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radialgradients.C
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1 /// \file
2 /// \ingroup tutorial_cocoa
3 /// This tutorial demonstrates how to use radial gradients,
4 /// custom colors, transparency.
5 /// Requires ROOT built for OS X with --enable-cocoa.
6 ///
7 /// \macro_code
8 ///
9 /// \author Timur Pocheptsov
10 
11 //Includes for ACLiC:
12 #include <cassert>
13 #include <cstdlib>
14 
15 #include "TColorGradient.h"
16 #include "TVirtualX.h"
17 #include "TEllipse.h"
18 #include "TRandom.h"
19 #include "TCanvas.h"
20 #include "TError.h"
21 
22 //Cocoa aux. functions.
23 #include "customcolor.h"
24 
25 namespace {
26 
27 //Just some colors (rgba) to build our
28 //fancy gradients from.
29 const Double_t basicColors[][4] =
30 {
31 {1., 0., 0., 1.},
32 {1., 0.3, 0., 1.},
33 {0., 0., 1., 1.},
34 {1., 1., 0., 1.},
35 {1., 0., 1., 1.},
36 {0., 1., 1., 1.},
37 {0., 1., 0., 1.},
38 {0., 0.5, 0., 1.},
39 //transparent colors:
40 {1., 0., 0., 0.5},
41 {1., 0.3, 0., 0.5},
42 {0., 0., 1., 0.5},
43 {1., 1., 0., 0.5},
44 {1., 0., 1., 0.5},
45 {0., 1., 1., 0.5},
46 {0., 1., 0., 0.5},
47 {0., 0.5, 0., 0.5},
48 //and even more transparent:
49 {1., 0., 0., 0.2},
50 {1., 0.3, 0., 0.2},
51 {0., 0., 1., 0.2},
52 {1., 1., 0., 0.2},
53 {1., 0., 1., 0.2},
54 {0., 1., 1., 0.2},
55 {0., 1., 0., 0.2},
56 {0., 0.5, 0., 0.2}
57 };
58 
59 const unsigned nBasicColors = sizeof basicColors / sizeof basicColors[0];
60 
61 //______________________________________________________________________
62 Color_t CreateRandomGradientFill()
63 {
64  Color_t idx[1] = {};
66  return -1;
67 
68  const Double_t * const fromRGBA = basicColors[(std::rand() % (nBasicColors / 2))];
69  //With odd number of colors the last one is never selected :)
70  const Double_t * const toRGBA = basicColors[nBasicColors / 2 + (std::rand() % (nBasicColors / 2))];
71 
72  const Double_t locations[] = {0., 1.};
73  const Double_t rgbas[] = {fromRGBA[0], fromRGBA[1], fromRGBA[2], fromRGBA[3],
74  toRGBA[0], toRGBA[1], toRGBA[2], toRGBA[3]};
75 
76  TRadialGradient * const grad = new TRadialGradient(idx[0], 2, locations, rgbas);
77  grad->SetRadialGradient(TColorGradient::Point(0.5, 0.5), 0.5);
78 
79  return idx[0];
80 }
81 
82 //______________________________________________________________________
83 bool add_ellipse(const Double_t xC, const Double_t yC, const Double_t r)
84 {
85  assert(gPad != nullptr && "add_ellipse, no pad to add ellipse");
86 
87  const Color_t newColor = CreateRandomGradientFill();
88  if (newColor == -1) {
89  ::Error("add_ellipse", "failed to find a new color index for a gradient fill");
90  return false;
91  }
92 
93  TEllipse * const newEllipse = new TEllipse(xC, yC, r, r);
94  newEllipse->SetFillColor(newColor);
95  newEllipse->Draw();
96 
97  return true;
98 }
99 
100 }
101 
102 //______________________________________________________________________
103 void radialgradients()
104 {
105  gRandom->SetSeed(4357);//;)
106 
107  TCanvas * const cnv = new TCanvas("radial gradients", "radial gradients", 800, 800);
108  if (gVirtualX && !gVirtualX->InheritsFrom("TGCocoa")) {
109  ::Error("radialgradients",
110  "this demo requires OS X and ROOT built with --enable-cocoa");
111  delete cnv;
112  return;
113  }
114 
115  for (unsigned i = 0; i < 100; ++i)
116  if (!add_ellipse(gRandom->Rndm(), gRandom->Rndm(), 0.5 * gRandom->Rndm()))
117  break;
118 
119  cnv->Modified();
120  cnv->Update();
121 }
gVirtualX
#define gVirtualX
Definition: TVirtualX.h:338
r
ROOT::R::TRInterface & r
Definition: Object.C:4
TRandom.h
TColorGradient.h
TEllipse
Definition: TEllipse.h:23
TRadialGradient
Definition: TColorGradient.h:128
TVirtualX.h
TColorGradient::Point
Definition: TColorGradient.h:55
TCanvas.h
ROOT::CocoaTutorials::FindFreeCustomColorIndices
unsigned FindFreeCustomColorIndices(Color_t(&indices)[N])
Definition: customcolor.h:38
Color_t
short Color_t
Definition: RtypesCore.h:83
TEllipse::Draw
virtual void Draw(Option_t *option="")
Draw this ellipse with its current attributes.
Definition: TEllipse.cxx:168
TPad::Modified
void Modified(Bool_t flag=1)
Definition: TPad.h:414
customcolor.h
gRandom
R__EXTERN TRandom * gRandom
Definition: TRandom.h:62
TRandom::SetSeed
virtual void SetSeed(ULong_t seed=0)
Set the random generator seed.
Definition: TRandom.cxx:597
TRandom::Rndm
virtual Double_t Rndm()
Machine independent random number generator.
Definition: TRandom.cxx:541
Double_t
double Double_t
Definition: RtypesCore.h:59
TRadialGradient::SetRadialGradient
void SetRadialGradient(const Point &center, Double_t radius)
Set radial gradient.
Definition: TColorGradient.cxx:324
TCanvas
Definition: TCanvas.h:23
TCanvas::Update
virtual void Update()
Update canvas pad buffers.
Definition: TCanvas.cxx:2500
TEllipse.h
gPad
#define gPad
Definition: TVirtualPad.h:287
Error
void Error(const char *location, const char *msgfmt,...)
Use this function in case an error occurred.
Definition: TError.cxx:187
TError.h