Code snippets for use in myana
Display images from Princeton camera
Some variables are needed both in beginjob() and event() member functions. The myana solution is to declare them as global variables right after the necessary include-files.
#include <TH2I.h> TH2I* h_image; static int widthSxrRCI0; static int heightSxrRCI0; static int orgXSxrRCI0; static int orgYSxrRCI0; static int binXSxrRCI0; static int binYSxrRCI0;
In beginjob(), get configuration object and book histogram
// Processing Princeton Config Data
int fail = getPrincetonConfig( DetInfo::SxrEndstation, 0,
widthSxrRCI0, heightSxrRCI0,
orgXSxrRCI0, orgYSxrRCI0,
binXSxrRCI0, binYSxrRCI0 );
if ( fail == 0 ) {// success
printf( "Get Princeton config for SxrRCI0: width %d height %d org (%d,%d) binX %d binY %d\n",
widthSxrRCI0, heightSxrRCI0, orgXSxrRCI0, orgYSxrRCI0, binXSxrRCI0, binYSxrRCI0 );
}
// Book a histogram
h_image = new TH2I("h_image","Princeton images (summed)", // name and title
widthSxrRCI0,orgXSxrRCI0,widthSxrRCI0, // nBinsX, xmin, xmax
heightSxrRCI0,orgYSxrRCI0,heightSxrRCI0); // nBinsY, ymin, ymax
In event(), fetch data from Princeton camera for the current event. Add to histogram (which will hold the sum of all events). Note, we here use a root TH2 histogram. It's rather slow for images, so you may want to use some other display service...
unsigned short* pixels;
int fail = getPrincetonValue( DetInfo::SxrEndstation, 0, pixels);
// Fill histogram from 2D array
for(int irow=0; irow<heightSxrRCI0; irow++){
for(int icol=0; icol<widthSxrRCI0; icol++){
h_image->Fill(icol,irow,*pixels);
pixels++; // go to the next pixel
}
}
Once all events have been processed, you can display and/or store the histogram in myana's endjob() function.
h_image->Draw();
h_image->SaveAs("myana_princ_image.root");
// 1D projections
h_image->ProjectionX()->SaveAs("myana_princ_imageX.root");
h_image->ProjectionY()->SaveAs("myana_princ_imageY.root");
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