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hist003_TH1_draw.C File Reference

Detailed Description

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Draw a 1D histogram to a canvas.

Note
When using graphics inside a ROOT macro the objects must be created with new.
{
// Create and fill the histogram.
// See hist002_TH1_fillrandom_userfunc.C for more information about this section.
auto *form1 = new TFormula("form1", "abs(sin(x)/x)");
double rangeMin = 0.0;
double rangeMax = 10.0;
auto *sqroot = new TF1("sqroot", "x*gaus(0) + [3]*form1", rangeMin, rangeMax);
sqroot->SetLineColor(4);
sqroot->SetLineWidth(6);
sqroot->SetParameters(10.0, 4.0, 1.0, 20.0);
int nBins = 200;
auto *h1d = new TH1D("h1d", "Test random numbers", nBins, rangeMin, rangeMax);
h1d->FillRandom("sqroot", 10000);
// Create a canvas and draw the histogram
int topX = 200;
int topY = 10;
int width = 700;
int height = 900;
auto *c1 = new TCanvas("c1", "The FillRandom example", topX, topY, width, height);
// Split the canvas into two sections to plot both the function and the histogram
// The TPad's constructor accepts the relative coordinates (0 to 1) of the pad's boundaries
auto *pad1 = new TPad("pad1", "The pad with the function", 0.05, 0.50, 0.95, 0.95);
auto *pad2 = new TPad("pad2", "The pad with the histogram", 0.05, 0.05, 0.95, 0.45);
// Draw the two pads
pad1->Draw();
pad2->Draw();
// Select pad1 to draw the next objects into
pad1->cd();
pad1->SetGridx();
pad1->SetGridy();
pad1->GetFrame()->SetBorderMode(-1);
pad1->GetFrame()->SetBorderSize(5);
// Draw the function in pad1
sqroot->Draw();
// Add a label to the function.
// TPaveLabel's constructor accepts the pixel coordinates and the label string.
auto *lfunction = new TPaveLabel(5, 39, 9.8, 46, "The sqroot function");
lfunction->Draw();
c1->Update();
// Select pad2 to draw the next objects into
pad2->cd();
pad2->GetFrame()->SetBorderMode(-1);
pad2->GetFrame()->SetBorderSize(5);
h1d->SetFillColor(45);
h1d->Draw();
c1->Update();
}
Option_t Option_t width
Option_t Option_t TPoint TPoint const char GetTextMagnitude GetFillStyle GetLineColor GetLineWidth GetMarkerStyle GetTextAlign GetTextColor GetTextSize void char Point_t Rectangle_t height
The Canvas class.
Definition TCanvas.h:23
1-Dim function class
Definition TF1.h:233
The Formula class.
Definition TFormula.h:89
1-D histogram with a double per channel (see TH1 documentation)
Definition TH1.h:693
The most important graphics class in the ROOT system.
Definition TPad.h:28
A Pave (see TPave) with a text centered in the Pave.
Definition TPaveLabel.h:20
return c1
Definition legend1.C:41
Date
November 2024
Author
Rene Brun, Giacomo Parolini

Definition in file hist003_TH1_draw.C.