allow using emoji as favicon

nicegui/favicon.py

@@ -1,3 +1,4 @@
+import urllib
 from pathlib import Path
 from typing import TYPE_CHECKING, Optional
 
@@ -10,7 +11,7 @@ if TYPE_CHECKING:
 
 
 def create_favicon_route(path: str, favicon: Optional[str]) -> None:
-    if favicon and is_remote_url(favicon):
+    if favicon and (is_remote_url(favicon) or is_char(favicon)):
         return
     fallback = Path(__file__).parent / 'static' / 'favicon.ico'
     path = f'{"" if path == "/" else path}/favicon.ico'
@@ -24,6 +25,8 @@ def get_favicon_url(page: 'page', prefix: str) -> str:
         return favicon
     elif not favicon:
         return f'{prefix}/_nicegui/{__version__}/static/favicon.ico'
+    if is_char(favicon):
+        return char_to_data_url(favicon)
     elif page.path == '/':
         return f'{prefix}/favicon.ico'
     else:
@@ -32,3 +35,29 @@ def get_favicon_url(page: 'page', prefix: str) -> str:
 
 def is_remote_url(favicon: str) -> bool:
     return favicon.startswith('http://') or favicon.startswith('https://')
+
+
+def is_char(favicon: str) -> bool:
+    return len(favicon) == 1
+
+
+def char_to_data_url(char: str):
+    svg = f'''
+        <svg viewBox="0 0 128 128" width="128" height="128" xmlns="http://www.w3.org/2000/svg" >
+            <style>
+                @supports (-moz-appearance:none) {{
+                    text {{
+                        font-size: 100px;
+                        transform: translateY(0.1em);
+                    }}
+                }}
+                text {{
+                    font-family: Arial, sans-serif;
+                }}
+            </style>
+            <text y=".9em" font-size="128" font-family="Georgia, sans-serif">{char}</text>
+        </svg>
+    '''
+    svg_urlencoded = urllib.parse.quote(svg)
+    data_url = f"data:image/svg+xml,{svg_urlencoded}"
+    return data_url