Centering a frame into screen.

center to screen

// centering the images inside.
        CGSize boundsSize = self.view.bounds.size;
        CGRect frameToCenter = imageView.frame;
        
        // center horizontally
        if (frameToCenter.size.width < boundsSize.width)
            frameToCenter.origin.x = (boundsSize.width - frameToCenter.size.width) / 2;
        else
            frameToCenter.origin.x = 0;
        
        // center vertically
        if (frameToCenter.size.height < boundsSize.height) {
            frameToCenter.origin.y = (boundsSize.height - frameToCenter.size.height) / 2;
        }
        else {
            frameToCenter.origin.y = 0;
        }
        
        imageView.frame = frameToCenter;