Better usage of memoryview reduces heap allocation

DRIVERS.md

@@ -168,13 +168,14 @@ _index =\
 b'\x00\x00\x14\x00\x2e\x00\x4b\x00\x71\x00\x97\x00\xd2\x00\x0a\x01'\
 b'\x1b\x01\x35\x01\x4f\x01\x75\x01\x9e\x01\xb2\x01\xcc\x01\xe0\x01'\
 
+_mvfont = memoryview(_font)
     # Boilerplate code omitted
 
 def get_ch(ch):
     # validate ch, if out of range use '?'
     # get offsets into _font and retrieve char width
     # Return: memoryview of bitmap, height and width
-    return memoryview(_font[offset + 2, next_offset]), height, width
+    return mvfont[offset + 2, next_offset], height, width
 ```
 
 ``height`` and ``width`` are specified in bits (pixels).

font_to_py.py

@@ -348,7 +348,7 @@ STR01 = """# Code generated by font-to-py.py.
 version = '0.1'
 """
 
-STR02 = """
+STR02 = """_mvfont = memoryview(_font)
 
 def _chr_addr(ordch):
     offset = 2 * (ordch - 32)
@@ -360,7 +360,7 @@ def get_ch(ch):
     offset = _chr_addr(ordch)
     width = int.from_bytes(_font[offset:offset + 2], 'little')
     next_offs = _chr_addr(ordch +1)
-    return memoryview(_font[offset + 2:next_offs]), {}, width
+    return _mvfont[offset + 2:next_offs], {}, width
  
 """
 
@@ -399,7 +399,7 @@ def write_data(stream, fnt, font_path, monospaced, hmap, reverse):
     bw_index = ByteWriter(stream, '_index')
     bw_index.odata(index)
     bw_index.eot()
-    stream.write(STR02.format(height, height))
+    stream.write(STR02.format(height))
 
 # BINARY OUTPUT
 # hmap reverse magic bytes