From 85da764d2dad44a98ca94f5e1fdf828f7d55238d Mon Sep 17 00:00:00 2001
From: Rene Brun <Rene.Brun@cern.ch>
Date: Tue, 28 Nov 2000 07:26:58 +0000
Subject: [PATCH] Fix a problem in TCutG::IsInside (thanks Otto Schaille). The
original algorithm from Rolf Nierhaus did not work correctly in case the Y
value was equal to the Y of one of the points and two consecutive points had
the same Y value.
git-svn-id: http://root.cern.ch/svn/root/trunk@1088 27541ba8-7e3a-0410-8455-c3a389f83636
---
graf/src/TCutG.cxx | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/graf/src/TCutG.cxx b/graf/src/TCutG.cxx
index 9ea3cc39832..2937c4623ce 100644
--- a/graf/src/TCutG.cxx
+++ b/graf/src/TCutG.cxx
@@ -1,4 +1,4 @@
-// @(#)root/graf:$Name: $:$Id: TCutG.cxx,v 1.3 2000/08/10 14:03:59 brun Exp $
+// @(#)root/graf:$Name: $:$Id: TCutG.cxx,v 1.4 2000/09/08 07:41:00 brun Exp $
// Author: Rene Brun 16/05/97
/*************************************************************************
@@ -191,7 +191,7 @@ Int_t TCutG::IsInside(Double_t x, Double_t y)
//*. intersects the horizontal line.
//*. In this case XINT is set to the X-coordinate of the
//*. intersection point.
-//*. If inter is an odd number, then the point x,y is not within
+//*. If inter is an odd number, then the point x,y is within
//*. the polygon.
//*.
//*. This routine is based on an original algorithm
@@ -203,12 +203,12 @@ Int_t TCutG::IsInside(Double_t x, Double_t y)
Int_t inter = 0;
for (i=0;i<fNpoints-1;i++) {
if (fY[i] == fY[i+1]) continue;
- if (y < fY[i] && y < fY[i+1]) continue;
+ if (y <= fY[i] && y <= fY[i+1]) continue;
if (fY[i] < y && fY[i+1] < y) continue;
xint = fX[i] + (y-fY[i])*(fX[i+1]-fX[i])/(fY[i+1]-fY[i]);
if (x < xint) inter++;
}
- if (inter != 2*(inter/2)) return 1;
+ if (inter%2) return 1;
return 0;
}
--
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