/**
 * Class for creating a template for a simple Java program
 * 
 * @author Pat Troy: troy AT uic DOT edu
 */

// import the library with the color information
import java.awt.Color;

// Note the name of the class in the following line MUST
// match the name of the file.  This is stored in a file
// named: Template.java 
public class Lect107f
{
  
  public static void main (String[] args) 
  {
    System.out.println("Begin Java Exection");
    System.out.println("");

    // Select a picture for the turtle to draw on
    String filename = FileChooser.pickAFile();
    System.out.println (filename);
    Picture pict1 = new Picture(filename);
    
    // call the method to modify the picture
    modifyPicture (pict1);
    
    // display the picture
    pict1.explore();
    
    // Save the picture
    //String fname;
    //fname = FileChooser.pickAFile();
    //System.out.println ("File: " + filename);
    //pict1.write (fname);

    System.out.println("");
    System.out.println("End Java Exection");
  }   // end of the method main
  
  
 
  public static void modifyPicture (Picture pict1)
  {
    // get the width and height of the picture
    int width = pict1.getWidth();
    int height = pict1.getHeight();
    //System.out.println ("Width: " + width);
    //System.out.println ("Height: " + height);
    
    // set up a nested loop (one loop inside another) to access each pixel
    int xLoopCounter;
    int yLoopCounter;
    
    // the outer loop varies the X position (which column the pixel is in)
    xLoopCounter = 0;
    while (xLoopCounter < width)
    {
      // the inner loop varies the Y position (which row the pixel is in)
      yLoopCounter = 0;
      while (yLoopCounter < height)
      {
        // access a pixel
        Pixel p = pict1.getPixel (xLoopCounter, yLoopCounter); 
        
        // access the color values from the pixel
        int red = p.getRed();
        int green = p.getGreen();
        int blue = p.getBlue();
        
        // modify the color value as needed 
        int grayAmount = (red + green + blue) / 3;
        red = grayAmount;
        green = grayAmount;
        blue = grayAmount;
        
        // save the modified color values
        p.setRed(red);
        p.setGreen(green);
        p.setBlue(blue);
        
        yLoopCounter++;
      }
      
      xLoopCounter++;
    }
    
  }  // end of the method to modify the picture
  
} // end of Lect914b class