From 833034f301099cfd77abe4d57cba1bfd5659183a Mon Sep 17 00:00:00 2001
From: ifv <ifv@opencascade.com>
Date: Mon, 15 Apr 2019 12:47:08 +0300
Subject: [PATCH] 0030647: Geom2dGcc_Circ2d2TanRad not giving all the solutions

Method for calculation of correct number of sampling points is added for
Adaptor2d_OffsetCurve.
Now number of sampling points correspond with similar method for
Geom2dAdaptor_Curve for curve type GeomAbs_OffsetCurve
Test case added
---
 src/Adaptor2d/Adaptor2d_OffsetCurve.cxx | 33 ++++++++++++++++++++++++-
 src/Adaptor2d/Adaptor2d_OffsetCurve.hxx |  1 +
 tests/bugs/modalg_7/bug30647            | 30 ++++++++++++++++++++++
 3 files changed, 63 insertions(+), 1 deletion(-)
 create mode 100644 tests/bugs/modalg_7/bug30647

diff --git a/src/Adaptor2d/Adaptor2d_OffsetCurve.cxx b/src/Adaptor2d/Adaptor2d_OffsetCurve.cxx
index 4c4fa9b832..16e5dc412f 100644
--- a/src/Adaptor2d/Adaptor2d_OffsetCurve.cxx
+++ b/src/Adaptor2d/Adaptor2d_OffsetCurve.cxx
@@ -458,7 +458,7 @@ GeomAbs_CurveType Adaptor2d_OffsetCurve::GetType() const {
       return GeomAbs_Circle;
       
     default:
-      return GeomAbs_OtherCurve;
+      return GeomAbs_OffsetCurve;
       
     }
   }
@@ -650,3 +650,34 @@ Handle(Geom2d_BSplineCurve) Adaptor2d_OffsetCurve::BSpline() const
                                   "Adaptor2d_OffsetCurve::BSpline() - wrong curve type");
   return myCurve->BSpline();
 }
+
+static Standard_Integer nbPoints(const Handle(Adaptor2d_HCurve2d)& theCurve)
+{
+
+  Standard_Integer nbs = 20;
+
+  if (theCurve->GetType() == GeomAbs_Line)
+    nbs = 2;
+  else if (theCurve->GetType() == GeomAbs_BezierCurve)
+  {
+    nbs = 3 + theCurve->NbPoles();
+  }
+  else if (theCurve->GetType() == GeomAbs_BSplineCurve) {
+    nbs = theCurve->NbKnots();
+    nbs *= theCurve->Degree();
+  }
+
+  if (nbs > 200)
+    nbs = 200;
+  return nbs;
+
+}
+//=======================================================================
+//function : NbSamples
+//purpose  : 
+//=======================================================================
+
+Standard_Integer Adaptor2d_OffsetCurve::NbSamples() const
+{
+  return  nbPoints(myCurve);
+}
diff --git a/src/Adaptor2d/Adaptor2d_OffsetCurve.hxx b/src/Adaptor2d/Adaptor2d_OffsetCurve.hxx
index b1b1c356f3..fc379a0269 100644
--- a/src/Adaptor2d/Adaptor2d_OffsetCurve.hxx
+++ b/src/Adaptor2d/Adaptor2d_OffsetCurve.hxx
@@ -174,6 +174,7 @@ public:
   
   Standard_EXPORT Handle(Geom2d_BSplineCurve) BSpline() const Standard_OVERRIDE;
 
+  Standard_EXPORT  Standard_Integer NbSamples() const Standard_OVERRIDE;
 
 
 
diff --git a/tests/bugs/modalg_7/bug30647 b/tests/bugs/modalg_7/bug30647
new file mode 100644
index 0000000000..51f88b464f
--- /dev/null
+++ b/tests/bugs/modalg_7/bug30647
@@ -0,0 +1,30 @@
+puts "========"
+puts "0030647: Geom2dGcc_Circ2d2TanRad not giving all the solutions"
+puts "========"
+puts ""
+
+restore [locate_data_file bug30647_curve1_720.brep] c1
+restore [locate_data_file bug30647_curve2_720.brep] c2
+
+explode c1 e
+mk2dcurve q1 c1_1
+explode c2 e
+mk2dcurve q2 c2_1
+
+cirtang r -c q1 -c q2 -r 0.4
+
+smallview  -2D-
+
+2dclear q1
+2dfit
+display q1
+
+xwd ${imagedir}/${test_image}.png
+
+set NbCurv [llength [directory r_*]]
+
+if { $NbCurv == 8 } {
+  puts "OK: Number of circles is good"
+} else {
+  puts "Error: Not all solutions"
+}
-- 
2.39.5