From 3c7a25a4d9ea07f2aa8e4b70fecd84e33de82c2e Mon Sep 17 00:00:00 2001
From: Guido van Rossum <guido@python.org>
Date: Thu, 9 Aug 2001 16:42:07 +0000
Subject: [PATCH] Applied SF patch #438424 by Josh Cogliati:

Python's logolike module turtle.py did not display
the turtle except when actually drawing lines.
This patch changes the turtle.py module so that
it displays the turtle at all times when tracing is
on. This is similar to the the way that logo works.
When tracing is off the turtle will not be displayed.
---
 Lib/lib-tk/turtle.py | 46 ++++++++++++++++++++++++++++++++++++++++----
 1 file changed, 42 insertions(+), 4 deletions(-)

diff --git a/Lib/lib-tk/turtle.py b/Lib/lib-tk/turtle.py
index dde5725ffb..d5b445a9e2 100644
--- a/Lib/lib-tk/turtle.py
+++ b/Lib/lib-tk/turtle.py
@@ -11,6 +11,7 @@ class RawPen:
         self._canvas = canvas
         self._items = []
         self._tracing = 1
+        self._arrow = 0
         self.degrees()
         self.reset()
 
@@ -48,9 +49,15 @@ class RawPen:
         self._items = []
         for item in items:
             canvas.delete(item)
+        self._delete_turtle()
+        self._draw_turtle()
+
 
     def tracer(self, flag):
         self._tracing = flag
+        if not self._tracing:
+            self._delete_turtle()
+        self._draw_turtle()
 
     def forward(self, distance):
         x0, y0 = start = self._position
@@ -63,6 +70,7 @@ class RawPen:
 
     def left(self, angle):
         self._angle = (self._angle + angle) % self._fullcircle
+        self._draw_turtle()
 
     def right(self, angle):
         self.left(-angle)
@@ -87,7 +95,7 @@ class RawPen:
                     id = self._canvas.create_line(0, 0, 0, 0, fill=color)
                 except Tkinter.TclError:
                     raise Error, "bad color string: %s" % `color`
-                self._color = color
+                self._set_color(color)
                 return
             try:
                 r, g, b = color
@@ -103,7 +111,12 @@ class RawPen:
         assert 0 <= b <= 1
         x = 255.0
         y = 0.5
-        self._color = "#%02x%02x%02x" % (int(r*x+y), int(g*x+y), int(b*x+y))
+        self._set_color("#%02x%02x%02x" % (int(r*x+y), int(g*x+y), int(b*x+y)))
+
+    def _set_color(self,color):
+        self._color = color
+        self._draw_turtle()
+
 
     def write(self, arg, move=0):
         x, y = start = self._position
@@ -115,6 +128,7 @@ class RawPen:
         if move:
             x0, y0, x1, y1 = self._canvas.bbox(item)
             self._goto(x1, y1)
+        self._draw_turtle()
 
     def fill(self, flag):
         if self._filling:
@@ -205,20 +219,20 @@ class RawPen:
         if self._filling:
             self._path.append(self._position)
         if self._drawing:
-            if self._tracing:
+            if self._tracing:                
                 dx = float(x1 - x0)
                 dy = float(y1 - y0)
                 distance = hypot(dx, dy)
                 nhops = int(distance)
                 item = self._canvas.create_line(x0, y0, x0, y0,
                                                 width=self._width,
-                                                arrow="last",
                                                 capstyle="round",
                                                 fill=self._color)
                 try:
                     for i in range(1, 1+nhops):
                         x, y = x0 + dx*i/nhops, y0 + dy*i/nhops
                         self._canvas.coords(item, x0, y0, x, y)
+                        self._draw_turtle((x,y))
                         self._canvas.update()
                         self._canvas.after(10)
                     # in case nhops==0
@@ -233,6 +247,30 @@ class RawPen:
                                                 capstyle="round",
                                                 fill=self._color)
             self._items.append(item)
+        self._draw_turtle()
+
+    def _draw_turtle(self,position=[]):
+        if not self._tracing:
+            return
+        if position == []:
+            position = self._position
+        x,y = position
+        distance = 8
+        dx = distance * cos(self._angle*self._invradian)
+        dy = distance * sin(self._angle*self._invradian)
+        self._delete_turtle()
+        self._arrow = _canvas.create_line(x-dx,y+dy,x,y,
+                                          width=self._width,
+                                          arrow="last",
+                                          capstyle="round",
+                                          fill=self._color)
+        self._canvas.update()
+
+    def _delete_turtle(self):
+        if self._arrow != 0:
+            self._canvas.delete(self._arrow)
+        self._arrow = 0
+
 
 
 _root = None
-- 
2.50.1