timeonaxis3.C

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/// \file
/// \ingroup tutorial_graphics
/// \notebook
/// \preview 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);
      }
   }
}