Logo ROOT   6.21/01
Reference Guide
transparentpad.C
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1 /// \file
2 /// \ingroup tutorial_gl
3 /// This macro demonstrates semi-transparent pads.
4 /// Requires OpenGL.
5 ///
6 /// \macro_image(nobatch)
7 /// \macro_code
8 ///
9 /// \author Timur Pocheptsov
10 
11 //Includes for ACLiC (cling does not need them).
12 #include "TCanvas.h"
13 #include "TStyle.h"
14 #include "TError.h"
15 #include "TColor.h"
16 #include "TH1F.h"
17 
18 //Aux. functions for tutorials/gl.
19 #include "customcolorgl.h"
20 
21 void transparentpad()
22 {
23  //1. Try to 'allocate' free indices for our custom colors -
24  //we can use hard-coded indices like 1001, 1002, 1003 ... but
25  //I prefer to find free indices in a ROOT's color table
26  //to avoid possible conflicts with other tutorials.
28 
29  Int_t indices[3] = {};
31  ::Error("transparentpad", "failed to create new custom colors");
32  return;
33  }
34 
35  //2. Create a TCanvas.
36  TCanvas * const c1 = new TCanvas("transparent pad","transparent pad demo", 10, 10, 900, 500);
37  //We can check gVirtualX (its type):
38  if (!c1->UseGL()) {
39  ::Warning("transparentpad", "You can see the transparency ONLY in a pdf or png output (\"File\"->\"Save As\" ->...)\n"
40  "To have transparency in a canvas graphics, you need OpenGL rendering enabled");
41  }
42 
43  //2. Create special transparent colors.
44  new TColor(indices[0], 1., 0.2, 0.2, "transparent_pink", 0.25);
45  new TColor(indices[1], 0.2, 1., 0.2, "transparent_green", 0.25);
46  new TColor(indices[2], 0.2, 2., 1., "transparent_blue", 0.15);
47 
48  //3. Some arbitrary histograms.
49  TH1F * const h1 = new TH1F("TH1F 1", "TH1F 1", 100, -1.5, 1.5);
50  h1->FillRandom("gaus");
51 
52  TH1F * const h2 = new TH1F("TH1F 2", "TH1F 2", 100, -1.5, 0.);
53  h2->FillRandom("gaus");
54 
55  TH1F * const h3 = new TH1F("TH1F 3", "TH1F 3", 100, 0.5, 2.);
56  h3->FillRandom("landau");
57 
58  //4. Now overlapping transparent pads.
59  TPad * const pad1 = new TPad("transparent pad 1", "transparent pad 1", 0.1, 0.1, 0.7, 0.7);
60  pad1->SetFillColor(indices[0]);//here's the magic!
61  pad1->cd();
62  h1->Draw("lego2");
63  c1->cd();
64  pad1->Draw();
65 
66  TPad * const pad2 = new TPad("transparent pad 2", "transparent pad 2", 0.2, 0.2, 0.8, 0.8);
67  pad2->SetFillColor(indices[1]);//here's the magic!
68  pad2->cd();
69  h2->Draw();
70  c1->cd();
71  pad2->Draw();
72 
73  TPad * const pad3 = new TPad("transparent pad 3", "transparent pad 3", 0.3, 0.3, 0.9, 0.9);
74  pad3->SetFillColor(indices[2]);//here's the magic!
75  pad3->cd();
76  h3->Draw();
77  c1->cd();
78  pad3->Draw();
79 }
80 
unsigned FindFreeCustomColorIndices(T(&indices)[N])
Definition: customcolorgl.h:40
return c1
Definition: legend1.C:41
R__EXTERN TStyle * gStyle
Definition: TStyle.h:410
1-D histogram with a float per channel (see TH1 documentation)}
Definition: TH1.h:571
int Int_t
Definition: RtypesCore.h:41
TVirtualPad * cd(Int_t subpadnumber=0)
Set Current pad.
Definition: TPad.cxx:593
TH1F * h1
Definition: legend1.C:5
virtual void Draw(Option_t *option="")
Draw Pad in Current pad (re-parent pad if necessary).
Definition: TPad.cxx:1284
void Error(const char *location, const char *msgfmt,...)
void SetCanvasPreferGL(Bool_t prefer=kTRUE)
Definition: TStyle.h:323
virtual void FillRandom(const char *fname, Int_t ntimes=5000)
Fill histogram following distribution in function fname.
Definition: TH1.cxx:3428
virtual void Draw(Option_t *option="")
Draw this histogram with options.
Definition: TH1.cxx:2981
virtual void SetFillColor(Color_t fcolor)
Set the fill area color.
Definition: TAttFill.h:37
The most important graphics class in the ROOT system.
Definition: TPad.h:29
void Warning(const char *location, const char *msgfmt,...)
The Canvas class.
Definition: TCanvas.h:31
The color creation and management class.
Definition: TColor.h:19
const Bool_t kTRUE
Definition: RtypesCore.h:87