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Reference Guide
transparency.C
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1/// \file
2/// \ingroup tutorial_graphics
3/// \notebook
4/// This macro demonstrates the use of color transparency.
5///
6/// It is done by specifying the alpha value of a given color.
7/// For instance
8///
9/// ~~~
10/// ellipse->SetFillColorAlpha(9, 0.571);
11/// ~~~
12///
13/// changes the ellipse fill color to the index 9 with an alpha value of 0.571.
14/// 0. would be fully transparent (invisible) and 1. completely opaque (the default).
15///
16/// The transparency is available on all platforms when the flag
17/// `OpenGL.CanvasPreferGL` is set to `1` in `$ROOTSYS/etc/system.rootrc`, or
18/// on Mac with the Cocoa backend. X11 does not support transparency. On the file
19/// output it is visible with PDF, PNG, Gif, JPEG, SVG, TeX ... but not PostScript.
20///
21/// \macro_image
22/// \macro_code
23///
24/// \author Olivier Couet
25
26void transparency()
27{
28 auto c1 = new TCanvas("c1", "c1",224,330,700,527);
29 c1->Range(-0.125,-0.125,1.125,1.125);
30
31 auto tex = new TLatex(0.06303724,0.0194223,"This text is opaque and this line is transparent");
32 tex->SetLineWidth(2);
33 tex->Draw();
34
35 auto arrow = new TArrow(0.5555158,0.07171314,0.8939828,0.6195219,0.05,"|>");
36 arrow->SetLineWidth(4);
37 arrow->SetAngle(30);
38 arrow->Draw();
39
40 // Draw a transparent graph.
41 Double_t x[10] = {
42 0.5232808, 0.8724928, 0.9280086, 0.7059456, 0.7399714,
43 0.4659742, 0.8241404, 0.4838825, 0.7936963, 0.743553};
44 Double_t y[10] = {
45 0.7290837, 0.9631474, 0.4775896, 0.6494024, 0.3555777,
46 0.622012, 0.7938247, 0.9482072, 0.3904382, 0.2410359};
47 auto graph = new TGraph(10,x,y);
48 graph->SetLineColorAlpha(46, 0.1);
49 graph->SetLineWidth(7);
50 graph->Draw("l");
51
52 // Draw an ellipse with opaque colors.
53 auto ellipse = new TEllipse(0.1740688,0.8352632,0.1518625,0.1010526,0,360,0);
54 ellipse->SetFillColor(30);
55 ellipse->SetLineColor(51);
56 ellipse->SetLineWidth(3);
57 ellipse->Draw();
58
59 // Draw an ellipse with transparent colors, above the previous one.
60 ellipse = new TEllipse(0.2985315,0.7092105,0.1566977,0.1868421,0,360,0);
61 ellipse->SetFillColorAlpha(9, 0.571);
62 ellipse->SetLineColorAlpha(8, 0.464);
63 ellipse->SetLineWidth(3);
64 ellipse->Draw();
65
66 // Draw a transparent blue text.
67 tex = new TLatex(0.04871059,0.1837649,"This text is transparent");
68 tex->SetTextColorAlpha(9, 0.476);
69 tex->SetTextSize(0.125);
70 tex->SetTextAngle(26.0);
71 tex->Draw();
72
73 // Draw two transparent markers
74 auto marker = new TMarker(0.03080229,0.998008,20);
75 marker->SetMarkerColorAlpha(2, .3);
76 marker->SetMarkerStyle(20);
77 marker->SetMarkerSize(1.7);
78 marker->Draw();
79 marker = new TMarker(0.1239255,0.8635458,20);
80 marker->SetMarkerColorAlpha(2, .2);
81 marker->SetMarkerStyle(20);
82 marker->SetMarkerSize(1.7);
83 marker->Draw();
84
85 // Draw an opaque marker
86 marker = new TMarker(0.3047994,0.6344622,20);
87 marker->SetMarkerColor(2);
88 marker->SetMarkerStyle(20);
89 marker->SetMarkerSize(1.7);
90 marker->Draw();
91
92}
double Double_t
Definition: RtypesCore.h:55
Draw all kinds of Arrows.
Definition: TArrow.h:29
The Canvas class.
Definition: TCanvas.h:31
Draw Ellipses.
Definition: TEllipse.h:24
A Graph is a graphics object made of two arrays X and Y with npoints each.
Definition: TGraph.h:41
To draw Mathematical Formula.
Definition: TLatex.h:18
Manages Markers.
Definition: TMarker.h:23
return c1
Definition: legend1.C:41
Double_t y[n]
Definition: legend1.C:17
Double_t x[n]
Definition: legend1.C:17
Definition: graph.py:1