{
"cells": [
{
"cell_type": "markdown",
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"source": [
"# file\n",
"This macro displays the physical ROOT file structure\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 08:13 PM."
]
},
{
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"id": "8453a17a",
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"source": [
"TCanvas *c1 = new TCanvas(\"c1\",\"ROOT File description\",200,10,700,550);\n",
"\n",
"c1->Range(0,-0.25,21,14);\n",
"TPaveLabel *title = new TPaveLabel(5,12,15,13.7,c1->GetTitle());\n",
"title->SetFillColor(16);\n",
"title->Draw();"
]
},
{
"cell_type": "markdown",
"id": "a315bcd1",
"metadata": {},
"source": [
"horizontal file layout"
]
},
{
"cell_type": "code",
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"id": "dce8b8a0",
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"source": [
"TPave *file = new TPave(1,8.5,20,11);\n",
"file->SetFillColor(11);\n",
"file->Draw();\n",
"TPave *fileh = new TPave(1,8.5,2.5,11);\n",
"fileh->SetFillColor(44);\n",
"fileh->Draw();\n",
"TPave *lrh = new TPave(2.5,8.5,3.3,11,1);\n",
"lrh->SetFillColor(33);\n",
"lrh->Draw();\n",
"lrh->DrawPave(6.9,8.5,7.7,11,1);\n",
"lrh->DrawPave(10.5,8.5,11.3,11,1);\n",
"lrh->DrawPave(14.5,8.5,15.3,11,1);\n",
"TLine *ldot = new TLine(1,8.5,0.5,6.5);\n",
"ldot->SetLineStyle(kDashed);\n",
"ldot->Draw();\n",
"ldot->DrawLine(2.5, 8.5, 9.4, 6.5);\n",
"ldot->DrawLine(10.5, 8.5, 10, 6.5);\n",
"ldot->DrawLine(11.3, 8.5, 19.5, 6.5);\n",
"TLine *line = new TLine(2.6,11,2.6,11.5);\n",
"line->Draw();\n",
"line->DrawLine(2.6,11.5,7,11.5);\n",
"TArrow *arrow = new TArrow(7,11.5,7,11.1,0.01,\"|>\");\n",
"arrow->SetFillStyle(1001);\n",
"arrow->Draw();\n",
"line->DrawLine( 7, 8.5, 7, 8.0);\n",
"line->DrawLine( 7, 8.0, 10.6, 8);\n",
"arrow->DrawArrow( 10.6,8, 10.6, 8.4,0.01,\"|>\");\n",
"line->DrawLine( 10.6, 11, 10.6, 11.5);\n",
"line->DrawLine( 10.6, 11.5, 14.6, 11.5);\n",
"arrow->DrawArrow( 14.6,11.5, 14.6,11.1,0.01,\"|>\");\n",
"line->DrawLine( 14.6, 8.5, 14.6, 8.0);\n",
"line->DrawLine( 14.6, 8.0, 16, 8);\n",
"ldot->DrawLine(16, 8, 19, 8);\n",
"TText *vert = new TText(1.5,9.75,\"File\");\n",
"vert->SetTextAlign(21);\n",
"vert->SetTextAngle(90);\n",
"vert->SetTextSize(0.025);\n",
"vert->Draw();\n",
"vert->DrawText(2.0, 9.75,\"Header\");\n",
"vert->DrawText(2.9, 9.75,\"Logical Record\");\n",
"vert->DrawText(3.2, 9.75,\"Header\");\n",
"vert->DrawText(7.3, 9.75,\"Logical Record\");\n",
"vert->DrawText(7.6, 9.75,\"Header\");\n",
"vert->DrawText(10.9,9.75,\"Logical Record\");\n",
"vert->DrawText(11.2,9.75,\"Header\");\n",
"vert->DrawText(14.9,9.75,\"Logical Record\");\n",
"vert->DrawText(15.2,9.75,\"Header\");\n",
"TText *hori = new TText(4.75,10,\"Object\");\n",
"hori->SetTextAlign(22);\n",
"hori->SetTextSize(0.035);\n",
"hori->Draw();\n",
"hori->DrawText(4.75, 9.5,\"Data\");\n",
"hori->DrawText(9.2, 10,\"Deleted\");\n",
"hori->DrawText(9.2, 9.5,\"Object\");\n",
"line->DrawLine( 6.9, 8.5, 10.5, 11);\n",
"line->DrawLine( 6.9, 11, 10.5, 8.5);\n",
"TText *tbig = new TText(17,9.75,\"............\");\n",
"tbig->SetTextAlign(22);\n",
"tbig->SetTextSize(0.03);\n",
"tbig->Draw();\n",
"tbig->DrawText(2.6, 7, \"fBEGIN\");\n",
"tbig->DrawText(20., 7, \"fEND\");\n",
"arrow->DrawArrow( 2.6,7, 2.6,8.4,0.01,\"|>\");\n",
"arrow->DrawArrow( 20,7, 20,8.4,0.01,\"|>\");"
]
},
{
"cell_type": "markdown",
"id": "df0c6935",
"metadata": {},
"source": [
"file header"
]
},
{
"cell_type": "code",
"execution_count": 3,
"id": "6ac2975b",
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"collapsed": false,
"execution": {
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"shell.execute_reply": "2026-05-19T20:13:44.203838Z"
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"outputs": [],
"source": [
"TPaveText *header = new TPaveText(0.5,.2,9.4,6.5);\n",
"header->SetFillColor(44);\n",
"header->Draw();\n",
"TText *fh=header->AddText(\"File Header\");\n",
"fh->SetTextAlign(22);\n",
"fh->SetTextSize(0.04);\n",
"header->SetTextSize(0.027);\n",
"header->SetTextAlign(12);\n",
"header->AddText(\" \");\n",
"header->AddLine(0,0,0,0);\n",
"header->AddText(\"\\\"root\\\": Root File Identifier\");\n",
"header->AddText(\"fVersion: File version identifier\");\n",
"header->AddText(\"fBEGIN: Pointer to first data record\");\n",
"header->AddText(\"fEND: Pointer to first free word at EOF\");\n",
"header->AddText(\"fSeekFree: Pointer to FREE data record\");\n",
"header->AddText(\"fNbytesFree: Number of bytes in FREE\");\n",
"header->AddText(\"fNfree: Number of free data records\");\n",
"header->AddText(\"fNbytesName: Number of bytes in name/title\");\n",
"header->AddText(\"fUnits: Number of bytes for pointers\");\n",
"header->AddText(\"fCompress: Compression level\");"
]
},
{
"cell_type": "markdown",
"id": "66fd1f08",
"metadata": {},
"source": [
"logical record header"
]
},
{
"cell_type": "code",
"execution_count": 4,
"id": "16c95da6",
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"Info in : png file file.png has been created\n"
]
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],
"source": [
"TPaveText *lrecord = new TPaveText(10,0.2,19.5,6.5);\n",
"lrecord->SetFillColor(33);\n",
"lrecord->Draw();\n",
"TText *tlrh = lrecord->AddText(\"Logical Record Header (TKEY)\");\n",
"tlrh->SetTextAlign(22);\n",
"tlrh->SetTextSize(0.04);\n",
"lrecord->SetTextSize(0.027);\n",
"lrecord->SetTextAlign(12);\n",
"lrecord->AddText(\" \");\n",
"lrecord->AddLine(0,0,0,0);\n",
"lrecord->AddText(\"fNbytes: Length of compressed object\");\n",
"lrecord->AddText(\"fVersion: Key version identifier\");\n",
"lrecord->AddText(\"fObjLen: Length of uncompressed object\");\n",
"lrecord->AddText(\"fDatime: Date/Time when written to store\");\n",
"lrecord->AddText(\"fKeylen: Number of bytes for the key\");\n",
"lrecord->AddText(\"fCycle : Cycle number\");\n",
"lrecord->AddText(\"fSeekKey: Pointer to object on file\");\n",
"lrecord->AddText(\"fSeekPdir: Pointer to directory on file\");\n",
"lrecord->AddText(\"fClassName: class name of the object\");\n",
"lrecord->AddText(\"fName: name of the object\");\n",
"lrecord->AddText(\"fTitle: title of the object\");\n",
"\n",
"c1->Update();\n",
"c1->Print(\"file.png\");"
]
},
{
"cell_type": "markdown",
"id": "e068618f",
"metadata": {},
"source": [
"Draw all canvases "
]
},
{
"cell_type": "code",
"execution_count": 5,
"id": "61d2c585",
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"source": [
"gROOT->GetListOfCanvases()->Draw()"
]
}
],
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"kernelspec": {
"display_name": "ROOT C++",
"language": "c++",
"name": "root"
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