TH2Poly SetLineColor etc. has no effect

[mxr]

Hello,
sorry, perhaps a totally stupid question, but I am stuck…
I have a TH2Poly and want to style the appearance of the bin borders (line color, line style, line width, etc…). None of the methods I am trying has the desired effect. What am I doing wrong? How can I achieve the desired behavior?

void plotPixelPlane(){
        TFile *f = new TFile("FOCALPixelPlane.root", "READ");
        TH2Poly *p = (TH2Poly*) f->Get("h2polyFOCALPixelPlane");
        p->SetLineColor(kRed);
        p->SetLineStyle(2);
        p->SetLineWidth(4);
        TCanvas *c = new TCanvas("c","c",600,600);
        p->Draw("L");
        c->SaveAs("cPixelPlane.png");
}

FOCALPixelPlane.root (126.0 KB)
plotPixelPlane.C (295 Bytes)

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Setup

ROOT v6.30/01
Built for linuxx8664gcc on Mar 05 2024, 02:22:43
From tags/v6-30-01-alice3@v6-25-02-6401-g65d7dbc65f
With c++ (GCC) 12.2.0
Binary directory: /home/mxr/dev/cern/alice/sw/ubuntu2204_x86-64/ROOT/v6-30-01-alice3-1/bin

___

[linev]

Hi and welcome on the forum,

Try with root --web plotPixelPlane.C. This will use web-based rendering - which works as expected:

To get result with normal graphics, you need to change attributes of individual TH2PolyBin:

   TIter iter(p->GetBins());
   while(auto bin = (TH2PolyBin *) iter()) {
      TGraph *gr = (TGraph *) bin->GetPolygon();
      gr->SetLineColor(kRed);
      gr->SetLineStyle(2);
      gr->SetLineWidth(4);
   }

[mxr]

Thanks a lot! This helped.

[couet]

I’ll check the normal root

[couet]

Actually this does not fly because on can set the color individually for each bin when you add them in the TH2Poly.

[linev]

Hi Olivier,

Please check why line width / line style for individual graphs are ignored.
After my modifications in the macro I see:

My macro:
plotPixelPlane.C (501 Bytes)

Regards,
Sergey

[couet]

Yes I see that line width/style are ignored. I ll provide a fix. but you cannot set a global color like in the original example. Your version is correct. Only It requires a fix. The way web graphics behave is wrong.

[linev]

I will wait your fix and then sync with JSROOT

[mxr]

Ah, yes, didn’t notice, but also for me width and style methods are ignored. Line color works, which is for the moment sufficient for my application. Thanks again.

[couet]

I am on it … gime some times

[couet]

This PR fixes the problem Make sure the option L draws closed polygon for TH2Poly by couet · Pull Request #14975 · root-project/root · GitHub

Thanks to have seen it.