- (void) scaleFrom: (float) s_old
                to: (float) s_new
              time: (float) t
{
    CABasicAnimation * scaleAnimation = [CABasicAnimation animationWithKeyPath: @"transform.scale"];

    [scaleAnimation setDuration:  t ];
    [scaleAnimation setFromValue:  (id) [NSNumber numberWithDouble: s_old] ];
    [scaleAnimation setToValue:  (id) [NSNumber numberWithDouble: s_new] ];
    [scaleAnimation setTimingFunction:  [CAMediaTimingFunction functionWithName: kCAMediaTimingFunctionEaseOut] ];
    [scaleAnimation setFillMode: kCAFillModeForwards];
    scaleAnimation.removedOnCompletion = NO;

    [self.contentsLayer addAnimation: scaleAnimation
                              forKey: @"transform.scale"];

    if (self.displayShadow && self.shadowLayer)
        [self.shadowLayer addAnimation: scaleAnimation
                                forKey: @"transform.scale"];

    size = s_new;
}

// - - -

- (void) resize: (float) newSize
{
    [self scaleFrom: size
                 to: newSize
               time: 1.];
}