import objectdraw.*;

// Enables a user to draw crosshairs that can be positioned
// using the mouse. Draws an initial set of centered crosshairs
// at the start of the program.
public class Crosshairs extends FrameWindowController {

    // the crosshair lines
    private Line horiz;
    private Line vert;

    // draw a set of crosshairs centered in the window
    public void begin() {
        new Line(0, canvas.getHeight() / 2, canvas.getWidth(), canvas.getHeight() / 2, canvas);
        new Line(canvas.getWidth() / 2, 0, canvas.getWidth() / 2, canvas.getHeight(), canvas);
    }

    // display the crosshairs as soon as the mouse button is pressed
    public void onMousePress(Location point) { 
        // create the lines for the crosshairs
        horiz = new Line(0, point.getY(), canvas.getWidth(), point.getY(), canvas);
        vert = new Line(point.getX(), 0, point.getX(), canvas.getHeight(), canvas);
    }

    // move the crosshairs as the mouse is dragged about the window
    public void onMouseDrag(Location point) {   
        // reposition the crosshair lines
        horiz.removeFromCanvas();
        vert.removeFromCanvas();
        horiz = new Line(0, point.getY(), canvas.getWidth(), point.getY(), canvas);
        vert = new Line(point.getX(), 0, point.getX(), canvas.getHeight(), canvas);
    }

}