C++ 使用matplot++ 处理数据生成svg图表

python的图表库很丰富，C++依赖于python的 matplotlib的库却有很多功能不足，显得很鸡肋，其他的一些库没有过多的研究，

这里主要说说不依赖于python的纯C++ 的图表库 Matplot++
Matplot++官网

使用Matplot++同时需要下载安装gnuplot，并将gnuplot的bin加入到环境变量

Matplot++编译需要依赖一堆第三方库，可以参考官网，但是github上也提供了编译好的静态库，
Matplot++静态库下载链接
 gnuplot官网

这里主要使用官网提供的静态库。

将include、lib加入到对应的位置，并配置好路径和库连接，这部分不多说了。

以下直接上代码

下方案例主要针对2D坐标系，共享坐标系实现一个SVG图形的生成。

头文件

cpp 复制代码

#include <fstream>
#include <sstream>
#include <string>
#include <vector>
#include <chrono>
#include <cassert>
#include "matplot/matplot.h"
using namespace matplot;
class GSTestMaplotlib
{
public:
	explicit GSTestMaplotlib();
	~GSTestMaplotlib();
public:
	void InitAxez();
	void TestFunc();
	std::vector<double> CaculatePower(std::vector<double>& u, std::vector<double>& i);
	void AddIVData(axes_handle&,std::vector<double>& u, std::vector<double>& i);
	void ADDPVData(axes_handle&,std::vector<double>& u, std::vector<double>& i);
	void GetIVPointsData(const char* path,std::vector<double>& x,std::vector<double>& y);
	void GetStringOfSub(std::string src, std::string splitStr, std::vector<std::string>& strVec, int isRFind);

private:
	axes_handle parent_axes;
	figure_handle parent_figure;
};

cpp文件

cpp 复制代码

#include "GSTestMaplotlib.h"
#include <QtCore/QCoreApplication>
GSTestMaplotlib::GSTestMaplotlib()
{
    InitAxez();
}

GSTestMaplotlib::~GSTestMaplotlib()
{
}

void GSTestMaplotlib::InitAxez()
{
    parent_figure = figure(true);    //设置为quiet_mode模式，即只处理数据，不会调用gnuplot的UI显示窗口

    //parent_figure= figure_no_backend(true);

    this->parent_axes = axes();    
    this->parent_axes->grid(true);
    this->parent_axes->grid_alpha(0.5);
    this->parent_axes->grid_color({ 125,125,125,0 });
    this->parent_axes->xlabel("Voltage(V)");
    this->parent_axes->ylabel("Currect(A)");
    this->parent_axes->y2label("Currect(P)");
    this->parent_axes->hold(on);

    parent_figure->add_axes(this->parent_axes,true, true);
    //parent_figure->current_axes(this->parent_axes);
    parent_figure->reactive_mode(false);
    std::string path = QString(QCoreApplication::applicationDirPath() + "/area_4.svg").toStdString();
    parent_figure->backend()->output(path);
    
}
#include <QThread>
void GSTestMaplotlib::TestFunc()
{
    std::vector<double> u;
    std::vector<double> i;
    GetIVPointsData("0000000001-T1M1.csv", u, i);
    std::vector<double> p = CaculatePower(u, i);
    for (int  ii= 0; ii <5; ii++)
    {
        AddIVData(parent_axes, u, i);
        ADDPVData(parent_axes, u, p);
        QThread::msleep(20);
    } 
    std::string path = QString(QCoreApplication::applicationDirPath() + "/area_4.svg").toStdString();
    bool ret = parent_figure->save(path);
    parent_figure->draw();
   
}

void GSTestMaplotlib::AddIVData(axes_handle& parent_axes,std::vector<double>& u, std::vector<double>& i)
{
    auto start = std::chrono::steady_clock::now();
    auto parent = parent_axes->plot(u, i); 
    parent->touch();
    auto end = std::chrono::steady_clock::now();
    auto time_diff = end - start;
    auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(time_diff);
    std::cout << "Operation cost IV : " << duration.count() << "ms" << std::endl;       
}

void GSTestMaplotlib::ADDPVData(axes_handle& parent_axes,std::vector<double>& u, std::vector<double>& p)
{    
    auto start = std::chrono::steady_clock::now();
    auto parent = parent_axes->plot(u, p);
    parent->use_y2(true);	//使用右侧Y轴
    y2label("Currect(P)");	//必需设置
    parent->touch(); 
    auto end = std::chrono::steady_clock::now();
    auto time_diff = end - start;
    auto duration = std::chrono::duration_cast<std::chrono::milliseconds>(time_diff);
    std::cout << "Operation cost PV : " << duration.count() << "ms" << std::endl;   
}

std::vector<double> GSTestMaplotlib::CaculatePower(std::vector<double>& u, std::vector<double>& i)
{
    std::vector<double> powerVec;
    auto itorV = u.begin();
    auto itorI = i.begin();
    for (; itorV != u.end(); itorV++, itorI++)
    {        
        double power = (*itorV)*(*itorI);
        powerVec.emplace_back(power);
    }
    return powerVec;
}

void GSTestMaplotlib::GetIVPointsData(const char* path, std::vector<double>& x, std::vector<double>& y)
{
    std::ifstream fileIn;
    fileIn.open(path);
    assert(fileIn.is_open());
    std::string line;
    std::vector<std::string> axisData;
    while (getline(fileIn, line))
    {        
        GetStringOfSub(line,",", axisData,1);
        x.emplace_back(atof(axisData[0].c_str()));
        y.emplace_back(atof(axisData[1].c_str()));
        axisData.clear();
    }
    fileIn.close();
}

void GSTestMaplotlib::GetStringOfSub(std::string src, std::string splitStr, std::vector<std::string>& strVec, int isRFind)
{
    if (isRFind == 0)       //反向查找
    {
        int pos = src.rfind(splitStr);
        if (pos != -1)
        {
            std::string dstStr = src.substr(pos, src.length() - 1);
            strVec.emplace_back(dstStr);
            std::string srcStr = src.substr(0, pos);
            GetStringOfSub(srcStr, splitStr, strVec, isRFind);
        }
        else
        {
            strVec.emplace_back(src);
        }
    }
    else
    {
        int pos = src.find(splitStr);
        if (pos != -1)
        {
            std::string dstStr = src.substr(0, pos);
            strVec.emplace_back(dstStr);
            std::string srcStr = src.substr(pos + 1, src.length());
            GetStringOfSub(srcStr, splitStr, strVec, isRFind);
        }
        else
        {
            strVec.emplace_back(src);
        }
    }
}