-virtual methods:
  void set(const QCPDataContainer<DataType> &data);

4.3 设置画图区域的背景色

	QBrush backRole;
    backRole.setColor("skyblue");
    backRole.setStyle(Qt::SolidPattern);//不加 SolidPattern，画出来的图是透明的
    myPlot->setBackground(backRole);

4.4 实时显示

qcustomplot实时滚动显示，内存释放删除数据
QCustomPlot实现实时动态曲线
QCustomPlot系列(5)-实时动态曲线
QCustomPlot系列

4.5、小例子

//设定背景为黑色
		//ui->widget->setBackground(QBrush(Qt::black));
        //设定右上角图形标注可见
        ui->widget->legend->setVisible(true);
        //设定右上角图形标注的字体
        ui->widget->legend->setFont(QFont("Helvetica", 9));
        QVector<double> x(101),y(101);
            //图形为y=x^3
            for(int i=0;i<101;i++)
            {
                x[i] = i/5.0-10;
                y[i] = x[i]*x[i]*x[i];//qPow(x[i],3)
            }
            //添加图形
            ui->widget->addGraph();
            //设置画笔
            ui->widget->graph(0)->setPen(QPen(Qt::blue));
            //设置画刷,曲线和X轴围成面积的颜色
             ui->widget->graph(0)->setBrush(QBrush(QColor(255,255,0)));
            //设置右上角图形标注名称
            ui->widget->graph(0)->setName("曲线");
            //传入数据，setData的两个参数类型为double
            ui->widget->graph(0)->setData(x,y);

            QVector<double> temp(20);
            QVector<double> temp1(20);
            //图形为y = 100*x;
            for(int i=0;i<20;i++)
            {
                temp[i] = i;
                temp1[i] = 10*i+10;
            }
            //添加图形
            ui->widget->addGraph();
            //设置画笔
            ui->widget->graph(1)->setPen(QPen(Qt::red));
            //设置画刷,曲线和X轴围成面积的颜色
            //ui->widget->graph(1)->setBrush(QBrush(QColor(0,255,0)));  
            //传入数据
            ui->widget->graph(1)->setData(temp,temp1);  
            
            /*-------------------------------------------*/
            //画动态曲线时，传入数据采用addData，通过定时器多次调用，并在之后调用ui->widget->replot(); 
            //动态曲线可以通过另一种设置坐标的方法解决坐标问题： 
            //setRange ( double  position, double  size, Qt::AlignmentFlag  alignment  )  
            //参数分别为：原点，偏移量，对其方式，有兴趣的读者可自行尝试，欢迎垂询  
            /*-------------------------------------------*/ 
            
            //设置右上角图形标注名称
            ui->widget->graph(1)->setName("直线");
            //设置X轴文字标注
            ui->widget->xAxis->setLabel("time");
            //设置Y轴文字标注
            ui->widget->yAxis->setLabel("temp/shidu");
            //设置X轴坐标范围
            ui->widget->xAxis->setRange(-20,20);
            //设置Y轴坐标范围
            ui->widget->yAxis->setRange(-1100,1100);
            //在坐标轴右侧和上方画线，和X/Y轴一起形成一个矩形
            ui->widget->axisRect()->setupFullAxesBox(); 

4.6 刻度设置、鼠标显示数据

QCustomPlot之QCPAxisTicker坐标轴类
QCustomPlot绘制天气曲线图并动态显示曲线坐标值
QCustomPlot中用直线标示曲线的值
QCustomplot使用分享(九) 绘制图表-多功能游标

//设置坐标轴刻度
QVector<double> vTick;
QVector<QString> vTickLabel;
this->xAxis->setTickVector();
this->xAxis->setTickVectorLabels();

4.7 动态曲线及性能

QCustomPlot 动态曲线和绘图效率测试(qcustomplot_solution.pro)
项目记录 - Qt QCustomPlot 实时动态数据曲线图，以时间为X轴，数据为Y轴（二）
动态时间轴 2.0版本

1.0版本中设置时间轴

	//设置X轴时间刻度
	ui->customplot->xAxis->setTickLabelType(QCPAxis::ltDateTime);
	ui->customplot->xAxis->setDateTimeFormat("hh:mm:ss");
	ui->customplot->xAxis->setDateTimeSpec(Qt::LocalTime);

2.0版本中设置时间轴

	//设置X轴时间刻度
	QSharedPointer<QCPAxisTickerDateTime> dateTick(new QCPAxisTickerDateTime);
    dateTick->setDateTimeFormat("hh:mm:ss");
    ui->customplot->xAxis->setTicker(dateTick);

动态时间轴的关键步骤：

//秒中间插入数据的关键是有小数，不能直接 /1000,而是/1000.0
double t = (double)(QDateTime::currentMSecsSinceEpoch()) / 1000.0;
pGraph->addData(t, y);
//时间轴滚动
double curSeclf = QDateTime::currentDateTime().toMSecsSinceEpoch()/1000.0;
 //(double)(QDateTime::currentMSecsSinceEpoch()) / 1000.0;
this->xAxis->setRange(curSeclf + 0.25, 4, Qt::AlignRight);
this->replot();
//删除滚动出图表的数据
pGraph->data().data()->removeBefore(0);

Y轴作为时间轴进行滚动：

QCPGraph * addGraph(QCPAxis * keyAxis = 0, QCPAxis * valueAxis = 0)
this->addGraph(yAxis,xAxis);//y轴为key值，x轴为value

删除过期数据：

V1.x版本中是有removeDataBefore()的，可以删除之前的数据，但v2.x时，这个函数被取缔了，但它经常会在绘制动态图中用到，可修改QCustomPlot源码进行添加，在QCPGraph类中增加公有成员函数。

//qcustomplot.h中
void removeDataBefore(int size);

//qcustomplot.cpp中
void QCPGraph::removeDataBefore(int size)
{
    mDataContainer->removeBefore(mDataContainer->size()-size);
}

//获取时间ms的不同方法
int QTime::msecsSinceStartOfDay();
QDateTime::currentDateTime().toMesecsSince Epoch()；
QTime curTime(QTime::currentTime());
int ms = curTime.hour()*60*60*1000+curTime.minute()*60*1000+curTime.second()*1000+curTime.msec();

4.8 坐标轴单位**

Qt QcustomPlot 多条Y轴在垂直布局中对齐的方法

/* 上面代码使得Y轴轴线始终对齐，下面的代码使得Y轴的标签始终对齐  */
QCPItemText *DataAquisition::setYaxisLabel(QCPAxis *yAxis, QString label, QCPAxisRect *rect)
{
    QCPItemText* yAxisLabel = new QCPItemText(ui->customplot);
    yAxisLabel->setText(label);
    yAxisLabel->setRotation(90);
    yAxisLabel->position->setAxisRect(rect);
    yAxisLabel->setClipToAxisRect(false);
    //x is absolut position
    yAxisLabel->position->setTypeX(QCPItemPosition::ptAbsolute);
    //y is relativ to AxesRect
    yAxisLabel->position->setTypeY(QCPItemPosition::ptAxisRectRatio);
    yAxisLabel->position->setAxes(0, yAxis);
    yAxisLabel->position->setCoords(10, 0.5);
 
    return yAxisLabel;
}

4.9 缩放

QCustomPlot实现矩形缩放图表
QCustomPlot系列： 实现X轴，Y轴的单独滚轮缩放数据

.h文件

#ifndef CROWDATAPLOT_H
#define CROWDATAPLOT_H

#include <QWidget>
#include "qcustomplot.h"

class CRowDataPlot : public QCustomPlot
{
public:
    CRowDataPlot(QWidget * parent = nullptr);

private slots:
    void onMouseWheel();
};

#endif // CROWDATAPLOT_H

.cpp文件

#include "crowdataplot.h"
CRowDataPlot::CRowDataPlot(QWidget * parent) :QCustomPlot(parent)
{
    //--1 设置plot属性
    setInteractions(QCP::iRangeDrag|QCP::iRangeZoom| QCP::iSelectAxes
                                    |QCP::iSelectLegend | QCP::iSelectPlottables);
    //--2 连接鼠标滚轮信号和槽
    connect(this, &CRowDataPlot::mouseWheel, this, &CRowDataPlot::onMouseWheel);
}

void CRowDataPlot::onMouseWheel()
{
    if (xAxis->selectedParts().testFlag(QCPAxis::spAxis))
        axisRect()->setRangeZoom(xAxis->orientation());
    else if (yAxis->selectedParts().testFlag(QCPAxis::spAxis))
        axisRect()->setRangeZoom(yAxis->orientation());
    else
        axisRect()->setRangeZoom(Qt::Horizontal|Qt::Vertical);
}

4.10 画圆

使用QCPItemEllipse画圆
qcustomplot画圆
.h文件：

private: 
    QCPItemEllipse *m_pCPItemEllipse;         //一个圆 
    QCPItemEllipse **m_pCPItemEllipseArray;    //多个圆

.cpp文件：

	//一个圆
	m_pCPItemEllipse = new QCPItemEllipse(ui->customPlot);
	QPen pen(Qt::green, 3, Qt::DashDotLine, Qt::RoundCap, Qt::RoundJoin);
	m_pCPItemEllipse->setPen(pen);
	//圆心C(x, y) 半径r
	//tL(x-r, y+r) bR(x+r, y-r)
	m_pCPItemEllipse->topLeft->setCoords(-120, -80);      //左上角位置 tL
	m_pCPItemEllipse->bottomRight->setCoords(-80, -120);  //右下角位置 bR
	ui->routeShowWidget->replot();

	//多个圆
	int number = 3;
	m_pCPItemEllipseArray = new QCPItemEllipse *[number];
	for(int vsi = 0; vsi < number; vsi++)
	{
	    m_pCPItemEllipseArray[vsi] = new QCPItemEllipse(ui->customPlot);
	    m_pCPItemEllipseArray[vsi]->topLeft->setCoords(100 + 2 * vsi, 80);   //左上角位置 tL
	    m_pCPItemEllipseArray[vsi]->bottomRight->setCoords(80, 120);         //右下角位置 bR
	 }
	ui->routeShowWidget->replot();

4.11 游标

游标及鼠标跟踪显示数值
QCustomPlot 标记点和文本标签

4.12 切屏屏闪

解决办法就是在我们的qcustomplot.cpp文件中，找到一个函数void QCPPaintBufferGlFbo::draw(QCPPainter *painter) const函数，大约在899行。
在代码painter->drawImage(0, 0, mGlFrameBuffer->toImage());之前加上一下代码：

  if(QOpenGLContext::currentContext() != mGlContext.data()) 
  {
      mGlContext.data()->makeCurrent(mGlContext.data()->surface());
  }

4.13 数据选中、框选放大

QCustomPlot之数据与图例的选中，曲线的显示与隐藏，放大被框选数据等操作

4.14 图例

QCustomPlot 设定图例的位置

customPlot->legend->setVisible(true);				//可见
customPlot->axisRect()->insetLayout()->setInsetAlignment(0,Qt::AlignTop|Qt::AlignRight);
customPlot->legend->setBrush(QColor(255,255,255,0));//设置图例背景
customPlot->graph(i)->setName(names);				//设置名称
customPlot->legend->setBorderPen(Qt::NoPen);		//无边框
customPlot->legend->setFont(QFont("Helvetica", 9));	//字体
customPlot->legend->setRowSpacing(-3);				//间隔
customPlot->legend->setTextColor(TextColor);		//文字颜色
customPlot->legend->setMargins(QMargins(0,0,0,0));	//到边框的距离
customPlot->legend->setIconSize(100, 20);			//设置图例大小

五、瀑布图

QCPColorMap实现瀑布图

六、极坐标图

QCustomPlot实现极坐标图

void FirstCustomPlot::polarPlotDemo()
{
    ui->qcustomplot->plotLayout()->clear();
    QCPPolarAxisAngular* angularAxis = new QCPPolarAxisAngular(ui->qcustomplot);
    ui->qcustomplot->plotLayout()->addElement(0,0,angularAxis);
    ui->qcustomplot->setInteractions(QCP::iRangeDrag|QCP::iRangeZoom);
    angularAxis->setRangeDrag(false);
    angularAxis->setTickLabelMode(QCPPolarAxisAngular::lmUpright);
    angularAxis->radialAxis()->setTickLabelRotation(0);
    angularAxis->radialAxis()->setAngle(45);
 
    angularAxis->grid()->setAngularPen(QPen(QColor(200,200,200),0,Qt::SolidLine));
    angularAxis->grid()->setSubGridType(QCPPolarGrid::gtAll);
 
    QCPPolarGraph* g1 = new QCPPolarGraph(angularAxis,angularAxis->radialAxis());
    QCPPolarGraph* g2 = new QCPPolarGraph(angularAxis,angularAxis->radialAxis());
    g2->setPen(QPen(QColor(255,150,20)));
    g2->setBrush(QColor(255,150,20,50));
    g1->setScatterStyle(QCPScatterStyle::ssStar);
    g1->setPen(QPen(Qt::blue));
//    g1->setLineStyle(QCPPolarGraph::lsNone);
    for(int i=0;i<100;i++){
        g1->addData(i/100.0*360.0,qSin(i/100.0*M_PI*8)*8+1);
        g2->addData(i/100.0*360.0,qSin(i/100.0*M_PI*6)*2);
    } 
    angularAxis->setRange(0,360);
    angularAxis->radialAxis()->setRange(-10,10);
}