Expanding content within UIScrollView

I'm building a cell-based game that essentially works like dominoes: you start开发者_Python百科 with one tile in the center, then connect additional tiles to it that can branch out in all directions. I have my game table all set up and working great... now I just need to make it scroll to accommodate the expanding content.

So, this doesn't seem to fit easily into a UIScrollView's built-in behavior. For one thing, cells expand in all directions – potentially going into the negative coordinate space of the UIScrollView. As far as I can tell, UIScrollView does not allow an actual CGRect with size AND origin to be defined for the scrolling content area. It appears you can only define a width and height for the content area that extends from point (0,0). Is this true, or am I missing something?

Assuming my understanding of the content area limitations are correct, how would one ideally handle this problem? My go-to idea would be to shift all subviews into positive coordinate space as the game board expands, then update the ScrollView's contentOffset property to counter the shift and make the transition invisible. I just want to make sure I'm not reinventing an inferior wheel before I start developing this.

Thanks in advance for any and all ideas!

I believe your idea is the good one, every time a tile is added, you may need to adjust your content view in order to be able to center on the tile that just was added.
Hence if this is "backward" (-x or -y) and your on top of your view (or nearly), you'll have to extend your contentView (surely the same way you do for +x, +y) and thus, adjust every of your tiles with the translation you did to your contentView's down-right corner.

Following up... yep, that did it. I set up the display so that it redraws the grid of cells from the upper-left corner. Whenever a new row or column of cells is added to the top or the left, the UIScrollView's contentOffset shifts by the newly added pixels to hide the change in content position.