diff --git a/EGkCurveComposite.h b/EGkCurveComposite.h
index 0ce9a62..63f293d 100644
--- a/EGkCurveComposite.h
+++ b/EGkCurveComposite.h
@@ -56,6 +56,7 @@ class __declspec( novtable) ICurveComposite : public ICurve
       virtual bool ModifyCurveToLine( int nCrv) = 0 ;
       virtual bool ArcsToBezierCurves( void) = 0 ;
       virtual bool ArcsBezierCurvesToArcsPerpExtr( double dLinTol, double dAngTolDeg) = 0 ;
+      virtual bool StraightArcsToLines( double dLinTol, double dAngTolDeg) = 0 ;
       virtual bool MergeCurves( double dLinTol, double dAngTolDeg, bool bStartEnd = true, bool bNeedSameProp = false) = 0 ;
       virtual bool RemoveSmallDefects( double dLinTol, double dAngTolDeg, bool bAlsoSpikes = false) = 0 ;
       virtual bool RemoveUndercutOnY( double dLinTol, double dAngTolDeg) = 0 ;