AdaptiveFont.cs

using System.Collections;
using System.Collections.Generic;
using UnityEngine.UI;
using UnityEngine;

public class AdaptiveFont : MonoBehaviour
{
    Text txt;
    public bool continualUpdate = true;

    public int fontSizeAtDefaultResolution = 24;
    public static float defaultResolution = 2229f;


    // Use this for initialization
    void Start ()
    {
        //print(Screen.height + Screen.width);

        txt = GetComponent<Text>();

        if(continualUpdate)
        {
            InvokeRepeating("Adjust", 0f, Random.Range(0.5f, 2f));
        }
        else
        {
            Adjust();
            enabled = false;
        }

    }

    void Adjust()
    {
        if (!enabled || !gameObject.activeInHierarchy)
        {
            return;
        }

        float totalCurrentRes = Screen.height + Screen.width;
        float perc = totalCurrentRes / defaultResolution;
        int fontsize = Mathf.RoundToInt((float)fontSizeAtDefaultResolution * perc);

        txt.fontSize = fontsize;

    }
}