A small category for UIScrollView to programatically zoom to a CGPoint as opposed to a CGRect. Currently in use in my iOS app, iComics (http://icomics.co)

UIScrollView+ZoomToPoint.m

@implementation UIScrollView (ZoomToPoint)

- (void)zoomToPoint:(CGPoint)zoomPoint withScale: (CGFloat)scale animated: (BOOL)animated
{
    //Normalize current content size back to content scale of 1.0f
    CGSize contentSize;
    contentSize.width = (self.contentSize.width / self.zoomScale);
    contentSize.height = (self.contentSize.height / self.zoomScale);

    //translate the zoom point to relative to the content rect
    zoomPoint.x = (zoomPoint.x / self.bounds.size.width) * contentSize.width;
    zoomPoint.y = (zoomPoint.y / self.bounds.size.height) * contentSize.height;

    //derive the size of the region to zoom to
    CGSize zoomSize;
    zoomSize.width = self.bounds.size.width / scale;
    zoomSize.height = self.bounds.size.height / scale;

    //offset the zoom rect so the actual zoom point is in the middle of the rectangle
    CGRect zoomRect;
    zoomRect.origin.x = zoomPoint.x - zoomSize.width / 2.0f;
    zoomRect.origin.y = zoomPoint.y - zoomSize.height / 2.0f;
    zoomRect.size.width = zoomSize.width;
    zoomRect.size.height = zoomSize.height;

    //apply the resize
    [self zoomToRect: zoomRect animated: animated];
}

@end