Partial polyfill of boxShadow for iOS

[efoken]

Describe the feature request

I know that boxShadow is not fully compatible with iOS shadows, but at least it can be translated under several conditions, similar to the translation of textShadow, which is already there.

Code in parseShadow.js can be re-used. The boxShadow can be translated if:

• there is only one shadow
• it's not inset
• it does not have a spread radius

Example:

let parsedShadow = parseShadow(styleValue);
if (parsedShadow.length > 1) {
  warnMsg('unsupported multiple values for style property "boxShadow".');
}
result.shadowColor = parsedShadow[0].color; // maybe alpha value can be extracted from rgba/hsla
result.shadowOffset = {
  height: parsedShadow[0].offsetY,
  width: parsedShadow[0].offsetX,
};
result.shadowOpacity = 1; // when color contains alpha value this can simply be 1
result.shadowRadius = parsedShadow[0].blurRadius;
delete result.boxShadow;

[necolas]

Unfortunately this isn't possible because shadows in iOS are also inherited by inner text as text shadows. We actually have a native implementation of boxShadow coming to RN though

[efoken]

Wow okay, native boxShadow would be even better! Thanks for the info 🙏 🎉