Added a cleanup step to re calulate the center

This change calculates the center of each entry and compares it to the
current center. If they are different, the center get's updated.

tools/formatter.py

@@ -188,7 +188,49 @@ def convert_subreddit_to_website(entry: dict):
 			entry["subreddit"] = ""
 
 	return entry
-	
+
+def calculate_center(path: list):
+	"""
+	Caluclates the center of a polygon
+
+	adapted from /web/_js/draw.js:calucalteCenter()
+	"""
+	area = 0
+	x = 0
+	y = 0
+
+	for i in range(len(path)):
+		point1 = path[i]
+		point2 = path[i-1 if i != 0 else len(path)-1]
+		f = point1[0] * point2[1] - point2[0] * point1[1]
+		area += f
+		x += (point1[0] + point2[0]) * f
+		y += (point1[1] + point2[1]) * f
+
+	area *= 3
+
+	if area != 0:
+		return [x // area + 0.5, y // area + 0.5]
+	else:
+		# get the center of a straight line
+		max_x = max(i[0] for i in path)
+		min_x = min(i[0] for i in path)
+		max_y = max(i[1] for i in path)
+		min_y = min(i[1] for i in path)
+		return [(max_x + min_x) // 2 + 0.5, (max_y + min_y) // 2 + 0.5]
+
+def update_center(entry: dict):
+	"""
+	checks if the center of a entry is up to date, and updates it if it's either missing or outdated
+	"""
+	if 'path' not in entry:
+		return entry
+	path = entry['path']
+	if len(path) > 1:
+		calculated_center = calculate_center(path)
+		if 'center' not in entry or entry['center'] != calculated_center:
+			entry['center'] = calculated_center
+	return entry
 
 def validate(entry: dict):
 	"""
@@ -256,6 +298,8 @@ def print_(*args, **kwargs):
 	entry = fix_no_protocol_urls(entry)
 	print_("Removing extras...")
 	entry = remove_extras(entry)
+	print_("Updating center")
+	entry = update_center(entry)
 	print_("Validating...")
 	status_code = validate(entry)
 	print_("Completed!")
@@ -287,4 +331,4 @@ def go(path):
 
 		print("Writing completed. All done.")
 
-	go("../web/atlas.json")
+	go("../web/atlas.json")