import java.awt.*;
  /**
  * Create Triangle
  *
  * @author (Hendra Ramadani 05111740000055)
  *
  * @version (0.0001)
  */
  public class Triangle
  {
   private int height;
   private int width;
   private int xPosition;
   private int yPosition;
   private String color;
   private boolean isVisible;
   /**
   * Create a new triangle at default position with default color.
   */
   public Triangle()
   {
    height = 30;
    width = 40;
    xPosition = 50;
    yPosition = 15;
    color = "green";
    isVisible = false;
   }
   /**
   * Make this triangle visible. If it was already visible, do nothing.
   */
   public void makeVisible()
   {
    isVisible = true;
    draw();
   }
   /**
   * Make this triangle invisible. If it was already invisible, do nothing.
   */
   public void makeInvisible()
   {
    erase();
    isVisible = false;
   }
   /**
   * Move the triangle a few pixels to the right.
   */
   public void moveRight()
   {
    moveHorizontal(20);
   }
   /**
   * Move the triangle a few pixels to the left.
   */
   public void moveLeft()
   {
    moveHorizontal(-20);
   }
   /**
   * Move the triangle a few pixels up.
   */
   public void moveUp()
   {
    moveVertical(-20);
   }
   /**
   * Move the triangle a few pixels down.
   */
   public void moveDown()
   {
    moveVertical(20);
   }
   /**
   * Move the triangle horizontally by 'distance' pixels.
   */
   public void moveHorizontal(int distance)
   {
    erase();
    xPosition += distance;
    draw();
   }
   /**
   * Move the triangle vertically by 'distance' pixels.
   */
   public void moveVertical(int distance)
   {
    erase();
    yPosition += distance;
    draw();
   }
   /**
   * Slowly move the triangle horizontally by 'distance' pixels.
   */
   public void slowMoveHorizontal(int distance)
   {
    int delta;
    if(distance < 0)
    {
     delta = -1;
     distance = -distance;
    }
    else
    {
     delta = 1;
    }
    for(int i = 0; i < distance; i++)
    {
     xPosition += delta;
     draw();
    }
   }
   /**
   * Slowly move the triangle vertically by 'distance' pixels.
   */
   public void slowMoveVertical(int distance)
   {
    int delta;
    if(distance < 0)
    {
     delta = -1;
     distance = -distance;
    }
    else
    {
     delta = 1;
    }
    for(int i = 0; i < distance; i++)
    {
     yPosition += delta;
     draw();
    }
   }
   /**
   * Change the size to the new size (in pixels). Size must be >= 0.
   */
   public void changeSize(int newHeight, int newWidth)
   {
    erase();
    height = newHeight;
    width = newWidth;
    draw();
   }
   /**
   * Change the color. Valid colors are "red", "yellow", "blue", "green",
   * "magenta" and "black".
   */
   public void changeColor(String newColor)
   {
    color = newColor;
    draw();
   }
   /*
   * Draw the triangle with current specifications on screen.
   */
   private void draw()
   {
    if(isVisible) {
     Canvas canvas = Canvas.getCanvas();
     int[] xpoints = { xPosition, xPosition + (width/2), xPosition - (width/2) };
     int[] ypoints = { yPosition, yPosition + height, yPosition + height };
     canvas.draw(this, color, new Polygon(xpoints, ypoints, 3));
     canvas.wait(10);
    }
   }
   /*
   * Erase the triangle on screen.
   */
   private void erase()
   {
    if(isVisible) {
     Canvas canvas = Canvas.getCanvas();
     canvas.erase(this);
    }
   }
  }