`fontVariant` does not work with certain fonts

🐛 Bug Report

The fontVariant style prop doesn’t seem to work with most fonts. At first I thought this was only on custom fonts, but even commonly used “pre-packaged” fonts (Arial, Helvetica, Courier, etc.) cause the fontVariant prop to have no effect.

To Reproduce

Use the fontVariant style prop in conjunction with a font other than the system font. See Code Example below.

Expected Behavior

Expected the fontVariant props to have the same effect on style when used with other fonts. For example, when using fontFamily: 'Times', fontVariant: ['small-caps'] the lower-case letters SHOULD change to be smaller versions of the upper-case letter. However, this only occurs when using the System font.

Code Example

https://snack.expo.io/@charliecruzan/fontvarianttest The above Snack shows the issue just in regards to fontVariant: ['small-caps'], but you can also use the React-Native Tester testExample in a react-native app and just change the fontFamily to see the issue happen with all FontVariant options.

Environment

React Native Environment Info: System: OS: macOS 10.14.3 CPU: (12) x64 Intel® Core™ i7-8750H CPU @ 2.20GHz Memory: 313.39 MB / 16.00 GB Shell: 5.3 - /bin/zsh Binaries: Node: 11.6.0 - ~/.nvm/versions/node/v11.6.0/bin/node npm: 6.9.0 - ~/.nvm/versions/node/v11.6.0/bin/npm Watchman: 4.9.0 - /usr/local/bin/watchman SDKs: iOS SDK: Platforms: iOS 12.1, macOS 10.14, tvOS 12.1, watchOS 5.1 IDEs: Xcode: 10.1/10B61 - /usr/bin/xcodebuild npmPackages: react: 16.8.3 => 16.8.3 react-native: 0.59.1 => 0.59.1 npmGlobalPackages: react-native-cli: 2.0.1

Thanks, and let me know if there’s anything else I can provide to help out!

[kelset]

One thing we should try first is if we can get this working just in a vanilla ObjC/Swift app to see if it’s RN or just an iOS quirk.

yup this is the best approach, actually I believe it may have something to do with the Font itself and not strictly RN.

I’ll close this for now, please let me know if you can manage to prove that it’s actually a RN issue (maybe test with another font that on a native iOS app works the expected way and not in RN?).

[cruzach]

Yeah just tried getting this working in a Swift app…doesn’t seem to work. Although it’s definitely possible I’m doing something wrong. Code is in this repo, you can run it in Xcode and see that Systemfont correctly uses small caps, but Hoefler Text doesn’t.