JKQtPlotter/examples/rgbimageplot_opencv/rgbimageplot_opencv.cpp
2022-08-26 22:32:48 +02:00

94 lines
3.2 KiB
C++

/** \example rgbimageplot_opencv.cpp
* JKQTPlotter: Examples: Simple RGB image plot, showing a 3-channel OpenCV cv::Mat
*
* \ref JKQTPlotterImagePlotRGBOpenCV
*/
#include "jkqtpexampleapplication.h"
#include <QApplication>
#include <cmath>
#include "jkqtplotter/jkqtplotter.h"
#include "jkqtplotter/graphs/jkqtpscatter.h"
#include "jkqtplotter/graphs/jkqtpimagergb.h"
#include "jkqtplotter/jkqtpinterfaceopencv.h"
#include <opencv2/opencv.hpp>
#include <opencv2/imgcodecs.hpp>
int main(int argc, char* argv[])
{
QApplication app(argc, argv);
JKQTPlotter plot;
// 1. create a plotter window and get a pointer to the internal datastore (for convenience)
plot.getPlotter()->setUseAntiAliasingForGraphs(true); // nicer (but slower) plotting
plot.getPlotter()->setUseAntiAliasingForSystem(true); // nicer (but slower) plotting
plot.getPlotter()->setUseAntiAliasingForText(true); // nicer (but slower) text rendering
JKQTPDatastore* ds=plot.getDatastore();
// 2. now we open a BMP-file and load it into an OpenCV cv::Mat
cv::Mat picture = cv::imread("rgbimageplot_opencv_example.bmp");
qDebug()<<picture.rows<<"x"<<picture.cols<<"x"<<picture.channels();
// 3. make data available to JKQTPlotter by adding it to the internal datastore.
// In this step the contents of each channel of the openCV cv::Mat is copied into a column
// of the datastore in row-major order
size_t cPictureR=JKQTPCopyCvMatToColumn(ds, picture, "R-channel", 2);
size_t cPictureG=JKQTPCopyCvMatToColumn(ds, picture, "G-channel", 1);
size_t cPictureB=JKQTPCopyCvMatToColumn(ds, picture, "B-channel", 0);
// 4. create a graph (JKQTPColumnRGBMathImage) with the columns created above as data
JKQTPColumnRGBMathImage* graph=new JKQTPColumnRGBMathImage(&plot);
graph->setTitle("");
// where does the image start in the plot, given in plot-axis-coordinates (bottom-left corner)
graph->setX(0);
graph->setY(0);
// width and height of the image in plot-axis-coordinates
graph->setWidth(picture.cols);
graph->setHeight(picture.rows);
// image column with the data
graph->setImageRColumn(static_cast<int>(cPictureR));
graph->setImageGColumn(static_cast<int>(cPictureG));
graph->setImageBColumn(static_cast<int>(cPictureB));
// determine min/max of each channel manually
graph->setImageMinR(0);
graph->setImageMaxR(255);
graph->setImageMinG(0);
graph->setImageMaxG(255);
graph->setImageMinB(0);
graph->setImageMaxB(255);
// 5. add the graphs to the plot, so it is actually displayed
plot.addGraph(graph);
// 6. set axis labels
plot.getXAxis()->setAxisLabel("x [pixels]");
plot.getYAxis()->setAxisLabel("y [pixels]");
// 6.1 invert y-axis, so image is oriented correctly
plot.getYAxis()->setInverted(true);
// 7. fix axis aspect ratio to width/height, so pixels are square
plot.getPlotter()->setMaintainAspectRatio(true);
plot.getPlotter()->setAspectRatio(double(picture.cols)/double(picture.rows));
// 8. autoscale the plot so the graph is contained
plot.zoomToFit();
// show plotter and make it a decent size
plot.show();
plot.resize(800,600);
plot.setWindowTitle("JKQTPColumnRGBMathImage");
return app.exec();
}