+ case 'A': // TAngential arc by end point
+ {
+ if (n1 != 3) goto badargs;
+ Standard_Real vx = a(1).RealValue();
+ Standard_Real vy = a(2).RealValue();
+ if (a(0) == "AA") {
+ vx -= x;
+ vy -= y;
+ }
+ Standard_Real det = dx * vy - dy * vx;
+ if ( Abs(det) > Precision::Confusion()) {
+ // Cosine of alpha = arc of angle / 2 , alpha in [0,Pi]
+ Standard_Real c = (dx * vx + dy * vy) / Sqrt((dx * dx + dy * dy) * (vx * vx + vy * vy));
+ // radius = distance between start and end point / 2 * sin(alpha)
+ // radius is > 0 or < 0
+ radius = (vx * vx + vy * vy)* Sqrt(dx * dx + dy * dy) / (2.0 * det);
+ if (Abs(radius) > Precision::Confusion()) {
+ angle = 2.0 * acos(c); // angle in [0,2Pi]
+ move = circle;
+ }
+ else
+ move = none;
+ break;
+ }
+ else
+ move = none;
+ break;
+ }
+ case 'U': // Arc by end point and radiUs
+ {
+ if (n1 != 5) goto badargs;
+ Standard_Real vx = a(1).RealValue();
+ Standard_Real vy = a(2).RealValue();
+ radius = a(3).RealValue();
+ reversed = a(4).IntegerValue();
+ if (a(0) == "UU") { // Absolute
+ vx -= x;
+ vy -= y;
+ }
+ Standard_Real length = Sqrt(vx * vx + vy * vy);
+ if ( (4.0 - (vx * vx + vy * vy) / (radius * radius) >= 0.0 ) && (length > Precision::Confusion()) ) {
+ // Cosine of alpha = arc angle / 2 , alpha in [0,Pi/2]
+ Standard_Real c = 0.5 * Sqrt(4.0 - (vx * vx + vy * vy) / (radius * radius));
+ angle = 2.0 * acos(c); // angle in [0,Pi]
+ if ( reversed == 2 )
+ angle = angle - 2 * M_PI;
+ dx = 0.5 * ( vy * 1.0/radius
+ + vx * Sqrt(4.0 / (vx * vx + vy * vy) - 1.0 / (radius * radius)));
+ dy = - 0.5 * ( vx * 1.0/radius
+ - vy * Sqrt(4.0 / (vx * vx + vy * vy) - 1.0 / (radius * radius)));
+ move = circle;
+ }
+ else{
+ move = none;
+ }
+ break;
+ }
+ case 'E': // Arc by end point and cEnter
+ {
+ if (n1 != 7) goto badargs;
+ Standard_Real vx = a(1).RealValue();
+ Standard_Real vy = a(2).RealValue();
+ Standard_Real vxc = a(3).RealValue();
+ Standard_Real vyc = a(4).RealValue();
+ reversed = a(5).IntegerValue();
+ control_Tolerance = a(6).IntegerValue();
+
+ if (a(0) == "EE") { // Absolute
+ vx -= x;
+ vy -= y;
+ vxc -= x;
+ vyc -= y;
+ }
+ radius = Sqrt( vxc * vxc + vyc * vyc );
+ Standard_Real det = vx * vyc - vy * vxc;
+ Standard_Real length = Sqrt(vx * vx + vy * vy);
+ Standard_Real length2 = Sqrt((vx-vxc) * (vx-vxc) + (vy-vyc) * (vy-vyc));
+ Standard_Real length3 = Sqrt(vxc * vxc + vyc * vyc);
+ Standard_Real error = Abs(length2 - radius);
+ myError = error;
+ if ( error > Precision::Confusion() ){
+ MESSAGE("Warning : The specified end point is not on the Arc, distance = "<<error);
+ }
+ if ( error > Precision::Confusion() && control_Tolerance == 1) // Don't create the arc if the end point
+ move = none; // is too far from it
+ else if ( (length > Precision::Confusion()) &&
+ (length2 > Precision::Confusion()) &&
+ (length3 > Precision::Confusion()) ) {
+ Standard_Real c = ( radius * radius - (vx * vxc + vy * vyc) )
+ / ( radius * Sqrt((vx-vxc) * (vx-vxc) + (vy-vyc) * (vy-vyc)) ) ; // Cosine of arc angle
+ angle = acos(c); // angle in [0,Pi]
+ if ( reversed == 2 )
+ angle = angle - 2 * M_PI;
+ if (det < 0)
+ angle = -angle;
+ dx = vyc / radius;
+ dy = -vxc / radius;
+ move = circle;
+ }
+ else {
+ move = none;
+ }
+ break;
+ }