X-Git-Url: http://git.salome-platform.org/gitweb/?a=blobdiff_plain;f=src%2FGeomAPI%2FGeomAPI_Circ2d.cpp;h=5edbab178a47cf77eeac99025a51608f603dc488;hb=857f94a96eb62e69746221f2b919335140b117c6;hp=a5815140920eb6e6f12a01800c0fe6d6518ec8a0;hpb=b9a93c1ac199671649cf2371dfe9fda2bbe65fd0;p=modules%2Fshaper.git

diff --git a/src/GeomAPI/GeomAPI_Circ2d.cpp b/src/GeomAPI/GeomAPI_Circ2d.cpp
index a58151409..5edbab178 100644
--- a/src/GeomAPI/GeomAPI_Circ2d.cpp
+++ b/src/GeomAPI/GeomAPI_Circ2d.cpp
@@ -39,7 +39,7 @@ static gp_Circ2d* newCirc2d(const double theCenterX, const double theCenterY,
   if (aCenter.IsEqual(aPoint, Precision::Confusion()))
     return NULL;
 
-  gp_Dir2d aDir(theCenterX - thePointX, theCenterY - thePointY);
+  gp_Dir2d aDir(thePointX - theCenterX, thePointY - theCenterY);
 
   return newCirc2d(theCenterX, theCenterY, aDir, aRadius);
 }
@@ -55,15 +55,29 @@ static gp_Circ2d* newCirc2d(const std::shared_ptr<GeomAPI_Pnt2d>& theFirstPoint,
   gp_XY aVec12 = aSecondPnt - aFirstPnt;
   gp_XY aVec23 = aThirdPnt - aSecondPnt;
   gp_XY aVec31 = aFirstPnt - aThirdPnt;
+
+  // coefficients to calculate center
+  double aCoeff1, aCoeff2, aCoeff3;
+
   // square of parallelogram
   double aSquare2 = aVec12.Crossed(aVec23);
   aSquare2 *= aSquare2 * 2.0;
-  if (aSquare2 < 1.e-20)
-    return NULL;
-  // coefficients to calculate center
-  double aCoeff1 = aVec23.Dot(aVec23) / aSquare2 * aVec12.Dot(aVec31.Reversed());
-  double aCoeff2 = aVec31.Dot(aVec31) / aSquare2 * aVec23.Dot(aVec12.Reversed());
-  double aCoeff3 = aVec12.Dot(aVec12) / aSquare2 * aVec31.Dot(aVec23.Reversed());
+  if (aSquare2 < 1.e-20) {
+    // if two points are equal, build a circle on two different points as on diameter
+    double aSqLen12 = aVec12.SquareModulus();
+    double aSqLen23 = aVec23.SquareModulus();
+    double aSqLen31 = aVec31.SquareModulus();
+    if (aSqLen12 < Precision::SquareConfusion() &&
+        aSqLen23 < Precision::SquareConfusion() &&
+        aSqLen31 < Precision::SquareConfusion())
+      return NULL;
+    aCoeff1 = aCoeff2 = aCoeff3 = 1.0 / 3.0;
+  }
+  else {
+    aCoeff1 = aVec23.Dot(aVec23) / aSquare2 * aVec12.Dot(aVec31.Reversed());
+    aCoeff2 = aVec31.Dot(aVec31) / aSquare2 * aVec23.Dot(aVec12.Reversed());
+    aCoeff3 = aVec12.Dot(aVec12) / aSquare2 * aVec31.Dot(aVec23.Reversed());
+  }
   // center
   gp_XY aCenter = aFirstPnt * aCoeff1 + aSecondPnt * aCoeff2 + aThirdPnt * aCoeff3;
   // radius
@@ -143,7 +157,8 @@ const bool GeomAPI_Circ2d::parameter(const std::shared_ptr<GeomAPI_Pnt2d> thePoi
                                    double& theParameter) const
 {
   Handle(Geom2d_Circle) aCurve = new Geom2d_Circle(*MY_CIRC2D);
-  return GeomLib_Tool::Parameter(aCurve, thePoint->impl<gp_Pnt2d>(), theTolerance, theParameter) == Standard_True;
+  return GeomLib_Tool::Parameter(aCurve, thePoint->impl<gp_Pnt2d>(),
+                                 theTolerance, theParameter) == Standard_True;
 }
 
 //=================================================================================================