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"# hist021_TH2_reverse_axis\n",
"\n",
"\n",
"\n",
"\n",
"**Author:** Olivier Couet \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."
]
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"outputs": [],
"source": [
"void ReverseXAxis(TH1 *h);\n",
"void ReverseYAxis(TH1 *h);"
]
},
{
"cell_type": "markdown",
"id": "aea19c14",
"metadata": {},
"source": [
" Definition of a helper function: "
]
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"source": [
"%%cpp -d\n",
"void ReverseXAxis(TH1 *h)\n",
"{\n",
" // Remove the current axis\n",
" h->GetXaxis()->SetLabelOffset(999);\n",
" h->GetXaxis()->SetTickLength(0);\n",
"\n",
" // Redraw the new axis\n",
" gPad->Update();\n",
" TGaxis *newaxis = new TGaxis(gPad->GetUxmax(), gPad->GetUymin(), gPad->GetUxmin(), gPad->GetUymin(),\n",
" h->GetXaxis()->GetXmin(), h->GetXaxis()->GetXmax(), 510, \"-\");\n",
" newaxis->SetLabelOffset(-0.03);\n",
" newaxis->Draw();\n",
"}"
]
},
{
"cell_type": "markdown",
"id": "e7e65da3",
"metadata": {},
"source": [
" Definition of a helper function: "
]
},
{
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"execution_count": 3,
"id": "04eb329c",
"metadata": {
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"outputs": [],
"source": [
"%%cpp -d\n",
"void ReverseYAxis(TH1 *h)\n",
"{\n",
" // Remove the current axis\n",
" h->GetYaxis()->SetLabelOffset(999);\n",
" h->GetYaxis()->SetTickLength(0);\n",
"\n",
" // Redraw the new axis\n",
" gPad->Update();\n",
" TGaxis *newaxis = new TGaxis(gPad->GetUxmin(), gPad->GetUymax(), gPad->GetUxmin() - 0.001, gPad->GetUymin(),\n",
" h->GetYaxis()->GetXmin(), h->GetYaxis()->GetXmax(), 510, \"+\");\n",
" newaxis->SetLabelOffset(-0.03);\n",
" newaxis->Draw();\n",
"}"
]
},
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],
"source": [
"TH2F *hpxpy = new TH2F(\"hpxpy\", \"py vs px\", 40, -4, 4, 40, -4, 4);\n",
"Float_t px, py;\n",
"TRandom r;\n",
"for (Int_t i = 0; i < 25000; i++) {\n",
" r.Rannor(px, py);\n",
" hpxpy->Fill(px, py);\n",
"}\n",
"TCanvas *c1 = new TCanvas(\"c1\");\n",
"hpxpy->Draw(\"colz\");\n",
"ReverseXAxis(hpxpy);\n",
"ReverseYAxis(hpxpy);"
]
},
{
"cell_type": "markdown",
"id": "035e4ce5",
"metadata": {},
"source": [
"Draw all canvases "
]
},
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"execution_count": 5,
"id": "78e72183",
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"source": [
"gROOT->GetListOfCanvases()->Draw()"
]
}
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