Several optimizations:

self.__chips now contains the list of rgbtuple values for the
    chips named i - 1 (Tkinter counts from 1, we count from zero).
    The chip number was just the index + 1.  This means color lookup
    need not do an itemcget(), it can just index into __chips.

    instead of calling __canvas.itemconfigure(), we glom up a huge Tcl
    script and call tk.eval() directly.  Actually we do many appends
    to a Python list, then string.join() them together into one huge
    string.  This reduces the overhead of Tkinter but making one fast
    call to Tcl.

Tools/pynche/StripViewer.py

@@ -1,7 +1,9 @@
+import string
 from Tkinter import *
 import Pmw
 import ColorDB
 
+
 class LeftArrow:
     _ARROWWIDTH = 30
     _ARROWHEIGHT = 15
@@ -74,7 +76,7 @@ class StripWidget(Pmw.MegaWidget):
 
     def __init__(self, parent=None, **kw):
 	options = (('color',      (128, 128, 128),  self.__set_color),
-		   ('delegate', None, None),
+		   ('delegate',   None,             self.__set_delegate),
 		   ('chipwidth',  self._CHIPWIDTH,  Pmw.INITOPT),
 		   ('chipheight', self._CHIPHEIGHT, Pmw.INITOPT),
 		   ('numchips',   self._NUMCHIPS,   Pmw.INITOPT),
@@ -116,12 +118,13 @@ class StripWidget(Pmw.MegaWidget):
 	x = 1
 	y = 30
 	for c in range(self.__numchips):
+	    color = 'grey'
 	    rect = self.__canvas.create_rectangle(
 		x, y, x+chipwidth, y+chipheight,
-		fill='grey', outline='grey')
+		fill=color, outline=color)
 
 	    x = x + chipwidth + 1		  # for outline
-	    chips.append(rect)
+	    chips.append(color)
 
 	# create the string tag
 	self.__label = self.__canvas.create_text(
@@ -140,24 +143,37 @@ class StripWidget(Pmw.MegaWidget):
 	self.__axis = self['axis']
 	assert self.__axis in (0, 1, 2)
 	self.initialiseoptions(StripWidget)
+	self.__delegate = self['delegate']
 
     def __set_color(self):
 	rgbtuple = self['color']
 	self.set_color(self, rgbtuple)
 
     def __arrow_x(self, chipnum):
-	coords = self.__canvas.coords(self.__chips[chipnum])
+	coords = self.__canvas.coords(chipnum+1)
 	assert coords
 	x0, y0, x1, y1 = coords
 	return (x1 + x0) / 2.0
 
     def __select_chip(self, event=None):
-	chip = self.__canvas.find_closest(event.x, event.y)
+	chip = self.__canvas.find_closest(event.x, event.y)[0]
-	delegate = self['delegate']
+	if chip and self.__delegate:
-	if chip and delegate:
+	    color = self.__chips[chip-1]
-	    color = self.__canvas.itemcget(chip, 'fill')
 	    rgbtuple = ColorDB.rrggbb_to_triplet(color)
-	    delegate.set_color(self, rgbtuple)
+	    self.__delegate.set_color(self, rgbtuple)
+
+## 	    import profile
+## 	    import pstats
+## 	    import tempfile
+## 	    statfile = tempfile.mktemp()
+## 	    p = profile.Profile()
+## 	    p.runcall(self.__delegate.set_color, self, rgbtuple)
+## 	    p.dump_stats(statfile)
+## 	    s = pstats.Stats(statfile)
+## 	    s.strip_dirs().sort_stats('time').print_stats(10)
+
+    def __set_delegate(self):
+	self.__delegate = self['delegate']
 	
 
     #
@@ -166,18 +182,33 @@ class StripWidget(Pmw.MegaWidget):
 
     def set_color(self, obj, rgbtuple):
 	red, green, blue = rgbtuple
-	if self.__generator:
+	assert self.__generator
-	    i = 0
+	i = 1
 	chip = 0
+	chips = self.__chips = []
+	tclcmd = []
 	for t in self.__generator(self.__numchips, rgbtuple):
 	    rrggbb = ColorDB.triplet_to_rrggbb(t)
-		self.__canvas.itemconfigure(self.__chips[i],
+	    chips.append(rrggbb)
-					    fill=rrggbb,
+## 	    self.__canvas.itemconfigure(i,
-					    outline=rrggbb)
+## 					fill=rrggbb,
+## 					outline=rrggbb)
+	    tclcmd.append(self.__canvas._w)
+	    tclcmd.append('itemconfigure')
+	    tclcmd.append(`i`)
+	    tclcmd.append('-fill')
+	    tclcmd.append(rrggbb)
+	    tclcmd.append('-outline')
+	    tclcmd.append(rrggbb)
+	    tclcmd.append('\n')
 	    tred, tgreen, tblue = t
 	    if tred <= red and tgreen <= green and tblue <= blue:
 		chip = i
 	    i = i + 1
+	# call the raw tcl script
+	script = string.join(tclcmd, ' ')
+	self.__canvas.tk.eval(script)
+
 	# get the arrow's text
 	coloraxis = rgbtuple[self.__axis]
 	text = repr(coloraxis)
@@ -186,12 +217,12 @@ class StripWidget(Pmw.MegaWidget):
 	if coloraxis <= 128:
 	    # use the left chip
 	    self.__leftarrow.set_text(text)
-		self.__leftarrow.move_to(self.__arrow_x(chip))
+	    self.__leftarrow.move_to(self.__arrow_x(chip-1))
 	    self.__rightarrow.move_to(-100)
 	else:
 	    # use the right chip
 	    self.__rightarrow.set_text(text)
-		self.__rightarrow.move_to(self.__arrow_x(chip))
+	    self.__rightarrow.move_to(self.__arrow_x(chip-1))
 	    self.__leftarrow.move_to(-100)
 	# and set the chip's outline
 	pmwrgb = ColorDB.triplet_to_pmwrgb(rgbtuple)
@@ -200,5 +231,4 @@ class StripWidget(Pmw.MegaWidget):
 	    outline = 'white'
 	else:
 	    outline = 'black'
-	    self.__canvas.itemconfigure(self.__chips[chip],
+	self.__canvas.itemconfigure(chip, outline=outline)
-					outline=outline)