Extract the symbol drawing logic into a helper class.

yagicard/__init__.py

@@ -44,6 +44,25 @@ class Images ():
     def __setitem__ (self, key, value):
         self.images[key] = value
 
+class SymbolDrawer ():
+    def __init__ (self, size, direction="ltr"):
+        self.direction = direction
+        self.image = Image.new("RGBA", size)
+        self.symbol_pos = (0, 0)
+
+    def add_symbol (self, symbol):
+        if isinstance(symbol, str):
+            symbol = symbols[symbol]
+
+        self.image.paste(symbol, self.symbol_pos)
+        if self.direction == "ltr":
+            self.symbol_pos = (self.symbol_pos[0] + symbol.width, self.symbol_pos[1])
+        elif self.direction == "ttb":
+            self.symbol_pos = (self.symbol_pos[0], self.symbol_pos[1] + symbol.height)
+
+    def draw_onto (self, target_image, dest):
+        target_image.alpha_composite(self.image, dest)
+
 images  = Images(IMAGES_DIRECTORY)
 symbols = Images(SYMBOLS_DIRECTORY)
 
@@ -118,20 +137,15 @@ def draw_symbols (image, draw, field):
     height    = field.get("height", image.height)
     direction = field.get("direction", "ltr")
 
-    symbols_image = Image.new(image.mode, (width, height))
+    symbol_drawer = SymbolDrawer((width, height), direction)
 
     symbol_pos = (0, 0)
     for symbol_name in symbol_text.split(" "):
         if symbol_name:
             symbol = symbols[symbol_name]
-            symbols_image.paste(symbol, symbol_pos)
+            symbol_drawer.add_symbol(symbol)
 
-            if direction == "ltr":
-                symbol_pos = (symbol_pos[0] + symbol.width, symbol_pos[1])
-            elif direction == "ttb":
-                symbol_pos = (symbol_pos[0], symbol_pos[1] + symbol.height)
-
-    image.alpha_composite(symbols_image, (field.get("x"), field.get("y")))
+    symbol_drawer.draw_onto(image, (field.get("x"), field.get("y")))
 
 def rescale_text_for_sizes (*args):
     def scaler (value):