Color.java

import java.lang.Math;
import java.util.function.*;

public class Color {  
  public int r, g, b;

  public Color(int r, int g, int b) {
    this.r = r;
    this.g = g;
    this.b = b;
  }
  
  public Color(int value) {
    this(value, value, value);
  }
  
  public Color clone() {
    return new Color(r, g, b);
  }

  public static Color brighten(Color source, float factor) {
    Function<Integer, Integer> brighten = x -> (int)(x * factor);
    return new Color(brighten.apply(source.r), brighten.apply(source.g), brighten.apply(source.b));
  }

  public static Color gradient(Color startingColor, Color endingColor, float progress) {
    return new Color(
      lerp(startingColor.r, endingColor.r, progress),
      lerp(startingColor.g, endingColor.g, progress),
      lerp(startingColor.b, endingColor.b, progress)
      );
  }

  private static int lerp(int a, int b, float t) {
    if (t < 0 || t > 1) throw new IllegalArgumentException("t must be a value from 0 to 1!");
    return Math.round(a + (b - a) * t);
  }
}