/**
 * ScrolliingSun example from chapter 3 of Java: An Eventful Approach
 */

import objectdraw.*;
import java.awt.*;

public class ScrollingSun extends WindowController {

    private FilledOval sun;     // Circle that represents the sun
    private Text instructions;  // Display of instructions

    // Place the sun and some brief instructions on the screen
    public void begin() {
        sun = new FilledOval( canvas.getWidth()/4,
                              canvas.getHeight() - canvas.getWidth()/4,
                              canvas.getWidth()/2,
                              canvas.getWidth()/2, canvas);

        instructions = new Text("Drag the mouse up or down",
                                                0, 0, canvas);
        instructions.moveTo((canvas.getWidth()-instructions.getWidth() )/2, 20);
    }

    // Move the sun to follow the mouse's vertical motion
    public void onMouseDrag( Location mousePosition ) {
        sun.moveTo(canvas.getWidth()/4, mousePosition.getY());
        instructions.hide();
    }
    
    // Move the sun back to its starting position and redisplay
    // the instructions
    public void onMouseExit( Location point ) {
        sun.moveTo(canvas.getWidth()/4, canvas.getHeight() - canvas.getWidth()/4);
        instructions.show();
    }
}