Hi,

There are currently 2 ways to achieve the tab appearance you're asking for. The first way is to use a custom image like our Tab Custom sample in the NucliOS sample browser, and the second way manually creates a tab that has a circle shape layer. The source for the second method is found below.

- (void)initializeTabs
{
    //Create the slide tab view
    _slidetabView = [[IGSlideTabView alloc] initWithFrame:self.view.bounds];
    _slidetabView.autoresizingMask = UIViewAutoresizingFlexibleWidth|UIViewAutoresizingFlexibleHeight;
    [self.view addSubview:_slidetabView];

    //Create the circle shape layer
    _circleShapeLayer = [CAShapeLayer layer];
    _circleShapeLayer.path = [UIBezierPath bezierPathWithOvalInRect: CGRectMake(0, 0, 40, 40)].CGPath;
    _circleShapeLayer.fillColor = [UIColor colorWithRed:91/255.0f green:172/255.0f blue:225/255.0f alpha:1.0].CGColor;

    //Create the left tab that holds the circle shape
    _leftTabView = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 40, 40)];
    [_leftTabView.layer addSublayer:_circleShapeLayer];

    //Create the circle shape label
    _circleLabel = [[UILabel alloc] initWithFrame:_leftTabView.bounds];
    _circleLabel.textColor = [UIColor whiteColor];
    _circleLabel.textAlignment = NSTextAlignmentCenter;
    _circleLabel.font = [UIFont fontWithName:@"HelveticaNeue" size:20];
    _circleLabel.text = @"\u2794";
    [_leftTabView addSubview:_circleLabel];

    //Create a content view
    _leftContent = [[UIView alloc] initWithFrame:CGRectMake(0, 0, 200, 200)];
    _leftContent.backgroundColor = [UIColor colorWithWhite:0.9 alpha:1.0];

    //Create the slide tab item
    _slideTabLeft = [IGSlideTabItem tabWithLocation:IGSlideTabLocationLeft title:nil tabView:_leftTabView contentView:_leftContent];
    _slideTabLeft.tabSize = _leftTabView.bounds.size;
    _slideTabLeft.contentSize = [IGSlideTabContentSize sizeWithWidth:200 height:200];
    [_slidetabView addTab:_slideTabLeft];
}