Updating the C:GPath Function
Update the C:GPath function by adding reactor creation logic.
To add reactor creation logic to C:GPath
- Replace your version of gpmain.lsp with the updated version shown below. Copy this code from the <AutoCAD directoryTutorialVisualLISPLesson6 directory:
(defun C:GPath (/ gp_PathData gp_dialogResults PolylineName tileList ) (setvar "OSMODE" 0) ;; Turn off object snaps ;| ;; Lesson 6 adds a stubbed-out command reactor to AutoCAD ;; However, it would be undesirable to react to every ;; drawing of a circle should the COMMAND tile creation ;; method be chosen by the user. So, disable the ;; *commandReactor* in case it exists. |; (if *commandReactor* (progn (setq *commandReactor* nil) (vlr-remove-all :VLR-Command-Reactor) ) ) ;; Ask the user for input: first for path location and ;; direction, then for path parameters. Continue only if you ;; have valid input. Store the data in gp_PathData. (if (setq gp_PathData (gp:getPointInput)) (if (setq gp_dialogResults (gp:getDialogInput (cdr (assoc 40 gp_PathData)) ) ;_ end of gp:getDialogInput ) ;_ end of set q (progn ;; Now take the results of gp:getPointInput and append this to ;; the added information supplied by gp:getDialogInput (setq gp_PathData (append gp_PathData gp_DialogResults)) ;; At this point, you have all the input from the user ;; Draw the outline, storing the resulting polyline "pointer" ;; in the variable called PolylineName (setq PolylineName (gp:drawOutline gp_PathData)) ;; Next, it is time to draw the tiles within the boundary. ;; The gp_tileList contains a list of the object pointers for ;; the tiles. By counting up the number of points (using the ;; length function), we can print out the results of how many ;; tiles were drawn. (princ " The path required ") (princ (length (setq tileList (gp:Calculate-and-Draw-Tiles gp_PathData)) ) ;_ end of length ) ;_ end of princ (princ " tiles.") ;; Add the list of pointers to the tiles (returned by ;; gp:Calculate-and-Draw-Tiles) to gp_PathData. This will ;; be stored in the reactor data for the reactor attached ;; to the boundary polyline. With this data, the polyline ;; "knows" what tiles (circles) belong to it. (setq gp_PathData (append (list (cons 100 tileList)) ; all the tiles gp_PathData ) ;_ end of append ) ;_ end of set q ;; Before we attach reactor data to an object, let's look at ;; the function vlr-object-reactor ;; vlr-object-reactor has the following arguments: ;; (vlr-object-reactor owner's data callbacks) ;; The callbacks Argument is a list comprised ;; '(event_name . callback_function) ;; ;; For this exercise we will use all arguments ;; associated with vlr-object-reactor ;; These reactor functions will execute only if ;; the polyline in PolylineName is modified or erased (vlr-object-reactor ;; The first argument for vlr-object-reactor is ;; the "Owner's List" argument. This is where to ;; place the object to be associated with the ;; reactor. In this case, it is the vlaObject ;; stored in PolylineName. (list PolylineName) ;; The second argument contains the data for the path gp_PathData ;; The third argument is the list of specific reactor ;; types that we are interested in using ' ( ;; reactor that is called upon modification of the object (:vlr-modified . gp:outline-changed) ;; reactor that is called upon erasure of the object (:vlr-erased . gp:outline-erased) ) ) ;_ end of vlr-object-reactor ;; Next, register a command reactor to adjust the polyline ;; when the changing command is finished (if (not *commandReactor*) (setq *commandReactor* (VLR-Command-Reactor nil ; No data is associated with the command reactor '( (:vlr-commandWillStart . gp:command-will-start) (:vlr-commandEnded . gp:command-ended) ) ) ;_ end of vlr-command-reactor ) ) ;; The following code removes all reactors when the drawing is ;; closed. This is extremely important!!!!!!!!! ;; Without this notification, AutoCAD may crash upon exiting! (if (not *DrawingReactor*) (setq *DrawingReactor* (VLR-DWG-Reactor nil ; No data is associated with the drawing reactor '((:vlr-beginClose . gp:clean-all-reactors) ) ) ;_ end of vlr-DWG-reactor ) ) ) ;_ end of progn (princ " Function cancelled.") ) ;_ end of if (princ " Incomplete information to draw a boundary.") ) ;_ end of if (princ) ; exit quietly ) ;_ end of defun ;;; Display a message to let the user know the command name. (princ " Type GPATH to draw a garden path.") (princ)
- Review the code modifications and comments describing what each new statement does.
This tutorial shows all modified code in boldface.
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