Android/app/src/main/java/protect/card_locker/Utils.java

package protect.card_locker;

import android.content.Context;
import android.graphics.Color;

import androidx.core.graphics.ColorUtils;

public class Utils {
    static final double LUMINANCE_MIDPOINT = 0.5;

    static public LetterBitmap generateIcon(Context context, String store, Integer backgroundColor) {
        if (store.length() == 0) {
            return null;
        }

        int tileLetterFontSize = context.getResources().getDimensionPixelSize(R.dimen.tileLetterFontSize);
        int pixelSize = context.getResources().getDimensionPixelSize(R.dimen.cardThumbnailSize);

        return new LetterBitmap(context, store, store,
                tileLetterFontSize, pixelSize, pixelSize, backgroundColor, needsDarkForeground(backgroundColor) ? Color.BLACK : Color.WHITE);
    }

    static public boolean needsDarkForeground(Integer backgroundColor) {
        return ColorUtils.calculateLuminance(backgroundColor) > LUMINANCE_MIDPOINT;
    }
}