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SUBROUTINE HIDPV (Z1,ZE,Z2, NR,NP, PL2)
C$ (Polar View)
C$ Produce a perspective drawing of a single-valued function
C$ defined in polar coordinates, in such a way as to exhibit
C$ the radial and circumferential arcs. The arguments are:
C$
C$ (Z1,Z2)........Range of function values.
C$ ZE(NR,NP)......Array of function values. ZE(I,J) contains
C$ z(r(I),phi(J)), where
C$ r(I) = 0.02 + 0.98*(I-1)/(NR-1)
C$ and
C$ phi(J) = 360.0*(J-1)/(NP-1),
C$ such that r steps from 0.02 to 1.0, and phi
C$ steps from 0 to 360 degrees. For the figure
C$ to join properly, it follows that ZE(*,1)
C$ must be identical to ZE(*,NP); it is the
C$ user's responsibility to ensure this.
C$ NR.............Number of points on one radius.
C$ NP.............Number of polar angles. This must be an
C$ integer of the form 4*N+1 to ensure that the
C$ four quadrants of the figure join properly.
C$ PL2............2-D pen movement subroutine, normally PL2CA.
C$
C$ The polar view produced is an orthographic
C$ (non-perspective) view along a line passing through the
C$ points (0,0,0) and (0,-1,0.44), with the z axis projecting
C$ onto the vertical screen axis. This is an elevation of
C$ about 26.56 degrees above the xy plane. Since the polar
C$ angle, phi, is measured about the z axis counterclockwise
C$ from the x axis, in the plot, phi = 0 degrees is on the
C$ extreme right, phi = 180 degrees is on the extreme left,
C$ and phi = 270 degrees is at the front center of the
C$ drawing.
C$
C$ The actual transformation to Normalized Device Coordinates
C$ (u,v,w) is
C$
C$ (u,v,w,1) = (x,y,z,1) (1/2 0 0 0)
C$ ( 0 1/6 0 0)
C$ ( 0 2/3 1 0)
C$ (1/2 1/6 0 1)
C$
C$ This maps x on the interval -1..1 into u on 0..1 and y on
C$ -1..1 into v on (2/3)z..(2/3)z+(1/3). With z on 0..1, v is
C$ then on 0..1. The specified function range Z1..Z2 is
C$ mapped onto z on 0..1.
C$ (15-APR-82)