Pascal Perrodo wrote: > > Hi, > > First as a new root user thanks to root authors to provide a free product > adapted to Scientific (e.g. Particle Physics) Work!!! > > My problem: > I call root in a C++ code. In there I succeed to open a canvas, fill histos > and draw them in the canvas. Now when I go in the canvas and try to do > anything interactively with the mouse, the canvas is not refreshed and > the histograms don't appear any longer. > How to solve that? > I am working with root > Version 1.01/04 4 June 1997 > on HP-UX 9.x > > thanks in advance for help. > > Pascal Perrodo. In the root/test directory, we have an example hworld (see code below) illustrating how to call ROOT in batch and activate the event loop. Rene Brun //__________________________example hworld.cxx ________________________________ // This small demo shows the traditional "Hello World". Its main use is // to show how to use ROOT graphics and how to enter the eventloop to // be able to interact with the graphics. #include "TROOT.h" #include "TApplication.h" #include "TCanvas.h" #include "TLine.h" #include "TPaveLabel.h" extern void InitGui(); VoidFuncPtr_t initfuncs[] = { InitGui, 0 }; int Error; // needed by Motif TROOT root("hello","Hello World", initfuncs); int main(int argc, char **argv) { TApplication theApp("App", &argc, argv); TCanvas *c = new TCanvas("Hello", "The Hello Canvas", 400, 400); c->Show(); TPaveLabel *hello = new TPaveLabel(0.2,0.4,0.8,0.6,"Hello World"); hello->Draw(); c->Update(); // Enter event loop, one can now interact with the objects in // the canvas. Select "Exit ROOT" from Canvas "File" menu to exit // the event loop and execute the next statements. theApp.Run(kTRUE); TLine *l = new TLine(0.1,0.2,0.5,0.9); l->Draw(); c->Update(); // Here we don't return from the eventloop. "Exit ROOT" will quit the app. theApp.Run(); return 0; }
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