import java.awt.image.BufferedImage;
import java.io.IOException;

import javax.imageio.ImageIO;


public class ImgTiles {
   
   static enum Tile {
      
      GRASS(0xff00ff00), //green
      WATER(0xff0000ff), //blue
      LAVA(0xffff0000);  //red
      
      public final int argb;
      
      Tile(int argb) {
         this.argb = argb;
      }
      
      public static Tile fromColor(int argb) {
         for (Tile t : Tile.values())
            if (t.argb == argb)
               return t;
         return null;
      }
      
   }

   public static void main(String[] args) throws IOException {
      BufferedImage img = ImageIO.read(ImgTiles.class.getResource("map.png"));
      int width = img.getWidth();
      int height = img.getHeight();
      int[] pixels = img.getRGB(0, 0, width, height, null, 0, width);
      
      //our map, using 2D array for convenience
      Tile[][] map = new Tile[width][height];
      
      for (int i=0; i<width * height; i++) {
         //the ARGB packed integer
         int value = pixels[i];
         
         //determine tile from ARGB color
         Tile t = Tile.fromColor(value);
         
         //determine (x, y) position
         int y = i / width;
         int x = i - width*y;
         
         //place tile in our 2D grid for handy access
         map[x][y] = t;
         
         //if you wanted to use ARGB values for something...
         //this is how you decode them to integers in the range 0-255 
         int a = ((value & 0xff000000) >>> 24);
         int r = ((value & 0x00ff0000) >>> 16);
         int g = ((value & 0x0000ff00) >>> 8);
         int b = (value & 0x000000ff);

         //...
      }

      //now we can access our map like normal
      System.out.println(map[0][0]); //will print GRASS, LAVA, or WATER.. or null if the color did not match
   }
}