From ed7766cee941e36af05b19a315b442edf738ef80 Mon Sep 17 00:00:00 2001
From: Jakub Piasecki <jakub.piasecki@swmansion.com>
Date: Fri, 19 Apr 2024 10:20:15 -0700
Subject: [PATCH] Don't enlarge font when `adjustFontSizeToFit` is set on iOS
 on the new architecture (#44163)

Summary:
On the old architecture `adjustFontSizeToFit` only shrinks the font size when there's too little space, while on the new arch it's also enlarged when there's too much space so that it always takes the entire width. This PR changes this behavior so that it only shrinks the text.

Fixes https://github.com/facebook/react-native/issues/42044

bypass-github-export-checks

## Changelog:

[IOS] [FIXED] - Fixed font size enlarging when `adjustFontSizeToFit` is set

Pull Request resolved: https://github.com/facebook/react-native/pull/44163

Test Plan:
<details>
<summary>Tested on the following code</summary>

```jsx
import { Text, SafeAreaView, View, StyleSheet } from 'react-native';

export default function Test() {
  return (
    <SafeAreaView style={styles.container}>
      <View style={{margin: 4, borderWidth: 1, borderColor: 'black'}}>
        <Text style={{ fontSize: 16 }}>
          Some text that fits (no adjust, unlimited height)
        </Text>
      </View>

      <View style={{margin: 4, borderWidth: 1, borderColor: 'black'}}>
        <Text style={{ fontSize: 16 }} adjustsFontSizeToFit>
          Some text that fits (adjust, unlimited height)
        </Text>
      </View>

      <View style={{margin: 4, borderWidth: 1, borderColor: 'black'}}>
        <Text style={{ fontSize: 16 }} numberOfLines={1}>
          Some text that fits (no adjust, 1 line)
        </Text>
      </View>

      <View style={{margin: 4, borderWidth: 1, borderColor: 'black'}}>
        <Text style={{ fontSize: 16 }} adjustsFontSizeToFit numberOfLines={1}>
          Some text that fits (adjust, 1 line)
        </Text>
      </View>

      <View style={{margin: 4, borderWidth: 1, borderColor: 'black'}}>
        <Text style={{ fontSize: 16 }}>
          Some longer text that doesn't fit if displayed in one line (no adjust, unlimited height)
        </Text>
      </View>

      <View style={{margin: 4, borderWidth: 1, borderColor: 'black'}}>
        <Text style={{ fontSize: 16 }} adjustsFontSizeToFit>
          Some longer text that doesn't fit if displayed in one line (adjust, unlimited height)
        </Text>
      </View>

      <View style={{margin: 4, borderWidth: 1, borderColor: 'black'}}>
        <Text style={{ fontSize: 16 }} numberOfLines={1}>
          Some longer text that doesn't fit if displayed in one line (no adjust, 1 line)
        </Text>
      </View>

      <View style={{margin: 4, borderWidth: 1, borderColor: 'black'}}>
        <Text style={{ fontSize: 16 }} adjustsFontSizeToFit numberOfLines={1}>
        Some longer text that doesn't fit if displayed in one line (adjust, 1 line)
        </Text>
      </View>

      <View style={{margin: 4, borderWidth: 1, borderColor: 'black'}}>
        <Text style={{ fontSize: 16 }}>
          Even longer text that doesn't even fit if it has as much as two entire lines for itself, what a darn shame (no adjust, unlimited height)
        </Text>
      </View>

      <View style={{margin: 4, borderWidth: 1, borderColor: 'black'}}>
        <Text style={{ fontSize: 16 }} adjustsFontSizeToFit>
          Even longer text that doesn't even fit if it has as much as two entire lines for itself, what a darn shame (adjust, unlimited height)
        </Text>
      </View>

      <View style={{margin: 4, borderWidth: 1, borderColor: 'black'}}>
        <Text style={{ fontSize: 16 }} numberOfLines={2}>
          Even longer text that doesn't even fit if it has as much as two entire lines for itself, what a darn shame (no adjust, 2 lines)
        </Text>
      </View>

      <View style={{margin: 4, borderWidth: 1, borderColor: 'black'}}>
        <Text style={{ fontSize: 16 }} numberOfLines={2} adjustsFontSizeToFit>
          Even longer text that doesn't even fit if it has as much as two entire lines for itself, what a darn shame (adjust, 2 lines)
        </Text>
      </View>
    </SafeAreaView>
  );
}
```

</details>

|Old arch (without this PR)|Old arch (with this PR)|
|-|-|
|<img width="546" alt="old_no_change" src="https://github.com/facebook/react-native/assets/21055725/f9682c0c-9a23-46b3-984d-607f83811d9e">|<img width="546" alt="old_changed" src="https://github.com/facebook/react-native/assets/21055725/c07f88fb-8ca2-415e-95c9-27bf718fc510">|

|New arch (without this PR)|New arch (with this PR)|
|-|-|
|<img width="546" alt="new_no_change" src="https://github.com/facebook/react-native/assets/21055725/173ac140-a836-4a40-83ef-c5365972700f">|<img width="546" alt="new_changed" src="https://github.com/facebook/react-native/assets/21055725/b0b00e45-17d2-4756-8ae5-a21c4ec242d9">|

Reviewed By: cortinico

Differential Revision: D56356139

Pulled By: cipolleschi

fbshipit-source-id: d11a5f4b95fb7da28a24d9136d41349d39851d9e
---
 .../Libraries/Text/Text/NSTextStorage+FontScaling.m          | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/packages/react-native/Libraries/Text/Text/NSTextStorage+FontScaling.m b/packages/react-native/Libraries/Text/Text/NSTextStorage+FontScaling.m
index ee391a20f6c..fa86a458970 100644
--- a/packages/react-native/Libraries/Text/Text/NSTextStorage+FontScaling.m
+++ b/packages/react-native/Libraries/Text/Text/NSTextStorage+FontScaling.m
@@ -19,6 +19,11 @@ typedef NS_OPTIONS(NSInteger, RCTTextSizeComparisonOptions) {
                minimumFontSize:(CGFloat)minimumFontSize
                maximumFontSize:(CGFloat)maximumFontSize
 {
+  // Don't scale the font if it already fits
+  if ([self compareToSize:size thresholdRatio:0.01] & RCTTextSizeComparisonSmaller) {
+    return;
+  }
+
   CGFloat bottomRatio = 1.0 / 128.0;
   CGFloat topRatio = 128.0;
   CGFloat ratio = 1.0;