{
"cells": [
{
"cell_type": "markdown",
"id": "582d3064",
"metadata": {},
"source": [
"# hist003_TH1_draw\n",
"Draw a 1D histogram to a canvas.\n",
"\n",
"\n",
"\n",
"\n",
"\n",
"**Author:** Rene Brun, Giacomo Parolini \n",
"This notebook tutorial was automatically generated with ROOTBOOK-izer from the macro found in the ROOT repository on Tuesday, May 19, 2026 at 08:11 PM."
]
},
{
"cell_type": "code",
"execution_count": 1,
"id": "c13b985f",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:11:49.083572Z",
"iopub.status.busy": "2026-05-19T20:11:49.083424Z",
"iopub.status.idle": "2026-05-19T20:11:50.046358Z",
"shell.execute_reply": "2026-05-19T20:11:50.043385Z"
}
},
"outputs": [],
"source": [
"import ROOT"
]
},
{
"cell_type": "markdown",
"id": "99fb9311",
"metadata": {},
"source": [
"Create and fill the histogram.\n",
"See hist002_TH1_fillrandom_userfunc.C for more information about this section."
]
},
{
"cell_type": "code",
"execution_count": 2,
"id": "afd59fca",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:11:50.048090Z",
"iopub.status.busy": "2026-05-19T20:11:50.047929Z",
"iopub.status.idle": "2026-05-19T20:11:50.242149Z",
"shell.execute_reply": "2026-05-19T20:11:50.240978Z"
}
},
"outputs": [],
"source": [
"form1 = ROOT.TFormula(\"form1\", \"abs(sin(x)/x)\")\n",
"rangeMin = 0.0\n",
"rangeMax = 10.0\n",
"sqroot = ROOT.TF1(\"sqroot\", \"x*gaus(0) + [3]*form1\", rangeMin, rangeMax)\n",
"sqroot.SetLineColor(4)\n",
"sqroot.SetLineWidth(6)\n",
"sqroot.SetParameters(10.0, 4.0, 1.0, 20.0)\n",
"\n",
"nBins = 200\n",
"h1d = ROOT.TH1D(\"h1d\", \"Test random numbers\", nBins, rangeMin, rangeMax)\n",
"\n",
"h1d.FillRandom(\"sqroot\", 10000)"
]
},
{
"cell_type": "markdown",
"id": "563fca77",
"metadata": {},
"source": [
"Create a canvas and draw the histogram"
]
},
{
"cell_type": "code",
"execution_count": 3,
"id": "beb9ca02",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:11:50.243866Z",
"iopub.status.busy": "2026-05-19T20:11:50.243738Z",
"iopub.status.idle": "2026-05-19T20:11:50.383000Z",
"shell.execute_reply": "2026-05-19T20:11:50.381944Z"
}
},
"outputs": [],
"source": [
"topX = 200\n",
"topY = 10\n",
"width = 700\n",
"height = 900\n",
"c1 = ROOT.TCanvas(\"c1\", \"The FillRandom example\", topX, topY, width, height)"
]
},
{
"cell_type": "markdown",
"id": "3827a61b",
"metadata": {},
"source": [
"Split the canvas into two sections to plot both the function and the histogram\n",
"The TPad's constructor accepts the relative coordinates (0 to 1) of the pad's boundaries"
]
},
{
"cell_type": "code",
"execution_count": 4,
"id": "cc16dc4f",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:11:50.384695Z",
"iopub.status.busy": "2026-05-19T20:11:50.384548Z",
"iopub.status.idle": "2026-05-19T20:11:50.496541Z",
"shell.execute_reply": "2026-05-19T20:11:50.495463Z"
}
},
"outputs": [],
"source": [
"pad1 = ROOT.TPad(\"pad1\", \"The pad with the function\", 0.05, 0.50, 0.95, 0.95)\n",
"pad2 = ROOT.TPad(\"pad2\", \"The pad with the histogram\", 0.05, 0.05, 0.95, 0.45)"
]
},
{
"cell_type": "markdown",
"id": "61570a7e",
"metadata": {},
"source": [
"Draw the two pads"
]
},
{
"cell_type": "code",
"execution_count": 5,
"id": "73a42ba2",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:11:50.498254Z",
"iopub.status.busy": "2026-05-19T20:11:50.498126Z",
"iopub.status.idle": "2026-05-19T20:11:50.615491Z",
"shell.execute_reply": "2026-05-19T20:11:50.614398Z"
}
},
"outputs": [],
"source": [
"pad1.Draw()\n",
"pad2.Draw()"
]
},
{
"cell_type": "markdown",
"id": "4586e7c2",
"metadata": {},
"source": [
"Select pad1 to draw the next objects into"
]
},
{
"cell_type": "code",
"execution_count": 6,
"id": "f34262ba",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:11:50.617173Z",
"iopub.status.busy": "2026-05-19T20:11:50.617043Z",
"iopub.status.idle": "2026-05-19T20:11:50.737070Z",
"shell.execute_reply": "2026-05-19T20:11:50.735996Z"
}
},
"outputs": [],
"source": [
"pad1.cd()\n",
"pad1.SetGridx()\n",
"pad1.SetGridy()\n",
"pad1.GetFrame().SetBorderMode(-1)\n",
"pad1.GetFrame().SetBorderSize(5)"
]
},
{
"cell_type": "markdown",
"id": "b00287cf",
"metadata": {},
"source": [
"Draw the function in pad1"
]
},
{
"cell_type": "code",
"execution_count": 7,
"id": "c3843085",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:11:50.738822Z",
"iopub.status.busy": "2026-05-19T20:11:50.738698Z",
"iopub.status.idle": "2026-05-19T20:11:50.847977Z",
"shell.execute_reply": "2026-05-19T20:11:50.846829Z"
}
},
"outputs": [],
"source": [
"sqroot.Draw()"
]
},
{
"cell_type": "markdown",
"id": "a581ec87",
"metadata": {},
"source": [
"Add a label to the function.\n",
"TPaveLabel's constructor accepts the pixel coordinates and the label string."
]
},
{
"cell_type": "code",
"execution_count": 8,
"id": "dec0351b",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:11:50.849727Z",
"iopub.status.busy": "2026-05-19T20:11:50.849567Z",
"iopub.status.idle": "2026-05-19T20:11:51.110013Z",
"shell.execute_reply": "2026-05-19T20:11:51.103473Z"
}
},
"outputs": [
{
"data": {
"text/html": [
"\n",
"\n",
"\n",
"
\n",
"\n",
"\n",
"\n"
],
"text/plain": [
""
]
},
"metadata": {},
"output_type": "display_data"
}
],
"source": [
"lfunction = ROOT.TPaveLabel(5, 39, 9.8, 46, \"The sqroot function\")\n",
"lfunction.Draw()\n",
"c1.Update()"
]
},
{
"cell_type": "markdown",
"id": "c11ea118",
"metadata": {},
"source": [
"Select pad2 to draw the next objects into"
]
},
{
"cell_type": "code",
"execution_count": 9,
"id": "e427d711",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:11:51.114183Z",
"iopub.status.busy": "2026-05-19T20:11:51.114048Z",
"iopub.status.idle": "2026-05-19T20:11:51.236947Z",
"shell.execute_reply": "2026-05-19T20:11:51.236551Z"
}
},
"outputs": [],
"source": [
"pad2.cd()\n",
"pad2.GetFrame().SetBorderMode(-1)\n",
"pad2.GetFrame().SetBorderSize(5)\n",
"\n",
"h1d.SetFillColor(45)\n",
"h1d.Draw()\n",
"c1.Update()"
]
},
{
"cell_type": "markdown",
"id": "8946c752",
"metadata": {},
"source": [
"Draw all canvases "
]
},
{
"cell_type": "code",
"execution_count": 10,
"id": "c6810b9e",
"metadata": {
"collapsed": false,
"execution": {
"iopub.execute_input": "2026-05-19T20:11:51.244048Z",
"iopub.status.busy": "2026-05-19T20:11:51.243919Z",
"iopub.status.idle": "2026-05-19T20:11:51.357043Z",
"shell.execute_reply": "2026-05-19T20:11:51.356627Z"
}
},
"outputs": [
{
"data": {
"text/html": [
"\n",
"\n",
"\n",
"
\n",
"\n",
"\n",
"\n"
],
"text/plain": [
""
]
},
"metadata": {},
"output_type": "display_data"
}
],
"source": [
"from ROOT import gROOT \n",
"gROOT.GetListOfCanvases().Draw()"
]
}
],
"metadata": {
"kernelspec": {
"display_name": "Python 3",
"language": "python",
"name": "python3"
},
"language_info": {
"codemirror_mode": {
"name": "ipython",
"version": 3
},
"file_extension": ".py",
"mimetype": "text/x-python",
"name": "python",
"nbconvert_exporter": "python",
"pygments_lexer": "ipython3",
"version": "3.12.12"
}
},
"nbformat": 4,
"nbformat_minor": 5
}