Add simple turtle graphics generator

svgturtle.py

@@ -0,0 +1,54 @@
+import math
+import sys
+
+class SvgTurtle():
+    def __init__(self, homex=0, homey=0):
+        self.homex    = homex
+        self.homey    = homey
+        self.cvtangle = math.tau/360
+        self.reset()
+
+    def penup(self):
+        self.pen      = False
+
+    def pendown(self):
+        self.pen      = True
+
+    def forward(self, distance):
+        if self.pen and (self.path == ''):
+            self.path = "M %.2f,%.2f" % (self.x,self.y)
+        dx = distance*math.cos(self.heading)
+        dy = distance*math.sin(self.heading)
+        self.x += dx
+        self.y += dy
+        if self.pen:
+            if abs(dy) < .01:
+                self.path += " h %.2f" % dx
+            elif abs(dx) < .01:
+                self.path += " v %.2f" % dy
+            else:
+                self.path += " l %.2f,%.2f" % (dx, dy)
+        elif self.path != '':
+            self.path += " m %.2f, %.2f" % (dx, dy)
+
+    def back(self, distance):
+        self.forward(-distance)
+
+    def left(self, angle):
+        self.right(-angle)
+
+    def right(self, angle):
+        self.heading = (self.heading + angle*self.cvtangle) % math.tau
+
+    def to_s(self):
+        return self.path
+
+    def home(self):
+        self.x        = self.homex
+        self.y        = self.homey
+        self.heading  = 0
+
+    def reset(self):
+        self.path = ''
+        self.pen  = True
+        self.home()