BImage a;

void setup()
{
  size(250,333);
  a = loadImage("house1.gif");
}

void loop()
{
  background(266);
  //we're only going to process a portion of the image so let's set the whole image as the background first
  image(a,40,40,160,240);

  //For drawing a black rectangle defining area for processing
  stroke(0);
  noFill();
  rectMode (CENTER_DIAMETER);
  //drawing sensor lines
  line(mouseX,mouseY+50,440-mouseX,mouseY);
  line(mouseX,mouseY+50,400-mouseX,mouseY);
  line(mouseX,mouseY+50,355-mouseX,mouseY);
    line(mouseX,mouseY+50,325-mouseX,mouseY);
  line(mouseX,mouseY+50,300-mouseX,mouseY);
  line(mouseX,mouseY+50,255-mouseX,mouseY);
   line(mouseX,mouseY+50,235-mouseX,mouseY);
  line(mouseX,mouseY+50,200-mouseX,mouseY);
  line(mouseX,mouseY+50,150-mouseX,mouseY);
  line(mouseX,mouseY+50,100-mouseX,mouseY);
  line(mouseX,mouseY+50,50-mouseX,mouseY);
   line(mouseX,mouseY+50,35-mouseX,mouseY);
  line(mouseX,mouseY+50,25-mouseX,mouseY);
  line(mouseX,mouseY+50,15-mouseX,mouseY);
  line(mouseX,mouseY+50,10-mouseX-100,mouseY);
  line(mouseX,mouseY+50,5-mouseX-50,mouseY);

  //what are the boundaries for the pixels we are processing
  int X1 = constrain(mouseX-40,0,a.width);
  int Y1 = constrain(mouseY-40,0,a.height);
  int X2 = constrain(mouseX+40,0,a.width);
  int Y2 = constrain(mouseY+40,0,a.height);

  //begin our loop for every pixel
  for (int x = X1; x < X2; x++) {
    for (int y = Y1; y < Y2; y++ ) {
      //calculate the 1D location from a 2D grid
      int loc = x + y*a.width;
      //get the R,G,B values from image
      float r,g,b;
      r = red   (a.pixels[loc]);
      g = green (a.pixels[loc]);
      b = blue  (a.pixels[loc]);
      //make a new color and set pixel in the window
      color c = color(0,g,b);
      pixels[loc] = c;//a.pixels[loc];

    }
  }
}