How to get text scaling from Android and IOS settings?

[Sammasas]

I have to make my Application accessible and I want to use the text scaling that is set in the phones settings. Is there a universal way for Android and IOS to get those settings? I know there is the sp unit for text size that should scale accordingly but I can't find a way to implement that in QT.

[Sammasas]

@Sammasas
I didn't find a universal way, but with an QJNIObject and objective c it works now. Java with JNiObject:

package Klingelball;

import android.content.Context;
import android.content.res.Configuration;
import android.util.DisplayMetrics;
import android.view.WindowManager;

public class AndroidSettings {
   public static float getFontScale(Context context) {
       //return getResources().getConfiguration().fontScale;
       Configuration configuration = context.getResources().getConfiguration();

               // Get the font scale from the configuration
               float fontScale = configuration.fontScale;

               return fontScale;
   }
}

It's important that the file is under src/mypackage.

.cpp file:

#ifdef Q_OS_ANDROID
    QJniObject context = QNativeInterface::QAndroidApplication::context();
    if(QJniObject::isClassAvailable("Klingelball/AndroidSettings")) {
        QJniObject androidSettingsJavaObject = QJniObject("Klingelball/AndroidSettings");

        fontScale = new float(androidSettingsJavaObject.callStaticMethod<jfloat>("Klingelball/AndroidSettings", "getFontScale", "(Landroid/content/Context;)F", context.object<jobject>()));
        qDebug() <<"Font scale:" << *fontScale;
        setup_fontAndroid(*fontScale);

    }
    else {
        qDebug() << "JAVA CLASS UNAVAIABLE!";
        fontScale = new float(1);
        setup_fontAndroid(*fontScale);

    }
#endif

iOs with objective-c:
.mm file:

include "iOSSettings.h"
#include <UIKit/UIKit.h>


int iOSSettings::getPrefferedFont() {
    return [UIFont preferredFontForTextStyle:UIFontTextStyleBody].pointSize;
}

.h file:

class iOSSettings {
public:
    static int getPrefferedFont();
};

.cpp file:

#ifdef Q_OS_IOS
        
        fontScale = new float(getfontScalefrompointSize(iOSSettings::getPrefferedFont()));
        setup_fontiOS(iOSSettings::getPrefferedFont());
#endif

iOS returns the preffered Fontsize, I implemented a function that returns a factor based on the fontsize because I had to scale the Icons too.
Hope this helps somebody :)