import objectdraw.*;

// This program shows how one might enable a user to pinpoint the coordinates
// of a particular spot in a digital image by providing crosshairs that can
// be positioned using the mouse and displaying the numeric coordinates as
// the crosshairs move.

public class Crosshairs extends FrameWindowController {
        
        // the crosshair lines
        private Line vert, horiz;
       
        // display the crosshairs as soon as the mouse button is pressed
        public void onMousePress(Location point) { 
                // create the lines for the crosshairs
                vert = new Line(point.getX(), 0, point.getX(), canvas.getHeight(), canvas);
                horiz = new Line(0, point.getY(), canvas.getWidth(), point.getY(), canvas);
        }
        
        // remove the crosshairs as soon as the mouse is released.
        public void onMouseRelease(Location point){
                vert.removeFromCanvas();
                horiz.removeFromCanvas();
        }
        
        // move the crosshairs as the mouse is dragged about the window
        public void onMouseDrag(Location point) {   
                // reposition the crosshair lines
                vert.setEndPoints(point.getX(), 0, point.getX(), canvas.getHeight());                               
                horiz.setEndPoints(0, point.getY(), canvas.getWidth(), point.getY());
        }
        
}