// This class uses the border of the component that caught

// the mouse event to determine the drag direction.

sclass WindowResizeDragger extends MouseAdapter {

  int cornerSize = 10; // how big do we assume the corners are

  bool debug;

  Pt minWindowSize = pt(20, 20);

  MouseEvent mouseDownEvent; // if != null, we're engaged

  JComponent src;

  Window window;

  Rect originalPosition, srcBounds;

  int dragX, dragY; // -1, 0 or 1 depending on what we are dragging

  Cursor originalCursor, ourCursor;

  *(JComponent *src) {

    addMouseAndMotionListener(src, this);

  }

  bool engaged() { ret mouseDownEvent != null; } 

  void start(MouseEvent e) {

    this.mouseDownEvent = e;

    window = getWindow(src);

    if (window == null) ret;

    originalPosition = toRect(getBounds(window));

    cursorCalc(e, true);

  }

  void cursorCalc(MouseEvent e, bool inside) {

    srcBounds = toRect(boundsOnScreen(src));

    Pt mouse = pt(e.getXOnScreen(), e.getYOnScreen());

    if (distance(mouse.y, srcBounds.y2()) <= cornerSize)

      dragY = 1;

    else if (distance(mouse.y, srcBounds.y1()) <= cornerSize)

      dragY = -1;

    else

      dragY = 0;

    if (distance(mouse.x, srcBounds.x2()) <= cornerSize)

      dragX = 1;

    else if (distance(mouse.x, srcBounds.x1()) <= cornerSize)

      dragX = -1;

    else

      dragX = 0;

    originalCursor = src.getCursor();

    int iCursor = dragY*3+dragX+4;

    int cursor = new int[] {

      Cursor.NW_RESIZE_CURSOR,

      Cursor.N_RESIZE_CURSOR,

      Cursor.NE_RESIZE_CURSOR,

      Cursor.W_RESIZE_CURSOR,

      -1,

      Cursor.E_RESIZE_CURSOR,

      Cursor.SW_RESIZE_CURSOR,

      Cursor.S_RESIZE_CURSOR,

      Cursor.SE_RESIZE_CURSOR,

    }[iCursor];

    Cursor newCursor = cursor >= 0 && inside ? Cursor.getPredefinedCursor(cursor) : null;

    if (debug) printVars(iCursor, +ourCursor, +newCursor);

    if (newCursor != ourCursor) {

      ourCursor = newCursor;

      src.setCursor(newCursor);

    }

    /*if (debug)

      printVars("WindowResizeDragger", +dragX, +dragY, +mouse, +srcBounds, +cornerSize);*/

  }

  @Override public void mouseEntered(MouseEvent e) {

    if (debug) print("mouseEntered");

    if (!engaged())

      cursorCalc(e, true);

  }

  @Override public void mouseExited(MouseEvent e) {

    if (debug) print("mouseExited");

    if (!engaged())

      cursorCalc(e, false);

  }

  public void mousePressed(MouseEvent e) {

    if (e.getButton() != MouseEvent.BUTTON1) ret;

    //if (window cast JFrame && isMaximized(window)) ret;

    if (engaged()) ret; // what?

    start(e);

  }

  public void mouseDragged(MouseEvent e) {

    if (!engaged()) ret;

    updatePosition(e);

  }

  public void mouseMoved(MouseEvent e) {

    cursorCalc(e, true);

  }

  public void mouseReleased(MouseEvent e) {

    if (e.getButton() != mouseDownEvent.getButton()) ret;

    updatePosition(e);

    if (debug) print("drag done");

    if (src.getCursor() == ourCursor)

      src.setCursor(originalCursor);

    mouseDownEvent = null;

    dragDone();

  }

  void updatePosition(MouseEvent e) {

    //if (debug) printVars("updatePosition", +e);

    Rect w = toRect(window.getBounds());

    Pt a = topLeftCorner(w), b = bottomRightCorner(w);

    Pt mouse = pt(e.getXOnScreen(), e.getYOnScreen());

    if (dragX < 0)

      a.x = min(b.x-minWindowSize.x, mouse.x + originalPosition.x - mouseDownEvent.getXOnScreen());

    else if (dragX > 0)

      b.x = max(a.x+minWindowSize.x, mouse.x + originalPosition.x2() - mouseDownEvent.getXOnScreen());

    if (dragY < 0)

      a.y = min(b.y-minWindowSize.y, mouse.y + originalPosition.y - mouseDownEvent.getYOnScreen());

    else if (dragY > 0)

      b.y = max(a.y+minWindowSize.y, mouse.y + originalPosition.y2() - mouseDownEvent.getYOnScreen());

    Rect r = rectFromPoints(a, b);

    if (debug) printVars("updatePosition", +w, +mouse, +a, +b, +dragX, +dragY);

    window.setBounds(toRectangle(r));

  }

  void dragDone {}

}