'\"
'\" Copyright (c) 1993 The Regents of the University of California.
'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
'\" Copyright (c) 2005 Karl Lehenbauer
'\"
'\" See the file "license.terms" for information on usage and redistribution
'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
'\" 
'\" RCS: @(#) $Id: spline.n,v 1.1 2005-11-24 03:55:22 karl Exp $
'\" 
'\".so man.macros
.TH read n 0.0 TclSpline "Spline Extension for Tcl"
.BS
'\" Note:  do not modify the .SH NAME line immediately below!
.SH NAME
spline \- Generate a set of quadratic splines based on an input list
.SH SYNOPSIS
\fBspline \fR \fInSteps pointList\fR
.sp
\fBspline_raw \fInSteps pointList\fR
.BE

.SH DESCRIPTION
.PP
Input is an integer number of steps, \fInSteps\fR, and a list containing
three or more pairs of x and y coordinates.  \fBspline\fR reads that
list and generates a new list of x and y coordinate pairs representing
a curve based on the passed points, rendered as a set of quadratic
splines: one spline is drawn for the first and second line segments, one 
for the second and third, and so on.  
.PP
Straight-line segments can be generated within
a curve by duplicating the end-points of the desired line segment.
.PP
\fBspline_raw\fR indicates that the list should also be returned as a 
curve, but the list of coordinates is such that the first coordinate pair 
(and every third coordinate pair thereafter) is a knot point on a cubic 
Bezier curve, and the other coordinates are control points on the cubic 
Bezier curve.
.PP
Straight line segments can be generated within a curve by making control 
points equal to their neighboring knot points.  If the last point is a
control point and not a knot point, the point is repeated (one or two
times) so that it also becomes a knot point.
.PP
\fInSteps\fR specifies the degree of smoothness desired for curves: each 
spline will be approximated with \fInSteps\fR line segments.