Bug

If a line of text with textAnchor="middle" comprises multiple <TSpan>s, each span is centred on itself (from the position it would have been in with textAnchor="start"), rather than as a whole line of text.

Probably easier to explain with a screenshot:

I'll push up a PR in a minute that solves this particular issue, however not being much of a Native Android/Java developer it's likely there's a better way to do this, and I can't be sure this hasn't broken something else.

Environment info

React native info output:

System:
    OS: macOS Mojave 10.14.5
    CPU: (4) x64 Intel(R) Core(TM) i5-4308U CPU @ 2.80GHz
    Memory: 57.91 MB / 16.00 GB
    Shell: 3.2.57 - /bin/bash
  Binaries:
    Node: 12.3.1 - ~/.nvm/versions/node/v12.3.1/bin/node
    Yarn: 1.16.0 - /usr/local/bin/yarn
    npm: 6.9.0 - ~/.nvm/versions/node/v12.3.1/bin/npm
    Watchman: 4.9.0 - /usr/local/bin/watchman
  SDKs:
    iOS SDK:
      Platforms: iOS 13.2, DriverKit 19.0, macOS 10.15, tvOS 13.2, watchOS 6.1
    Android SDK:
      API Levels: 23, 25, 26, 27, 28
      Build Tools: 23.0.1, 26.0.1, 26.0.2, 26.0.3, 27.0.3, 28.0.3
      System Images: android-23 | Intel x86 Atom_64, android-23 | Google APIs Intel x86 Atom_64, android-27 | Google APIs Intel x86 Atom, android-27 | Google Play Intel x86 Atom, android-28 | Google APIs Intel x86 Atom_64, android-28 | Google Play Intel x86 Atom_64
      Android NDK: 19.2.5345600
  IDEs:
    Android Studio: 3.4 AI-183.6156.11.34.5522156
    Xcode: 11.2/11B52 - /usr/bin/xcodebuild
  npmPackages:
    react: 16.9.0 => 16.9.0
    react-native: 0.61.5 => 0.61.5

Library version: 9.13.3

Steps To Reproduce

1. Add a <Text textAnchor="middle"> element containing multiple <TSpan>s
2. See only the first span on each line is aligned to the middle of the screen.

Describe what you expected to happen:

1. The entire line should be aligned correctly

Reproducible sample code

https://github.com/mjmasn/TSpanIssue