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transp.C File Reference

Detailed Description

This demo shows how to use transparency.

On MacOS X you can see the transparency in a canvas, you can save canvas contents as pdf/png (and thus you'll have an image with transparency on every platform).

//Includes for ACLiC (cling does not need them).
#include "TCanvas.h"
#include "TColor.h"
#include "TError.h"
#include "TStyle.h"
#include "TH1F.h"
//Aux. functions for tutorials/gl.
#include "customcolorgl.h"
void transp()
//1. Try to find 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.
Int_t indices[2] = {};
::Error("transp", "failed to create new custom colors");
//2. Now that we have indices, create our custom colors.
const Int_t redIndex = indices[0], greeIndex = indices[1];
new TColor(redIndex, 1., 0., 0., "red", 0.85);
new TColor(greeIndex, 0., 1., 0., "green", 0.5);
TCanvas * const cnv = new TCanvas("trasnparency", "transparency demo", 600, 400);
TH1F * const hist = new TH1F("a5", "b5", 10, -2., 3.);
TH1F * const hist2 = new TH1F("c6", "d6", 10, -3., 3.);
hist->FillRandom("landau", 100000);
hist2->FillRandom("gaus", 100000);
int Int_t
Definition RtypesCore.h:45
const Bool_t kTRUE
Definition RtypesCore.h:91
void Error(const char *location, const char *msgfmt,...)
Use this function in case an error occurred.
Definition TError.cxx:187
R__EXTERN TStyle * gStyle
Definition TStyle.h:412
virtual void SetFillColor(Color_t fcolor)
Set the fill area color.
Definition TAttFill.h:37
The Canvas class.
Definition TCanvas.h:23
TVirtualPad * cd(Int_t subpadnumber=0) override
Set current canvas & pad.
Definition TCanvas.cxx:708
The color creation and management class.
Definition TColor.h:19
1-D histogram with a float per channel (see TH1 documentation)}
Definition TH1.h:575
virtual void FillRandom(const char *fname, Int_t ntimes=5000, TRandom *rng=nullptr)
Fill histogram following distribution in function fname.
Definition TH1.cxx:3525
virtual void Draw(Option_t *option="")
Draw this histogram with options.
Definition TH1.cxx:3073
void SetCanvasPreferGL(Bool_t prefer=kTRUE)
Definition TStyle.h:325
unsigned FindFreeCustomColorIndices(T(&indices)[N])
Timur Pocheptsov

Definition in file transp.C.