From: Chris Hanson <org/chris-hanson/cph>
Date: Tue, 21 Mar 2000 04:49:14 +0000 (+0000)
Subject: Initial registration with CVS.
X-Git-Tag: 20090517-FFI~4182
X-Git-Url: https://birchwood-abbey.net/git?a=commitdiff_plain;h=78301a64aa0e173d0ba9b36464deb1229bf2dffb;p=mit-scheme.git

Initial registration with CVS.
---

diff --git a/v7/src/swat/scheme/demo-plotter.scm b/v7/src/swat/scheme/demo-plotter.scm
new file mode 100644
index 000000000..4172c7d57
--- /dev/null
+++ b/v7/src/swat/scheme/demo-plotter.scm
@@ -0,0 +1,1183 @@
+;;; -*- Scheme -*-
+
+(declare (usual-integrations))
+
+;;;; Plotting Package for Scheme Widget Application Toolkit
+
+;;; Working from the Scheme Prompt
+
+;;;(PLOTTER) 
+;;;  Creates a new plotter.
+;;; 
+;;;     Example: (define p (plotter))
+;;;
+;;;(PLOT plotter . options)
+;;;  The options list sequentially describes one or more curves to be
+;;;  plotted, in the following manner: 
+;;;
+;;;    (PLOT plotter
+;;;          <function1> '<option> <value> '<option> <value> ... ;first curve 
+;;;          <function2> '<option> <value> ...                   ;second curve
+;;;          ...
+;;;          ...)
+;;;  Returns a single curve if only one function is specified, and a
+;;;  list of curves if more than one function is supplied.
+;;;
+;;;     Example: (define c0 (plot p sin 'xmin -10 'xmax 5))
+;;;              (define c1&2 (plot p cos 'pt-style 0 tan 'pt-style 5))
+;;;
+;;;  The first parameter to PLOT after plotter must always be a
+;;;  function. Curve-specific options affect only the function they
+;;;  follow, and thus can and should be repeated.  Any instance of a
+;;;  global option after the first will be ignored. 
+;;;
+;;;  Global options and arguments: 
+;;;    'XMIN:  The minimum value of x to be displayed on the plot.
+;;;            The default is 0. 
+;;;    'XMAX:  The maximum value of x to be displayed on the plot.
+;;;            The default is 1. 
+;;;    'YMIN:  The minimum value of y to be displayed on the plot.
+;;;            If not specified, the plot will be automatically scaled.
+;;;    'YMAX:  The maximum value of y to be displayed on the plot.
+;;;            If not specified, the plot will be automatically scaled.
+;;;    'AXIS-X:  The value of x at which the y-axis will be drawn.
+;;;              The default is 0. 
+;;;    'AXIS-Y:  The value of y at which the x-axis will be drawn.
+;;;              The default is 0. 
+;;;    'XTICKS:  A list of pairs describing ticks on the x axis.  The
+;;;              car of each pair is the value of x at which to make
+;;;              the tick.  The cdr is a string to be displayed as a
+;;;              label.  The procedure MAKE-VALS can be used to return
+;;;              a list of values for labels at regular intervals. If
+;;;              not specified, only the extreme values will be labeled. 
+;;;    'YTICKS:  A list of pairs describing ticks on the y axis.  Same
+;;;              format as XTICKS.  If not specified, only the extreme
+;;;              values will be labeled. 
+;;;
+;;;  Curve-specific options and arguments
+;;;    'NUM-PTS:  The number of points to be calculated for the curve.
+;;;               The default is one for every 10 pixels.
+;;;    'PT-STYLE:  A number representing the style in which the curve
+;;;                will be drawn: 
+;;;                  0  --  lines to the x-axis
+;;;                  1  --  large unfilled circles
+;;;                  2  --  large unfilled squares
+;;;                  3  --  x's
+;;;                  4  --  +'s
+;;;                  5  --  small filled circles
+;;;                  6  --  small filled squares
+;;;                  7  --  dots
+;;;                  10  --  large unfilled circles with lines to the x-axis
+;;;                  20  --  large unfilled squares with lines to the x-axis
+;;;                  30  --  x's with lines to the x-axis
+;;;                  40  --  +'s with lines to the x-axis
+;;;                  50  --  small filled circles with lines to the x-axis
+;;;                  60  --  small filled squares with lines to the x-axis
+;;;                  100  --  lines between successive points
+;;;                The default for the first curve is 0, and for all
+;;;                others 100. 
+;;;    'COLOR:  The color of the curve, as a string or color-value.
+;;;             The default for the first curve is black, and for all
+;;;             others gray. 
+;;;    'SHOW-VALS:  A list of values of x at which to label the
+;;;                 corresponding value of y.  The procedure
+;;;                 MAKE-VALS can be used to return a list of values
+;;;                 at regular intervals.  The default is null.
+;;;
+;;;
+;;;(SET-PLOTTER-PARAMS plotter '<option> <value> ... '<option> <value>)
+;;;  Options are the same as global options in PLOT.  This does
+;;;  basically the same thing as PLOT, but no *new* curve is drawn.
+;;;  Parameters are reset and all the existing (non-cleared) curves
+;;;  are redrawn.  Thus, an alternative way to write the example above
+;;;  is: 
+;;;
+;;;     Example: (set-plotter-params p 'xmin -10 'xmax 5)
+;;;              (define c0 (plot p sin))
+;;;
+;;;(RESET-PLOTTER-PARAMS plotter)
+;;;  Resets plotter's parameters to default params (the ones you see
+;;;  when the plotter first comes up).
+;;;
+;;;
+;;;(MAKE-VALS min max spacing . centered?)
+;;;  Returns a list of pairs that can be used for 'XTICKS 'YTICKS, or
+;;;  'SHOW-VALS. If centered? is #t, the ticks will be centered about
+;;;  0, with a tick at 0.  Otherwise, the ticks will begin at the min
+;;;  value. 
+;;; 
+;;;     Example: (define c0 (plot p sin 'xmin -5 'xmax 5
+;;;                                     'xticks (make-vals -5 5 1)))
+;;;
+;;;(CHANGE-COLOR curve color)
+;;;  Changes the color of the given curve and replots the curve.
+;;;  Replots the curve if it's not cleared.
+;;;
+;;;(CHANGE-PT-STYLE curve pt-style)
+;;;  Changes the point style of the given curve and replots the curve.
+;;;  Replots the curve if it's not cleared.
+;;;
+;;;(CHANGE-NUM-PTS curve num-pts)
+;;;  Changes the number of points calculated for the given curve and
+;;;  replots the curve. Replots the curve if it's not cleared.
+;;;
+;;;
+;;;(CLEAR-CURVE curve)
+;;;  Clears the given curve from the screen without deleting the curve
+;;;  from the plotter.
+;;;
+;;;(PLOT-CURVE curve)
+;;;  Replots the curve that has been cleared.
+;;;
+;;;(DELETE-CURVE curve)
+;;;  Deletes the given curve from the plotter.
+;;;
+;;;(ADD-SHOW-VALS curve show-vals)
+;;;  Add show-vals to a curve.
+;;;
+;;;(CLEAR-SHOW-VALS curve)
+;;;  Clears all the curve's show vals, w/o deleting them from the curve.
+;;;
+;;;(DRAW-SHOW-VALS curve)
+;;;  Redraws the cleared show-vals.
+;;;
+;;;(DELETE-SHOW-VALS curve)
+;;;  Clears the curve's show-vals and deletes them from a curve.
+;;;
+;;;
+;;;(ADD-XTICKS plotter xticks)
+;;;  Adds the specified xticks.
+;;;
+;;;(ADD-YTICKS plotter yticks)
+;;;  Adds the specified yticks.
+;;;
+;;;(CLEAR-TICKS plotter)
+;;;  Clears ticks from the axes of the plotter, without deleting them
+;;;  from the plotter.
+;;;
+;;;(DRAW-TICKS plotter)
+;;;  Redraws the cleared ticks.
+;;;
+;;;(DELETE-TICKS plotter)
+;;;  Clears ticks from the axes of the plotter and deletes them from
+;;;  the plotter.
+;;;
+;;;
+;;;(CLEAR-PLOTTER plotter)
+;;;  Clears all plotter's curves and ticks.
+;;;
+;;;(REPLOT plotter)
+;;;  Redraws all plotter's curves and ticks (including the cleared ones).
+;;;
+;;;(RESET-PLOTTER plotter)
+;;;  Deletes all plotter's curves and ticks.
+
+
+
+;;;-------------------
+;;; Interface Monster
+;;;-------------------
+
+;;; Customizable Variables
+
+(define button-background-color "yellow")
+(define button-active-background-color "red")
+(define button-active-foreground-color "white")
+(define canvas-background-color "white")
+(define canvas-width 500)
+(define canvas-height 300)
+(define canvas-border-size 15)
+(define font "-Adobe-Helvetica-Bold-R-Normal--*-100-*")
+
+(define tick-precision 2)
+(define vals-precision 2)
+
+(define curve-max-num-pts 200)
+
+(define plotter-default-num-pts 50)
+(define plotter-default-pt-style 100)
+(define plotter-default-curve-color "black")
+(define plotter-default-xmin -5)
+(define plotter-default-xmax 5)
+(define plotter-default-ymin -1)
+(define plotter-default-ymax 1)
+(define plotter-default-axis-x 0)
+(define plotter-default-axis-y 0)
+(define plotter-default-xticks '())
+(define plotter-default-yticks '())
+
+
+(define (plotter)
+  (let* ((plot-app (make-application "Plotter"))
+	 (plotter
+	  (make-plot-canvas canvas-width canvas-height canvas-background-color))
+	 (plot-canvas (plotter 'the-canvas))
+	 (func-button (make-button '(-text "Function")))
+	 (func-box #f)
+	 (options-menu (make-menu))
+	 (options-button (make-menubutton options-menu '(-text "Options")))
+	 (precision (add-to-menu options-menu 'command '-label "Precision"))
+	 (prec-box #f)
+	 (range (add-to-menu options-menu 'command '-label "Range"))
+	 (range-box #f)
+	 (plot-button (make-button '(-text "Plot")))
+	 (reset-button (make-button '(-text "Reset")))
+	 (button-box (make-hbox func-button options-button plot-button reset-button))
+	 (interface (make-vbox plot-canvas button-box)))
+
+      (for-each (lambda (button)
+		  (ask-widget
+		   button
+		   `(configure -background ,button-background-color
+			       -activebackground ,button-active-background-color
+			       -activeforeground ,button-active-foreground-color)))
+		(list func-button options-button plot-button reset-button))
+    
+      (for-each (lambda (button)
+		  (ask-widget
+		   button
+		   `(configure -background ,button-background-color
+			       -activebackground ,button-background-color)))
+		(list range precision))
+    
+      (add-event-handler! plot-canvas "<Configure>" (plotter 'handle-resize))
+
+      (set-callback!
+       func-button
+       (lambda ()
+	 (if (not func-box)
+	     (let ((new-func-box (make-func-box plot-app plotter)))
+	       (on-death! new-func-box 'func-dead (lambda () (set! func-box #f)))
+	       (set! func-box new-func-box)))))
+
+      (set-callback!
+       precision
+       (lambda ()
+	 (if (not prec-box)
+	     (let ((new-prec-box (make-prec-box plot-app plotter)))
+	       (on-death! new-prec-box 'prec-dead (lambda () (set! prec-box #f)))
+	       (set! prec-box new-prec-box)))))
+
+      (set-callback!
+       range
+       (lambda ()
+	 (if (not range-box)
+	     (let ((new-range-box (make-range-box plot-app plotter)))
+	       (on-death! new-range-box 'range-dead (lambda () (set! range-box #f)))
+	       (set! range-box new-range-box)))))
+
+      (set-callback! plot-button (lambda () (plotter 'plot-current-func)))
+      (set-callback! reset-button (lambda () (plotter 'clear-curves)))
+
+      (on-death! interface 'interface-dead 
+		 (lambda ()
+		   (if func-box  (remove-child! plot-app func-box))
+		   (if range-box (remove-child! plot-app range-box))
+		   (if prec-box  (remove-child! plot-app prec-box))))
+      
+      (swat-open-in-application plot-app interface)
+      plotter))
+
+(define (make-func-box plot-app plotter)
+  (let* ((func-entry (make-entry `(-width 40 -background ,canvas-background-color)))
+	 (func-ok-button
+	  (make-button
+	   `(-text "Ok" -background ,button-background-color
+	     -activebackground ,button-active-background-color
+	     -activeforeground ,button-active-foreground-color)))
+	 (func-box (make-hbox func-entry func-ok-button)))
+    (define (function-callback)
+      (let ((exp (ask-widget func-entry '(get))))
+	(if (not (string-null? exp))
+	    ;; Of course, this could get an error while evaling; maybe
+	    ;; need something more clever.
+	    (let ((proc (eval (with-input-from-string exp read)
+			      user-initial-environment)))
+	      (if (not (procedure? proc))
+		  (error "Not a procedure" proc)
+		  ((plotter 'set-function) proc))))))
+    (add-event-handler! func-entry "<KeyPress> <Return>" function-callback)
+    (set-callback! func-ok-button function-callback)
+    (swat-open-in-application plot-app func-box '-title "Enter a function of x")
+    func-box))
+
+(define (make-prec-box plot-app plotter)
+  (let* ((prec-scale
+	  (make-scale `(-from 0 -to ,curve-max-num-pts -orient horizontal
+		        -length ,(inexact->exact (* 1.5 curve-max-num-pts))
+			-background ,canvas-background-color
+			-sliderforeground ,button-background-color
+			-activeforeground ,button-active-background-color)))
+	 (prec-redraw
+	  (make-button `(-text "Redraw Curves" -background ,button-background-color
+			 -activebackground ,button-active-background-color
+			 -activeforeground ,button-active-foreground-color)))
+	 (prec-box (make-vbox prec-scale prec-redraw)))
+    (ask-widget prec-scale `(set ,(plotter 'default-num-pts)))
+    (add-event-handler!
+     prec-scale
+     "<ButtonRelease-1>"
+     (lambda ()
+       ((plotter 'set-default-num-pts)
+	(string->number (ask-widget prec-scale '(get))))))
+    (set-callback! prec-redraw (lambda () (plotter 'plot-curves)))
+    (swat-open-in-application plot-app prec-box '-title "Number of points:")
+    prec-box))
+
+(define (make-range-box plot-app plotter)
+  (let* ((range-ok-button
+	  (make-button `(-text "Ok" -background ,button-background-color
+			 -activebackground ,button-active-background-color
+			 -activeforeground ,button-active-foreground-color)))
+	 (xmin-text (make-active-variable plot-app))
+	 (xmax-text (make-active-variable plot-app))
+	 (ymin-text (make-active-variable plot-app))
+	 (ymax-text (make-active-variable plot-app))
+	 (xmin-entry (make-entry `(-textvariable ,xmin-text)))
+	 (xmax-entry (make-entry `(-textvariable ,xmax-text)))
+	 (ymin-entry (make-entry `(-textvariable ,ymin-text)))
+	 (ymax-entry (make-entry `(-textvariable ,ymax-text)))
+	 (x-label (make-label '(-text "Values of x:")))
+	 (xmin-label (make-label '(-text "From")))
+	 (xmax-label (make-label '(-text "To")))
+	 (y-label (make-label '(-text "Values of y:")))
+	 (ymin-label (make-label '(-text "From")))
+	 (ymax-label (make-label '(-text "To")))
+	 (x-box
+	  (make-vbox x-label
+		     (make-hbox xmin-label xmin-entry xmax-label xmax-entry)))
+	 (y-box
+	  (make-vbox y-label
+		     (make-hbox ymin-label ymin-entry ymax-label ymax-entry)))
+	 (range-box (make-hbox (make-vbox x-box y-box) range-ok-button)))
+    (for-each (lambda (label)
+		(ask-widget label `(configure -background ,canvas-background-color)))
+	      (list x-label xmin-label xmax-label y-label ymin-label ymax-label))
+    (for-each (lambda (entry)
+		;; background color?
+		(ask-widget entry `(configure -width 5)))
+	      (list xmin-entry xmax-entry ymin-entry ymax-entry))
+    (set-callback!
+     range-ok-button
+     (lambda ()
+       (let ((xmin (plotter 'xmin))
+	     (xmax (plotter 'xmax))
+	     (ymin (plotter 'ymin))
+	     (ymax (plotter 'ymax))
+	     (new-xmin (string->number (ask-widget xmin-entry '(get))))
+	     (new-xmax (string->number (ask-widget xmax-entry '(get))))
+	     (new-ymin (string->number (ask-widget ymin-entry '(get))))
+	     (new-ymax (string->number (ask-widget ymax-entry '(get)))))
+	 (if (not (and (eqv? xmin new-xmin)
+		       (eqv? xmax new-xmax)
+		       (eqv? ymin new-ymin)
+		       (eqv? ymax new-ymax)))
+	     (begin
+	       ((plotter 'set-xmin) new-xmin)
+	       ((plotter 'set-xmax) new-xmax)
+	       ((plotter 'set-ymin) new-ymin)
+	       ((plotter 'set-ymax) new-ymax)
+	       (plotter 'clear)
+	       (draw-axes plotter)
+	       (plotter 'plot-curves))))))
+    (swat-open-in-application plot-app range-box '-title "Range")
+    (set-active-variable! xmin-text (plotter 'xmin))
+    (set-active-variable! xmax-text (plotter 'xmax))
+    (set-active-variable! ymin-text (plotter 'ymin))
+    (set-active-variable! ymax-text (plotter 'ymax))
+    range-box))
+
+
+;;;-------------
+;;; The Plotter
+;;;-------------
+
+(define (make-plot-canvas hsize vsize bgrnd-color)
+  (let ((default-num-pts plotter-default-num-pts)
+	(default-pt-style plotter-default-pt-style)
+	(default-color plotter-default-curve-color)
+	(xmin plotter-default-xmin)
+	(xmax plotter-default-xmax)
+	(ymin plotter-default-ymin)
+	(ymax plotter-default-ymax)
+	(yaxis.xval plotter-default-axis-x)
+	(xaxis.yval plotter-default-axis-y)
+	(xticks plotter-default-xticks)
+	(yticks plotter-default-yticks)
+	(current-func #f)
+	(current-func-curve #f)
+	(curve-list '())
+	(resize-flag #f))
+    (let* ((the-canvas (make-canvas `(-width ,hsize -height ,vsize
+				      -background ,bgrnd-color)))
+	   (axes-tag (make-canvas-item-group the-canvas '()))
+	   (ticks-tag (make-canvas-item-group the-canvas '())))
+      (define (plotter messg)
+	(case messg
+	  ((hsize) hsize)
+	  ((vsize) vsize)
+	  ((the-canvas) the-canvas)
+	  ((curve-list) curve-list)
+	  ((default-num-pts) default-num-pts)
+	  ((set-default-num-pts)
+	   (lambda (new-num-pts) (set! default-num-pts new-num-pts)))
+	  ((default-pt-style) default-pt-style)
+	  ((set-default-pt-style)
+	   (lambda (new-pt-style) (set! default-pt-style new-pt-style)))
+	  ((default-color) default-color)
+	  ((set-default-color)
+	   (lambda (new-color) (set! default-color new-color)))
+	  ((function) current-func)
+	  ((set-function)
+	   (lambda (func)
+	     (set! current-func-curve #f)
+	     (set! current-func func)))
+	  ((xmin) xmin)
+	  ((set-xmin) (lambda (new-xmin) (set! xmin new-xmin)))
+	  ((xmax) xmax)
+	  ((set-xmax) (lambda (new-xmax) (set! xmax new-xmax)))
+	  ((ymin) ymin)
+	  ((set-ymin) (lambda (new-ymin) (set! ymin new-ymin)))
+	  ((ymax) ymax)
+	  ((set-ymax) (lambda (new-ymax) (set! ymax new-ymax)))
+	  ((xaxis.yval) xaxis.yval)
+	  ((yaxis.xval) yaxis.xval)
+	  ((xaxis.y)
+	   (let ((y-range (- ymax ymin)))
+	     (if (= y-range 0)
+		 (error "ymin and ymax are the same--MAKE-PLOT-CANVAS" ymin)
+		 (+ (* (exact->inexact (/ (- (* canvas-border-size 2) vsize)
+					  y-range))
+		       (- xaxis.yval ymin))
+		    vsize
+		    (- canvas-border-size)))))
+	  ((yaxis.x)
+	   (let ((x-range (- xmax xmin)))
+	     (if (= x-range 0)
+		 (error "xmin and xmax are the same--MAKE-PLOT-CANVAS" xmin)
+		 (+ (* (exact->inexact (/ (- hsize (* canvas-border-size 2))
+					  (- xmax xmin)))
+		       (- yaxis.xval xmin))
+		    canvas-border-size))))
+	  ((xticks) xticks)
+	  ((set-xticks) (lambda (new-xticks) (set! xticks new-xticks)))
+	  ((yticks) yticks)
+	  ((set-yticks) (lambda (new-yticks) (set! yticks new-yticks)))
+	  ((axes-tag) axes-tag)
+	  ((ticks-tag) ticks-tag)
+	  ((set-params)
+	   (lambda (new-xmin new-xmax new-ymin new-ymax
+			     new-yaxis.xval new-xaxis.yval new-xticks new-yticks)
+	     (set! xmin new-xmin)
+	     (set! xmax new-xmax)
+	     (set! ymin new-ymin)
+	     (set! ymax new-ymax)
+	     (set! yaxis.xval new-yaxis.xval)
+	     (set! xaxis.yval new-xaxis.yval)
+	     (set! xticks new-xticks)
+	     (set! yticks new-yticks)
+	     'set))
+	  ((x:val->pix) (x:val->pix xmin xmax hsize))
+	  ((y:val->pix) (y:val->pix ymin ymax vsize))
+	  ((add-curve)
+	   (lambda (curve) (set! curve-list (append curve-list (list curve)))))
+	  ((plot-current-func)
+	   (if (and current-func (not current-func-curve))
+	       (let ((new-curve
+		      (make-curve plotter current-func default-pt-style
+				  default-num-pts default-color #f)))
+		 (set! current-func-curve new-curve)
+		 (set! curve-list (cons new-curve curve-list))
+		 (new-curve 'plot))))
+	  ((plot-curves)
+	   (for-each (lambda (curve)
+		       (if (not (curve 'cleared?))
+			   (curve 'plot)))
+		     curve-list)
+	   'plotted)
+	  ((clear)
+	   (ask-widget the-canvas '(delete all))
+	   'cleared)
+	  ((clear-curves)
+	   (for-each (lambda (curve) (curve 'clear)) curve-list)
+	   'cleared)
+	  ((delete-curve)
+	   (lambda (curve)
+	     (curve 'clear)
+	     (set! curve-list (delq curve curve-list))
+	     'deleted))
+	  ((delete-curves)
+	   (for-each (lambda (curve) (curve 'clear)) curve-list)
+	   (set! curve-list #f)
+	   'deleted)
+	  ((clear-axes)
+	   (ask-widget axes-tag '(delete))
+	   'cleared)
+	  ((clear-ticks)
+	   (ask-widget ticks-tag '(delete))
+	   'cleared)
+	  ((delete-ticks)
+	   (set! xticks '())
+	   (set! yticks '())
+	   (ask-widget ticks-tag '(delete))
+	   'deleted)
+	  ((handle-resize)
+	   (lambda ()
+	     ;; For some reason, the "<Configure>" event gets generated
+	     ;; twice per window resize -- so skip one of them.
+	     (if (not resize-flag)
+		 (set! resize-flag #t)
+		 (begin
+		   (set! resize-flag #f)
+		   (ask-widget the-canvas '(delete all))
+		   (let ((old-width hsize)
+			 (width (UITKRectangle.width
+				 (assigned-screen-area the-canvas)))
+			 (height (UITKRectangle.height
+				  (assigned-screen-area the-canvas))))
+		     (set! hsize width)
+		     (set! vsize height)
+		     (set! default-num-pts (round (* default-num-pts
+						     (/ width old-width))))
+		     (draw-axes plotter)
+		     (for-each
+		      (lambda (curve)
+			(curve-scale-num-pts!
+			 curve (exact->inexact (/ width old-width)))
+			(if (not (curve 'cleared?))
+			    (begin (curve 'clear)
+				   (curve 'plot))))
+		      curve-list))))))
+	  (else (error "Bad message--PLOTTER" messg))))
+      plotter)))
+
+(define ((x:val->pix xmin xmax hsize) x)
+  (+ (* (exact->inexact
+	 (/ (- hsize (* canvas-border-size 2))
+	    (- xmax xmin)))
+	(- x xmin))
+     canvas-border-size))
+
+(define ((y:val->pix ymin ymax vsize) y)
+  (+ (* (exact->inexact
+	 (/ (- (* canvas-border-size 2) vsize)
+	    (- ymax ymin)))
+	(- y ymin))
+     vsize
+     (- canvas-border-size)))
+
+(define (draw-xticks plotter)
+  (let ((xticks (plotter 'xticks)))
+    (if xticks
+	(let ((plot-canvas (plotter 'the-canvas))
+	      (x:val->pix (plotter 'x:val->pix))
+	      (xmin (plotter 'xmin))
+	      (xmax (plotter 'xmax))
+	      (xaxis.y (plotter 'xaxis.y))
+	      (ticks-tag (plotter 'ticks-tag))
+	      (factor (expt 10 tick-precision)))
+	  (for-each
+	   (lambda (tick)
+	     (if (> xmax tick xmin)
+		 (let ((val (x:val->pix tick))
+		       (tag (swat:number->string
+			     (/ (truncate (* factor tick)) factor))))
+		   (add-to-canvas-item-group
+		    ticks-tag
+		    (make-line-on-canvas plot-canvas
+					 val (- xaxis.y 4)
+					 val (+ xaxis.y 4)))
+		   (add-to-canvas-item-group
+		    ticks-tag
+		    (make-text-on-canvas plot-canvas
+					 val (- xaxis.y 9)
+					 `(-text ,tag -font ,font))))))
+	   xticks))))
+  'drawn)
+
+(define (draw-yticks plotter)
+  (let ((yticks (plotter 'yticks)))
+    (if yticks
+	(let ((plot-canvas (plotter 'the-canvas))
+	      (y:val->pix (plotter 'y:val->pix))
+	      (ymin (plotter 'ymin))
+	      (ymax (plotter 'ymax))
+	      (yaxis.x (plotter 'yaxis.x))
+	      (ticks-tag (plotter 'ticks-tag))
+	      (factor (expt 10 tick-precision)))
+	  (for-each
+	   (lambda (tick)
+	     (if (> ymax tick ymin)
+		 (let ((val (y:val->pix tick))
+		       (tag (swat:number->string
+			     (/ (truncate (* factor tick)) factor))))
+		   (add-to-canvas-item-group
+		    ticks-tag
+		    (make-line-on-canvas plot-canvas
+					 (- yaxis.x 4) val
+					 (+ yaxis.x 4) val))
+		   (add-to-canvas-item-group
+		    ticks-tag
+		    (make-text-on-canvas plot-canvas
+					 (+ yaxis.x 6) val
+					 `(-text ,tag -anchor w
+						 -font ,font))))))
+	   yticks))))
+  'drawn)
+
+(define (draw-axes plotter)
+  (let* ((plot-canvas (plotter 'the-canvas))
+	 (hsize (plotter 'hsize))
+	 (vsize (plotter 'vsize))
+	 (xmin  (plotter 'xmin))
+	 (xmax  (plotter 'xmax))
+	 (ymin  (plotter 'ymin))
+	 (ymax  (plotter 'ymax))
+	 (xaxis.yval (plotter 'xaxis.yval))
+	 (yaxis.xval (plotter 'yaxis.xval))
+	 (xaxis.y (plotter 'xaxis.y))
+	 (yaxis.x (plotter 'yaxis.x))
+	 (axes-tag (plotter 'axes-tag))
+	 (trim 3)
+	 (x-.x trim)
+	 (x+.x (- hsize trim))
+	 (y-.y trim)
+	 (y+.y (- vsize trim)))
+    (if (>= ymax xaxis.yval ymin)
+	(begin
+	  (add-to-canvas-item-group
+	   axes-tag
+	   (make-line-on-canvas plot-canvas x+.x xaxis.y x-.x xaxis.y '(-arrow both)))
+	  (draw-xticks plotter)
+	  (make-text-on-canvas plot-canvas
+			       (- hsize trim) (- xaxis.y trim)
+			       `(-text ,(swat:number->string xmax) -anchor se)) ;
+	  (make-text-on-canvas plot-canvas
+			       trim (- xaxis.y trim)
+			       `(-text ,(swat:number->string xmin) -anchor sw))))
+    (if (>= xmax yaxis.xval xmin)
+	(begin
+	  (add-to-canvas-item-group
+	   axes-tag
+	   (make-line-on-canvas plot-canvas yaxis.x y+.y yaxis.x y-.y '(-arrow both)))
+	  (draw-yticks plotter)
+	  (let ((factor (expt 10 tick-precision)))
+	    (make-text-on-canvas plot-canvas
+				 (+ yaxis.x 8) trim
+				 `(-text ,(swat:number->string
+					   (/ (round (* ymax factor)) factor))
+					 -anchor nw))
+	    (make-text-on-canvas plot-canvas
+				 (+ yaxis.x 8) vsize
+				 `(-text ,(swat:number->string
+					   (/ (round (* ymin factor)) factor))
+					 -anchor sw)))))
+    'done))
+
+;;;--------
+;;; Curves
+;;;--------
+
+(define (make-curve plotter function pt-style num-pts color show-vals)
+  (let* ((plot-canvas (plotter 'the-canvas))
+	 (curve-tag (make-canvas-item-group plot-canvas '()))
+	 (outline-tag (make-canvas-item-group plot-canvas '()))
+	 (vals-tag (make-canvas-item-group plot-canvas '()))
+	 (cleared? #f))
+    (lambda (messg)
+      (case messg
+	((plotter) plotter)
+	((num-pts) num-pts)
+	((set-num-pts) (lambda (new-num-pts) (set! num-pts new-num-pts)))
+	((show-vals) show-vals)
+	((set-show-vals) (lambda (new-vals) (set! show-vals new-vals)))
+	((cleared?) cleared?)
+	((change-pt-style)
+	 (lambda (new-pt-style)
+	   (cond ((pt-style? new-pt-style)
+		  (set! pt-style new-pt-style))
+		 (else (write-line "Not a style--MAKE-CURVE") pt-style))))
+	((change-color)
+	 (lambda (new-color)
+	   (set! color new-color)
+	   (if (not cleared?)
+	       (begin
+		 (ask-widget curve-tag `(configure -fill ,color))
+		 (ask-widget outline-tag `(configure -outline ,color))
+		 (ask-widget vals-tag `(configure -fill ,color))))))
+	((get-extreme-vals)
+	 (lambda (min max)
+	   (get-extreme-vals function min max num-pts)))
+	((plot)
+	 (graph function plotter curve-tag outline-tag pt-style num-pts color)
+	 (if show-vals
+	     (graph-vals function plotter show-vals vals-tag color))
+	 (set! cleared? #f)
+	 'plotted)
+	((draw-vals)
+	 (if show-vals
+	     (graph-vals function plotter show-vals vals-tag color))
+	 'drawn)
+	((clear-vals)
+	 (ask-widget vals-tag '(delete))
+	 'cleared)
+	((delete-vals)
+	 (ask-widget vals-tag '(delete))
+	 (set! show-vals #f)
+	 'removed)
+	((clear)
+	 (ask-widget curve-tag '(delete))
+	 (ask-widget outline-tag '(delete))
+	 (ask-widget vals-tag '(delete))
+	 (set! cleared? #t)
+	 'cleared)
+	(else (error "Bad message--MAKE-CURVE" messg))))))
+
+(define (get-extreme-vals function min max num-pts)
+  (let* ((factor (expt 10 vals-precision))
+	 (first-val (function min))
+	 (min-val first-val)
+	 (max-val first-val)
+	 (step (exact->inexact (/ (- max min) num-pts))))
+    (define (calculate x)
+      (let ((val (function x)))
+	(cond ((> x max)
+	       (list (/ (round (* min-val factor)) factor)
+		     (/ (round (* max-val factor)) factor)))
+	      ((< val min-val) (set! min-val val)
+			       (calculate (+ x step)))
+	      ((> val max-val) (set! max-val val)
+			       (calculate (+ x step)))
+	      (else (calculate (+ x step))))))
+    (calculate (+ min step))))
+
+(define (pt-style? val)
+  (memv val '(0 1 2 3 4 5 6 7 10 20 30 40 50 60 100)))
+
+(define (curve-scale-num-pts! curve factor)
+  ((curve 'set-num-pts) (round (* (curve 'num-pts) factor))))
+
+(define (maybe-replot-curve curve)
+  (if (not (curve 'cleared?))
+      (begin (curve 'clear)
+	     (curve'plot))))
+
+(define (graph function plotter curve-tag outline-tag pt-style num-pts color)
+  (let ((plot-canvas (plotter 'the-canvas))
+	(xmin (plotter 'xmin))
+	(xmax (plotter 'xmax))
+	(xaxis.yval (plotter 'xaxis.yval))
+	(x:val->pix (plotter 'x:val->pix))
+	(y:val->pix (plotter 'y:val->pix)))
+    (let ((xaxis.y (y:val->pix xaxis.yval)))
+
+      (define (draw-0 x y)
+	  (add-to-canvas-item-group
+	   curve-tag (make-line-on-canvas plot-canvas x xaxis.y x y)))
+      (define (draw-1 x y)
+	(add-to-canvas-item-group
+	 outline-tag
+	 (make-oval-on-canvas plot-canvas (- x 3) (- y 3) (+ x 3) (+ y 3))))
+      (define (draw-2 x y)
+	(add-to-canvas-item-group
+	 outline-tag 
+	 (make-rectangle-on-canvas plot-canvas (- x 3) (- y 3) (+ x 3) (+ y 3))))
+      (define (draw-3 x y)
+	(add-to-canvas-item-group
+	 curve-tag 
+	 (make-line-on-canvas plot-canvas (- x 2) (- y 2) (+ x 3) (+ y 3)))
+	(add-to-canvas-item-group
+	 curve-tag
+	 (make-line-on-canvas plot-canvas (+ x 2) (- y 2) (- x 2) (+ y 2))))
+      (define (draw-4 x y)
+	(add-to-canvas-item-group
+	 curve-tag (make-line-on-canvas plot-canvas x (- y 2) x (+ y 3)))
+	(add-to-canvas-item-group
+	 curve-tag (make-line-on-canvas plot-canvas (- x 2) y (+ x 3) y)))
+      (define (draw-5 x y)
+	(let ((seg (make-oval-on-canvas plot-canvas
+					(- x 2) (- y 2) (+ x 2) (+ y 2))))
+	  (add-to-canvas-item-group curve-tag seg)
+	  (add-to-canvas-item-group outline-tag seg)))
+      (define (draw-6 x y)
+	(let ((seg (make-rectangle-on-canvas plot-canvas
+					     (- x 2) (- y 2) (+ x 2) (+ y 2))))
+	  (add-to-canvas-item-group curve-tag seg)
+	  (add-to-canvas-item-group outline-tag seg)))
+      (define (draw-7 x y)
+	(add-to-canvas-item-group
+	 curve-tag (make-text-on-canvas plot-canvas x (- y 2) '(-text "."))))
+      (define (draw-10 x y)
+	(add-to-canvas-item-group
+	 curve-tag (make-line-on-canvas plot-canvas x xaxis.y x (+ y 3)))
+	(add-to-canvas-item-group
+	 outline-tag (make-oval-on-canvas
+		      plot-canvas (- x 3) (- y 3) (+ x 3) (+ y 3))))
+      (define (draw-20 x y)
+	(add-to-canvas-item-group
+	 curve-tag (make-line-on-canvas plot-canvas x xaxis.y x (+ y 2)))
+	(add-to-canvas-item-group
+	 outline-tag
+	 (make-rectangle-on-canvas plot-canvas
+				   (- x 3) (- y 3) (+ x 3) (+ y 3))))
+      (define (draw-30 x y)
+	(add-to-canvas-item-group
+	 curve-tag (make-line-on-canvas plot-canvas
+					 (- x 2) (- y 2) (+ x 3) (+ y 3)))
+	(add-to-canvas-item-group
+	 curve-tag (make-line-on-canvas plot-canvas
+					 (+ x 2) (- y 2) (- x 2) (+ y 2)))
+	(add-to-canvas-item-group
+	 curve-tag (make-line-on-canvas plot-canvas x xaxis.y x y)))
+      (define (draw-40 x y)
+	(add-to-canvas-item-group
+	 curve-tag (make-line-on-canvas plot-canvas x (- y 2) x xaxis.y))
+	(add-to-canvas-item-group
+	 curve-tag (make-line-on-canvas plot-canvas (- x 2) y (+ x 3) y)))
+      (define (draw-50 x y)
+	(let ((seg1 (make-oval-on-canvas plot-canvas
+					 (- x 2) (- y 2) (+ x 2) (+ y 2)))
+	      (seg2 (make-line-on-canvas plot-canvas x xaxis.y x (+ y 2))))
+	  (add-to-canvas-item-group outline-tag seg1)
+	  (add-to-canvas-item-group curve-tag seg1)
+	  (add-to-canvas-item-group curve-tag seg2)))
+      (define (draw-60 x y)
+	(let ((seg1 (make-rectangle-on-canvas plot-canvas
+					      (- x 2) (- y 2) (+ x 2) (+ y 2)))
+	      (seg2 (make-line-on-canvas plot-canvas x xaxis.y x (+ y 2))))
+	  (add-to-canvas-item-group outline-tag seg1)
+	  (add-to-canvas-item-group curve-tag seg1)
+	  (add-to-canvas-item-group curve-tag seg2)))
+
+      (define (draw-dispatch pt-style)
+	(cond ((= pt-style 0) draw-0)
+	      ((= pt-style 1) draw-1)
+	      ((= pt-style 2) draw-2)
+	      ((= pt-style 3) draw-3)
+	      ((= pt-style 4) draw-4)
+	      ((= pt-style 5) draw-5)
+	      ((= pt-style 6) draw-6)
+	      ((= pt-style 7) draw-7)
+	      ((= pt-style 10) draw-10)
+	      ((= pt-style 20) draw-20)
+	      ((= pt-style 30) draw-30)
+	      ((= pt-style 40) draw-40)
+	      ((= pt-style 50) draw-50)
+	      ((= pt-style 60) draw-60)))
+
+      (let* ((draw (draw-dispatch pt-style))
+	     (xstep (exact->inexact (/ (- xmax xmin) num-pts))))
+	(define (calc-100 last-x last-y x y)
+	  (if (not (> x xmax))
+	      (let ((segment
+		     (make-line-on-canvas plot-canvas
+					  (x:val->pix last-x)
+					  (y:val->pix last-y)
+					  (x:val->pix x)
+					  (y:val->pix y))))
+		(add-to-canvas-item-group curve-tag segment)
+		(calc-100 x y (+ x xstep) (function (+ x xstep))))))
+	(define (calculate x y)
+	  (if (not (> x xmax))
+	      (begin (draw (x:val->pix x) (y:val->pix y))
+		     (calculate (+ x xstep) (function (+ x xstep))))))
+
+	(if (= pt-style 100)
+	    (calc-100 xmin (function xmin) (+ xmin xstep) (function (+ xmin xstep)))
+	    (calculate xmin (function xmin)))
+	(ask-widget curve-tag `(configure -fill ,color))
+	(ask-widget outline-tag `(configure -outline ,color))))))
+
+(define (graph-vals function plotter show-vals vals-tag color)
+  (let ((factor (expt 10 vals-precision))
+	(x:val->pix (plotter 'x:val->pix))
+	(y:val->pix (plotter 'y:val->pix))
+	(plot-canvas (plotter 'the-canvas)))
+    (let marker ((show-vals show-vals))
+      (if (not (null? show-vals))
+	  (let* ((x-val (car show-vals))
+		 (x (x:val->pix x-val))
+		 (y-val (function x-val))
+		 (y (y:val->pix y-val))
+		 (pos-y? (>= y-val (plotter 'xaxis.yval))))
+	    (add-to-canvas-item-group
+	     vals-tag
+	     (make-text-on-canvas
+	      plot-canvas x (if pos-y? (- y 3) (+ y 6))
+	      `(-text ,(swat:number->string (/ (round (* y-val factor)) factor))
+		-anchor ,(if pos-y? 's 'n))))
+	    (add-to-canvas-item-group
+	     vals-tag
+	     (make-text-on-canvas plot-canvas x y '(-text "|")))
+	    (marker (cdr show-vals)))))
+    (ask-widget vals-tag `(configure -fill ,color))))
+
+
+;;;-------------------------
+;;; Scheme-prompt Interface
+;;;-------------------------
+
+(define (plot plotter . spec-list)
+  (define (package-curves arg-list)
+    (let package-loop ((result (list (car arg-list)))
+		       (rest (cdr arg-list)))
+      (cond ((null? rest) (list (reverse result)))
+	    ((procedure? (car rest))
+	     (cons (reverse result) (package-curves rest)))
+	    (else (package-loop (cons (car rest) result) (cdr rest))))))
+  (if (not (null? spec-list))
+      (let* ((curve-desc-list (package-curves spec-list))
+	     (old-xmin (plotter 'xmin))
+	     (old-xmax (plotter 'xmax))
+	     (old-ymin (plotter 'ymin))
+	     (old-ymax (plotter 'ymax))
+	     (old-axis-y (plotter 'xaxis.yval))
+	     (old-axis-x (plotter 'yaxis.xval))
+	     (old-xticks (plotter 'xticks))
+	     (old-yticks (plotter 'yticks))
+	     (xmin~ #f) (axis-x~ #f) (num-pts~ #f)
+	     (xmax~ #f) (axis-y~ #f) (pt-style~ #f) 
+	     (ymin~ #f) (xticks~ #f) (color~ #f)
+	     (ymax~ #f) (yticks~ #f) (show-vals~ #f)
+	     (default-num-pts  (plotter 'default-num-pts))
+	     (default-pt-style (plotter 'default-pt-style))
+	     (default-color    (plotter 'default-color))
+	     (curve-list '()))
+
+	(define (process-next-curve curve-desc)
+	  (let ((f (car curve-desc))
+		(curve-options (cdr curve-desc)))
+	    (let curve-loop ((curve-options curve-options))
+	      (if (not (null? curve-options))
+		  (let ((option-name (car curve-options)))
+		    (cond ((not (symbol? option-name))
+			   (error "Bad option--PLOT" option-name))
+			  ((null? (cdr curve-options))
+			   (error "PLOT: No value specified for option"
+				  option-name))
+			  (else
+			   (let ((option-value (cadr curve-options)))
+			     (process-option option-name option-value)
+			     (curve-loop (cddr curve-options))))))))
+	    (make-curve plotter
+			f
+			(or pt-style~ default-pt-style)
+			(or num-pts~ default-num-pts)
+			(or color~ default-color)
+			show-vals~)))
+
+	(define (process-option name value)
+	  (case name
+	    ;; global options
+	    ((xmin) (if (not xmin~) (set! xmin~ value)))
+	    ((xmax) (if (not xmax~) (set! xmax~ value)))
+	    ((ymin) (if (not ymin~) (set! ymin~ value)))
+	    ((ymax) (if (not ymax~) (set! ymax~ value)))
+	    ((axis-x) (if (not axis-x~) (set! axis-x~ value)))
+	    ((axis-y) (if (not axis-y~) (set! axis-y~ value)))
+	    ((xticks) (if (not xticks~) (set! xticks~ value)))
+	    ((yticks) (if (not yticks~) (set! xticks~ value)))
+	    ;; curve-specific options
+	    ((num-pts) (set! num-pts~ value))
+	    ((pt-style) (set! pt-style~ value))
+	    ((color) (set! color~ value))
+	    ((show-vals) (set! show-vals~ value))
+	    (else (error "Illegal option--PLOT" name))))
+
+	(define (reset-options!)
+	  (set! num-pts~ #f)
+	  (set! pt-style~ #f)
+	  (set! color~ #f)
+	  (set! show-vals~ #f))
+
+	  (let process-loop ((curve-desc-list (reverse curve-desc-list)))
+	    (if (not (null? curve-desc-list))
+		(let ((new-curve (process-next-curve (car curve-desc-list))))
+		  ((plotter 'add-curve) new-curve)
+		  (set! curve-list (cons new-curve curve-list))
+		  (reset-options!)
+		  (process-loop (cdr curve-desc-list)))))
+	
+	  (let* ((xmin (or xmin~ old-xmin))
+		 (xmax (or xmax~ old-xmax))
+		 (get-extremes
+		  (lambda (xmin xmax)
+		    (map (lambda (curve) ((curve 'get-extreme-vals) xmin xmax))
+			 curve-list)))
+		 (extremes #f)
+		 (ymin
+		  (or ymin~
+		      (min
+		       old-ymin
+		       (let ((xtremes (get-extremes xmin xmax)))
+			 (set! extremes xtremes)
+			 (apply min (cons 0 (map (lambda (e) (car e)) xtremes)))))))
+		 (ymax
+		  (or ymax~
+		      (max
+		       old-ymax
+		       (let ((xtremes
+			      (if extremes extremes (get-extremes xmin xmax))))
+			 (apply max (cons 0 (map (lambda (e) (cadr e)) xtremes)))))))
+		 (axis-y (or axis-y~ old-axis-y))
+		 (axis-x (or axis-x~ old-axis-x)))
+
+	    (if (and (= xmin old-xmin)
+		     (= xmax old-xmax)
+		     (= ymin old-ymin)
+		     (= ymax old-ymax)
+		     (= axis-x old-axis-x)
+		     (= axis-y old-axis-y)
+		     (equal? xticks~ old-xticks)
+		     (equal? yticks~ old-yticks))
+		;; only plot the new curves
+		(for-each (lambda (new-curve) (new-curve 'plot))
+			  curve-list)
+	        ;; if a global param changed, replot everything
+		(begin
+		  ((plotter 'set-params)
+		   xmin xmax ymin ymax axis-x axis-y xticks~ yticks~)
+		  (plotter 'clear)
+		  (draw-axes plotter)
+		  (plotter 'plot-curves)))
+	    
+	    ;; return the curve if there's only one, list of curves if more.
+	    (and (pair? curve-list)
+		 (if (= (length curve-list) 1)
+		     (car curve-list)
+		     curve-list))))))
+
+(define (set-plotter-params plotter . spec-list)
+  (let ((xmin (plotter 'xmin))
+	(xmax (plotter 'xmax))
+	(ymin (plotter 'ymin))
+	(ymax (plotter 'ymax))
+	(axis-x (plotter 'yaxis.xval))
+	(axis-y (plotter 'xaxis.yval))
+	(xticks (plotter 'xticks))
+	(yticks (plotter 'yticks)))
+    (define (process-option name value)
+      (case name
+	;; global options
+	((xmin) (set! xmin value))
+	((xmax) (set! xmax value))
+	((ymin) (set! ymin value))
+	((ymax) (set! ymax value))
+	((axis-x) (set! axis-x value))
+	((axis-y) (set! axis-y value))
+	((xticks) (set! xticks value))
+	((yticks) (set! xticks value))
+	(else (error "Illegal option--SET-PLOTTER-PARAMS" name))))
+    (let process-loop ((options spec-list))
+      (if (not (null? options))
+	  (let ((option-name (car options)))
+	    (cond ((not (symbol? option-name))
+		   (error "Bad option--PLOT" option-name))
+		  ((null? (cdr options))
+		   (error "SET-PLOTTER-PARAMS: No value specified for option"
+			  option-name))
+		  (else
+		   (let ((option-value (cadr options)))
+		     (process-option option-name option-value)
+		     (process-loop (cddr options))))))))
+    ((plotter 'set-params) xmin xmax ymin ymax axis-x axis-y xticks yticks)
+    (plotter 'clear)
+    (draw-axes plotter)
+    (plotter 'plot-curves)))
+
+(define (reset-plotter-params plotter)
+  (apply set-plotter-params
+	 (list 'xmin plotter-default-xmin
+	       'xmax plotter-default-xmax
+	       'ymin plotter-default-ymin
+	       'ymax plotter-default-ymax
+	       'axis-x plotter-default-axis-x
+	       'axis-y plotter-default-axis-y
+	       'xticks plotter-default-xticks
+	       'yticks plotter-default-yticks)))
+
+
+(define (make-vals min max spacing . center?)
+  (let ((min (if center? (* spacing (round (/ min spacing))) min)))
+    (define (tick-maker val)
+      (if (> val max)
+	  '()
+	  (cons val (tick-maker (+ val spacing)))))
+    (tick-maker min)))
+
+
+(define (change-color curve color)
+  ((curve 'change-color) color))
+  
+(define (change-pt-style curve pt-style)
+  ((curve 'change-pt-style) pt-style)
+  (maybe-replot-curve curve))
+
+(define (change-num-pts curve num-pts)
+  ((curve 'set-num-pts) num-pts)
+  (maybe-replot-curve curve))
+
+(define (clear-curve curve)
+  (curve 'clear))
+
+(define (plot-curve curve)
+  (if (curve 'cleared?)
+      (curve 'plot)))
+
+(define (delete-curve curve)
+  (((curve 'plotter) 'delete-curve) curve))
+
+(define (add-show-vals curve show-vals)
+  (curve 'clear-vals)
+  ((curve 'set-show-vals)
+   (append (curve 'show-vals) show-vals))
+  (curve 'draw-vals))
+
+(define (clear-show-vals curve)
+  (curve 'clear-vals))
+
+(define (draw-show-vals curve)
+  (curve 'draw-vals))
+
+(define (delete-show-vals curve)
+  (curve 'delete-vals))
+
+			 
+(define (add-xticks plotter xticks)
+  ((plotter 'set-xticks)
+   (append (plotter 'xticks) xticks))
+  (plotter 'clear-axes)
+  (draw-axes plotter))
+
+(define (add-yticks plotter yticks)
+  ((plotter 'set-yticks)
+   (append (plotter 'xticks) yticks))
+  (plotter 'clear-axes)
+  (draw-axes plotter))
+
+(define (clear-ticks plotter)
+  (plotter 'clear-ticks))
+
+(define (draw-ticks plotter)
+  (draw-xticks plotter)
+  (draw-yticks plotter))
+
+(define (delete-ticks plotter)
+  (plotter 'delete-ticks))
+
+(define (clear-plotter plotter)
+  (plotter 'clear-curves)
+  (plotter 'clear-ticks))
+
+(define (replot plotter)
+  (draw-ticks plotter)
+  (for-each plot-curve (plotter 'curve-list))
+  'replotted)
+
+(define (reset-plotter plotter)
+  (plotter 'delete-curves)
+  (plotter 'delete-ticks)
+  (plotter 'clear)
+  (draw-axes plotter)
+  'reset)
+