5898817fc1
Summary:
`letterSpacing` is completely missing from RN Android at the moment.
I've reviewed the `letterSpacing` implementations in #13199, #13877 and #16801 (that all seem to have stalled) and managed to put together an improved one based on #13199, updated to merge cleanly post 6114f863c3, that resolves the [issues](https://github.com/facebook/react-native/pull/13199#issuecomment-354568863) I've identified with that code.
I believe this is the closest PR yet to a correct implementation of this feature, with a few caveats:
- As with the other PRs, this only works on Android >= 5.0 (silently falling back to no letter spacing on older versions). Is this acceptable for a RN feature, in general? Would a dev mode warning be desirable?
- The other PRs seem to have explored the space of potential solutions to the layout issue ([Android renders space _around_ glyphs](https://issuetracker.google.com/issues/37079859), iOS to the _right_ of each one) and come up empty, so I've opted to merely document the difference.
- I have neither updated nor tested the "Flat" UI implementation - everything compiles but I've taken [this comment](https://github.com/facebook/react-native/issues/12770#issuecomment-294052694) to mean there's no point in trying to wade through it on my own right now; I'm happy to tackle it if given some pointers.
- The implementation in `ReactEditText` is only there to handle the placeholder text, as `ReactBaseTextShadowNode` already affects the input control's contents correctly.
- I'm not sure whether `<TextInput>` is meant to respect `allowFontScaling`; I've taken my cue here from `ReactTextInputManager.setFontSize()`, and used the same units (SP) to interpret the value in `ReactEditText.setLetterSpacingPt()`.
- I'm not sure whether `<TextInput>` is even meant to support `letterSpacing` - it doesn't actually work on iOS. I'm not going to be able to handle the Objective-C side of this, not as part of this PR at least.
- I have not added unit tests to `ReactTextTest` - is this desirable? I see that some other props such as `lineHeight` aren't covered there (unless I'm not looking in the right place).
- Overall, I'm new to this codebase, so it's likely I've missed something not mentioned here.
Note comment re: unit tests above; RNTester screenshots follow.
| iOS (existing functionality, amended test) | Android (new functionality & test) |
| - | - |
| <img src=https://user-images.githubusercontent.com/2246565/34458459-c8d59498-edcb-11e7-8c8f-e7426f723886.png width=300> | <img src=https://user-images.githubusercontent.com/2246565/34458473-2a1ca368-edcc-11e7-9ce6-30c6d3a48660.png width=300> |
| iOS _(not implemented, test not in this branch)_ | Android (new functionality & test) |
| - | - |
| <img src=https://user-images.githubusercontent.com/2246565/34458481-6c60a36e-edcc-11e7-9af5-9734dd722ced.png width=300> | <img src=https://user-images.githubusercontent.com/2246565/34458486-8b3cdcf8-edcc-11e7-974b-25c6085fa674.png width=300> |
| iOS _(not implemented, test not in this branch)_ | Android (new functionality & test) |
| - | - |
| <img src=https://user-images.githubusercontent.com/2246565/34458492-d69a77be-edcc-11e7-896f-21212621dbee.png width=300> | <img src=https://user-images.githubusercontent.com/2246565/34458490-b3a1139e-edcc-11e7-88c8-79d4430d1514.png width=300> |
https://github.com/facebook/react-native-website/pull/105 - this docs PR is edited slightly from what's in `TextStylePropTypes` here; happy to align either one to the other after a review.
[ANDROID] [FEATURE] [Text] - Implemented letterSpacing
Closes https://github.com/facebook/react-native/pull/17398
Reviewed By: mdvacca
Differential Revision: D6837718
Pulled By: hramos
fbshipit-source-id: 5c9d49e9cf4af6457b636416ce5fe15315aab72c
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