.\" @(#)PEXTransformPoints2D.3 1.4 95/03/24 SMI;
.so man3/pex.macs
.TH PEXTransformPoints2D 3 "May 1995" "Solaris PEXlib Reference Manual" ""
.SH NAME
PEXTransformPoints2D - utility function
.SH SYNTAX
.HP
int PEXTransformPoints2D\^(\^PEXMatrix3x3 \fItransform\fP, int \fIcount\fP, PEXCoord2D *\fIpoints\fP, PEXCoord2D *\fIpoints_return\fP\^)
.SH PARAMETERS
.IP \fItransform\fP 1i
The transformation matrix to apply to the points.
.IP \fIcount\fP 1i
The number of points to transform.
.IP \fIpoints\fP 1i
A pointer to an array of 2D points to transform.
.IP \fIpoints_return\fP 1i
A pointer to an array in which to store the transformed points.
.SH RETURNS
.LP
Zero if successful; otherwise, one of the following:
.TP
.B PEXBadHomoCoord
One or more of the transformed points has a homogeneous
coordinate of 0.
.SH DESCRIPTION
.\" indexing
.IX PEXTransformPoints2D
.LP
This function applies the specified homogeneous
transformation matrix to the list of
.I points.
In applying
the transformation, the
.I points
are first converted to
homogeneous points by assigning them a homogeneous
coordinate of 1.  The transformation is then applied:
.LP
.RS
P' = TxP
.RE
.LP
Where P is the point, treated as a column vector, and T is the
transformation matrix.  The
.I points
are then mapped to 2D by
dividing their first three coordinates by the computed
homogeneous coordinate.
.LP
If the function returns unsuccessfully, all
.I points
other than those with a
homogeneous coordinate of 0 will be transformed and returned.
.LP
If the return array is the same as the input array, the function will
overwrite the input values with the transformed values.
.SH ERRORS
.LP
None
.SH SEE ALSO
.LP
.nf
.BR PEXTransformPoints (3)
.BR PEXTransformPoints4D (3)
.BR PEXTransformPoints2DH (3)
.fi