[hist] use same n contours for background histogram

ferdymercury · web-flow · commit 1e040cde6904 · 2025-11-15T18:18:02.000+01:00
Fixes #20436
diff --git a/hist/histpainter/src/TGraphPainter.cxx b/hist/histpainter/src/TGraphPainter.cxx
@@ -4474,6 +4474,7 @@ void TGraphPainter::PaintScatter(TScatter *theScatter, Option_t* chopt)
    }
 
    TH2F *h = theScatter->GetHistogram();
+   h->SetContour(gStyle->GetNumberOfColors()); // Ensure same number of divisions in underlying hist than in TScatter palette
    if (optionAxis) {
       h->Paint(" ");
       if (h->GetMinimum() < h->GetMaximum()) {

Original file line number	Diff line number	Diff line change
`@@ -4474,6 +4474,7 @@ void TGraphPainter::PaintScatter(TScatter theScatter, Option_t chopt)`
`4474`	`4474`	`}`
`4475`	`4475`
`4476`	`4476`	`TH2F *h = theScatter->GetHistogram();`
	`4477`	`+ h->SetContour(gStyle->GetNumberOfColors()); // Ensure same number of divisions in underlying hist than in TScatter palette`
`4477`	`4478`	`if (optionAxis) {`
`4478`	`4479`	`h->Paint(" ");`
`4479`	`4480`	`if (h->GetMinimum() < h->GetMaximum()) {`