Is there a lightweight method to check if emoji is supported in iOS

Question

I'm gonna implement a emoji picker supporting Emoji List, v14.0, which could show only compatible emojis, but I don't know how to check if specific emoji is compatible on current iOS version. There are several ways I found:

1. Render to PNG and compare it with default PNG, which might be CPU-intensive.
2. Ask CTFontGetGlyphsForCharacters to check if current emoji could be supported  which seems good, but it fails to check emoji consists of two or more emojis. For example, 😮‍💨 = (😮 U+1F62E U+200D 💨 U+1F4A8), which is actually not supported on iOS 13, but CTFontGetGlyphsForCharacters still returns true because it could be represented as 😮💨.
3. Persist emoji list to several .plist files for each iOS version, which requires some effort to maintain a lot of emoji lists

Answer 1

You can easily override theme by wrapping your view into a new Theme instance with custom properties.

You could do the following :

return new MaterialApp(
  // default theme here
  theme: new ThemeData(),
  builder: (context, child) {
    final defaultTheme = Theme.of(context);
    if (defaultTheme.platform == TargetPlatform.iOS) {
      return new Theme(
        data: defaultTheme.copyWith(
          primaryColor: Colors.purple
        ),
        child: child,
      );
    }
    return child;
  }
);

Which would specify a default theme. And then override primaryColor for IOS.