/** We must import the Graphics classes from uwcse.jar for this
 *  example.  If Dr. Java cannot find this package, select the
 *  Edit>Preferences menu item, and press the Add button to add
 *  the .jar to the ClassPath.  After pressing the Add button just
 *  navigate to and select the uwcse.jar file, wherever it is on
 *  your computer.
 */

import uwcse.graphics.*;
import java.awt.Color;


/** A class just to wrap the looping functionality we are demonstrating.
 */
public class LoopTest {

/** The graphics window is an instance variable, for persistence.
 */
  GWindow gw;
 
/** Constructor initializes the window.
 */
  public LoopTest() {
    gw = new GWindow();
  }
 
/** Endlessly running method to move a rectangle back and forth
 */
  public void run() {
    //  rect is local to this method.  Create it and add it to the window
    Rectangle rect = new Rectangle();
    gw.add(rect);

    int i = 0;
    while ( true ) {  //i.e. do this outer loop forever.
      rect.setColor(Color.red);  //static constants defined in class Color
      while ( i < 250) {  //nested inner loop to move to the right
        rect.moveTo(rect.getX() + 1, rect.getY()); 
        i = i + 1;
      }
      rect.setColor(Color.green);
       while ( i > 20 ) {  //nested inner loop to move to the left
        rect.moveTo(rect.getX() - 1, rect.getY());
        i = i - 1;
      }
       
    }
  }
     
/** Draw a shaded stripe across and down.   Demonstrate for-loop construct.
 */
    public void oneShot() {
      
      for (int i = 10; i < 250; i++) {  //standard for loop structure.
        Rectangle newRect = new Rectangle();      //NOTE:  new Rectangle created EVERY ITERATION temporarily help in local var
        Color newColor = new Color(i, i/2, 200);  //NOTE:  same goes for this new Color
        newRect.setColor(newColor);
        gw.add(newRect);
             
        newRect.moveTo(2*i, i);
      }     
       // Local variables have vanished by this point. 
       // Rectangles stay on the screen because they are referenced by gw, which persists.
    }
    
}