PEVMM(3g) — Subroutines
Name
PEVMM − Creates a view mapping matrix.
Operating States: PHOP, ∗, ∗, ∗
PHIGS standard function
Syntax
PEVMM (VWWNLM, PJVPLM, ERRIND, VWMPMT)
Argument Data Type Access Description
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VWWNLM(4) Array of reals Read View window limits, in view
reference coordinates (UMIN, UMAX,
VMIN, VMAX)
PJVPLM(4) Array of reals Read Projection viewport limits, in
normalized projection coordinates
(XMIN, XMAX, YMIN, YMAX)
ERRIND Integer Write Error indicator
VWMPMT(3,3) Array of reals Write View mapping matrix
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Description
PEVMM creates a view mapping matrix, which can be passed as input to the PSVWR function. (This transforms the PHIGS coordinate system from view reference coordinate points to normalized projection coordinate points.)
To create the view mapping matrix, use the following procedure:
•Specify window limits within view reference coordinate space in the order UMIN, UMAX, VMIN, VMAX.
The following restrictions apply:
UMIN < UMAX
VMIN < VMAX
The formation of the v- and u-axes in the view reference coordinate system is described in Getting Started with DEC PHIGS.
•Specify projection viewport limits (view clipping limits) within normalized projection coordinate space in the order XMIN, XMAX, YMIN, YMAX.
The following restrictions apply:
XMIN < XMAX
YMIN < YMAX
XMIN, XMAX, YMIN, and YMAX must be in the range [0,1],
inclusive.
Projection and the normalized projection coordinate system are described in Getting Started with DEC PHIGS and DEC PHIGS Developer’s Guide.
If the view mapping parameters are consistent and well defined (that is, if they conform to the specified rules and restrictions), a call to this function returns the 3 x 3 view mapping matrix. Otherwise, a nonzero error indicator is returned.
See Also
PEVMM3
PEVOM
PQVWF
PQVWR
PSVWI
PSVWR