Documentation update

[modules/shaper.git] / src / GeomAPI / GeomAPI_Circ2d.cpp

diff --git a/src/GeomAPI/GeomAPI_Circ2d.cpp b/src/GeomAPI/GeomAPI_Circ2d.cpp
index c809e567e843c9b099b546887e4f33c6931df122..cbb16dd4be9757a23c4c84b90dc6cef6553a33ca 100644 (file)
--- a/src/GeomAPI/GeomAPI_Circ2d.cpp
+++ b/src/GeomAPI/GeomAPI_Circ2d.cpp
@@ -39,11 +39,54 @@ 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);
 }
 
+static gp_Circ2d* newCirc2d(const std::shared_ptr<GeomAPI_Pnt2d>& theFirstPoint,
+                            const std::shared_ptr<GeomAPI_Pnt2d>& theSecondPoint,
+                            const std::shared_ptr<GeomAPI_Pnt2d>& theThirdPoint)
+{
+  gp_XY aFirstPnt(theFirstPoint->x(), theFirstPoint->y());
+  gp_XY aSecondPnt(theSecondPoint->x(), theSecondPoint->y());
+  gp_XY aThirdPnt(theThirdPoint->x(), theThirdPoint->y());
+
+  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) {
+    // 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
+  double aRadius = (aFirstPnt - aCenter).Modulus();
+
+  gp_Dir2d aDir(aFirstPnt - aCenter);
+  return newCirc2d(aCenter.X(), aCenter.Y(), aDir, aRadius);
+}
+
 GeomAPI_Circ2d::GeomAPI_Circ2d(const std::shared_ptr<GeomAPI_Pnt2d>& theCenter,
                                const std::shared_ptr<GeomAPI_Pnt2d>& theCirclePoint)
     : GeomAPI_Interface(
@@ -56,7 +99,13 @@ GeomAPI_Circ2d::GeomAPI_Circ2d(const std::shared_ptr<GeomAPI_Pnt2d>& theCenter,
     : GeomAPI_Interface(
         newCirc2d(theCenter->x(), theCenter->y(), theDir->impl<gp_Dir2d>(), theRadius))
 {
+}
 
+GeomAPI_Circ2d::GeomAPI_Circ2d(const std::shared_ptr<GeomAPI_Pnt2d>& theFirstPoint,
+                               const std::shared_ptr<GeomAPI_Pnt2d>& theSecondPoint,
+                               const std::shared_ptr<GeomAPI_Pnt2d>& theThirdPoint)
+    : GeomAPI_Interface(newCirc2d(theFirstPoint, theSecondPoint, theThirdPoint))
+{
 }
 
 const std::shared_ptr<GeomAPI_Pnt2d> GeomAPI_Circ2d::project(
@@ -89,12 +138,16 @@ const std::shared_ptr<GeomAPI_Pnt2d> GeomAPI_Circ2d::project(
 
 const std::shared_ptr<GeomAPI_Pnt2d> GeomAPI_Circ2d::center() const
 {
+  if (!MY_CIRC2D)
+    return std::shared_ptr<GeomAPI_Pnt2d>();
   const gp_Pnt2d& aCenter = MY_CIRC2D->Location();
   return std::shared_ptr<GeomAPI_Pnt2d>(new GeomAPI_Pnt2d(aCenter.X(), aCenter.Y()));
 }
 
 double GeomAPI_Circ2d::radius() const
 {
+  if (!MY_CIRC2D)
+    return 0.0;
   return MY_CIRC2D->Radius();
 }