sprite library cleanupv9

6 files changed, 312 insertions, 149 deletions

diff --git a/MANIFEST b/MANIFEST
index de98468..5ec78a0 100644
--- a/MANIFEST
+++ b/MANIFEST
@@ -29,3 +29,4 @@ icons/Con.svg
 icons/Aon.svg
 icons/Coff.svg
 icons/Aoff.svg
+sliderule.py
diff --git a/NEWS b/NEWS
index f9d5676..5671e6c 100644
--- a/NEWS
+++ b/NEWS
@@ -1,3 +1,7 @@
+9
+
+* new licensing file
+
 8
 
 * sprite library clean-up
diff --git a/SlideruleActivity.py b/SlideruleActivity.py
index d141e20..5231d29 100644
--- a/SlideruleActivity.py
+++ b/SlideruleActivity.py
@@ -131,14 +131,15 @@ class SlideruleActivity(activity.Activity):
 
         # Read the slider positions from the Journal
         try:
-            self.tw.A.spr.x = int(self.metadata['A'])
-            self.tw.C.spr.x = int(self.metadata['C'])
-            self.tw.C_tab_left.spr.x = int(self.metadata['C'])
-            self.tw.C_tab_right.spr.x = int(self.metadata['C'])+SWIDTH-100
-            self.tw.D.spr.x = int(self.metadata['D'])
-            self.tw.R.spr.x = int(self.metadata['R'])
-            self.tw.R_tab_top.spr.x = int(self.metadata['R'])
-            self.tw.R_tab_bot.spr.x = int(self.metadata['R'])
+            self.tw.A.spr.move_relative((int(self.metadata['A']),0))
+            self.tw.C.spr.move_relative((int(self.metadata['C']),0))
+            self.tw.C_tab_left.spr.move_relative((int(self.metadata['C']),0))
+            self.tw.C_tab_right.spr.move_relative((int(self.metadata['C'])+\
+                                                   SWIDTH-100,0))
+            self.tw.D.spr.move_relative((int(self.metadata['D']),0))
+            self.tw.R.spr.move_relative((int(self.metadata['R']),0))
+            self.tw.R_tab_top.spr.move_relative((int(self.metadata['R']),0))
+            self.tw.R_tab_bot.spr.move_relative((int(self.metadata['R']),0))
             self.tw.slider_on_top = self.metadata['slider']
             if self.tw.slider_on_top == 'A':
                 self._show_a()
@@ -156,7 +157,7 @@ class SlideruleActivity(activity.Activity):
     def _show_c(self):
         self.c_slider.set_icon("Con")
         self.a_slider.set_icon("Aoff")
-        hide(self.tw.A.spr)
+        self.tw.A.spr.hide()
         self.tw.C.draw_slider(1000)
         self.tw.C_tab_left.draw_slider(1000)
         self.tw.C_tab_right.draw_slider(1000)
@@ -169,9 +170,9 @@ class SlideruleActivity(activity.Activity):
     def _show_a(self):
         self.c_slider.set_icon("Coff")
         self.a_slider.set_icon("Aon")
-        hide(self.tw.C.spr)
-        hide(self.tw.C_tab_left.spr)
-        hide(self.tw.C_tab_right.spr)
+        self.tw.C.spr.hide()
+        self.tw.C_tab_left.spr.hide()
+        self.tw.C_tab_right.spr.hide()
         self.tw.A.draw_slider(1000)
         self.tw.slider_on_top = "A"
         return True
@@ -182,14 +183,18 @@ class SlideruleActivity(activity.Activity):
     def write_file(self, file_path):
         _logger.debug("Write slider on top: " + self.tw.slider_on_top)
         self.metadata['slider'] = self.tw.slider_on_top
-        _logger.debug("Write A offset: " + str(self.tw.A.spr.x))
-        self.metadata['A'] = str(self.tw.A.spr.x)
-        _logger.debug("Write C offset: " + str(self.tw.C.spr.x))
-        self.metadata['C'] = str(self.tw.C.spr.x)
-        _logger.debug("Write D offset: " + str(self.tw.D.spr.x))
-        self.metadata['D'] = str(self.tw.D.spr.x)
-        _logger.debug("Write r offset: " + str(self.tw.R.spr.x))
-        self.metadata['R'] = str(self.tw.R.spr.x)
+        x,y = self.tw.A.spr.get_xy()
+        _logger.debug("Write A offset: " + str(x))
+        self.metadata['A'] = str(x)
+        x,y = self.tw.C.spr.get_xy()
+        _logger.debug("Write C offset: " + str(x))
+        self.metadata['C'] = str(x)
+        x,y = self.tw.D.spr.get_xy()
+        _logger.debug("Write D offset: " + str(x))
+        self.metadata['D'] = str(x)
+        x,y = self.tw.R.spr.get_xy()
+        _logger.debug("Write r offset: " + str(x))
+        self.metadata['R'] = str(x)
 
 
 #
diff --git a/activity/activity.info b/activity/activity.info
index b94d05c..24e91f8 100644
--- a/activity/activity.info
+++ b/activity/activity.info
@@ -1,6 +1,6 @@
 [Activity]
 name = Sliderule
-activity_version = 8
+activity_version = 9
 license = GPLv3
 bundle_id = org.sugarlabs.SlideruleActivity
 exec = sugar-activity SlideruleActivity.SlideruleActivity
diff --git a/sprites.py b/sprites.py
index 3f7c5eb..a361ba0 100644
--- a/sprites.py
+++ b/sprites.py
@@ -1,7 +1,7 @@
 # -*- coding: utf-8 -*-
 
 #Copyright (c) 2007-8, Playful Invention Company.
-#Copyright (c) 2008-9, Walter Bender
+#Copyright (c) 2008-10 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
@@ -21,6 +21,57 @@
 #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.
+
+There are two classes:
+
+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
+
+        # Create a new sprite collection for a gtk Drawing Area.
+        my_drawing_area = gtk.DrawingArea()
+        self.sprite_list = Sprites(my_drawing_area)
+
+        # Create a "pixbuf" (in this example, from SVG).
+        my_pixbuf = svg_str_to_pixbuf("<svg>...some svg code...</svg>")
+
+        # Create a sprite at position x1, y1.
+        my_sprite = sprites.Sprite(self.sprite_list, x1, y1, my_pixbuf)
+
+        # Move the sprite to a new position.
+        my_sprite.move((x1+dx, y1+dy))
+
+        # Create another "pixbuf".
+        your_pixbuf = svg_str_to_pixbuf("<svg>...some svg code...</svg>")
+
+        # Create a sprite at position x2, y2.
+        your_sprite = sprites.Sprite(self.sprite_list, x2, y2, my_pixbuf)
+
+        # Assign the sprites to layers.
+        # In this example, your_sprite will be on top of my_sprite.
+        my_sprite.set_layer(100)
+        your_sprite.set_layer(200)
+
+        # Now put my_sprite on top of your_sprite.
+        my_sprite.set_layer(300)
+
+# method for converting SVG to a gtk pixbuf
+def svg_str_to_pixbuf(svg_string):
+    pl = gtk.gdk.PixbufLoader('svg')
+    pl.write(svg_string)
+    pl.close()
+    pixbuf = pl.get_pixbuf()
+    return pixbuf
+"""
+
 import pygtk
 pygtk.require('2.0')
 import gtk
@@ -30,11 +81,16 @@ import pango
 #
 # A class for the list of sprites and everything they share in common
 #
+
 class Sprites:
-    def __init__(self, canvas):
+    def __init__(self, canvas, area=None, gc=None):
         self.canvas = canvas
-        self.area = self.canvas.window
-        self.gc = self.area.new_gc()
+        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()
         self.list = []
 
@@ -47,10 +103,10 @@ class Sprites:
     def length_of_list(self):
         return(len(self.list))
 
-    def append_to_list(self,spr):
+    def append_to_list(self, spr):
         self.list.append(spr)
 
-    def insert_in_list(self,spr,i):
+    def insert_in_list(self, spr, i):
         if i < 0:
             self.list.insert(0, spr)
         elif i > len(self.list)-1:
@@ -58,7 +114,7 @@ class Sprites:
         else:
             self.list.insert(i, spr)
 
-    def remove_from_list(self,spr):
+    def remove_from_list(self, spr):
         if spr in self.list:
             self.list.remove(spr)
 
@@ -73,149 +129,238 @@ class Sprites:
         for spr in self.list:
             spr.draw()
 
-
 #
 # A class for the individual sprites
 #
 class Sprite:
     def __init__(self, sprites, x, y, image):
-        self.sprites = sprites
-        self.x = x
-        self.y = y
+        self._sprites = sprites
+        self._x = int(x)
+        self._y = int(y)
+        self._scale = [12]
+        self._rescale = [True]
+        self._horiz_align = ["center"]
+        self._vert_align = ["middle"]
+        self._fd = None
+        self._bold = False
+        self._italic = False
+        self._color = None
+        self._width = 0
+        self._height = 0
+        self._margins = [0,0,0,0]
         self.layer = 100
-        self.label = None
-        self.scale = 24
-        self.rescale = True
-        self.horiz_align = "center"
-        self.vert_align = "middle"
-        self.fd = None
-        self.color = None
+        self.labels = []
+        self.images = []
+        self._dx = [] # image offsets
+        self._dy = []
         self.set_image(image)
-        self.sprites.append_to_list(self)
+        self._sprites.append_to_list(self)
 
-    def set_image(self, image):
-        self.image = image
-        if isinstance(self.image,gtk.gdk.Pixbuf):
-            self.width = self.image.get_width()
-            self.height = self.image.get_height()
+    def set_image(self, image, i=0, dx=0, dy=0):
+        while len(self.images) < i+1:
+           self.images.append(None)
+           self._dx.append(0)
+           self._dy.append(0)
+        self.images[i] = image
+        self._dx[i] = dx
+        self._dy[i] = dy
+        if isinstance(self.images[i], gtk.gdk.Pixbuf):
+            _w = self.images[i].get_width()
+            _h = self.images[i].get_height()
+        else:
+            _w, _h = self.images[i].get_size()
+        if i == 0: # Always reset width and height when base image changes.
+            self._width = _w + dx
+            self._height = _h + dy
         else:
-            self.width, self.height = self.image.get_size()
+            if _w + dx > self._width:
+                self._width = _w + dx
+            if _h + dy > self._height:
+                self._height = _h + dy
 
     def move(self, pos):
         self.inval()
-        self.x,self.y = pos
+        self._x,self._y = int(pos[0]),int(pos[1])
         self.inval()
 
-    def set_shape(self, image):
+    def move_relative(self, pos):
         self.inval()
-        self.set_image(image)
+        self._x += int(pos[0])
+        self._y += int(pos[1])
+        self.inval()
+
+    def get_xy(self):
+        return (self._x, self._y)
+
+    def get_dimensions(self):
+        return (self._width, self._height)
+
+    def get_layer(self):
+        return self.layer
+
+    def set_shape(self, image, i=0):
+        self.inval()
+        self.set_image(image, i)
         self.inval()
 
     def set_layer(self, layer):
-        self.sprites.remove_from_list(self)
+        self._sprites.remove_from_list(self)
         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)
+        for i in range(self._sprites.length_of_list()):
+            if layer < self._sprites.get_sprite(i).layer:
+                self._sprites.insert_in_list(self, i)
                 self.inval()
                 return
-        self.sprites.append_to_list(self)
+        self._sprites.append_to_list(self)
         self.inval()
 
-    def set_label(self, label):
-        if type(label) is str or type(label) is unicode:
-            self.label = label.replace("\0"," ") # pango doesn't like nulls
+    def set_label(self, new_label, i=0):
+        self._extend_labels_array(i)
+        if type(new_label) is str or type(new_label) is unicode:
+            # pango doesn't like nulls
+            self.labels[i] = new_label.replace("\0"," ")
         else:
-            self.label = str(label)
-        if self.fd is None:
-            self.fd = pango.FontDescription('Sans')
-        if self.color is None:
-            self.color = self.sprites.cm.alloc_color('black')
+            self.labels[i] = str(new_label)
         self.inval()
 
-    def set_label_font(self, font):
-        self.fd = pango.FontDescription(font)
+    def set_margins(self, l=0, t=0, r=0, b=0):
+        self._margins = [l,t,r,b]
+
+    def _extend_labels_array(self, i):
+        if self._fd is None:
+           self.set_font('Sans')
+        if self._color is None:
+           self._color = self._sprites.cm.alloc_color('black')
+        while len(self.labels) < i+1:
+           self.labels.append(" ")
+           self._scale.append(self._scale[0])
+           self._rescale.append(self._rescale[0])
+           self._horiz_align.append(self._horiz_align[0])
+           self._vert_align.append(self._vert_align[0])
 
-    def set_label_color(self, r, g, b):
-        self.color = self.sprites.cm.alloc_color(r, g, b)
+    def set_font(self, font):
+        self._fd = pango.FontDescription(font)
 
-    def set_label_attributes(self, scale, horiz_align="center",
-                             vert_align="middle", rescale="True"):
-        self.scale = scale
-        self.horiz_align = horiz_align
-        self.vert_align = vert_align
-        self.rescale = rescale
+    def set_label_color(self, rgb):
+        self._color = self._sprites.cm.alloc_color(rgb)
 
-    def show(self):
-        self.set_layer(self.layer)
+    def set_label_attributes(self, scale, rescale=True, horiz_align="center",
+                             vert_align="middle", i=0):
+        self._extend_labels_array(i)
+        self._scale[i] = scale
+        self._rescale[i] = rescale
+        self._horiz_align[i] = horiz_align
+        self._vert_align[i] = vert_align
 
     def hide(self):
         self.inval()
-        self.sprites.remove_from_list(self)
+        self._sprites.remove_from_list(self)
 
     def inval(self):
-        self.sprites.area.invalidate_rect(
-            gtk.gdk.Rectangle(self.x,self.y,self.width,self.height), False)
+        self._sprites.area.invalidate_rect(
+            gtk.gdk.Rectangle(self._x,self._y,self._width,self._height), False)
 
     def draw(self):
-        if isinstance(self.image,gtk.gdk.Pixbuf):
-            self.sprites.area.draw_pixbuf(
-                self.sprites.gc, self.image, 0, 0, self.x, self.y)
-        else:
-            self.sprites.area.draw_drawable(
-                self.sprites.gc, self.image, 0, 0, self.x, self.y, -1, -1)
-        if self.label is not None:
+        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._x+self._dx[i],
+                                                 self._y+self._dy[i])
+            elif img is not None:
+                self._sprites.area.draw_drawable(
+                    self._sprites.gc, img, 0, 0, self._x+self._dx[i],
+                                                 self._y+self._dy[i], -1, -1)
+        if len(self.labels) > 0:
             self.draw_label()
 
     def hit(self, pos):
         x, y = pos
-        if x < self.x:
+        if x < self._x:
             return False
-        if x > self.x+self.width:
+        if x > self._x+self._width:
             return False
-        if y < self.y:
+        if y < self._y:
             return False
-        if y > self.y+self.height:
+        if y > self._y+self._height:
             return False
         return True
 
     def draw_label(self):
-        if self.label is None:
-            return
-        if len(str(self.label)) == 0:
-            return
-        if self.width == 0 or self.height == 0:
-            return
-        pl = self.sprites.canvas.create_pango_layout(self.label)
-        self.fd.set_size(int(self.scale*pango.SCALE))
-        pl.set_font_description(self.fd)
-        w = pl.get_size()[0]/pango.SCALE
-        if w > self.width:
-            if self.rescale is True:
-                self.fd.set_size(int(self.scale*pango.SCALE*self.width/w))
-                pl.set_font_description(self.fd)
-                w = pl.get_size()[0]/pango.SCALE
+        my_width = self._width-self._margins[0]-self._margins[2]
+        if my_width < 0:
+            my_width = 0
+        my_height = self._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]))
+            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 > my_width:
+                if self._rescale[i] is True:
+                    self._fd.set_size(
+                                    int(self._scale[i]*pango.SCALE*my_width/w))
+                    pl.set_font_description(self._fd)
+                    w = pl.get_size()[0]/pango.SCALE
+                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:])
+                        self._fd.set_size(int(self._scale[i]*pango.SCALE))
+                        pl.set_font_description(self._fd)
+                        w = pl.get_size()[0]/pango.SCALE        
+                        j -= 1
+            if self._horiz_align[i] == "center":
+                x = int(self._x+self._margins[0]+(my_width-w)/2)
+            elif self._horiz_align[i] == 'left':
+                x = int(self._x+self._margins[0])
+            else: # right
+                x = int(self._x+self._width-w-self._margins[2])
+            h = pl.get_size()[1]/pango.SCALE
+            if self._vert_align[i] == "middle":
+                y = int(self._y+self._margins[1]+(my_height-h)/2)
+            elif self._vert_align[i] == "top":
+                y = int(self._y+self._margins[1])
+            else: # bottom
+                y = int(self._y+self._height-h-self._margins[3])
+            self._sprites.gc.set_foreground(self._color)
+            self._sprites.area.draw_layout(self._sprites.gc, x, y, pl)
+
+    def label_width(self):
+        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
+
+    def label_safe_width(self):
+        return self._width-self._margins[0]-self._margins[2]
+    
+    def label_safe_height(self):
+        return self._height-self._margins[1]-self._margins[3]
+    
+    def label_left_top(self):
+        return (self._margins[0], self._margins[1])
+
+    def get_pixel(self, pos, i=0):
+        x, y = pos
+        x = x-self._x
+        y = y-self._y
+        if y > self.images[i].get_height()-1:
+            return (-1,-1,-1,-1)
+        try:
+            array = self.images[i].get_pixels()
+            if array is not None:
+                offset = (y*self.images[i].get_width()+x)*4
+                r,g,b,a = ord(array[offset]), ord(array[offset+1]),\
+                          ord(array[offset+2]), ord(array[offset+3])
+                return (r,g,b,a)
             else:
-                i = len(self.label)-1
-                while(w > self.width and i > 0):
-                    label = "…"+self.label[len(self.label)-i:]
-                    pl = self.sprites.canvas.create_pango_layout(label)
-                    self.fd.set_size(int(self.scale*pango.SCALE))
-                    pl.set_font_description(self.fd)
-                    w = pl.get_size()[0]/pango.SCALE        
-                    i -= 1
-        if self.horiz_align == "center":
-            x = int(self.x+(self.width-w)/2)
-        elif self.horiz_align == 'left':
-            x = self.x
-        else: # right
-            x = int(self.x+self.width-w)
-        h = pl.get_size()[1]/pango.SCALE
-        if self.vert_align == "middle":
-            y = int(self.y+(self.height-h)/2)
-        elif self.vert_align == "top":
-            y = self.y
-        else: # bottom
-            y = int(self.y+self.height-h)
-        self.sprites.gc.set_foreground(self.color)
-        self.sprites.area.draw_layout(self.sprites.gc, x, y, pl)
+                return (-1,-1,-1,-1)
+        except IndexError:
+            print "Index Error: %d %d" % (len(array), offset)
+            return (-1,-1,-1,-1)
diff --git a/window.py b/window.py
index ed047e5..7f3e21b 100644
--- a/window.py
+++ b/window.py
@@ -131,29 +131,26 @@ def _mouse_move_cb(win, event, tw):
     dx = x-tw.dragpos
     if tw.press == tw.D.spr or tw.press == tw.A.spr:
         # everything moves
-        tw.C.spr.move((tw.C.spr.x+dx,tw.C.spr.y))
-        tw.C_tab_left.spr.move((tw.C_tab_left.spr.x+dx,tw.C_tab_left.spr.y))
-        tw.C_tab_right.spr.move((tw.C_tab_right.spr.x+dx,tw.C_tab_right.spr.y))
-        tw.A.spr.move((tw.A.spr.x+dx,tw.A.spr.y))
-        tw.D.spr.move((tw.D.spr.x+dx,tw.D.spr.y))
-        tw.R_tab_top.spr.move((tw.R_tab_top.spr.x+dx,tw.R_tab_top.spr.y))
-        tw.R_tab_bot.spr.move((tw.R_tab_bot.spr.x+dx,tw.R_tab_bot.spr.y))
-        tw.R.spr.move((tw.R.spr.x+dx,tw.R.spr.y))
-        tw.R.spr.show()
+        tw.C.spr.move_relative((dx,0))
+        tw.C_tab_left.spr.move_relative((dx,0))
+        tw.C_tab_right.spr.move_relative((dx,0))
+        tw.A.spr.move_relative((dx,0))
+        tw.D.spr.move_relative((dx,0))
+        tw.R_tab_top.spr.move_relative((dx,0))
+        tw.R_tab_bot.spr.move_relative((dx,0))
+        tw.R.spr.move_relative((dx,0))
     elif tw.press == tw.R_tab_top.spr or \
          tw.press == tw.R_tab_bot.spr or \
          tw.press == tw.R.spr:
-        tw.R_tab_top.spr.move((tw.R_tab_top.spr.x+dx,tw.R_tab_top.spr.y))
-        tw.R_tab_bot.spr.move((tw.R_tab_bot.spr.x+dx,tw.R_tab_bot.spr.y))
-        tw.R.spr.move((tw.R.spr.x+dx,tw.R.spr.y))
-        tw.R.spr.show()
+        tw.R_tab_top.spr.move_relative((dx,0))
+        tw.R_tab_bot.spr.move_relative((dx,0))
+        tw.R.spr.move_relative((dx,0))
     elif tw.press == tw.C.spr or \
          tw.press == tw.C_tab_left.spr or \
          tw.press == tw.C_tab_right.spr:
-        tw.C.spr.move((tw.C.spr.x+dx,tw.C.spr.y))
-        tw.C_tab_left.spr.move((tw.C_tab_left.spr.x+dx,tw.C_tab_left.spr.y))
-        tw.C_tab_right.spr.move((tw.C_tab_right.spr.x+dx,tw.C_tab_right.spr.y))
-        tw.R.spr.show()
+        tw.C.spr.move_relative((dx,0))
+        tw.C_tab_left.spr.move_relative((dx,0))
+        tw.C_tab_right.spr.move_relative((dx,0))
 
     # reset drag position
     tw.dragpos = x
@@ -197,24 +194,31 @@ def _update_results_label(tw):
     return True
 
 def _calc_C(tw):
-    dx = tw.R.spr.x - tw.C.spr.x    
+    rx,ry = tw.R.spr.get_xy()
+    cx,cy = tw.C.spr.get_xy()
+    dx = rx-cx
     if dx < 0:
         dx = math.log(10.)*SCALE + dx
     C = math.exp(dx/SCALE)
     return float(int(C*100)/100.)
 
 def _calc_A(tw):
-    dx = tw.R.spr.x - tw.A.spr.x
+    rx,ry = tw.R.spr.get_xy()
+    ax,ay = tw.A.spr.get_xy()
+    dx = rx-ax
     if dx < 0:
         dx = math.log(10.)*SCALE + dx
     A = math.exp(2*dx/SCALE) # two-decade rule
     return float(int(A*100)/100.)
 
 def _calc_D(tw):
+    x,y = tw.D.spr.get_xy()
     if tw.slider_on_top == "A":
-        dx = tw.A.spr.x - tw.D.spr.x
+        ax,ay = tw.A.spr.get_xy()
+        dx = ax-x
     else:
-        dx = tw.C.spr.x - tw.D.spr.x
+        cx,cy = tw.C.spr.get_xy()
+        dx = cx-x
     if dx < 0:
         dx = math.log(10.)*SCALE + dx
         tw.factor = 10
@@ -224,14 +228,18 @@ def _calc_D(tw):
     return float(int(D*100)/100.)
 
 def _calc_DC(tw):
-    dx = tw.R.spr.x - tw.D.spr.x    
+    rx,ry = tw.R.spr.get_xy()
+    x,y = tw.D.spr.get_xy()
+    dx = rx-x
     if dx < 0:
         dx = math.log(10.)*SCALE + dx
     DC = math.exp(dx/SCALE)
     return float(int(DC*100)/100.)
 
 def _calc_DA(tw):
-    dx = tw.R.spr.x - tw.D.spr.x    
+    rx,ry = tw.R.spr.get_xy()
+    x,y = tw.D.spr.get_xy()
+    dx = rx-x
     if dx < 0:
         dx = math.log(100.)*SCALE + dx
     DA = math.exp(dx/SCALE)