// @(#)root/test:$Id$ // Author: Fons Rademakers 04/04/97 // 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 "TApplication.h" #include "TCanvas.h" #include "TLine.h" #include "TPaveLabel.h" int main(int argc, char **argv) { TApplication theApp("App", &argc, argv); TCanvas *c = new TCanvas("c", "The Hello Canvas", 400, 400); TPaveLabel *hello = new TPaveLabel(0.2,0.4,0.8,0.6,"Hello World"); hello->Draw(); TPaveLabel *quit = new TPaveLabel(0.2,0.2,0.8,0.3,"Close via menu File/Quit"); quit->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(); quit->SetLabel("Select File/Quit again to exit app"); c->Update(); // Here we don't return from the eventloop. "Exit ROOT" will quit the app. theApp.Run(); return 0; }