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SUBROUTINE HIDRVS (Z0, Z1,ZE,Z2, MX,MY, NX,NY, LX,LY, S, X ROT, PL2) C$ (Rotated View - Stereo) C$ Produce a stereo parallel projection drawing of a C$ single-valued function defined in Cartesian coordinates, C$ exhibiting arcs on the surface parallel to the coordinate C$ axes. For greater variety in presentation, the entire C$ figure may be rotated through an angle, which should be C$ specified in degrees. The scale of the drawing is adjusted C$ to approximately fill the frame, and thus depends upon the C$ rotation angle chosen. The arguments are: C$ C$ Z0......Cutoff value. Only function values, ZE(I,J), above C$ (S .GT. 0.0) or below (S .LT. 0) Z0 are visible. C$ ZE......Array containing the surface. ZE(I,J) = C$ F(X(I),Y(J)). C$ Z1,Z2...Span of surface values. C$ MX,MY...Actual declared dimensions of the array ZE(*,*). C$ NX,NY...Sections of ZE(*,*) actually used. C$ LX,LY...Increments in X and Y directions (.GT. 0). Values C$ of LX and LY larger than 1 produce a coarser mesh C$ on the drawing without losing the smoothness of the C$ complete surface. LX should be an integral divisor C$ of NX-1, and LY of NY-1. If this is not the case, C$ the next smallest value which satisfies this C$ requirement is used internally. C$ S.......=+1.0, graph positive part of function, C$ =-1.0, graph negative part of function, C$ = 0.0, graph both positive and negative parts. C$ If S = 0.0, the cutoff value Z0 has no effect. C$ ROT.....Angle of rotation in degrees. Positive angles C$ correspond to looking down the positive Z axis in a C$ right-handed coordinate system and rotating C$ counterclockwise. Rotation angles which are C$ multiples of 90 degrees, or within a degree or so C$ of such a number, should be avoided, since drawings C$ then deteriorate because of the way the scan C$ algorithm in the hidden line routine works. C$ PL2.....2-D pen movement subroutine, usually PL2CA C$ C$ (04-FEB-82)