Qt QCustomPlot画色阶图

        工作中用到QCustomPlot画曲线图和色阶图，并且在色阶图上添加文字，圆圈或者几条线段画一些图形，这里写个简单的例子把这几个功能记录一下，代码在这里： 

https://download.csdn.net/download/Sakuya__/89681279https://download.csdn.net/download/Sakuya__/89681279        本文代码效果如下：

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 代码之路

        MainWindow.h

#ifndef MAINWINDOW_H
#define MAINWINDOW_H#include "CustomPlot/qcustomplot.h"#include <QMainWindow>QT_BEGIN_NAMESPACE
namespace Ui { class MainWindow; }
QT_END_NAMESPACEclass MainWindow : public QMainWindow
{Q_OBJECTpublic:MainWindow(QWidget *parent = nullptr);~MainWindow();// 初始化界面void initWindow();private slots:void on_Btn_Clear_clicked();void on_Btn_AddText_clicked();void on_Btn_AddEllipse_clicked();void on_Btn_AddLine_clicked();private:Ui::MainWindow *ui;QVector<QCPItemText*> m_itemText;           // 文字QVector<QCPItemEllipse*> m_itemEllipse;     // 圆QVector<QCPItemLine*> m_itemLine;           // 线
};
#endif // MAINWINDOW_H

        MainWindow.cpp

#include "MainWindow.h"
#include "ui_MainWindow.h"MainWindow::MainWindow(QWidget *parent): QMainWindow(parent), ui(new Ui::MainWindow)
{ui->setupUi(this);initWindow();
}MainWindow::~MainWindow()
{delete ui;
}void MainWindow::initWindow()
{// 配置轴矩形，允许通过拖拽/缩放尺度改变颜色范围ui->customPlot->setInteractions(QCP::iRangeDrag|QCP::iRangeZoom| QCP::iSelectPlottables);ui->customPlot->axisRect()->setupFullAxesBox(true);// 设置x轴和y轴的坐标轴名字ui->customPlot->xAxis->setLabel("横向距离(m)");ui->customPlot->yAxis->setLabel("纵向距离(m)");// 创建QCPColorMap对象QCPColorMap *colorMap = new QCPColorMap(ui->customPlot->xAxis, ui->customPlot->yAxis);colorMap->setAntialiased(true);// 设置QCPColorMap的数据点为 nx*ny 个int nx = 257;int ny = 257;colorMap->data()->setSize(nx, ny);// 设置X轴和Y轴的坐标范围colorMap->data()->setRange(QCPRange(-3, 3), QCPRange(-3, 3));// 打开文件，读取数据QFile file(":/Resouce/data.txt");file.open(QIODevice::ReadOnly | QIODevice::Text);QTextStream in(&file);QList<double> data;while (!in.atEnd()){QString line = in.readLine();double a = line.toDouble();data.push_back(a);}// 根据读到的数据，为QCPColorMap的每个单元格点设置数据double x, y, z;for (int xIndex = 0; xIndex < nx; ++xIndex){for (int yIndex = 0; yIndex < ny; ++yIndex){// 把xIndex和yIndex表示的单元格索引，转换为此QCPColorMapData的单元格索引colorMap->data()->cellToCoord(xIndex, yIndex, &x, &y);// 把读到的数据值赋值给QCPColorMap的每个单元格z = data.at(xIndex * 257 + yIndex);colorMap->data()->setCell(xIndex, yIndex, z);}}// 添加右侧的色带QCPColorScale *colorScale = new QCPColorScale(ui->customPlot);// 设置色带值的范围colorScale->setDataRange(QCPRange(-190, 0));// 将颜色图与色标关联colorMap->setColorScale(colorScale);// 设置色带刻度垂直条，刻度线/坐标轴标签右侧（实际上，右侧已经是默认值）colorScale->setType(QCPAxis::atRight);// 设置色带右侧的名字colorScale->axis()->setLabel("Strength Value");// 色条使用的颜色渐变QCPColorGradient gradient;gradient.setColorStopAt(0.0, QColor("#f6efa6"));   // 设置色条开始时的颜色gradient.setColorStopAt(1.0, QColor("#bf444c"));   // 设置色条结束时的颜色// 将其添加到主轴矩形的右侧ui->customPlot->plotLayout()->addElement(0, 1, colorScale);// 使用插值，界面不显示小方块(默认是禁用的)colorMap->setInterpolate(true);// 将颜色贴图的“颜色渐变”设置为其中一个预设colorMap->setGradient(QCPColorGradient::gpJet);// 确保轴rect和色标同步其底边距和顶边距，以便它们对齐QCPMarginGroup *marginGroup = new QCPMarginGroup(ui->customPlot);ui->customPlot->axisRect()->setMarginGroup(QCP::msBottom|QCP::msTop, marginGroup);colorScale->setMarginGroup(QCP::msBottom|QCP::msTop, marginGroup);// 重新缩放数据维度（颜色），以使所有数据点都位于颜色渐变显示的范围内(由于已经使用setDataRange主动设置了色带的值范围，两个选一个就行)
//    colorMap->rescaleDataRange();// 重新缩放x轴和y轴，以便可以看到整个颜色图ui->customPlot->rescaleAxes();ui->customPlot->replot();
}void MainWindow::on_Btn_Clear_clicked()
{// 清除文字、圆和线段for (int i = 0; i < m_itemText.size(); ++i){if (m_itemText[i] == nullptr)continue;ui->customPlot->removeItem(m_itemText[i]);m_itemText[i] = nullptr;}for (int i = 0; i < m_itemEllipse.size(); ++i){if (m_itemEllipse[i] == nullptr)continue;ui->customPlot->removeItem(m_itemEllipse[i]);m_itemEllipse[i] = nullptr;}for (int i = 0; i < m_itemLine.size(); ++i){if (m_itemLine[i] == nullptr)continue;ui->customPlot->removeItem(m_itemLine[i]);m_itemLine[i] = nullptr;}ui->customPlot->clearPlottables();ui->customPlot->replot();
}void MainWindow::on_Btn_AddText_clicked()
{m_itemText.resize(2);QList<QPoint> list;list << QPoint(1.2, 1.8) << QPoint(-1.2, -1.8);for (int i = 0; i < 2; ++i){m_itemText[i] = new QCPItemText(ui->customPlot);m_itemText[i]->setText("S" + QString::number(i));m_itemText[i]->position->setType(QCPItemPosition::ptPlotCoords); // 位置类型m_itemText[i]->position->setCoords(list[i].x(), list[i].y());m_itemText[i]->setFont(QFont(font().family(), 12)); // 字体大小m_itemText[i]->setColor(Qt::black);}ui->customPlot->replot();
}void MainWindow::on_Btn_AddEllipse_clicked()
{m_itemEllipse.resize(2);QList<QPoint> list;list << QPoint(1.2, 1.8) << QPoint(-1.2, -1.8);for (int i = 0; i < 2; ++i){m_itemEllipse[i] = new QCPItemEllipse(ui->customPlot);m_itemEllipse[i]->setAntialiased(true);double r = 0.2;//每个通道的圆半径大小m_itemEllipse[i]->topLeft->setCoords(list[i].x() - r, list[i].y() + r);m_itemEllipse[i]->bottomRight->setCoords(list[i].x() + r, list[i].y() - r);m_itemEllipse[i]->setPen(QPen(Qt::black, 1));}ui->customPlot->replot();
}void MainWindow::on_Btn_AddLine_clicked()
{m_itemLine.resize(2);QList<QPoint> list;list << QPoint(1.2, 1.8) << QPoint(-1.2, -1.8);for (int i = 0; i < 2; ++i){m_itemLine[i] = new QCPItemLine(ui->customPlot);m_itemLine[i]->start->setCoords(list[i].x() - 0.2, list[i].y());m_itemLine[i]->end->setCoords(list[i].x() + 0.2, list[i].y());m_itemLine[i]->setPen(QPen(Qt::black, 1));}ui->customPlot->replot();
}