Adding conversion from points to arcs

Allows detection of arcs from segments in a SHAPE_LINE_CHAIN, converting
them to SHAPE_ARCs in the chain

libs/kimath/include/geometry/shape_line_chain.h

@@ -609,6 +609,13 @@ public:
      */
     SHAPE_LINE_CHAIN& Simplify( bool aRemoveColinear = true );
 
+    /**
+     * Detects arcs in a chain and converts them from segments to true arcs by adding an arc
+     * and the associated references.  The original segment points are not changed.
+     * @return reference to self
+     */
+    SHAPE_LINE_CHAIN& DetectArcs();
+
     /**
      * Convert an arc to only a point chain by removing the arc and references.
      *

libs/kimath/src/geometry/shape_line_chain.cpp

@@ -223,6 +223,20 @@ bool SHAPE_LINE_CHAIN_BASE::Collide( const SEG& aSeg, int aClearance, int* aActu
 }
 
 
+SHAPE_LINE_CHAIN& SHAPE_LINE_CHAIN::DetectArcs()
+{
+    for( int ii = 0; ii < PointCount(); ++ii )
+    {
+        if( ssize_t ind = ArcIndex( ii ) >= 0 )
+        {
+            const SHAPE_ARC& arc = Arc( ind );
+        }
+    }
+
+    return *this;
+}
+
+
 const SHAPE_LINE_CHAIN SHAPE_LINE_CHAIN::Reverse() const
 {
     SHAPE_LINE_CHAIN a( *this );