57                 fA = DBL_EPSILON; // push it from 0 to slightly negative (y() returns -a)  in cubicEndPoints()
66             fA = DBL_EPSILON; // push it from 0 to slightly negative (y() returns -a)  in cubicEndPoints()
72         fA = pts[s].fY - pts[e].fY;  in cubicEndPoints()
86         fA = pts[0].fY - pts[1].fY;  in lineEndPoints()
105             fA = DBL_EPSILON;  in quadEndPoints()
111         fA = pts[s].fY - pts[e].fY;  in quadEndPoints()
122         return fA * fA + fB * fB;  in normalSquared()
128             fA = fB = fC = 0;  in normalize()
132         fA *= reciprocal;  in normalize()
142             distance[index].fY = fA * pts[index].fX + fB * pts[index].fY + fC;  in cubicDistanceY()
150             distance[index].fY = fA * pts[index].fX + fB * pts[index].fY + fC;  in quadDistanceY()
156         return fA * pts[index].fX + fB * pts[index].fY + fC;  in controlPtDistance()
160         return fA * pts[1].fX + fB * pts[1].fY + fC;  in controlPtDistance()
164         return fA * pt.fX + fB * pt.fY + fC;  in pointDistance()
172         return -fA;  in dy()
176     double fA;