fix(legacy): cleanup bitmaps, use 1-bit PNG, update generate script

legacy/gen/bitmaps/generate.py

@@ -11,7 +11,7 @@ imgs = []
 
 def encode_pixels(img):
     r = ""
-    img = [(x[0] + x[1] + x[2] > 384 and "1" or "0") for x in img]
+    img = ["1" if x >= 128 else "0" for x in img]
     for i in range(len(img) // 8):
         c = "".join(img[i * 8 : i * 8 + 8])
         r += "0x%02x, " % int(c, 2)