allowFontScaling = false not working on react native 0.78.1

[Ahmed-Bilal-01]

I have developed an app and currently working on it iOS side. By increasing the font size from mobile's setting disturbs all the UI of the app even have applied allowFontScaling = false globally from index.js.

With normal scaling:

With increasing font scale:

my index.js:

import { Text,TextInput, AppRegistry } from "react-native";
import App from "./App";
import { name as appName } from "./app.json";

Text.defaultProps = Text.defaultProps || {};
TextInput.defaultProps = TextInput.defaultProps || {};
Text.defaultProps.allowFontScaling = false;
TextInput.defaultProps.allowFontScaling = false;

AppRegistry.registerComponent(appName, () => App);

[lukewalczak]

Hey @Ahmed-Bilal-01, if you want to completely disable font scaling you can try the following code:

if (Text.defaultProps == null) {
  Text.defaultProps = {};
  Text.defaultProps.allowFontScaling = false;
}

However, text components should have the property *maxFontSizeMultiplier so you can adjust the largest possible scale a font can reach only when allowFontScaling is enabled.

[Ahmed-Bilal-01]

Hi @lukewalczak, thank you for your response. I tried :
if (Text.defaultProps == null) { Text.defaultProps = {}; Text.defaultProps.allowFontScaling = false; }

inserting in index.js but it is not effecting globally through the app. I found that allowFontScaling= false is only working when implemented individually in every Text field separately which is making it difficult to enable it through out the app as I am working on already build large app.

[lukewalczak]

I tested it on our example app — it's using React Native 0.76, but it looks like disabling font scaling works as expected. Please make sure you are importing Text from react-native-paper.

[Ahmed-Bilal-01]

I tried it again using react-native-paper still didn't work in react native 0.78.1. This issue was not popping till 0.77 version i guess.

[lukewalczak]

When using the Text component from react-native with font scaling disabled, does it behave as expected?

Edit: The support for defaultProps were removed, so there is no easy way to handle it.

[Ahmed-Bilal-01]

Nope it was also not working.

[lukewalczak]

As mentioned earlier, defaultProps are no longer supported, so you'll need to find an alternative approach to disable font scaling if that’s a requirement.

Closing the issue, since it's not specific directly to the library.