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Reference Guide
transp_text.C
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1 /// \file
2 /// \ingroup tutorial_gl
3 /// This macro is based on labels1.C by Rene Brun.
4 /// Updated by Timur Pocheptsov to use transparent text.
5 /// The macro requires OpenGL - either enable by
6 /// `gStyle->SetCanvasPreferGL(kTRUE);` or by setting
7 /// `OpenGL.CanvasPreferGL` to 1 in `$ROOTSYS/etc/system.rootrc`.
8 ///
9 /// \macro_image(nobatch)
10 /// \macro_code
11 ///
12 /// \author Timur Pocheptsov
13 
14 //Includes for ACLiC (cling does not need them).
15 #include "TPaveText.h"
16 #include "TCanvas.h"
17 #include "TRandom.h"
18 #include "TError.h"
19 #include "TColor.h"
20 #include "TStyle.h"
21 #include "TH1F.h"
22 
23 //Aux. functions for tutorials/gl.
24 #include "customcolorgl.h"
25 
26 void transp_text()
27 {
28  //1. Try to 'allocate' free indices for our custom colors -
29  //we can use hard-coded indices like 1001, 1002, 1003 ... but
30  //I prefer to find free indices in a ROOT's color table
31  //to avoid possible conflicts with other tutorials.
32  Int_t indices[2] = {};
34  Error("transp_text", "failed to create new custom colors");
35  return;
36  }
37 
38  //2. Create special transparent colors for both pavetext fill color and text color.
39  const Int_t grayColorIndex = indices[0], blackColorIndex = indices[1];
40  new TColor(grayColorIndex, 0.8, 0.8, 0.8, "transparent_gray", 0.85);
41  new TColor(blackColorIndex, 0., 0., 0., "transparent_black", 0.5);
42 
43  //3. Create a TCanvas.
45 
46  TCanvas * const c1 = new TCanvas("transparent text","transparent text demo", 10, 10, 900, 500);
47  if (!c1->UseGL())
48  ::Warning("transp_text", "to use this macro you need OpenGL");
49 
50  c1->SetGrid();
51  c1->SetBottomMargin(0.15);
52 
53  const Int_t nx = 20;
54  const char *people[nx] = {"Jean","Pierre","Marie","Odile",
55  "Sebastien","Fons","Rene","Nicolas","Xavier","Greg",
56  "Bjarne","Anton","Otto","Eddy","Peter","Pasha",
57  "Philippe","Suzanne","Jeff","Valery"};
58 
59  TH1F * const h = new TH1F("h4", "test", nx, 0, nx);
60 
61  h->SetFillColor(38);
62  for (Int_t i = 0; i < 5000; ++i)
63  h->Fill(gRandom->Gaus(0.5 * nx, 0.2 * nx));
64 
65  h->SetStats(0);
66  for (Int_t i = 1; i <= nx; ++i)
67  h->GetXaxis()->SetBinLabel(i, people[i - 1]);
68 
69  h->Draw();
70 
71  TPaveText * const pt = new TPaveText(0.3, 0.3, 0.98, 0.98, "brNDC");
72  //Transparent 'rectangle' with transparent text.
73  pt->SetFillColor(grayColorIndex);
74  pt->SetTextColor(blackColorIndex);
75 
76  pt->SetTextSize(0.5);
77  pt->SetTextAlign(12);
78 
79  pt->AddText("Hello");
80  pt->Draw();
81 }
unsigned FindFreeCustomColorIndices(T(&indices)[N])
Definition: customcolorgl.h:40
virtual void Draw(Option_t *option="")
Draw this pavetext with its current attributes.
Definition: TPaveText.cxx:233
virtual Double_t Gaus(Double_t mean=0, Double_t sigma=1)
Samples a random number from the standard Normal (Gaussian) Distribution with the given mean and sigm...
Definition: TRandom.cxx:263
return c1
Definition: legend1.C:41
R__EXTERN TStyle * gStyle
Definition: TStyle.h:410
virtual TText * AddText(Double_t x1, Double_t y1, const char *label)
Add a new Text line to this pavetext at given coordinates.
Definition: TPaveText.cxx:182
1-D histogram with a float per channel (see TH1 documentation)}
Definition: TH1.h:571
int Int_t
Definition: RtypesCore.h:41
void Error(const char *location, const char *msgfmt,...)
virtual void SetTextAlign(Short_t align=11)
Set the text alignment.
Definition: TAttText.h:41
void SetCanvasPreferGL(Bool_t prefer=kTRUE)
Definition: TStyle.h:323
TPaveText * pt
virtual void SetFillColor(Color_t fcolor)
Set the fill area color.
Definition: TAttFill.h:37
void Warning(const char *location, const char *msgfmt,...)
R__EXTERN TRandom * gRandom
Definition: TRandom.h:62
#define h(i)
Definition: RSha256.hxx:106
The Canvas class.
Definition: TCanvas.h:31
A Pave (see TPave) with text, lines or/and boxes inside.
Definition: TPaveText.h:21
The color creation and management class.
Definition: TColor.h:19
virtual void SetTextColor(Color_t tcolor=1)
Set the text color.
Definition: TAttText.h:43
virtual void SetTextSize(Float_t tsize=1)
Set the text size.
Definition: TAttText.h:46
const Bool_t kTRUE
Definition: RtypesCore.h:87