mirror of
https://github.com/jkriege2/JKQtPlotter.git
synced 2024-11-16 10:35:49 +08:00
100 lines
3.6 KiB
C++
100 lines
3.6 KiB
C++
/** \example filledgraphs.cpp
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* Shows how to use filled graphs with JKQTPlotter
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*
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* \ref JKQTPlotterFilledGraphs
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*/
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#include <QApplication>
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#include "jkqtplotter/jkqtplotter.h"
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#include "jkqtplotter/graphs/jkqtpfilledcurve.h"
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int main(int argc, char* argv[])
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{
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QApplication app(argc, argv);
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// 1. create a plotter window and get a pointer to the internal datastore (for convenience)
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JKQTPlotter plot;
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JKQTPDatastore* ds=plot.getDatastore();
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// 2. now we create 4 datacolumns with length 256 entries in the datastore
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// these will later hold the RGB-histogram and a linear x-values vector
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// - the x-values are directly initialized as linear vector 0..255 in 256 steps
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// - the other columns are generated and size_t-type indexes are stored for later
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// reference to these columns in the graphs-
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size_t columnX=ds->addLinearColumn(256, 0, 255, "x");
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size_t columnR=ds->addColumn(256, "historam_R");
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size_t columnG=ds->addColumn(256, "historam_G");
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size_t columnB=ds->addColumn(256, "historam_B");
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// - now all columns for RGB are initialized to 0
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ds->setAll(columnG, 0);
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ds->setAll(columnR, 0);
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ds->setAll(columnB, 0);
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// 3. now we open a BMP-file and load it into a QImage
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QImage image(":/example.bmp");
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// ... and calculate the RGB-histograms
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for (int y=0; y<image.height(); y++) {
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for (int x=0; x<image.width(); x++) {
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QRgb pix=image.pixel(x,y);
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ds->inc(columnR, qRed(pix), 1);
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ds->inc(columnG, qGreen(pix), 1);
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ds->inc(columnB, qBlue(pix), 1);
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}
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}
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// ... and normalize histograms
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ds->scaleColumnValues(columnR, 100.0/static_cast<double>(image.width()*image.height()));
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ds->scaleColumnValues(columnG, 100.0/static_cast<double>(image.width()*image.height()));
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ds->scaleColumnValues(columnB, 100.0/static_cast<double>(image.width()*image.height()));
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// 4. now we add three semi-transparent, filled curve plots, one for each histogram
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JKQTPFilledCurveXGraph* graphR=new JKQTPFilledCurveXGraph(&plot);
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JKQTPFilledCurveXGraph* graphG=new JKQTPFilledCurveXGraph(&plot);
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JKQTPFilledCurveXGraph* graphB=new JKQTPFilledCurveXGraph(&plot);
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// set graph titles
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graphR->setTitle("R-channel");
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graphG->setTitle("G-channel");
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graphB->setTitle("B-channel");
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// set graph colors (lines: non-transparent, fill: semi-transparent) and style
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QColor col;
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col=QColor("red"); graphR->setColor(col);
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col.setAlphaF(0.25); graphR->setFillColor(col);
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col=QColor("green"); graphG->setColor(col);
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col.setAlphaF(0.25); graphG->setFillColor(col);
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col=QColor("blue"); graphB->setColor(col);
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col.setAlphaF(0.25); graphB->setFillColor(col);
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graphR->setLineWidth(1);
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graphG->setLineWidth(1);
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graphB->setLineWidth(1);
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// set data
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graphR->setXColumn(columnX); graphR->setYColumn(columnR);
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graphG->setXColumn(columnX); graphG->setYColumn(columnG);
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graphB->setXColumn(columnX); graphB->setYColumn(columnB);
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// add the graphs to the plot, so they are actually displayed
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plot.addGraph(graphB);
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plot.addGraph(graphG);
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plot.addGraph(graphR);
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// 5. set axis labels
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plot.getXAxis()->setAxisLabel("R/G/B-value");
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plot.getYAxis()->setAxisLabel("normalized frequency [%]");
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// 4. set the maximum size of the plot to 0..100% and 0..256
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plot.setAbsoluteX(0,256);
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plot.setAbsoluteY(0,100);
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// ... and scale plot automatically
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plot.zoomToFit();
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// 5. show plotter and make it a decent size
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plot.show();
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plot.resize(600,400);
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return app.exec();
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}
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