Added the wiki_symbol shield factory

wmt_shields/common/shield_maker.py

@@ -9,6 +9,8 @@
 from io import BytesIO
 from xml.dom.minidom import parseString as xml_parse
 from xml.parsers.expat import ExpatError
+from urllib.parse import urlparse
+from urllib.request import urlopen
 
 import cairo
 import gi
@@ -60,7 +62,11 @@ def dimensions(self):
     def find_resource(self, subdir, filename):
         subdir_str = str(subdir) if subdir is not None else ''
         filename = str(filename)
-        if os.path.isabs(filename):
+        if(urlparse(filename).netloc):
+            with urlopen(filename) as response:
+                return response.read()
+
+        elif os.path.isabs(filename):
             abspath = filename
         elif subdir is not None \
            and (os.path.isabs(subdir_str) or subdir_str.startswith('{data}')):

wmt_shields/styles/wiki_symbol.py

@@ -0,0 +1,63 @@
+# SPDX-License-Identifier: GPL-3.0-only
+#
+# This file is part of the Waymarked Trails Map Project
+# Copyright (C) 2023 Stéphane Chatty
+# 
+
+import sys
+from urllib.parse import urlparse, quote as urlquote
+
+import hashlib
+import re
+
+import gi
+gi.require_version('Rsvg', '2.0')
+from gi.repository import Rsvg
+import os
+
+from ..common.tags import Tags
+from ..common.config import ShieldConfig
+from ..common.shield_maker import ShieldMaker
+
+class WikiSymbol(ShieldMaker):
+    """ A shield with an SVG image located in the OSM wiki.
+    """
+
+    def __init__(self, uuid, url, config):
+        self.uuid_pattern = uuid
+        self.url = url
+        self.config = config
+
+    def render(self, ctx, w, h):
+        data = self.find_resource('', self.url)
+        rhdl = Rsvg.Handle.new_from_data(data)
+        dim = rhdl.get_dimensions()
+
+        ctx.scale(w/dim.width, h/dim.height)
+        rhdl.render_cairo(ctx)
+
+
+def create_for(tags: Tags, region: str, config: ShieldConfig):
+    wiki_symbol = tags.get('wiki:symbol')
+    if not (wiki_symbol):
+        return None
+
+    print(f'wiki:symbol = {wiki_symbol}', file=sys.stderr)
+    if(urlparse(wiki_symbol).netloc):
+        print(f'URLs are not accepted in tag wiki:symbol: {wiki_symbol}', file=sys.stderr)
+        return None
+
+    match_svg = re.search('(.*)\.svg$',  wiki_symbol)
+    if not (match_svg):
+        print(f'only SVG files are handled in tag wiki:symbol: {wiki_symbol}', file=sys.stderr)
+        return None
+
+    md5 = hashlib.md5(wiki_symbol.encode('utf-8')).hexdigest()
+    c1 = md5[0]
+    c2 = md5[1]
+    filebasename = match_svg.group(1)
+    filename =  urlquote(wiki_symbol.encode('utf-8'))
+    url = f'https://wiki.openstreetmap.org/w/images/{c1}/{c1}{c2}/{filename}'
+    print(f'     {url}', file=sys.stderr)
+    return WikiSymbol(f'wiki_{filebasename}', url, config)
+