TRAJECTORY-FOLLOWER documentationD. Austin Henderson, Jr.Initially released: April 23, 1983Last revised: April 23, 1983TRAJECTORY-FOLLOWER (and .DCOM) provides a function which causes a"snake" to crawl along a trajectory. Comments on both interface and functionality are welcomed.TRAJECTORY.FOLLOW (KNOTS CLOSED N DELAY BITMAP WINDOW) The trajectory isspecified by KNOTS (a set of knots) and CLOSED (a flag indicating whether it is an open orclosed curve). N is the length of the snake in points along the curve. DELAY is the time (inmilliseconds) between each move along the curve; DELAY = 0 or NIL means go as fast as youcan. BITMAP is the brush to be used at each point in creating the snake. WINDOW is the windowin whose coordinate system the knots are given and in which the snake is to be drawn; if NIL, thenthe SCREEN bitmap is used. The snake is moved by INVERTing the bitmap at the points alongthe curve, and then INVERTing the bitmap back out again.A demonstration function is also provided with the package:TRAJECTORY.FOLLOWER.TEST ( ) Interacts with the user through prompting in thepromptwindow to gather up arguments for TRAJECTORY.FOLLOW and then carries it out.Closed curves are snaked around repeatedly until the left shift key is depress when it reaches thecurve's starting point.The internal functions used by this package are also available for use. They are:TRAJECTORY.FOLLOWER.SETUP (WINDOW N DELAY BITMAP) Initializes drawingvariables.TRAJECTORY.FOLLOWER.POINT (X Y WINDOW) Defines the next point on the curve. Notethat the argument structure of this function is appropriate for use as a BRUSH with the curvedrawing functions DRAWCURVE, DRAWCIRCLE, and DRAWELLIPSE. (For an example, seethe demonstration function TRAJECTORY.FOLLOWER.TEST.)TRAJECTORY.FOLLOWER.WRAPUP ( ) Finishes the job after all the points have been defined. bp! _q ](" [: Vpqpq T$; P4p.q NFO LX.. JjG H|O F.4 DL B8 >J; 9p5q6 7#/ 6 U 4 /Q +Eph#i q )W $p&q" ##: !> %5 pq+ D u=H TIMESROMAN  TIMESROMAN :j/TRAJECTORY-FOLLOWER.bravo AHenderson.PAApril 23, 1983 5:52 PM