/**
 * Filter that stores filters the intensity for one of the RGB values for each 
 * row. The alternating patterns of R,G and G,B rows are stored. Green appears
 * more because human eye is sensitive to it and needs more accuracy.
 * @author Parag
 * @version February 25, 2003
 * 
 * DO NOT MODIFY THIS CLASS
 * This class does the transformation from an image to the mosaic pattern first 
 * recorded by a digital camera.
 */
public class DigitalCameraFilter implements Filter {
  
  /** filter this image - as done by a digital camera */
  public void filter(PixelImage pi) {
    Pixel[][] data = pi.getData();
    int pixelColor;
    
    for (int row = 0; row < pi.getHeight(); row++) {
      for (int col = 0; col < pi.getWidth(); col++) {
        
        //get the color for this pixel - we want a pattern of the form R,G,R,G
        //alternating with rows of the form G,B,G,B...   
        
        if(row%2 == 0 && col%2 == 0) {
          pixelColor = Pixel.Red;
        } else {
          if (row%2 != 0 && col%2 != 0) {
            pixelColor = Pixel.Blue;
          } else {
            pixelColor = Pixel.Green;   
          }
        }     
        Pixel pixel = data[row][col];
        data[row][col] = getSingleColor(pixel,pixelColor);
      }
    }
    pi.setData(data);
  }
  
  /** extract the intensity for the specifed color and copy this value 
   * for other colors as well. For example, if we want to retain the Green 
   * Value, we extract the green intensity from the pixel and copy this
   * value for all the 3 colors intensities */
  private Pixel getSingleColor(Pixel originalPixel,int color) {
    int intensity;
    if(color == Pixel.Red) {
      intensity = originalPixel.red;
    } else {
      if(color == Pixel.Green) {
        intensity = originalPixel.green;
      } else {
        intensity = originalPixel.blue;
      }
    }
    return new Pixel(intensity,color);
  }
}