{
"cells": [
{
"cell_type": "markdown",
"id": "e18f925e",
"metadata": {},
"source": [
"# hist015_TH1_read_and_draw\n",
"We attach (or generate) the ROOT file in `$ROOTSYS/tutorials/hsimple.root`\n",
"or `$PWD/hsimple.root`\n",
"We draw one histogram in different formats.\n",
"\n",
"\n",
"\n",
"\n",
"**Author:** Rene Brun \n",
"This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Tuesday, May 19, 2026 at 08:12 PM."
]
},
{
"cell_type": "markdown",
"id": "9d16be11",
"metadata": {},
"source": [
"Fetch and open the hsimple.root File"
]
},
{
"cell_type": "code",
"execution_count": 1,
"id": "3f32f546",
"metadata": {
"collapsed": false,
"execution": {
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"outputs": [
{
"name": "stdout",
"output_type": "stream",
"text": [
"TFile**\t\t/github/home/ROOT-CI/build/tutorials/hsimple.root\tDemo ROOT file with histograms\n",
" TFile*\t\t/github/home/ROOT-CI/build/tutorials/hsimple.root\tDemo ROOT file with histograms\n",
" KEY: TH1F\thpx;1\tThis is the px distribution\n",
" KEY: TH2F\thpxpy;1\tpy vs px\n",
" KEY: TProfile\thprof;1\tProfile of pz versus px\n",
" KEY: TNtuple\tntuple;1\tDemo ntuple\n"
]
}
],
"source": [
"TFile *example = TFile::Open(gROOT->GetTutorialDir() + \"/hsimple.root\");\n",
"\n",
"example->ls(); // Show the file contents"
]
},
{
"cell_type": "markdown",
"id": "05ce8a89",
"metadata": {},
"source": [
"Get the histogram from the ROOT File"
]
},
{
"cell_type": "code",
"execution_count": 2,
"id": "fc98368f",
"metadata": {
"collapsed": false,
"execution": {
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}
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"outputs": [],
"source": [
"TH1 *hpx = nullptr; // pointer to base class TH1 is enough\n",
"example->GetObject(\"hpx\", hpx);\n",
"\n",
"TCanvas *c1 = new TCanvas(\"c1\", \"Histogram Drawing Options\", 200, 10, 700, 900);\n",
"TPad *pad1 = new TPad(\"pad1\", \"The pad with the function\", 0.03, 0.62, 0.50, 0.92);\n",
"TPad *pad2 = new TPad(\"pad2\", \"The pad with the histogram\", 0.51, 0.62, 0.98, 0.92);\n",
"TPad *pad3 = new TPad(\"pad3\", \"The pad with the histogram\", 0.03, 0.02, 0.97, 0.57);\n",
"pad1->Draw();\n",
"pad2->Draw();\n",
"pad3->Draw();"
]
},
{
"cell_type": "markdown",
"id": "aaaeb1da",
"metadata": {},
"source": [
"Draw a global picture title"
]
},
{
"cell_type": "code",
"execution_count": 3,
"id": "3c75b11d",
"metadata": {
"collapsed": false,
"execution": {
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"shell.execute_reply": "2026-05-19T20:12:13.395713Z"
}
},
"outputs": [],
"source": [
"TPaveLabel *title = new TPaveLabel(0.1, 0.94, 0.9, 0.98, \"Drawing options for one dimensional histograms\");\n",
"title->SetTextFont(52);\n",
"title->Draw();"
]
},
{
"cell_type": "markdown",
"id": "88e3de96",
"metadata": {},
"source": [
"Draw histogram hpx in first pad with the default option."
]
},
{
"cell_type": "code",
"execution_count": 4,
"id": "c9fe989e",
"metadata": {
"collapsed": false,
"execution": {
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"shell.execute_reply": "2026-05-19T20:12:13.601897Z"
}
},
"outputs": [],
"source": [
"pad1->cd();\n",
"pad1->GetFrame()->SetFillColor(18);\n",
"hpx->SetFillColor(45);\n",
"hpx->DrawCopy();\n",
"TPaveLabel *label1 = new TPaveLabel(-3.5, 700, -1, 800, \"Default option\");\n",
"label1->Draw();"
]
},
{
"cell_type": "markdown",
"id": "46b478d5",
"metadata": {},
"source": [
"Draw hpx as a lego. Clicking on the lego area will show\n",
"a \"transparent cube\" to guide you rotating the lego in real time."
]
},
{
"cell_type": "code",
"execution_count": 5,
"id": "86fd3f26",
"metadata": {
"collapsed": false,
"execution": {
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"shell.execute_reply": "2026-05-19T20:12:13.807797Z"
}
},
"outputs": [],
"source": [
"pad2->cd();\n",
"hpx->DrawCopy(\"lego1\");\n",
"TPaveLabel *label2 = new TPaveLabel(-0.72, 0.74, -0.22, 0.88, \"option Lego1\");\n",
"label2->Draw();\n",
"TPaveLabel *label2a = new TPaveLabel(-0.93, -1.08, 0.25, -0.92, \"Click on lego to rotate\");\n",
"label2a->Draw();"
]
},
{
"cell_type": "markdown",
"id": "4c925bee",
"metadata": {},
"source": [
"Draw hpx with its errors and a marker."
]
},
{
"cell_type": "code",
"execution_count": 6,
"id": "9791f371",
"metadata": {
"collapsed": false,
"execution": {
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"shell.execute_reply": "2026-05-19T20:12:14.014419Z"
}
},
"outputs": [],
"source": [
"pad3->cd();\n",
"pad3->SetGridx();\n",
"pad3->SetGridy();\n",
"hpx->SetMarkerStyle(21);\n",
"hpx->Draw(\"e1p\");\n",
"TPaveLabel *label3 = new TPaveLabel(2, 600, 3.5, 650, \"option e1p\");\n",
"label3->Draw();"
]
},
{
"cell_type": "markdown",
"id": "9a234163",
"metadata": {},
"source": [
"The following illustrates how to add comments using a PaveText.\n",
"Attributes of text/lines/boxes added to a PaveText can be modified.\n",
"The AddText function returns a pointer to the added object."
]
},
{
"cell_type": "code",
"execution_count": 7,
"id": "2ca60099",
"metadata": {
"collapsed": false,
"execution": {
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"shell.execute_reply": "2026-05-19T20:12:14.228394Z"
}
},
"outputs": [
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"text/html": [
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],
"source": [
"TPaveText *pave = new TPaveText(-3.78, 500, -1.2, 750);\n",
"TText *t1 = pave->AddText(\"You can move\");\n",
"t1->SetTextColor(4);\n",
"t1->SetTextSize(0.05);\n",
"pave->AddText(\"Title and Stats pads\");\n",
"pave->AddText(\"X and Y axis\");\n",
"pave->AddText(\"You can modify bin contents\");\n",
"pave->Draw();\n",
"c1->Update();"
]
},
{
"cell_type": "markdown",
"id": "a633410a",
"metadata": {},
"source": [
"Draw all canvases "
]
},
{
"cell_type": "code",
"execution_count": 8,
"id": "1172d01d",
"metadata": {
"collapsed": false,
"execution": {
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],
"source": [
"%jsroot on\n",
"gROOT->GetListOfCanvases()->Draw()"
]
}
],
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"kernelspec": {
"display_name": "ROOT C++",
"language": "c++",
"name": "root"
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