timeonaxis3.C

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/// \file
/// \ingroup tutorial_graphs
/// \notebook
/// This example compares what the system time function gmtime and localtime give
/// with what gives TGaxis. It can be used as referenced test to check if TGaxis
/// is working properly.
/// The original code was developed by Philippe Gras (CEA Saclay. IRFU/SEDI)
///
/// \macro_image
/// \macro_code
///
/// \authors Philippe Gras, Bertrand Bellenot, Olivier Couet
 
#include "TAxis.h"
#include "TGaxis.h"
#include "TCanvas.h"
#include "TString.h"
#include "TLine.h"
#include "TLatex.h"
#include <ctime>
#include <cstdio>
 
TString stime(time_t* t, bool utc = false, bool display_time_zone = true) {
   struct tm* tt;
   if (utc) tt = gmtime(t);
   else     tt = localtime(t);
   char buf[256];
   if (display_time_zone) strftime(buf, sizeof(buf), "%Y-%m-%d  %H:%M:%S %Z", tt);
   else                   strftime(buf, sizeof(buf), "%Y-%m-%d %H:%M:%S", tt);
   return TString(buf);
}
 
 
void timeonaxis3() {
   double f = 1.8;
 
   auto c = new TCanvas;
 
   TLatex tex1;
   tex1.SetNDC();
   tex1.SetTextFont(102);
   tex1.SetTextSize(0.055*f);
 
   TLatex tex3;
   tex3.SetNDC();
   tex3.SetTextFont(102);
   tex3.SetTextSize(0.07*f);
   tex3.SetTextColor(kBlue+2);
 
   TLatex tex2;
   tex2.SetNDC();
   tex2.SetTextFont(102);
   tex2.SetTextSize(0.07*f);
   tex2.SetTextColor(kOrange+3);
 
   time_t offset[] = {0,                   0, 1325376000, 1341100800};
   time_t t[]      = {1331150400, 1336417200,          0, 36000};
 
   c->SetTopMargin(0); c->SetBottomMargin(0);
   c->SetLeftMargin(0); c->SetRightMargin(0);
   c->Divide(2, 4, -1, -1);
   TLine l;
   l.DrawLine(0.5, 0, 0.5, 1.);
 
   for(int i = 0; i < 4; ++i){
      for(int gmt = 0; gmt < 2; ++gmt){
         const char* opt = (gmt ? "gmt" : "local");
         TVirtualPad* p = c->cd(2*i + gmt + 1);
         p->SetTopMargin(0); p->SetBottomMargin(0);
         p->SetLeftMargin(0); p->SetRightMargin(0);
         p->SetFillStyle(4000);
 
         TGaxis* ga = new TGaxis (.4, .25, 5., .25, t[i], t[i] + 1,  1, "t");
         ga->SetTimeFormat("TGaxis label: #color[2]{%Y-%m-%d %H:%M:%S}");
         ga->SetLabelFont(102);
         ga->SetLabelColor(kBlue+2);
 
         ga->SetTimeOffset(offset[i], opt);
         ga->SetLabelOffset(0.04*f);
         ga->SetLabelSize(0.07*f);
         ga->SetLineColor(0);
         ga->Draw();
 
         // Get offset string of axis time format: there is not accessor
         // to time format in TGaxis.
         // Assumes TAxis use the same format.
         TAxis a(10, 0, 1600000000);
         a.SetTimeOffset(offset[i], opt);
         const char* offsettimeformat = a.GetTimeFormat();
 
         char buf[256];
         if (offset[i] < t[i]) {
            snprintf(buf, 256, "#splitline{%s, %s}{offset: %ld, option %s}",
                    stime(t+i).Data(), stime(t+i, true).Data(), offset[i], opt);
         } else {
            int h = t[i] / 3600;
            int m = (t[i] - 3600 * h) / 60 ;
            int s = (t[i] - h * 3600 - m * 60);
            snprintf(buf, 256, "#splitline{%d h %d m %d s}{offset: %s, option %s}",
                    h, m, s, stime(offset + i, gmt).Data(), opt);
         }
         tex1.DrawLatex(.01, .75, buf);
         tex2.DrawLatex(.01, .50, offsettimeformat);
         time_t t_ = t[i] + offset[i];
         snprintf(buf, 256, "Expecting:    #color[2]{%s}", stime(&t_, gmt, false).Data());
         tex3.DrawLatex(.01, .24, buf);
         if(i > 0) l.DrawLine(0, 0.95, 1, 0.95);
      }
   }
}