.m

- (void)panningChangedWithTranslation:(CGPoint)translation
{
    if (self.playerViewAnimator.isRunning)
    {
        return;
    }

    CGFloat translatedY = self.view.center.y + translation.y;

    CGFloat progress;
    switch (self.playerState) {
        case PlayerStateThumbnail:
            progress = 1 - (translatedY / self.view.center.y);
            break;
        case PlayerStateFullscreen:
            progress = (translatedY / self.view.center.y) - 1;
    }

    progress = MAX(0.001, MIN(0.999, progress));

    self.playerViewAnimator.fractionComplete = progress;
}