Align text

Author: charlesx2013

ReactAndroid/src/main/java/com/facebook/react/views/text/CustomLineHeightSpan.java

@@ -21,30 +21,38 @@ public CustomLineHeightSpan(float height) {
     this.mHeight = (int) Math.ceil(height);
   }
 
+  /**
+   * Discord Story time!
+   *
+   * So since we decided to be _very_ flexible with channel names, users have decided that they were gonna name their channels
+   * shit like ‧͙⁺˚･༓☾text☽༓･˚⁺‧͙ | l̶̟̦͚͎̦͑̎m̵̮̥̫͕͚̜̱̫̺̪͍̯̉̂̔͌́̚̕a̶͖̫͍͇̯̯̭͎͋̅́̿́̕͘͘͝͝ò̶̧̢͎̃̋͆̉͠ | and other fun non-standard channel names.
+   *
+   * This caused issues with line heights, because the RN implementation decided that it would try as best as possible to
+   * fit the text within the lineHeight that was given to it by the react component, causing text to be shifted upward
+   * and look terrible (see: https://canary.discord.com/channels/281683040739262465/912423796915462154/101286117376867126
+   * for an example).
+   *
+   * We (Jerry + Charles) decided that to fix this issue, we would instead ignore lineHeights _only_ if the text
+   * height was larger than the lineHeight provided to it.
+   *
+   * This is a much simpler implementation that what was previously here.
+   *
+   * _IF_ the lineHeight is larger than the text height, we default to centering the text as much as possible within
+   * that line height.
+   */
   @Override
   public void chooseHeight(
-      CharSequence text, int start, int end, int spanstartv, int v, Paint.FontMetricsInt fm) {
-    // This is more complicated that I wanted it to be. You can find a good explanation of what the
-    // FontMetrics mean here: http://stackoverflow.com/questions/27631736.
-    // The general solution is that if there's not enough height to show the full line height, we
-    // will prioritize in this order: descent, ascent, bottom, top
-
-    if (fm.descent > mHeight) {
-      // Show as much descent as possible
-      fm.bottom = fm.descent = Math.min(mHeight, fm.descent);
-      fm.top = fm.ascent = 0;
-    } else if (-fm.ascent + fm.descent > mHeight) {
-      // Show all descent, and as much ascent as possible
-      fm.bottom = fm.descent;
-      fm.top = fm.ascent = -mHeight + fm.descent;
-    } else if (-fm.ascent + fm.bottom > mHeight) {
-      // Show all ascent, descent, as much bottom as possible
-      fm.top = fm.ascent;
-      fm.bottom = fm.ascent + mHeight;
-    } else if (-fm.top + fm.bottom > mHeight) {
-      // Show all ascent, descent, bottom, as much top as possible
-      fm.top = fm.bottom - mHeight;
-    } else {
+    CharSequence text, int start, int end, int spanstartv, int v, Paint.FontMetricsInt fm) {
+
+    final int originHeight = fm.descent - fm.ascent;
+    // If original height is not positive, do nothing.
+    if (originHeight <= 0) {
+      return;
+    }
+
+    int realTextHeight = fm.bottom - fm.top;
+
+    if (mHeight >= realTextHeight) {
       // Show proportionally additional ascent / top & descent / bottom
       final int additional = mHeight - (-fm.top + fm.bottom);