/tclspline/doc/spline.n

 1'\"
 2'\" Copyright (c) 1993 The Regents of the University of California.
 3'\" Copyright (c) 1994-1996 Sun Microsystems, Inc.
 4'\" Copyright (c) 2005 Karl Lehenbauer
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 6'\" See the file "license.terms" for information on usage and redistribution
 7'\" of this file, and for a DISCLAIMER OF ALL WARRANTIES.
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 9'\" RCS: @(#) $Id: spline.n,v 1.1 2005-11-24 03:55:22 karl Exp $
10'\" 
11'\".so man.macros
12.TH read n 0.0 TclSpline "Spline Extension for Tcl"
13.BS
14'\" Note:  do not modify the .SH NAME line immediately below!
15.SH NAME
16spline \- Generate a set of quadratic splines based on an input list
17.SH SYNOPSIS
18\fBspline \fR \fInSteps pointList\fR
19.sp
20\fBspline_raw \fInSteps pointList\fR
21.BE
22
23.SH DESCRIPTION
24.PP
25Input is an integer number of steps, \fInSteps\fR, and a list containing
26three or more pairs of x and y coordinates.  \fBspline\fR reads that
27list and generates a new list of x and y coordinate pairs representing
28a curve based on the passed points, rendered as a set of quadratic
29splines: one spline is drawn for the first and second line segments, one 
30for the second and third, and so on.  
31.PP
32Straight-line segments can be generated within
33a curve by duplicating the end-points of the desired line segment.
34.PP
35\fBspline_raw\fR indicates that the list should also be returned as a 
36curve, but the list of coordinates is such that the first coordinate pair 
37(and every third coordinate pair thereafter) is a knot point on a cubic 
38Bezier curve, and the other coordinates are control points on the cubic 
39Bezier curve.
40.PP
41Straight line segments can be generated within a curve by making control 
42points equal to their neighboring knot points.  If the last point is a
43control point and not a knot point, the point is repeated (one or two
44times) so that it also becomes a knot point.
45.PP
46\fInSteps\fR specifies the degree of smoothness desired for curves: each 
47spline will be approximated with \fInSteps\fR line segments.