From 706f2b32b0a730eb85da78943b2c1d1344f390d0 Mon Sep 17 00:00:00 2001
From: Fabian Wunsch <fabian@uriah.heep.sax.de>
Date: Sat, 9 Apr 2022 21:08:36 +0200
Subject: [PATCH] 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 | 48 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 46 insertions(+), 2 deletions(-)

diff --git a/tools/formatter.py b/tools/formatter.py
index 60681f3c..f9af7a1f 100644
--- a/tools/formatter.py
+++ b/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+	checks if the center of a entry is up to date, and updates it if it's either missing or outdated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")
\ No newline at end of file
+	go("../web/atlas.json")