transp_text.C

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/// \file
/// \ingroup tutorial_cocoa
/// This macro is based on labels1.C by Rene Brun.
/// Updated by Timur Pocheptsov to use transparent text (12/10/2012).
/// Requires OS X and ROOT configured with --enable-cocoa.
///
/// \macro_code
///
/// \author Timur Pocheptsov
 
// Includes for ACLiC (cling does not need them).
#include "TVirtualX.h"
#include "TPaveText.h"
#include "TCanvas.h"
#include "TRandom.h"
#include "TError.h"
#include "TColor.h"
#include "TH1F.h"
 
// Aux. functions for tutorials/cocoa.
#include "customcolor.h"
 
void transp_text()
{
   // 1. Try to 'allocate' free indices for our custom colors -
   // we can use hard-coded indices like 1001, 1002, 1003 ... but
   // I prefer to find free indices in a ROOT's color table
   // to avoid possible conflicts with other tutorials.
   Color_t indices[2] = {};
   if (ROOT::CocoaTutorials::FindFreeCustomColorIndices(indices) != 2) {
      ::Error("transp_text", "failed to create new custom colors");
      return;
   }
 
   // 2. Create special transparent colors for both pavetext fill color and text color.
   const Color_t grayColorIndex = indices[0], blackColorIndex = indices[1];
   new TColor(grayColorIndex, 0.8, 0.8, 0.8, "transparent_gray", 0.85);
   new TColor(blackColorIndex, 0., 0., 0., "transparent_black", 0.5);
 
   // 3. Create a TCanvas first to force gVirtualX initialization.
   TCanvas *const c1 = new TCanvas("transparent text", "transparent text demo", 10, 10, 900, 500);
   // We can check gVirtualX (its type):
   if (gVirtualX && !gVirtualX->InheritsFrom("TGCocoa")) {
      ::Warning("transt_text",
                "You can see the transparency ONLY in a pdf or png output (\"File\"->\"Save As\" ->...)\n"
                "To have transparency in a canvas graphics, you need OS X version with cocoa enabled");
   }
 
   c1->SetGrid();
   c1->SetBottomMargin(0.15);
 
   const Int_t nx = 20;
   const char *people[nx] = {"Jean",    "Pierre", "Marie",    "Odile",   "Sebastien", "Fons",  "Rene",
                             "Nicolas", "Xavier", "Greg",     "Bjarne",  "Anton",     "Otto",  "Eddy",
                             "Peter",   "Pasha",  "Philippe", "Suzanne", "Jeff",      "Valery"};
 
   TH1F *const h = new TH1F("h4", "test", nx, 0, nx);
 
   h->SetFillColor(38);
   for (Int_t i = 0; i < 5000; ++i)
      h->Fill(gRandom->Gaus(0.5 * nx, 0.2 * nx));
 
   h->SetStats(false);
   for (Int_t i = 1; i <= nx; ++i)
      h->GetXaxis()->SetBinLabel(i, people[i - 1]);
 
   h->Draw();
 
   TPaveText *const pt = new TPaveText(0.3, 0.3, 0.98, 0.98, "brNDC");
   // Transparent 'rectangle' with transparent text.
   pt->SetFillColor(grayColorIndex);
   pt->SetTextColor(blackColorIndex);
 
   pt->SetTextSize(0.5);
   pt->SetTextAlign(12);
 
   pt->AddText("Hello");
   pt->Draw();
}