doc/master/rf106__plotdecoration_8py.html

import ROOT


# Set up model

# ---------------------


# Create observables

x = ROOT.RooRealVar("x", "x", -10, 10)


# Create Gaussian

sigma = ROOT.RooRealVar("sigma", "sigma", 1, 0.1, 10)

mean = ROOT.RooRealVar("mean", "mean", -3, -10, 10)

gauss = ROOT.RooGaussian("gauss", "gauss", x, mean, sigma)


# Generate a sample of 1000 events with sigma=3

data = gauss.generate({x}, 1000)


# Fit pdf to data

gauss.fitTo(data, PrintLevel=-1)


# Plot pdf and data

# -------------------------------------


# Overlay projection of gauss on data

frame = x.frame(Name="xframe", Title="RooPlot with decorations", Bins=40)

data.plotOn(frame)

gauss.plotOn(frame)


# Add box with pdf parameters

# -----------------------------------------------------


# Left edge of box starts at 55% of Xaxis)

gauss.paramOn(frame, Layout=0.55)


# Add box with data statistics

# -------------------------------------------------------


# X size of box is from 55% to 99% of Xaxis range, of box is at 80% of

# Yaxis range)

data.statOn(frame, Layout=(0.55, 0.99, 0.8))


# Add text and arrow

# -----------------------------------


# Add text to frame

txt = ROOT.TText(2, 100, "Signal")

txt.SetTextSize(0.04)

txt.SetTextColor(ROOT.kRed)

frame.addObject(txt)


# Add arrow to frame

arrow = ROOT.TArrow(2, 100, -1, 50, 0.01, "|>")

arrow.SetLineColor(ROOT.kRed)

arrow.SetFillColor(ROOT.kRed)

arrow.SetLineWidth(3)

frame.addObject(arrow)


# Persist frame with all decorations in ROOT file

# ---------------------------------------------------------------------------------------------


f = ROOT.TFile("rf106_plotdecoration.root", "RECREATE")

frame.Write()

f.Close()


# To read back and plot frame with all decorations in clean root session do

# root> ROOT.TFile f("rf106_plotdecoration.root")

# root>  xframe.Draw()


c = ROOT.TCanvas("rf106_plotdecoration", "rf106_plotdecoration", 600, 600)

ROOT.gPad.SetLeftMargin(0.15)

frame.GetYaxis().SetTitleOffset(1.6)

frame.Draw()


c.SaveAs("rf106_plotdecoration.png")