doc/v614/draw__v6_8cxx.html

/*************************************************************************
 * Copyright (C) 1995-2017, Rene Brun and Fons Rademakers.               *
 * All rights reserved.                                                  *
 *                                                                       *
 * For the licensing terms see $ROOTSYS/LICENSE.                         *
 * For the list of contributors see $ROOTSYS/README/CREDITS.             *
 *************************************************************************/
R__LOAD_LIBRARY(libGpad);
#include <ROOT/TObjectDrawable.hxx>
#include <ROOT/TCanvas.hxx>
#include <TGraph.h>
#include <iostream>
// Show how to display v6 objects in a v7 TCanvas.
void draw_v6()
{
   using namespace ROOT;
   static constexpr int npoints = 4;
   double x[npoints] = {0., 1., 2., 3.};
   double y[npoints] = {.1, .2, .3, .4};
   auto gr = std::make_shared<TGraph>(npoints, x, y);
   auto canvas = Experimental::TCanvas::Create("v7 TCanvas showing a v6 TGraph");
   canvas->Draw(gr, "AL");
   canvas->Show(); // new window should popup and async update will be triggered
   // canvas->Show("opera");   // one could specify program name which should show canvas (like chromium or firefox)
   // canvas->Show("/usr/bin/chromium --app=$url &"); // one could use $url parameter, which replaced with canvas URL
   // synchronous, wait until painting is finished
   canvas->Update(false,
                  [](bool res) { std::cout << "First Update done = " << (res ? "true" : "false") << std::endl; });
   // canvas->Modified(); // when uncommented, invalidate canvas and force repainting with next Update()
   // call Update again, should return immediately if canvas was not modified
   canvas->Update(false,
                  [](bool res) { std::cout << "Second Update done = " << (res ? "true" : "false") << std::endl; });
   // request to create PNG file in asynchronous mode and specify lambda function as callback
   // when request processed by the client, callback invoked with result value
   canvas->SaveAs("draw.png", true,
                  [](bool res) { std::cout << "Producing PNG done res = " << (res ? "true" : "false") << std::endl; });
   // this function executed in synchronous mode (async = false is default),
   // mean previous file saving will be completed as well at this point
   canvas->SaveAs("draw.svg"); // synchronous
   // hide canvas after 10 seconds - close all connections and close all opened windows
   // gSystem->Sleep(10000);
   // canvas->Hide();
}