From 3210adefe8e5e53acfac6599b69783f7a164359c Mon Sep 17 00:00:00 2001
From: Michael Tremer <michael.tremer@ipfire.org>
Date: Thu, 21 Nov 2019 21:09:57 +0000
Subject: [PATCH] people: Render an avatar with letter if no avatar exists

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>
---
 src/web/people.py | 67 +++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 65 insertions(+), 2 deletions(-)

diff --git a/src/web/people.py b/src/web/people.py
index 893a8063..1da6c275 100644
--- a/src/web/people.py
+++ b/src/web/people.py
@@ -1,9 +1,12 @@
 #!/usr/bin/python
 
+import PIL
 import datetime
+import imghdr
+import io
 import ldap
 import logging
-import imghdr
+import os.path
 import tornado.web
 import urllib.parse
 
@@ -13,6 +16,9 @@ from . import auth
 from . import base
 from . import ui_modules
 
+COLOUR_LIGHT = (237,232,232)
+COLOUR_DARK  = (49,53,60)
+
 class IndexHandler(auth.CacheMixin, base.BaseHandler):
 	@tornado.web.authenticated
 	def get(self):
@@ -56,7 +62,8 @@ class AvatarHandler(base.BaseHandler):
 		if not avatar:
 			logging.debug("No avatar uploaded for %s" % account)
 
-			return self.redirect(self.static_url("img/default-avatar.jpg"))
+			# Generate a random avatar with only one letter
+			avatar = self._get_avatar(account, size=size)
 
 		# Guess content type
 		type = imghdr.what(None, avatar)
@@ -68,6 +75,62 @@ class AvatarHandler(base.BaseHandler):
 		# Deliver payload
 		self.finish(avatar)
 
+	def _get_avatar(self, account, size=None, **args):
+		letter = ("%s" % account)[0].upper()
+
+		if size is None:
+			size = 256
+
+		# The generated avatar cannot be larger than 1024px
+		if size >= 2048:
+			size = 2048
+
+		# Cache key
+		key = "avatar:letter:%s:%s" % (letter, size)
+
+		# Fetch avatar from the cache
+		avatar = self.memcached.get(key)
+		if not avatar:
+			avatar = self._make_avatar(letter, size=size, **args)
+
+			# Cache for forever
+			self.memcached.set(key, avatar)
+
+		return avatar
+
+	def _make_avatar(self, letter, format="PNG", size=None, **args):
+		# Generate an image of the correct size
+		image = PIL.Image.new("RGBA", (size, size), COLOUR_LIGHT)
+
+		# Have a canvas
+		draw = PIL.ImageDraw.Draw(image)
+
+		# Load font
+		font = PIL.ImageFont.truetype(os.path.join(
+			self.application.settings.get("static_path", ""),
+			"fonts/Mukta-Bold.ttf"
+		), size, encoding="unic")
+
+		# Determine size of the printed letter
+		w, h = font.getsize(letter)
+
+		# Mukta seems to be very broken and the height needs to be corrected
+		h //= 0.7
+
+		# Draw the letter in the center
+		draw.text(((size - w) / 2, (size - h) / 2), letter,
+			font=font, fill=COLOUR_DARK)
+
+		with io.BytesIO() as f:
+			# If writing out the image does not work with optimization,
+			# we try to write it out without any optimization.
+			try:
+				image.save(f, format, optimize=True, **args)
+			except:
+				image.save(f, format, **args)
+
+			return f.getvalue()
+
 
 class CallsHandler(auth.CacheMixin, base.BaseHandler):
 	@tornado.web.authenticated
-- 
2.47.3