From 4739976d0a96eb21b8f606c69ecc09ca7a1557de Mon Sep 17 00:00:00 2001
From: Walter Bender <walter.bender@gmail.com>
Date: Tue, 08 Nov 2011 00:12:29 +0000
Subject: Merge commit 'refs/merge-requests/3' of git://git.sugarlabs.org/turtleart/mainline into integration

Conflicts:
	NEWS
	activity/activity.info
---
diff --git a/NEWS b/NEWS
index 67881c6..3040c24 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,17 @@
+123
+
+ENHANCEMENTS
+* Using Cairo graphics
+ - antialiasing
+ - rotation of text and images
+ - filled arcs
+
+NOTE
+* For performance reasons, the coordinate grids are now drawn directly
+  onto the turtle canvas. This has two consequences: (1) the grids cannot
+  be erased except by erasing the entire screen; and (2) the turtle can
+  draw on top of the grid.
+
 122
 
 ENHANCEMENTS
@@ -26,6 +40,7 @@ ENHANCEMENTS
 BUG FIXES
 * Fixed type error introduced to arc commands by patch to address #3164
 
+
 118
 
 ENHANCEMENTS
diff --git a/TurtleArt/sprites.py b/TurtleArt/sprites.py
index 8bd3738..a67046f 100644
--- a/TurtleArt/sprites.py
+++ b/TurtleArt/sprites.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
 #Copyright (c) 2007-8, Playful Invention Company.
-#Copyright (c) 2008-10 Walter Bender
+#Copyright (c) 2008-11 Walter Bender
 
 #Permission is hereby granted, free of charge, to any person obtaining a copy
 #of this software and associated documentation files (the "Software"), to deal
@@ -21,29 +21,23 @@
 #OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
 #THE SOFTWARE.
 
-"""
+'''
 
 sprites.py is a simple sprites library for managing graphics objects,
-'sprites', on a canvas. It manages multiple sprites with methods such
-as move, hide, set_layer, etc.
+'sprites', on a gtk.DrawingArea. It manages multiple sprites with
+methods such as move, hide, set_layer, etc.
 
 There are two classes:
 
-class Sprites maintains a collection of sprites.
+class Sprites maintains a collection of sprites
 class Sprite manages individual sprites within the collection.
 
 Example usage:
         # Import the classes into your program.
         from sprites import Sprites Sprite
 
-        # In your expose callback event handler, call refresh
-        def _expose_cb(self, win, event):
-            self.sprite_list.refresh(event)
-            return True
-
-        # Create a new sprite collection for a gtk Drawing Area.
-        my_drawing_area = gtk.DrawingArea()
-        self.sprite_list = Sprites(my_drawing_area)
+        # Create a new sprite collection associated with your widget
+        self.sprite_list = Sprites(widget)
 
         # Create a "pixbuf" (in this example, from SVG).
         my_pixbuf = svg_str_to_pixbuf("<svg>...some svg code...</svg>")
@@ -52,7 +46,7 @@ Example usage:
         my_sprite = sprites.Sprite(self.sprite_list, x1, y1, my_pixbuf)
 
         # Move the sprite to a new position.
-        my_sprite.move_relative((dx, dy))
+        my_sprite.move((x1+dx, y1+dy))
 
         # Create another "pixbuf".
         your_pixbuf = svg_str_to_pixbuf("<svg>...some svg code...</svg>")
@@ -68,6 +62,10 @@ Example usage:
         # Now put my_sprite on top of your_sprite.
         my_sprite.set_layer(300)
 
+        cr = self.window.cairo_create()
+        # In your activity's do_expose_event, put in a call to redraw_sprites
+        self.sprites.redraw_sprites(event.area, cairo_context)
+
 # method for converting SVG to a gtk pixbuf
 def svg_str_to_pixbuf(svg_string):
     pl = gtk.gdk.PixbufLoader('svg')
@@ -75,46 +73,46 @@ def svg_str_to_pixbuf(svg_string):
     pl.close()
     pixbuf = pl.get_pixbuf()
     return pixbuf
-"""
+
+'''
 
 import pygtk
 pygtk.require('2.0')
 import gtk
 import pango
+import pangocairo
 
 
 class Sprites:
-    """ A class for the list of sprites and everything they share in common """
-
-    def __init__(self, canvas, area=None, gc=None):
-        """ Initialize an empty array of sprites """
-        self.canvas = canvas
-        if area == None:
-            self.area = self.canvas.window
-            self.gc = self.area.new_gc()
-        else:
-            self.area = area
-            self.gc = gc
-        self.cm = self.gc.get_colormap()
+    ''' A class for the list of sprites and everything they share in common '''
+
+    def __init__(self, widget):
+        ''' Initialize an empty array of sprites '''
+        self.widget = widget
         self.list = []
+        self.cr = None
+
+    def set_cairo_context(self, cr):
+        ''' Cairo context may be set or reset after __init__ '''
+        self.cr = cr
 
     def get_sprite(self, i):
-        """ Return a sprint from the array """
+        ''' Return a sprint from the array '''
         if i < 0 or i > len(self.list) - 1:
             return(None)
         else:
             return(self.list[i])
 
     def length_of_list(self):
-        """ How many sprites are there? """
+        ''' How many sprites are there? '''
         return(len(self.list))
 
     def append_to_list(self, spr):
-        """ Append a new sprite to the end of the list. """
+        ''' Append a new sprite to the end of the list. '''
         self.list.append(spr)
 
     def insert_in_list(self, spr, i):
-        """ Insert a sprite at position i. """
+        ''' Insert a sprite at position i. '''
         if i < 0:
             self.list.insert(0, spr)
         elif i > len(self.list) - 1:
@@ -123,43 +121,46 @@ class Sprites:
             self.list.insert(i, spr)
 
     def remove_from_list(self, spr):
-        """ Remove a sprite from the list. """
+        ''' Remove a sprite from the list. '''
         if spr in self.list:
             self.list.remove(spr)
 
-    def find_sprite(self, pos, alpha=True):
-        """ Search based on (x, y) position. Return the 'top/first' one. """
+    def find_sprite(self, pos):
+        ''' Search based on (x, y) position. Return the 'top/first' one. '''
         list = self.list[:]
         list.reverse()
         for spr in list:
             if spr.hit(pos):
-                if not alpha or spr.get_pixel(pos)[3] == 255:
-                    return spr
+                return spr
         return None
 
-    def refresh(self, event):
-        """ Handle expose event refresh """
-        self.redraw_sprites(event.area)
-
-    def redraw_sprites(self, area=None):
-        """ Redraw the sprites that intersect area. """
+    def redraw_sprites(self, area=None, cr=None):
+        ''' Redraw the sprites that intersect area. '''
+        # I think I need to do this to save Cairo some work
+        if cr is None:
+            cr = self.cr
+        else:
+            self.cr = cr
+        if cr is None:
+            print 'sprites.redraw_sprites: no Cairo context'
+            return
         for spr in self.list:
             if area == None:
-                spr.draw()
+                spr.draw(cr=cr)
             else:
                 intersection = spr.rect.intersect(area)
                 if intersection.width > 0 or intersection.height > 0:
-                    spr.draw()
+                    spr.draw(cr=cr)
 
 
 class Sprite:
-    """ A class for the individual sprites """
+    ''' A class for the individual sprites '''
 
     def __init__(self, sprites, x, y, image):
-        """ Initialize an individual sprite """
+        ''' Initialize an individual sprite '''
         self._sprites = sprites
-        self.rect = gtk.gdk.Rectangle(int(x), int(y), 0, 0)
         self.save_xy = (x, y)  # remember initial (x, y) position
+        self.rect = gtk.gdk.Rectangle(int(x), int(y), 0, 0)
         self._scale = [12]
         self._rescale = [True]
         self._horiz_align = ["center"]
@@ -172,16 +173,18 @@ class Sprite:
         self.layer = 100
         self.labels = []
         self.images = []
+        self.surfaces = []
         self._dx = []  # image offsets
         self._dy = []
+        self.type = None
         self.set_image(image)
-        if self._sprites is not None:
-            self._sprites.append_to_list(self)
+        self._sprites.append_to_list(self)
 
     def set_image(self, image, i=0, dx=0, dy=0):
-        """ Add an image to the sprite. """
+        ''' Add an image to the sprite. '''
         while len(self.images) < i + 1:
             self.images.append(None)
+            self.surfaces.append(None)
             self._dx.append(0)
             self._dy.append(0)
         self.images[i] = image
@@ -201,47 +204,42 @@ class Sprite:
             if h + dy > self.rect.height:
                 self.rect.height = h + dy
 
-    def move(self, pos, visible=True):
-        """ Move to new (x, y) position """
-        if visible:
-            self.inval()
+    def move(self, pos):
+        ''' Move to new (x, y) position '''
+        self.inval()
         self.rect.x, self.rect.y = int(pos[0]), int(pos[1])
-        if visible:
-            self.inval()
+        self.inval()
 
-    def move_relative(self, pos, visible=True):
-        """ Move to new (x+dx, y+dy) position """
-        if visible:
-            self.inval()
+    def move_relative(self, pos):
+        ''' Move to new (x+dx, y+dy) position '''
+        self.inval()
         self.rect.x += int(pos[0])
         self.rect.y += int(pos[1])
-        if visible:
-            self.inval()
+        self.inval()
 
     def get_xy(self):
-        """ Return current (x, y) position """
+        ''' Return current (x, y) position '''
         return (self.rect.x, self.rect.y)
 
     def get_dimensions(self):
-        """ Return current size """
+        ''' Return current size '''
         return (self.rect.width, self.rect.height)
 
     def get_layer(self):
-        """ Return current layer """
+        ''' Return current layer '''
         return self.layer
 
     def set_shape(self, image, i=0):
-        """ Set the current image associated with the sprite """
+        ''' Set the current image associated with the sprite '''
         self.inval()
         self.set_image(image, i)
         self.inval()
 
-    def set_layer(self, layer):
-        """ Set the layer for a sprite """
-        if self._sprites is None:
-            return
+    def set_layer(self, layer=None):
+        ''' Set the layer for a sprite '''
         self._sprites.remove_from_list(self)
-        self.layer = layer
+        if layer is not None:
+            self.layer = layer
         for i in range(self._sprites.length_of_list()):
             if layer < self._sprites.get_sprite(i).layer:
                 self._sprites.insert_in_list(self, i)
@@ -251,7 +249,7 @@ class Sprite:
         self.inval()
 
     def set_label(self, new_label, i=0):
-        """ Set the label drawn on the sprite """
+        ''' Set the label drawn on the sprite '''
         self._extend_labels_array(i)
         if type(new_label) is str or type(new_label) is unicode:
             # pango doesn't like nulls
@@ -261,15 +259,15 @@ class Sprite:
         self.inval()
 
     def set_margins(self, l=0, t=0, r=0, b=0):
-        """ Set the margins for drawing the label """
+        ''' Set the margins for drawing the label '''
         self._margins = [l, t, r, b]
 
     def _extend_labels_array(self, i):
-        """ Append to the labels attribute list """
+        ''' Append to the labels attribute list '''
         if self._fd is None:
             self.set_font('Sans')
         if self._color is None:
-            self._color = self._sprites.cm.alloc_color('black')
+            self._color = (0., 0., 0.)
         while len(self.labels) < i + 1:
             self.labels.append(" ")
             self._scale.append(self._scale[0])
@@ -278,16 +276,27 @@ class Sprite:
             self._vert_align.append(self._vert_align[0])
 
     def set_font(self, font):
-        """ Set the font for a label """
+        ''' Set the font for a label '''
         self._fd = pango.FontDescription(font)
 
     def set_label_color(self, rgb):
-        """ Set the font color for a label """
-        self._color = self._sprites.cm.alloc_color(rgb)
+        ''' Set the font color for a label '''
+        COLORTABLE = {'black': '#000000', 'white': '#FFFFFF',
+                      'red': '#FF0000', 'yellow': '#FFFF00',
+                      'green': '#00FF00', 'cyan': '#00FFFF',
+                      'blue': '#0000FF', 'purple': '#FF00FF',
+                      'gray': '#808080'}
+        if rgb.lower() in COLORTABLE:
+            rgb = COLORTABLE[rgb.lower()]
+        # Convert from '#RRGGBB' to floats
+        self._color = (int('0x' + rgb[1:3], 16) / 256.,
+                       int('0x' + rgb[3:5], 16) / 256.,
+                       int('0x' + rgb[5:7], 16) / 256.)
+        return
 
     def set_label_attributes(self, scale, rescale=True, horiz_align="center",
                              vert_align="middle", i=0):
-        """ Set the various label attributes """
+        ''' Set the various label attributes '''
         self._extend_labels_array(i)
         self._scale[i] = scale
         self._rescale[i] = rescale
@@ -295,37 +304,51 @@ class Sprite:
         self._vert_align[i] = vert_align
 
     def hide(self):
-        """ Hide a sprite """
-        if self._sprites is None:
-            return
+        ''' Hide a sprite '''
         self.inval()
         self._sprites.remove_from_list(self)
 
-    def inval(self):
-        """ Force a region redraw by gtk """
-        if self._sprites is None:
-            return
-        self._sprites.area.invalidate_rect(self.rect, False)
+    def restore(self):
+        ''' Restore a hidden sprite '''
+        self.set_layer()
 
-    def draw(self):
-        """ Draw the sprite (and label) """
-        if self._sprites is None:
+    def inval(self):
+        ''' Invalidate a region for gtk '''
+        # self._sprites.window.invalidate_rect(self.rect, False)
+        self._sprites.widget.queue_draw_area(self.rect.x,
+                                             self.rect.y,
+                                             self.rect.width,
+                                             self.rect.height)
+
+    def draw(self, cr=None):
+        ''' Draw the sprite (and label) '''
+        if cr is None:
+            print 'sprite.draw: no Cairo context.'
             return
+        # Fix me: Cache cairo surfaces
         for i, img in enumerate(self.images):
-            if isinstance(img, gtk.gdk.Pixbuf):
-                self._sprites.area.draw_pixbuf(self._sprites.gc, img, 0, 0,
-                                               self.rect.x + self._dx[i],
-                                               self.rect.y + self._dy[i])
-            elif img is not None:
-                self._sprites.area.draw_drawable(self._sprites.gc, img, 0, 0,
-                                                 self.rect.x + self._dx[i],
-                                                 self.rect.y + self._dy[i],
-                                                 -1, -1)
+            if self.surfaces[i] is not None:
+                cr.set_source_surface(self.surfaces[i],
+                                      self.rect.x + self._dx[i],
+                                      self.rect.y + self._dy[i])
+            elif isinstance(img, gtk.gdk.Pixbuf):
+                cr.set_source_pixbuf(img,
+                                     self.rect.x + self._dx[i],
+                                     self.rect.y + self._dy[i])
+                # self.surfaces[i] = cr.get_target()
+            else:
+                print 'sprite.draw: source not a pixbuf (%s)' % (type(img))
+            cr.rectangle(self.rect.x + self._dx[i],
+                         self.rect.y + self._dy[i],
+                         self.rect.width,
+                         self.rect.height)
+            cr.fill()
+
         if len(self.labels) > 0:
-            self.draw_label()
+            self.draw_label(cr)
 
     def hit(self, pos):
-        """ Is (x, y) on top of the sprite? """
+        ''' Is (x, y) on top of the sprite? '''
         x, y = pos
         if x < self.rect.x:
             return False
@@ -337,16 +360,18 @@ class Sprite:
             return False
         return True
 
-    def draw_label(self):
-        """ Draw the label based on its attributes """
-        if self._sprites is None:
-            return
+    def draw_label(self, cr):
+        ''' Draw the label based on its attributes '''
+        # Create a pangocairo context
+        cr = pangocairo.CairoContext(cr)
         my_width = self.rect.width - self._margins[0] - self._margins[2]
         if my_width < 0:
             my_width = 0
         my_height = self.rect.height - self._margins[1] - self._margins[3]
         for i in range(len(self.labels)):
-            pl = self._sprites.canvas.create_pango_layout(str(self.labels[i]))
+            pl = cr.create_layout()
+            pl.set_text(str(self.labels[i]))
+            # pl = self._sprites.canvas.create_pango_layout(str(self.labels[i]))
             self._fd.set_size(int(self._scale[i] * pango.SCALE))
             pl.set_font_description(self._fd)
             w = pl.get_size()[0] / pango.SCALE
@@ -359,8 +384,8 @@ class Sprite:
                 else:
                     j = len(self.labels[i]) - 1
                     while(w > my_width and j > 0):
-                        pl = self._sprites.canvas.create_pango_layout(
-                              "…" + self.labels[i][len(self.labels[i]) - j:])
+                        pl.set_text(
+                            "…" + self.labels[i][len(self.labels[i]) - j:])
                         self._fd.set_size(int(self._scale[i] * pango.SCALE))
                         pl.set_font_description(self._fd)
                         w = pl.get_size()[0] / pango.SCALE
@@ -369,44 +394,53 @@ class Sprite:
                 x = int(self.rect.x + self._margins[0] + (my_width - w) / 2)
             elif self._horiz_align[i] == 'left':
                 x = int(self.rect.x + self._margins[0])
-            else:  # right
+            else: # right
                 x = int(self.rect.x + self.rect.width - w - self._margins[2])
             h = pl.get_size()[1] / pango.SCALE
             if self._vert_align[i] == "middle":
                 y = int(self.rect.y + self._margins[1] + (my_height - h) / 2)
             elif self._vert_align[i] == "top":
                 y = int(self.rect.y + self._margins[1])
-            else:  # bottom
+            else: # bottom
                 y = int(self.rect.y + self.rect.height - h - self._margins[3])
-            self._sprites.gc.set_foreground(self._color)
-            self._sprites.area.draw_layout(self._sprites.gc, x, y, pl)
+            cr.save()
+            cr.translate(x, y)
+            cr.set_source_rgb(self._color[0], self._color[1], self._color[2])
+            cr.update_layout(pl)
+            cr.show_layout(pl)
+            cr.restore()
 
     def label_width(self):
-        """ Calculate the width of a label """
-        max = 0
-        for i in range(len(self.labels)):
-            pl = self._sprites.canvas.create_pango_layout(self.labels[i])
-            self._fd.set_size(int(self._scale[i] * pango.SCALE))
-            pl.set_font_description(self._fd)
-            w = pl.get_size()[0] / pango.SCALE
-            if w > max:
-                max = w
-        return max
+        ''' Calculate the width of a label '''
+        cr = pangocairo.CairoContext(self._sprites.cr)
+        if cr is not None:
+            max = 0
+            for i in range(len(self.labels)):
+                pl = cr.create_layout()
+                pl.set_text(self.labels[i])
+                self._fd.set_size(int(self._scale[i] * pango.SCALE))
+                pl.set_font_description(self._fd)
+                w = pl.get_size()[0] / pango.SCALE
+                if w > max:
+                    max = w
+            return max
+        else:
+            return self.rect.width
 
     def label_safe_width(self):
-        """ Return maximum width for a label """
+        ''' Return maximum width for a label '''
         return self.rect.width - self._margins[0] - self._margins[2]
 
     def label_safe_height(self):
-        """ Return maximum height for a label """
+        ''' Return maximum height for a label '''
         return self.rect.height - self._margins[1] - self._margins[3]
 
     def label_left_top(self):
-        """ Return the upper-left corner of the label safe zone """
+        ''' Return the upper-left corner of the label safe zone '''
         return(self._margins[0], self._margins[1])
 
     def get_pixel(self, pos, i=0, mode='888'):
-        """ Return the pixel at (x, y) """
+        ''' Return the pixel at (x, y) '''
         x, y = pos
         x = x - self.rect.x
         y = y - self.rect.y
@@ -452,3 +486,4 @@ class Sprite:
                 g = g << 2
                 b = b << 3
             return(r, g, b, 0)
+
diff --git a/TurtleArt/tablock.py b/TurtleArt/tablock.py
index d2292b1..03ddc05 100644
--- a/TurtleArt/tablock.py
+++ b/TurtleArt/tablock.py
@@ -280,7 +280,7 @@ class Block:
         self._set_label_attributes()
         self.svg.set_scale(self.scale)
         self.refresh()
-        self.spr.draw()
+        self.spr.inval()
 
     def refresh(self):
         if self.spr is None:
@@ -381,8 +381,9 @@ class Block:
             self.width = copy_block.width
             self.height = copy_block.height
             self.shapes[0] = copy_block.shapes[0]
-            self.spr = sprites.Sprite(sprite_list, x, y, self.shapes[0])
-            self.spr._margins = copy_block.spr._margins[:]
+            if sprite_list is not None:
+                self.spr = sprites.Sprite(sprite_list, x, y, self.shapes[0])
+                self.spr._margins = copy_block.spr._margins[:]
             if len(copy_block.shapes) > 1:
                 self.shapes[1] = copy_block.shapes[1]
             self.docks = copy_block.docks[:]
@@ -414,15 +415,19 @@ class Block:
             for i, n in enumerate(block_names[self.name]):
                 self._set_labels(i, n)
 
-        if copy_block is None:
+        if copy_block is None and self.spr is not None:
             if self.spr.label_width() > self.spr.label_safe_width():
                 self.resize()
 
     def _set_margins(self):
+        if self.spr is None:
+            return
         self.spr.set_margins(self.svg.margins[0], self.svg.margins[1],
                              self.svg.margins[2], self.svg.margins[3])
 
     def _set_label_attributes(self):
+        if self.spr is None:
+            return
         if self.name in content_blocks:
             n = len(self.values)
             if n == 0:
@@ -451,6 +456,8 @@ class Block:
                                               True, 'center', 'middle', i)
 
     def _set_labels(self, i, label):
+        if self.spr is None:
+            return
         self.spr.set_label(label, i)
 
     def _make_block(self, svg):
diff --git a/TurtleArt/tacanvas.py b/TurtleArt/tacanvas.py
index 59fcb1c..83f6461 100644
--- a/TurtleArt/tacanvas.py
+++ b/TurtleArt/tacanvas.py
@@ -21,9 +21,10 @@
 #THE SOFTWARE.
 
 import gtk
-from math import sin, cos, pi
+from math import sin, cos, atan, pi, sqrt
 import pango
 import cairo
+import pangocairo
 import base64
 from gettext import gettext as _
 
@@ -31,11 +32,11 @@ from sprites import Sprite
 from tasprite_factory import SVG
 from tautils import image_to_base64, get_path, data_to_string, round_int, \
     debug_output
-from taconstants import CANVAS_LAYER, BLACK, WHITE
+from taconstants import BLACK, WHITE
 
 
 def wrap100(n):
-    """ A variant on mod... 101 -> 99; 199 -> 1 """
+    ''' A variant on mod... 101 -> 99; 199 -> 1 '''
     n = int(n)
     n %= 200
     if n > 99:
@@ -43,25 +44,8 @@ def wrap100(n):
     return n
 
 
-def calc_poly_bounds(poly_points):
-    """ Calculate the minx, miny, width, height of polygon """
-    minx = poly_points[0][0]
-    miny = poly_points[0][1]
-    maxx, maxy = minx, miny
-    for p in poly_points:
-        if p[0] < minx:
-            minx = p[0]
-        elif p[0] > maxx:
-            maxx = p[0]
-        if p[1] < miny:
-            miny = p[1]
-        elif p[1] > maxy:
-            maxy = p[1]
-    return(minx, miny, maxx - minx, maxy - miny)
-
-
 def calc_shade(c, s, invert=False):
-    """ Convert a color to the current shade (lightness/darkness). """
+    ''' Convert a color to the current shade (lightness/darkness). '''
     # Assumes 16 bit input values
     if invert:
         if s < 0:
@@ -74,7 +58,7 @@ def calc_shade(c, s, invert=False):
 
 
 def calc_gray(c, g, invert=False):
-    """ Gray is a psuedo saturation calculation. """
+    ''' Gray is a psuedo saturation calculation. '''
     # Assumes 16 bit input values
     if g == 100:
         return c
@@ -90,7 +74,7 @@ def calc_gray(c, g, invert=False):
 colors = {}
 DEGTOR = 2 * pi / 360
 
-color_table = (
+COLOR_TABLE = (
     0xFF0000, 0xFF0D00, 0xFF1A00, 0xFF2600, 0xFF3300,
     0xFF4000, 0xFF4D00, 0xFF5900, 0xFF6600, 0xFF7300,
     0xFF8000, 0xFF8C00, 0xFF9900, 0xFFA600, 0xFFB300,
@@ -114,31 +98,24 @@ color_table = (
 
 
 class TurtleGraphics:
-    """ A class for the Turtle graphics canvas """
+    ''' A class for the Turtle graphics canvas '''
 
     def __init__(self, tw, width, height):
-        """ Create a sprite to hold the canvas. """
+        ''' Create a sprite to hold the canvas. '''
         self.tw = tw
         self.width = width
         self.height = height
-        if self.tw.interactive_mode:
-            self.canvas = Sprite(tw.sprite_list, 0, 0,
-                gtk.gdk.Pixmap(self.tw.area, self.width * 2,
-                               self.height * 2, -1))
-        else:
-            self.canvas = Sprite(None, 0, 0, self.tw.window)
-        self.canvas.set_layer(CANVAS_LAYER)
-        (self.cx, self.cy) = self.canvas.get_xy()
-        self.canvas.type = 'canvas'
-        self.gc = self.canvas.images[0].new_gc()
-        self.cm = self.gc.get_colormap()
+        
+        # Build a cairo.Context from a cairo.XlibSurface
+        self.canvas = cairo.Context(self.tw.turtle_canvas)
+        cr = gtk.gdk.CairoContext(self.canvas)
+        cr.set_line_cap(1)  # Set the line cap to be round
+
+        self.cx = 0
+        self.cy = 0
         self.fgrgb = [255, 0, 0]
-        self.fgcolor = self.cm.alloc_color('red')
         self.bgrgb = [255, 248, 222]
-        self.bgcolor = self.cm.alloc_color('#fff8de')
         self.textsize = 48  # deprecated
-        self.textcolor = self.cm.alloc_color('red')  # deprecated
-        self.tw.active_turtle.show()
         self.shade = 0
         self.pendown = False
         self.xcor = 0
@@ -152,17 +129,16 @@ class TurtleGraphics:
         self.svg = SVG()
         self.svg.set_fill_color('none')
         self.tw.svg_string = ''
-        self.clearscreen(False)
 
     def start_fill(self):
-        """ Start accumulating points of a polygon to fill. """
+        ''' Start accumulating points of a polygon to fill. '''
         self.fill = True
         self.poly_points = []
         if self.tw.saving_svg:
             self.tw.svg_string += '<g>'
 
     def stop_fill(self):
-        """ Fill the polygon. """
+        ''' Fill the polygon. '''
         self.fill = False
         if len(self.poly_points) == 0:
             return
@@ -172,7 +148,7 @@ class TurtleGraphics:
             for p in self.poly_points:
                 shared_poly_points.append((self.screen_to_turtle_coordinates(
                             p[0], p[1])))
-                event = "F|%s" % (data_to_string([self._get_my_nick(),
+                event = 'F|%s' % (data_to_string([self._get_my_nick(),
                                                   shared_poly_points]))
             self.tw.send_event(event)
         self.poly_points = []
@@ -180,14 +156,21 @@ class TurtleGraphics:
             self.tw.svg_string += '</g>'
 
     def fill_polygon(self, poly_points):
-        minx, miny, w, h = calc_poly_bounds(poly_points)
-        self.canvas.images[0].draw_polygon(self.gc, True, poly_points)
-        self.invalt(minx - self.pensize * self.tw.coord_scale / 2 - 3,
-                    miny - self.pensize * self.tw.coord_scale / 2 - 3,
-                    w + self.pensize * self.tw.coord_scale + 6,
-                    h + self.pensize * self.tw.coord_scale + 6)
+        ''' Draw the polygon... '''
+        self.canvas.new_path()
+        for i, p in enumerate(poly_points):
+            if p[0] == 'move':
+                self.canvas.move_to(p[1], p[2])
+            elif p[0] == 'rarc':
+                self.canvas.arc(p[1], p[2], p[3], p[4], p[5])
+            elif p[0] == 'larc':
+                self.canvas.arc_negative(p[1], p[2], p[3], p[4], p[5])
+            else:  # line
+                self.canvas.line_to(p[1], p[2])
+        self.canvas.close_path()
+        self.canvas.fill()
         if self.tw.saving_svg and self.pendown:
-            self.svg.set_fill_color("#%02x%02x%02x" % (self.fgrgb[0],
+            self.svg.set_fill_color('#%02x%02x%02x' % (self.fgrgb[0],
                                                        self.fgrgb[1],
                                                        self.fgrgb[2]))
             self.tw.svg_string += self.svg.new_path(poly_points[0][0],
@@ -196,20 +179,27 @@ class TurtleGraphics:
                 if p > 0:
                     self.tw.svg_string += self.svg.line_to(poly_points[p][0],
                                                            poly_points[p][1])
-            self.tw.svg_string += "\"\n"
+            self.tw.svg_string += '"\n'
             self.tw.svg_string += self.svg.style()
             self.svg.set_fill_color('none')
 
     def clearscreen(self, share=True):
-        """Clear the canvas and reset most graphics attributes to defaults."""
-        rect = gtk.gdk.Rectangle(0, 0, self.width * 2, self.height * 2)
-        self.gc.set_foreground(self.bgcolor)
-        self.canvas.images[0].draw_rectangle(self.gc, True, *rect)
-        self.invalt(0, 0, self.width, self.height)
+        '''Clear the canvas and reset most graphics attributes to defaults.'''
+        self.canvas.move_to(0, 0)
+        self.canvas.set_source_rgb(self.bgrgb[0] / 255.,
+                                   self.bgrgb[1] / 255.,
+                                   self.bgrgb[2] / 255.)
+        self.canvas.rectangle(0, 0, self.width * 2, self.height * 2)
+        self.canvas.fill()
+        self.inval()
         self.setpensize(5, share)
         self.setgray(100, share)
         self.setcolor(0, share)
         self.setshade(50, share)
+        self.tw.svg_string = ''
+        self.svg.reset_min_max()
+        self.fill = False
+        self.poly_points = []
         for turtle_key in iter(self.tw.turtles.dict):
             # Don't reset remote turtles
             if not self.tw.remote_turtle(turtle_key):
@@ -225,82 +215,82 @@ class TurtleGraphics:
                 self.setpen(True, share)
                 self.tw.active_turtle.hide()
         self.set_turtle(self.tw.default_turtle_name)
-        self.tw.svg_string = ''
-        self.svg.reset_min_max()
-        self.fill = False
-        self.poly_points = []
 
     def forward(self, n, share=True):
-        """ Move the turtle forward."""
+        ''' Move the turtle forward.'''
         nn = n * self.tw.coord_scale
-        self.gc.set_foreground(self.fgcolor)
+        self.canvas.set_source_rgb(self.fgrgb[0] / 255., self.fgrgb[1] / 255.,
+                                   self.fgrgb[2] / 255.)
         oldx, oldy = self.xcor, self.ycor
         try:
             self.xcor += nn * sin(self.heading * DEGTOR)
             self.ycor += nn * cos(self.heading * DEGTOR)
         except TypeError, ValueError:
-            debug_output("bad value sent to %s" % (__name__),
+            debug_output('bad value sent to %s' % (__name__),
                          self.tw.running_sugar)
             return
         if self.pendown:
             self.draw_line(oldx, oldy, self.xcor, self.ycor)
+
         self.move_turtle()
 
         if self.tw.sharing() and share:
-            event = "f|%s" % (data_to_string([self._get_my_nick(), int(n)]))
+            event = 'f|%s' % (data_to_string([self._get_my_nick(), int(n)]))
             self.tw.send_event(event)
+        self.inval()
 
     def seth(self, n, share=True):
-        """ Set the turtle heading. """
+        ''' Set the turtle heading. '''
         try:
             self.heading = n
         except TypeError, ValueError:
-            debug_output("bad value sent to %s" % (__name__),
+            debug_output('bad value sent to %s' % (__name__),
                          self.tw.running_sugar)
             return
         self.heading %= 360
         self.turn_turtle()
         if self.tw.sharing() and share:
-            event = "r|%s" % (data_to_string([self._get_my_nick(),
+            event = 'r|%s' % (data_to_string([self._get_my_nick(),
                                               round_int(self.heading)]))
             self.tw.send_event(event)
 
     def right(self, n, share=True):
-        """ Rotate turtle clockwise """
+        ''' Rotate turtle clockwise '''
         try:
             self.heading += n
         except TypeError, ValueError:
-            debug_output("bad value sent to %s" % (__name__),
+            debug_output('bad value sent to %s' % (__name__),
                          self.tw.running_sugar)
             return
         self.heading %= 360
         self.turn_turtle()
         if self.tw.sharing() and share:
-            event = "r|%s" % (data_to_string([self._get_my_nick(),
+            event = 'r|%s' % (data_to_string([self._get_my_nick(),
                                               round_int(self.heading)]))
             self.tw.send_event(event)
 
     def arc(self, a, r, share=True):
-        """ Draw an arc """
-        self.gc.set_foreground(self.fgcolor)
-        rr = r * self.tw.coord_scale
+        ''' Draw an arc '''
+        self.canvas.set_source_rgb(self.fgrgb[0] / 255., self.fgrgb[1] / 255.,
+                                   self.fgrgb[2] / 255.)
         try:
             if a < 0:
-                self.larc(-a, rr)
+                self.larc(-a, r)
             else:
-                self.rarc(a, rr)
+                self.rarc(a, r)
         except TypeError, ValueError:
-            debug_output("bad value sent to %s" % (__name__),
+            debug_output('bad value sent to %s' % (__name__),
                          self.tw.running_sugar)
             return
         self.move_turtle()
         if self.tw.sharing() and share:
-            event = "a|%s" % (data_to_string([self._get_my_nick(),
+            event = 'a|%s' % (data_to_string([self._get_my_nick(),
                                               [round_int(a), round_int(r)]]))
             self.tw.send_event(event)
 
     def rarc(self, a, r):
-        """ draw a clockwise arc """
+        ''' draw a clockwise arc '''
+        r *= self.tw.coord_scale
         if r < 0:
             r = -r
             a = -a
@@ -310,17 +300,21 @@ class TurtleGraphics:
         oldx, oldy = self.xcor, self.ycor
         cx = self.xcor + r * cos(self.heading * DEGTOR)
         cy = self.ycor - r * sin(self.heading * DEGTOR)
-        x, y = self.turtle_to_screen_coordinates(int(cx - r), int(cy + r))
-        w = int(2 * r)
-        h = w
         if self.pendown:
-            self.canvas.images[0].draw_arc(self.gc, False, int(x), int(y), w,
-                                           h, int(180 - self.heading - a) * 64,
-                                           int(a) * 64)
-            self.invalt(x - self.pensize * self.tw.coord_scale / 2 - 3,
-                        y - self.pensize * self.tw.coord_scale / 2 - 3,
-                        w + self.pensize * self.tw.coord_scale + 6,
-                        h + self.pensize * self.tw.coord_scale + 6)
+            x, y = self.turtle_to_screen_coordinates(cx, cy)
+            self.canvas.arc(x, y, r,
+                            (self.heading - 180) * DEGTOR,
+                            (self.heading - 180 + a) * DEGTOR)
+            self.canvas.stroke()
+            self.inval()
+
+        if self.fill:
+            if self.poly_points == []:
+                self.poly_points.append(('move', x, y))
+            self.poly_points.append(('rarc', x, y, r,
+                                     (self.heading - 180) * DEGTOR,
+                                     (self.heading - 180 + a) * DEGTOR))
+
         self.right(a, False)
         self.xcor = cx - r * cos(self.heading * DEGTOR)
         self.ycor = cy + r * sin(self.heading * DEGTOR)
@@ -329,11 +323,12 @@ class TurtleGraphics:
             self.tw.svg_string += self.svg.new_path(x, y)
             x, y = self.turtle_to_screen_coordinates(self.xcor, self.ycor)
             self.tw.svg_string += self.svg.arc_to(x, y, r, a, 0, s)
-            self.tw.svg_string += "\"\n"
+            self.tw.svg_string += '"\n'
             self.tw.svg_string += self.svg.style()
 
     def larc(self, a, r):
-        """ draw a counter-clockwise arc """
+        ''' draw a counter-clockwise arc '''
+        r *= self.tw.coord_scale
         if r < 0:
             r = -r
             a = -a
@@ -343,17 +338,21 @@ class TurtleGraphics:
         oldx, oldy = self.xcor, self.ycor
         cx = self.xcor - r * cos(self.heading * DEGTOR)
         cy = self.ycor + r * sin(self.heading * DEGTOR)
-        x, y = self.turtle_to_screen_coordinates(int(cx - r), int(cy + r))
-        w = int(2 * r)
-        h = w
         if self.pendown:
-            self.canvas.images[0].draw_arc(self.gc, False, int(x), int(y),
-                                           w, h, int(360 - self.heading) * 64,
-                                           int(a) * 64)
-            self.invalt(x - self.pensize * self.tw.coord_scale / 2 - 3,
-                        y - self.pensize * self.tw.coord_scale / 2 - 3,
-                        w + self.pensize * self.tw.coord_scale + 6,
-                        h + self.pensize * self.tw.coord_scale + 6)
+            x, y = self.turtle_to_screen_coordinates(cx, cy)
+            self.canvas.arc_negative(x, y, r,
+                                     (self.heading) * DEGTOR,
+                                     (self.heading - a) * DEGTOR)
+            self.canvas.stroke()
+            self.inval()
+
+        if self.fill:
+            if self.poly_points == []:
+                self.poly_points.append(('move', x, y))
+            self.poly_points.append(('larc', x, y, r,
+                                     (self.heading) * DEGTOR,
+                                     (self.heading - a) * DEGTOR))
+
         self.right(-a, False)
         self.xcor = cx + r * cos(self.heading * DEGTOR)
         self.ycor = cy - r * sin(self.heading * DEGTOR)
@@ -362,71 +361,73 @@ class TurtleGraphics:
             self.tw.svg_string += self.svg.new_path(x, y)
             x, y = self.turtle_to_screen_coordinates(self.xcor, self.ycor)
             self.tw.svg_string += self.svg.arc_to(x, y, r, a, 0, s)
-            self.tw.svg_string += "\"\n"
+            self.tw.svg_string += '"\n'
             self.tw.svg_string += self.svg.style()
 
     def setxy(self, x, y, share=True, pendown=True):
-        """ Move turtle to position x,y """
+        ''' Move turtle to position x,y '''
         oldx, oldy = self.xcor, self.ycor
         x *= self.tw.coord_scale
         y *= self.tw.coord_scale
         try:
             self.xcor, self.ycor = x, y
         except TypeError, ValueError:
-            debug_output("bad value sent to %s" % (__name__),
+            debug_output('bad value sent to %s' % (__name__),
                          self.tw.running_sugar)
             return
 
         if self.pendown and pendown:
-            self.gc.set_foreground(self.fgcolor)
+            self.canvas.set_source_rgb(self.fgrgb[0] / 255.,
+                                       self.fgrgb[1] / 255.,
+                                       self.fgrgb[2] / 255.)
             self.draw_line(oldx, oldy, self.xcor, self.ycor)
+            self.inval()
         self.move_turtle()
 
         if self.tw.sharing() and share:
-            event = "x|%s" % (data_to_string([self._get_my_nick(),
+            event = 'x|%s' % (data_to_string([self._get_my_nick(),
                                               [round_int(x), round_int(y)]]))
             self.tw.send_event(event)
 
     def setpensize(self, ps, share=True):
-        """ Set the pen size """
+        ''' Set the pen size '''
         try:
             if ps < 0:
                 ps = 0
             self.pensize = ps
         except TypeError, ValueError:
-            debug_output("bad value sent to %s" % (__name__),
+            debug_output('bad value sent to %s' % (__name__),
                          self.tw.running_sugar)
             return
         self.tw.active_turtle.set_pen_size(ps)
-        self.gc.set_line_attributes(int(self.pensize * self.tw.coord_scale),
-            gtk.gdk.LINE_SOLID, gtk.gdk.CAP_ROUND, gtk.gdk.JOIN_MITER)
+        self.canvas.set_line_width(ps)
         self.svg.set_stroke_width(self.pensize)
         if self.tw.sharing() and share:
-            event = "w|%s" % (data_to_string([self._get_my_nick(),
+            event = 'w|%s' % (data_to_string([self._get_my_nick(),
                                               round_int(ps)]))
             self.tw.send_event(event)
 
     def setcolor(self, c, share=True):
-        """ Set the pen color """
+        ''' Set the pen color '''
         try:
             self.color = c
         except TypeError, ValueError:
-            debug_output("bad value sent to %s" % (__name__),
+            debug_output('bad value sent to %s' % (__name__),
                          self.tw.running_sugar)
             return
         self.tw.active_turtle.set_color(c)
         self.set_fgcolor()
         if self.tw.sharing() and share:
-            event = "c|%s" % (data_to_string([self._get_my_nick(),
+            event = 'c|%s' % (data_to_string([self._get_my_nick(),
                                               round_int(c)]))
             self.tw.send_event(event)
 
     def setgray(self, g, share=True):
-        """ Set the gray level """
+        ''' Set the gray level '''
         try:
             self.gray = g
         except TypeError, ValueError:
-            debug_output("bad value sent to %s" % (__name__),
+            debug_output('bad value sent to %s' % (__name__),
                          self.tw.running_sugar)
             return
         if self.gray < 0:
@@ -436,47 +437,53 @@ class TurtleGraphics:
         self.set_fgcolor()
         self.tw.active_turtle.set_gray(self.gray)
         if self.tw.sharing() and share:
-            event = "g|%s" % (data_to_string([self._get_my_nick(),
+            event = 'g|%s' % (data_to_string([self._get_my_nick(),
                                               round_int(self.gray)]))
             self.tw.send_event(event)
 
+    def set_textcolor(self):
+        ''' Deprecated: Set the text color to foreground color. '''
+        return
+
     def settextcolor(self, c):  # deprecated
-        """ Set the text color """
+        ''' Set the text color '''
         return
 
     def settextsize(self, c):  # deprecated
-        """ Set the text size """
+        ''' Set the text size '''
         try:
             self.tw.textsize = c
         except TypeError, ValueError:
-            debug_output("bad value sent to %s" % (__name__),
+            debug_output('bad value sent to %s' % (__name__),
                          self.tw.running_sugar)
 
     def setshade(self, s, share=True):
-        """ Set the color shade """
+        ''' Set the color shade '''
         try:
             self.shade = s
         except TypeError, ValueError:
-            debug_output("bad value sent to %s" % (__name__),
+            debug_output('bad value sent to %s' % (__name__),
                          self.tw.running_sugar)
             return
         self.tw.active_turtle.set_shade(s)
         self.set_fgcolor()
         if self.tw.sharing() and share:
-            event = "s|%s" % (data_to_string([self._get_my_nick(),
+            event = 's|%s' % (data_to_string([self._get_my_nick(),
                                               round_int(s)]))
             self.tw.send_event(event)
 
     def fillscreen(self, c, s):
-        """ Fill screen with color/shade and reset to defaults """
+        ''' Fill screen with color/shade and reset to defaults '''
         oldc, olds = self.color, self.shade
         self.setcolor(c, False)
         self.setshade(s, False)
-        rect = gtk.gdk.Rectangle(0, 0, self.width * 2, self.height * 2)
-        self.gc.set_foreground(self.fgcolor)
+        self.canvas.set_source_rgb(self.fgrgb[0] / 255.,
+                                   self.fgrgb[1] / 255.,
+                                   self.fgrgb[2] / 255.)
         self.bgrgb = self.fgrgb[:]
-        self.canvas.images[0].draw_rectangle(self.gc, True, *rect)
-        self.invalt(0, 0, self.width, self.height)
+        self.canvas.rectangle(0, 0, self.width * 2, self.height * 2)
+        self.canvas.fill()
+        self.inval()
         self.setcolor(oldc, False)
         self.setshade(olds, False)
         self.tw.svg_string = ''
@@ -485,7 +492,7 @@ class TurtleGraphics:
         self.poly_points = []
 
     def set_fgcolor(self):
-        """ Set the foreground color """
+        ''' Set the foreground color '''
         if self.color == WHITE or self.shade == WHITE:
             r = 0xFF00
             g = 0xFF00
@@ -496,7 +503,7 @@ class TurtleGraphics:
             b = 0x0000
         else:
             sh = (wrap100(self.shade) - 50) / 50.0
-            rgb = color_table[wrap100(self.color)]
+            rgb = COLOR_TABLE[wrap100(self.color)]
             r = (rgb >> 8) & 0xff00
             r = calc_gray(r, self.gray)
             r = calc_shade(r, sh)
@@ -507,37 +514,45 @@ class TurtleGraphics:
             b = calc_gray(b, self.gray)
             b = calc_shade(b, sh)
         self.fgrgb = [r >> 8, g >> 8, b >> 8]
-        self.fgcolor = self.cm.alloc_color(r, g, b)
-        self.svg.set_stroke_color("#%02x%02x%02x" % (self.fgrgb[0],
+        self.svg.set_stroke_color('#%02x%02x%02x' % (self.fgrgb[0],
                                                      self.fgrgb[1],
                                                      self.fgrgb[2]))
 
-    def set_textcolor(self):
-        """ Deprecated: Set the text color to foreground color. """
-        return
-
     def setpen(self, bool, share=True):
-        """ Lower or raise the pen """
+        ''' Lower or raise the pen '''
         self.pendown = bool
         self.tw.active_turtle.set_pen_state(bool)
         if self.tw.sharing() and share:
-            event = "p|%s" % (data_to_string([self._get_my_nick(), bool]))
+            event = 'p|%s' % (data_to_string([self._get_my_nick(), bool]))
             self.tw.send_event(event)
 
     def draw_pixbuf(self, pixbuf, a, b, x, y, w, h, path, share=True):
-        """ Draw a pixbuf """
-        w *= self.tw.coord_scale
-        h *= self.tw.coord_scale
-        self.canvas.images[0].draw_pixbuf(self.gc, pixbuf, a, b, x, y)
-        self.invalt(x, y, w, h)
+        ''' Draw a pixbuf '''
+        # Build a gtk.gdk.CairoContext from a cairo.Context to access
+        # the set_source_pixbuf attribute.
+        cr = gtk.gdk.CairoContext(self.canvas)
+        cr.save()
+        # center the rotation on the center of the image
+        cr.translate(x + w / 2., y + h / 2.)
+        cr.rotate(self.heading * DEGTOR)
+        cr.translate(-x - w / 2., -y - h / 2.)
+        cr.set_source_pixbuf(pixbuf, x, y)
+        cr.rectangle(x, y, w, h)
+        cr.fill()
+        cr.restore()
+        self.inval()
         if self.tw.saving_svg:
             if self.tw.running_sugar:
-                # In Sugar, we need to embed the images inside the SVG
-                self.tw.svg_string += self.svg.image(x - self.width / 2,
-                    y, w, h, path, image_to_base64(pixbuf,
-                    get_path(self.tw.activity, 'instance')))
+                # In Sugar, we embed the images inside the SVG
+                tmp_file = os.path.join(get_path(tw.activity, 'instance'),
+                                       'tmpfile.png')
+                pixbuf.save(tmp_file, 'png', {'quality': '100'})
+                self.tw.svg_string += self.svg.image(
+                    x - self.width / 2, y, w, h, path,
+                    image_to_base64(tmp_file,
+                                    get_path(self.tw.activity, 'instance')))
             else:
-                # Outside of Sugar, we save a path
+                # In GNOME, we embed a path
                 self.tw.svg_string += self.svg.image(x - self.width / 2,
                                                      y, w, h, path)
         if self.tw.sharing() and share:
@@ -545,11 +560,14 @@ class TurtleGraphics:
                 tmp_path = get_path(self.tw.activity, 'instance')
             else:
                 tmp_path = '/tmp'
-            data = image_to_base64(pixbuf, tmp_path)
+            tmp_file = os.path.join(get_path(tw.activity, 'instance'),
+                                   'tmpfile.png')
+            pixbuf.save(tmp_file, 'png', {'quality': '100'})
+            data = image_to_base64(tmp_file, tmp_path)
             height = pixbuf.get_height()
             width = pixbuf.get_width()
             x, y = self.screen_to_turtle_coordinates(x, y)
-            event = "P|%s" % (data_to_string([self._get_my_nick(),
+            event = 'P|%s' % (data_to_string([self._get_my_nick(),
                                               [round_int(a), round_int(b),
                                                round_int(x), round_int(y),
                                                round_int(w), round_int(h),
@@ -559,110 +577,89 @@ class TurtleGraphics:
             self.tw.send_event(event)
 
     def draw_text(self, label, x, y, size, w, share=True):
-        """ Draw text """
+        ''' Draw text '''
         w *= self.tw.coord_scale
-        self.gc.set_foreground(self.fgcolor)
+        cr = pangocairo.CairoContext(self.canvas)
+        pl = cr.create_layout()
         fd = pango.FontDescription('Sans')
-        try:
-            fd.set_size(int(size * self.tw.coord_scale) * pango.SCALE)
-        except TypeError, ValueError:
-            debug_output("bad value sent to %s" % (__name__),
-                         self.tw.running_sugar)
-            return
-        if self.tw.interactive_mode:
-            if type(label) == str or type(label) == unicode:
-                pl = self.tw.window.create_pango_layout(
-                    label.replace('\0', ' '))
-            elif type(label) == float or type(label) == int:
-                pl = self.tw.window.create_pango_layout(str(label))
-            else:
-                pl = self.tw.window.create_pango_layout(str(label))
-            pl.set_font_description(fd)
-            pl.set_width(int(w) * pango.SCALE)
-            self.canvas.images[0].draw_layout(self.gc, int(x), int(y), pl)
-            w, h = pl.get_pixel_size()
-            self.invalt(x, y, w, h)
-        else:  # pixmap doesn't support pango
-            message = str(label).replace('\0', ' ')
-            context = self.canvas.images[0].cairo_create()
-            context.set_font_size(size)
-            q, k, w, h = context.text_extents(message)[:4]
-            context.set_source_rgb(0, 0, 0)
-            context.move_to(x, y + h)
-            context.show_text(message)
-
+        fd.set_size(int(size * self.tw.coord_scale) * pango.SCALE)
+        pl.set_font_description(fd)
+        if type(label) == str or type(label) == unicode:
+            pl.set_text(label.replace('\0', ' '))
+        elif type(label) == float or type(label) == int:
+            pl.set_text(str(label))
+        else:
+            pl.set_text(str(label))
+        pl.set_width(int(w) * pango.SCALE)
+        cr.save()
+        cr.translate(x, y)
+        cr.rotate(self.heading * DEGTOR)
+        self.canvas.set_source_rgb(self.fgrgb[0] / 255.,
+                                   self.fgrgb[1] / 255.,
+                                   self.fgrgb[2] / 255.)
+        cr.update_layout(pl)
+        cr.show_layout(pl)
+        cr.restore()
+        self.inval()
         if self.tw.saving_svg:  # and self.pendown:
             self.tw.svg_string += self.svg.text(x, # - self.width / 2,
                                                 y + size, size, w, label)
         if self.tw.sharing() and share:
-            event = "W|%s" % (data_to_string([self._get_my_nick(),
+            event = 'W|%s' % (data_to_string([self._get_my_nick(),
                                               [label, round_int(x),
                                                round_int(y), round_int(size),
                                                round_int(w)]]))
             self.tw.send_event(event)
 
     def turtle_to_screen_coordinates(self, x, y):
-        """ The origin of turtle coordinates is the center of the screen """
+        ''' The origin of turtle coordinates is the center of the screen '''
         return self.width / 2. + x, self.invert_y_coordinate(y)
 
     def screen_to_turtle_coordinates(self, x, y):
-        """ The origin of the screen coordinates is the upper left corner """
+        ''' The origin of the screen coordinates is the upper left corner '''
         return x - self.width / 2., self.invert_y_coordinate(y)
 
     def invert_y_coordinate(self, y):
-        """ Positive y goes up in turtle coordinates, down in sceeen
-        coordinates """
+        ''' Positive y goes up in turtle coordinates, down in sceeen
+        coordinates '''
         return self.height / 2. - y
 
     def draw_line(self, x1, y1, x2, y2):
-        """ Draw a line """
+        ''' Draw a line '''
         x1, y1 = self.turtle_to_screen_coordinates(x1, y1)
         x2, y2 = self.turtle_to_screen_coordinates(x2, y2)
-        if x1 < x2:
-            minx, maxx = int(x1), int(x2)
-        else:
-            minx, maxx = int(x2), int(x1)
-        if y1 < y2:
-            miny, maxy = int(y1), int(y2)
-        else:
-            miny, maxy = int(y2), int(y1)
-        w, h = maxx - minx, maxy - miny
-        self.canvas.images[0].draw_line(self.gc, int(x1), int(y1), int(x2),
-                                        int(y2))
-        if self.fill and self.poly_points == []:
-            self.poly_points.append((int(x1), int(y1)))
+
+        self.canvas.move_to(x1, y1)
+        self.canvas.line_to(x2, y2)
+        self.canvas.stroke()
+
         if self.fill:
-            self.poly_points.append((int(x2), int(y2)))
-        self.invalt(minx - int(self.pensize * self.tw.coord_scale / 2) - 3,
-                    miny - int(self.pensize * self.tw.coord_scale / 2) - 3,
-                    w + self.pensize * self.tw.coord_scale + 6,
-                    h + self.pensize * self.tw.coord_scale + 6)
+            if self.poly_points == []:
+                self.poly_points.append(('move', x1, y1))
+            self.poly_points.append(('line', x2, y2))
+
         if self.tw.saving_svg and self.pendown:
             self.tw.svg_string += self.svg.new_path(x1, y1)
             self.tw.svg_string += self.svg.line_to(x2, y2)
-            self.tw.svg_string += "\"\n"
+            self.tw.svg_string += '"\n'
             self.tw.svg_string += self.svg.style()
 
     def turn_turtle(self):
-        """ Change the orientation of the turtle """
+        ''' Change the orientation of the turtle '''
         self.tw.active_turtle.set_heading(self.heading)
 
     def move_turtle(self):
-        """ Move the turtle """
+        ''' Move the turtle '''
         x, y = self.turtle_to_screen_coordinates(self.xcor, self.ycor)
-        self.tw.active_turtle.move(
-            (int(self.cx + x - self.tw.active_turtle.spr.rect.width / 2.),
-             int(self.cy + y - self.tw.active_turtle.spr.rect.height / 2.)))
-
-    def invalt(self, x, y, w, h):
-        """ Mark a region for refresh """
         if self.tw.interactive_mode:
-            self.tw.area.invalidate_rect(
-                gtk.gdk.Rectangle(int(x + self.cx), int(y + self.cy),
-                                  int(w), int(h)), False)
+            self.tw.active_turtle.move(
+                (int(self.cx + x - self.tw.active_turtle.spr.rect.width / 2.),
+                 int(self.cy + y - self.tw.active_turtle.spr.rect.height / 2.)))
+        else:
+            self.tw.active_turtle.move((int(self.cx + x), int(self.cy + y)))
 
     def get_color_index(self, r, g, b, a=0):
-        """ Find the closest palette entry to the rgb triplet """
+        ''' Find the closest palette entry to the rgb triplet '''
         if self.shade != 50 or self.gray != 100:
             r <<= 8
             g <<= 8
@@ -681,7 +678,7 @@ class TurtleGraphics:
             b >>= 8
         min_distance = 1000000
         closest_color = -1
-        for i, c in enumerate(color_table):
+        for i, c in enumerate(COLOR_TABLE):
             cr = int((c & 0xff0000) >> 16)
             cg = int((c & 0x00ff00) >> 8)
             cb = int((c & 0x0000ff))
@@ -695,16 +692,31 @@ class TurtleGraphics:
         return closest_color
 
     def get_pixel(self):
-        """ Read the pixel at x, y """
+        ''' Read the pixel at x, y '''
+        # Fix me: Is there a more efficient way of doing this?
         if self.tw.interactive_mode:
             x, y = self.turtle_to_screen_coordinates(self.xcor, self.ycor)
-            return self.canvas.get_pixel((int(x), int(y)), 0,
-                                         self.tw.color_mode)
+            x = int(x)
+            y = int(y)
+            w = self.tw.turtle_canvas.get_width()
+            h = self.tw.turtle_canvas.get_height()
+            if x < 0 or x > (w - 1) or y < 0 or y > (h - 1):
+                return(-1, -1, -1, -1)
+            # Map the cairo surface onto a pixmap
+            pixmap = gtk.gdk.Pixmap(None, w, h, 24)
+            cr = pixmap.cairo_create()
+            cr.set_source_surface(self.tw.turtle_canvas, 0, 0)
+            cr.paint()
+            # Read the pixel
+            pixel = pixmap.get_image(x, y, 1, 1).get_pixel(0, 0)
+            return(int((pixel & 0xFF0000) >> 16),
+                   int((pixel & 0x00FF00) >> 8),
+                   int((pixel & 0x0000FF) >> 0), 0)
         else:
             return(-1, -1, -1, -1)
 
     def set_turtle(self, k, colors=None):
-        """ Select the current turtle and associated pen status """
+        ''' Select the current turtle and associated pen status '''
         if k not in self.tw.turtles.dict:
             # if it is a new turtle, start it in the center of the screen
             self.tw.active_turtle = self.tw.turtles.get_turtle(k, True, colors)
@@ -719,8 +731,9 @@ class TurtleGraphics:
         self.tw.active_turtle.show()
         tx, ty = self.tw.active_turtle.get_xy()
         self.xcor, self.ycor = self.screen_to_turtle_coordinates(tx, ty)
-        self.xcor += self.tw.active_turtle.spr.rect.width / 2.
-        self.ycor -= self.tw.active_turtle.spr.rect.height / 2.
+        if self.tw.interactive_mode:
+            self.xcor += self.tw.active_turtle.spr.rect.width / 2.
+            self.ycor -= self.tw.active_turtle.spr.rect.height / 2.
         self.heading = self.tw.active_turtle.get_heading()
         self.setcolor(self.tw.active_turtle.get_color(), False)
         self.setgray(self.tw.active_turtle.get_gray(), False)
@@ -729,14 +742,19 @@ class TurtleGraphics:
         self.setpen(self.tw.active_turtle.get_pen_state(), False)
 
     def svg_close(self):
-        """ Close current SVG graphic """
+        ''' Close current SVG graphic '''
         if self.tw.svg_string == '':
             return
         self.svg.calc_w_h(False)
-        self.tw.svg_string = "%s%s%s%s" % (self.svg.header(True),
-                              self.svg.background("#%02x%02x%02x" % \
-                              (self.bgrgb[0], self.bgrgb[1], self.bgrgb[2])),
-                              self.tw.svg_string, self.svg.footer())
+        self.tw.svg_string = '%s %s %s %s' % (
+            self.svg.header(True),
+            self.svg.background('#%02x%02x%02x' % (
+                    self.bgrgb[0], self.bgrgb[1], self.bgrgb[2])),
+            self.tw.svg_string, self.svg.footer())
 
     def _get_my_nick(self):
         return self.tw.nick
+
+    def inval(self):
+        ''' Invalidate a region for gtk '''
+        self.tw.inval_all()
diff --git a/TurtleArt/taconstants.py b/TurtleArt/taconstants.py
index 2bb9049..5a1b06a 100644
--- a/TurtleArt/taconstants.py
+++ b/TurtleArt/taconstants.py
@@ -25,8 +25,6 @@ from gettext import gettext as _
 # Sprite layers
 #
 
-HIDE_LAYER = 100
-CANVAS_LAYER = 500
 OVERLAY_LAYER = 525
 TURTLE_LAYER = 550
 BLOCK_LAYER = 600
diff --git a/TurtleArt/taexporthtml.py b/TurtleArt/taexporthtml.py
index 843b8b0..90dcc4d 100644
--- a/TurtleArt/taexporthtml.py
+++ b/TurtleArt/taexporthtml.py
@@ -78,40 +78,42 @@ def save_html(self, tw, embed_flag=True):
     """
     htmlcode = ''
     if len(tw.saved_pictures) > 0:
-        for i, p in enumerate(tw.saved_pictures):
+        for i, image_file in enumerate(tw.saved_pictures):
             htmlcode += HTML_GLUE['slide'][0] + str(i)
             htmlcode += HTML_GLUE['slide'][1] + \
                     HTML_GLUE['div'][0] + \
                     HTML_GLUE['h1'][0]
             if embed_flag:
-                f = open(p, 'r')
+                f = open(image_file, 'r')
                 imgdata = f.read()
                 f.close()
-                if p.endswith(('.svg')):
+                if image_file.endswith(('.svg')):
                     tmp = imgdata
                 else:
-                    pixbuf = gtk.gdk.pixbuf_new_from_file(p)
-                    imgdata = image_to_base64(pixbuf,
-                        get_path(tw.activity, 'instance'))
+                    imgdata = image_to_base64(image_file,
+                                              get_path(tw.activity, 'instance'))
                     tmp = HTML_GLUE['img2'][0]
                     tmp += imgdata
                     tmp += HTML_GLUE['img2'][1]
             else:
-                if p.endswith(('.svg')):
-                    f = open(p, 'r')
+                if image_file.endswith(('.svg')):
+                    f = open(image_file, 'r')
                     imgdata = f.read()
                     f.close()
                     tmp = imgdata
                 else:
                     tmp = HTML_GLUE['img3'][0]
-                    tmp += p
+                    tmp += image_file
                     tmp += HTML_GLUE['img3'][1]
             htmlcode += tmp + \
                     HTML_GLUE['h1'][1] + \
                     HTML_GLUE['div'][1]
     else:
         if embed_flag:
-            imgdata = image_to_base64(save_picture(self.tw.canvas),
+            tmp_file = os.path.join(get_path(tw.activity, 'instance'),
+                                   'tmpfile.png')
+            save_picture(self.tw.canvas, tmp_file)
+            imgdata = image_to_base64(tmp_file,
                                       get_path(tw.activity, 'instance'))
         else:
             imgdata = os.path.join(self.tw.load_save_folder, 'image')
diff --git a/TurtleArt/talogo.py b/TurtleArt/talogo.py
index 12be92f..25ffceb 100644
--- a/TurtleArt/talogo.py
+++ b/TurtleArt/talogo.py
@@ -585,14 +585,20 @@ class LogoCode:
                 debug_output("Couldn't open filepath %s" % (self.filepath),
                              self.tw.running_sugar)
         if pixbuf is not None:
+            x = self.tw.canvas.xcor
+            y = self.tw.canvas.ycor
+            w *= self.tw.coord_scale
+            h *= self.tw.coord_scale
             if center:
                 self.tw.canvas.draw_pixbuf(pixbuf, 0, 0,
                                            self.x2tx() - int(w / 2),
                                            self.y2ty() - int(h / 2), w, h,
                                            self.filepath)
             else:
-                self.tw.canvas.draw_pixbuf(pixbuf, 0, 0, self.x2tx(),
-                                           self.y2ty(), w, h, self.filepath)
+                self.tw.canvas.draw_pixbuf(pixbuf, 0, 0,
+                                           self.x2tx(),
+                                           self.y2ty(),
+                                           w, h, self.filepath)
 
     def insert_desc(self, mimetype=None, description=None):
         """ Description text only (at current x, y) """
diff --git a/TurtleArt/taturtle.py b/TurtleArt/taturtle.py
index 0ca72e4..c7bb768 100644
--- a/TurtleArt/taturtle.py
+++ b/TurtleArt/taturtle.py
@@ -25,7 +25,7 @@ from gettext import gettext as _
 
 from taconstants import TURTLE_LAYER, DEFAULT_TURTLE_COLORS
 from tasprite_factory import SVG, svg_str_to_pixbuf
-from tacanvas import wrap100, color_table
+from tacanvas import wrap100, COLOR_TABLE
 from sprites import Sprite
 from tautils import debug_output
 
@@ -161,8 +161,8 @@ class Turtle:
         elif use_color_table:
             fill = wrap100(int_key)
             stroke = wrap100(fill + 10)
-            self.colors = ['#%06x' % (color_table[fill]),
-                           '#%06x' % (color_table[stroke])]
+            self.colors = ['#%06x' % (COLOR_TABLE[fill]),
+                           '#%06x' % (COLOR_TABLE[stroke])]
             self.shapes = generate_turtle_pixbufs(self.colors)
         else:
             if turtles is not None:
diff --git a/TurtleArt/tautils.py b/TurtleArt/tautils.py
index a47c063..a402563 100644
--- a/TurtleArt/tautils.py
+++ b/TurtleArt/tautils.py
@@ -20,6 +20,7 @@
 #THE SOFTWARE.
 
 import gtk
+import cairo
 import pickle
 import subprocess
 import os.path
@@ -40,8 +41,8 @@ except (ImportError, AttributeError):
         OLD_SUGAR_SYSTEM = True
 from StringIO import StringIO
 
-from taconstants import HIDE_LAYER, COLLAPSIBLE, BLOCK_LAYER, HIT_HIDE, \
-    HIT_SHOW, XO1, XO15, XO175, UNKNOWN
+from taconstants import COLLAPSIBLE, HIT_HIDE, HIT_SHOW, XO1, XO15, XO175, \
+    UNKNOWN
 
 import logging
 _logger = logging.getLogger('turtleart-activity')
@@ -260,16 +261,26 @@ def do_dialog(dialog, suffix, load_save_folder):
     return _result, load_save_folder
 
 
-def save_picture(canvas, file_name=''):
-    """ Save the canvas to a file. """
-    _pixbuf = gtk.gdk.Pixbuf(gtk.gdk.COLORSPACE_RGB, False, 8, canvas.width,
-                             canvas.height)
-    _pixbuf.get_from_drawable(canvas.canvas.images[0],
-                              canvas.canvas.images[0].get_colormap(),
-                              0, 0, 0, 0, canvas.width, canvas.height)
-    if file_name != '':
-        _pixbuf.save(file_name, 'png')
-    return _pixbuf
+def save_picture(canvas, file_name):
+    """ Save the canvas to a file """
+    x_surface = canvas.canvas.get_target()
+    img_surface = cairo.ImageSurface(cairo.FORMAT_RGB24,
+                                     canvas.width, canvas.height)
+    cr = cairo.Context(img_surface)
+    cr.set_source_surface(x_surface)
+    cr.paint()
+    img_surface.write_to_png(file_name)
+
+
+def get_canvas_data(canvas):
+    x_surface = canvas.canvas.get_target()
+    img_surface = cairo.ImageSurface(cairo.FORMAT_RGB24,
+                                     canvas.width, canvas.height)
+    cr = cairo.Context(img_surface)
+    cr.set_source_surface(x_surface)
+    cr.paint()
+    return img_surface.get_data()
+
 
 
 def save_svg(string, file_name):
@@ -307,13 +318,10 @@ def get_path(activity, subpath):
                             "org.laptop.TurtleArtActivity", subpath))
 
 
-def image_to_base64(pixbuf, path_name):
+def image_to_base64(image_path, tmp_path):
     """ Convert an image to base64-encoded data """
-    file_name = os.path.join(path_name, 'imagetmp.png')
-    if pixbuf != None:
-        pixbuf.save(file_name, "png")
-    base64 = os.path.join(path_name, 'base64tmp')
-    cmd = "base64 <" + file_name + " >" + base64
+    base64 = os.path.join(tmp_path, 'base64tmp')
+    cmd = "base64 <" + image_path + " >" + base64
     subprocess.check_call(cmd, shell=True)
     file_handle = open(base64, 'r')
     data = file_handle.read()
@@ -491,7 +499,7 @@ def restore_stack(top):
             _dy += _newdy - _olddy
         else:
             if not _hit_bottom:
-                _blk.spr.set_layer(BLOCK_LAYER)
+                _blk.spr.restore()
                 _blk.status = None
             else:
                 _blk.spr.move_relative((_dx, _dy))
@@ -574,7 +582,7 @@ def collapse_stack(top):
             _dy += _newdy - _olddy
         else:
             if not _hit_bottom:
-                _blk.spr.set_layer(HIDE_LAYER)
+                _blk.spr.hide()
                 _blk.status = 'collapsed'
             else:
                 _blk.spr.move_relative((_dx, _dy))
diff --git a/TurtleArt/tawindow.py b/TurtleArt/tawindow.py
index f1917e8..f9f1696 100644
--- a/TurtleArt/tawindow.py
+++ b/TurtleArt/tawindow.py
@@ -80,10 +80,11 @@ class TurtleArtWindow():
     _PLUGIN_SUBPATH = 'plugins'
 
     def __init__(self, canvas_window, path, parent=None,
-                 mycolors=None, mynick=None):
+                 mycolors=None, mynick=None, turtle_canvas=None):
         self._loaded_project = ''
         self._sharing = False
         self.parent = parent
+        self.turtle_canvas = turtle_canvas
         self.send_event = None  # method to send events over the network
         self.gst_available = GST_AVAILABLE
         if type(canvas_window) == gtk.DrawingArea:
@@ -96,23 +97,11 @@ class TurtleArtWindow():
                 self.running_sugar = True
             else:
                 self.running_sugar = False
-            self.area = self.window.window
-            if self.area is not None:
-                self.gc = self.area.new_gc()
-            else:
-                # We lose...
-                debug_output('drawable area is None... punting',
-                             self.running_sugar)
-                exit()
             self._setup_events()
-        elif type(canvas_window) == gtk.gdk.Pixmap:
+        else:
             self.interactive_mode = False
             self.window = canvas_window
             self.running_sugar = False
-            if self.window is not None:
-                self.gc = self.window.new_gc()
-        else:
-            debug_output("bad win type %s" % (type(canvas_window)), False)
 
         if self.running_sugar:
             from sugar import profile
@@ -151,9 +140,9 @@ class TurtleArtWindow():
         self.orientation = HORIZONTAL_PALETTE
 
         self.hw = get_hardware()
+        self.lead = 1.0
         if self.hw in (XO1, XO15, XO175):
-            self.lead = 1.0
-            self.scale = 0.67
+            self.scale = 1.2  # slight scale-up of fonts on XO
             if self.hw == XO1:
                 self.color_mode = '565'
             else:
@@ -161,7 +150,6 @@ class TurtleArtWindow():
             if self.running_sugar and not self.activity.has_toolbarbox:
                 self.orientation = VERTICAL_PALETTE
         else:
-            self.lead = 1.0
             self.scale = 1.0
             self.color_mode = '888'  # TODO: Read visual mode from gtk image
 
@@ -201,19 +189,26 @@ class TurtleArtWindow():
         self.selector_shapes = []
         self.selected_blk = None
         self.selected_spr = None
+        self.selected_turtle = None
         self.drag_group = None
         self.drag_turtle = 'move', 0, 0
         self.drag_pos = 0, 0
         self.turtle_movement_to_share = None
-        self.paste_offset = 20
+        self.paste_offset = 20  # Don't paste on top of where you copied.
+        self.saving_svg = False
+        self.svg_string = ''
 
         self.block_list = Blocks(font_scale_factor=self.scale,
                                  decimal_point=self.decimal_point)
         if self.interactive_mode:
-            self.sprite_list = Sprites(self.window, self.area, self.gc)
+            self.sprite_list = Sprites(self.window)
         else:
             self.sprite_list = None
 
+        self.canvas = TurtleGraphics(self, self.width, self.height)
+        if self.interactive_mode:
+            self.sprite_list.set_cairo_context(self.canvas.canvas)
+
         self.turtles = Turtles(self.sprite_list)
         if self.nick is None:
             self.default_turtle_name = DEFAULT_TURTLE
@@ -224,11 +219,9 @@ class TurtleArtWindow():
         else:
             Turtle(self.turtles, self.default_turtle_name, mycolors.split(','))
         self.active_turtle = self.turtles.get_turtle(self.default_turtle_name)
+        self.active_turtle.show()
 
-        self.saving_svg = False
-        self.svg_string = ''
-        self.selected_turtle = None
-        self.canvas = TurtleGraphics(self, self.width, self.height)
+        self.canvas.clearscreen(False)
 
         CONSTANTS['titlex'] = int(-(self.canvas.width * TITLEXY[0]) / \
             (self.coord_scale * 2))
@@ -356,6 +349,7 @@ class TurtleArtWindow():
         self.window.add_events(gtk.gdk.BUTTON_RELEASE_MASK)
         self.window.add_events(gtk.gdk.POINTER_MOTION_MASK)
         self.window.add_events(gtk.gdk.KEY_PRESS_MASK)
+        # self.window.connect('realize', self.do_realize)
         self.window.connect("expose-event", self._expose_cb)
         self.window.connect("button-press-event", self._buttonpress_cb)
         self.window.connect("button-release-event", self._buttonrelease_cb)
@@ -417,11 +411,33 @@ class TurtleArtWindow():
         """ Check to see if project has any blocks in use """
         return len(self.just_blocks()) == 1
 
-    def _expose_cb(self, win, event):
+    def _expose_cb(self, win=None, event=None):
         """ Repaint """
-        self.sprite_list.refresh(event)
+        self.do_expose_event(event)
         return True
 
+    # Handle the expose-event by drawing
+    def do_expose_event(self, event=None):
+
+        # Create the cairo context
+        cr = self.window.window.cairo_create()
+
+        if event is None:
+            cr.rectangle(self.rect.x, self.rect.y,
+                         self.rect.width, self.rect.height)
+        else:
+        # Restrict Cairo to the exposed area; avoid extra work
+            cr.rectangle(event.area.x, event.area.y,
+                         event.area.width, event.area.height)
+        cr.clip()
+
+        if self.turtle_canvas is not None:
+            cr.set_source_surface(self.turtle_canvas)
+            cr.paint()
+
+        # Refresh sprite list
+        self.sprite_list.redraw_sprites(cr=cr)
+
     def eraser_button(self):
         """ Eraser_button (hide status block when clearing the screen.) """
         if self.status_spr is not None:
@@ -473,6 +489,12 @@ class TurtleArtWindow():
 
     def set_cartesian(self, flag):
         """ Turn on/off Cartesian coordinates """
+        if self.coord_scale == 1:
+            self.draw_overlay('Cartesian_labeled')
+        else:
+            self.draw_overlay('Cartesian')
+        return
+        '''
         if flag:
             if self.coord_scale == 1:
                 self.overlay_shapes['Cartesian_labeled'].set_layer(
@@ -486,24 +508,45 @@ class TurtleArtWindow():
             else:
                 self.overlay_shapes['Cartesian'].hide()
             self.cartesian = False
+        '''
 
     def set_polar(self, flag):
         """ Turn on/off polar coordinates """
+        self.draw_overlay('polar')
+        return
+        '''
         if flag:
             self.overlay_shapes['polar'].set_layer(OVERLAY_LAYER)
             self.polar = True
         else:
             self.overlay_shapes['polar'].hide()
             self.polar = False
+        '''
 
     def set_metric(self, flag):
         """ Turn on/off metric coordinates """
+        self.draw_overlay('metric')
+        return
+        '''
         if flag:
             self.overlay_shapes['metric'].set_layer(OVERLAY_LAYER)
             self.metric = True
         else:
             self.overlay_shapes['metric'].hide()
             self.metric = False
+        '''
+
+    def draw_overlay(self, overlay):
+        ''' Draw a coordinate grid onto the canvas. '''
+        save_heading = self.canvas.heading
+        self.canvas.heading = 0
+        w = self.overlay_shapes[overlay].rect[2]
+        h = self.overlay_shapes[overlay].rect[3]
+        self.canvas.draw_pixbuf(self.overlay_shapes[overlay].images[0],
+                                0, 0, (self.canvas.width - w) / 2.,
+                                (self.canvas.height - h) / 2.,
+                                w, h, '', share=False)
+        self.canvas.heading = save_heading
 
     def update_overlay_position(self, widget, event):
         """ Reposition the overlays when window size changes """
@@ -547,8 +590,12 @@ class TurtleArtWindow():
             self.hide = False
             if self.running_sugar:
                 self.activity.recenter()
+        self.inval_all()
 
-        self.canvas.canvas.inval()
+    def inval_all(self):
+        """ Force a refresh """
+        if self.interactive_mode:
+            self.window.queue_draw_area(0, 0, self.width, self.height)
 
     def hideshow_palette(self, state):
         """ Hide or show palette  """
@@ -1048,10 +1095,7 @@ class TurtleArtWindow():
 
         # Finally, check for anything else
         if hasattr(spr, 'type'):
-            if spr.type == "canvas":
-                pass
-                # spr.set_layer(CANVAS_LAYER)
-            elif spr.type == 'selector':
+            if spr.type == 'selector':
                 self._select_category(spr)
             elif spr.type == 'category':
                 if hide_button_hit(spr, x, y):
@@ -1187,6 +1231,7 @@ class TurtleArtWindow():
         for gblk in group:
             if collapsed(gblk):
                 collapse_stack(find_sandwich_top(gblk))
+
         # And resize any skins.
         for gblk in group:
             if gblk.name in BLOCKS_WITH_SKIN:
@@ -1563,7 +1608,11 @@ class TurtleArtWindow():
             self.rect.y = miny
             self.rect.width = maxx - minx
             self.rect.height = maxy - miny
-            self.sprite_list.area.invalidate_rect(self.rect, False)
+            self.window.queue_draw_area(self.rect.x,
+                                        self.rect.y,
+                                        self.rect.width,
+                                        self.rect.height)
+            # self._expose_cb()
 
         self.dx += dx
         self.dy += dy
@@ -1633,6 +1682,7 @@ class TurtleArtWindow():
         """ Button release """
         x, y = xy(event)
         self.button_release(x, y)
+        self._expose_cb()
         if self.turtle_movement_to_share is not None:
             self._share_mouse_move()
         return True
@@ -1724,9 +1774,8 @@ class TurtleArtWindow():
 
     def _move_turtle(self, x, y):
         """ Move the selected turtle to (x, y). """
-        (cx, cy) = self.canvas.canvas.get_xy()
-        self.canvas.xcor = x - cx
-        self.canvas.ycor = y + cy
+        self.canvas.xcor = x
+        self.canvas.ycor = y
         self.canvas.move_turtle()
         if self.running_sugar:
             self.display_coordinates()
@@ -1876,7 +1925,6 @@ class TurtleArtWindow():
                 restore_stack(top)  # deprecated (bottom block is invisible)
             elif top is not None:
                 collapse_stack(top)
-
         else:
             self._run_stack(blk)
 
@@ -1988,6 +2036,9 @@ class TurtleArtWindow():
         d = 200
         for selected_block_dockn in range(len(selected_block.docks)):
             for destination_block in self.just_blocks():
+                # Don't link to a block that is hidden
+                if destination_block.status == 'collapsed':
+                    continue
                 # Don't link to a block to which you're already connected
                 if destination_block in self.drag_group:
                     continue
@@ -2784,7 +2835,7 @@ class TurtleArtWindow():
             blk.spr.set_layer(BLOCK_LAYER)
         if check_dock:
             blk.connections = 'check'
-        if blk.spr.labels[0] is not None and \
+        if self.running_sugar and blk.spr.labels[0] is not None and \
                 blk.name not in ['', ' ', 'number', 'string']:
             if blk.spr.labels[0] not in self.used_block_list:
                 self.used_block_list.append(blk.spr.labels[0])
diff --git a/TurtleArtActivity.py b/TurtleArtActivity.py
index f5bdd69..fd44ebc 100644
--- a/TurtleArtActivity.py
+++ b/TurtleArtActivity.py
@@ -23,6 +23,7 @@
 import pygtk
 pygtk.require('2.0')
 import gtk
+import cairo
 import gobject
 import dbus
 
@@ -76,7 +77,7 @@ class TurtleArtActivity(activity.Activity):
         self._setup_toolbar()
 
         _logger.debug('_setup_canvas')
-        self._setup_canvas(self._setup_scrolled_window())
+        self._canvas = self._setup_canvas(self._setup_scrolled_window())
 
         _logger.debug('_setup_palette_toolbar')
         self._setup_palette_toolbar()
@@ -728,10 +729,17 @@ class TurtleArtActivity(activity.Activity):
 
     def _setup_canvas(self, canvas_window):
         ''' Initialize the turtle art canvas. '''
+        win = canvas_window.get_window()  # self._canvas.get_window()
+        cr = win.cairo_create()
+        surface = cr.get_target()
+        self.turtle_canvas = surface.create_similar(
+            cairo.CONTENT_COLOR, gtk.gdk.screen_width() * 2,
+            gtk.gdk.screen_height() * 2)
         bundle_path = activity.get_bundle_path()
         self.tw = TurtleArtWindow(canvas_window, bundle_path, self,
-                                  profile.get_color().to_string(),
-                                  profile.get_nick_name())
+                                  mycolors=profile.get_color().to_string(),
+                                  mynick=profile.get_nick_name(),
+                                  turtle_canvas=self.turtle_canvas)
         self.tw.window.grab_focus()
         path = os.path.join(os.environ['SUGAR_ACTIVITY_ROOT'], 'data')
         self.tw.save_folder = path
diff --git a/activity/activity.info b/activity/activity.info
index 5373b01..d8b7f81 100644
--- a/activity/activity.info
+++ b/activity/activity.info
@@ -1,6 +1,6 @@
 [Activity]
 name = Turtle Art
-activity_version = 122
+activity_version = 123
 license = MIT
 bundle_id = org.laptop.TurtleArtActivity
 exec = sugar-activity TurtleArtActivity.TurtleArtActivity
diff --git a/pysamples/set_rgb.py b/pysamples/set_rgb.py
index d4baa48..b77d9df 100644
--- a/pysamples/set_rgb.py
+++ b/pysamples/set_rgb.py
@@ -13,7 +13,6 @@
 def myblock(tw, rgb_array):
     ''' Set rgb color from values '''
     
-    rgb = "#%02x%02x%02x" % ((int(rgb_array[0]) % 256),
-                             (int(rgb_array[1]) % 256),
-                             (int(rgb_array[2]) % 256))
-    tw.canvas.fgcolor = tw.canvas.cm.alloc_color(rgb)
+    tw.canvas.fgrgb = [(int(rgb_array[0]) % 256),
+                       (int(rgb_array[1]) % 256),
+                       (int(rgb_array[2]) % 256)]
diff --git a/turtleart.py b/turtleart.py
index ca9153a..9afc238 100755
--- a/turtleart.py
+++ b/turtleart.py
@@ -24,6 +24,7 @@
 import pygtk
 pygtk.require('2.0')
 import gtk
+import cairo
 
 import getopt
 import sys
@@ -83,11 +84,13 @@ class TurtleMain():
         self._plugins = []
 
         if self.output_png:
+            # Fix me: We need to create a cairo surface to work with
             pixbuf = gtk.gdk.Pixbuf(gtk.gdk.COLORSPACE_RGB, False, 8,
                                     gtk.gdk.screen_width(),
                                     gtk.gdk.screen_height())
-            self.canvas, mask = pixbuf.render_pixmap_and_mask()
-            self._build_window()
+            # self.canvas, mask = pixbuf.render_pixmap_and_mask()
+            self.canvas = pixbuf
+            self._build_window(interactive=False)
             self._draw_and_quit()
         else:
             self._read_initial_pos()
@@ -174,11 +177,24 @@ class TurtleMain():
         self.tw.load_start(self.ta_file)
         self.tw.lc.trace = 0
         self.tw.run_button(0)
-        self.tw.save_as_image(self.ta_file, self.canvas)
+        self.tw.save_as_image(self.ta_file)
 
-    def _build_window(self):
+    def _build_window(self, interactive=True):
         ''' Initialize the TurtleWindow instance. '''
-        self.tw = TurtleArtWindow(self.canvas, self._dirname)
+        if interactive:
+            win = self.canvas.get_window()
+            cr = win.cairo_create()
+            surface = cr.get_target()
+        else:
+            img_surface = cairo.ImageSurface(cairo.FORMAT_RGB24,
+                                             1024, 768)
+            cr = cairo.Context(img_surface)
+            surface = cr.get_target()
+        self.turtle_canvas = surface.create_similar(
+            cairo.CONTENT_COLOR, gtk.gdk.screen_width() * 2,
+            gtk.gdk.screen_height() * 2)
+        self.tw = TurtleArtWindow(self.canvas, self._dirname,
+                                  turtle_canvas=self.turtle_canvas)
         self.tw.save_folder = os.path.expanduser('~')
 
     def _init_vars(self):
--
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