How can i make infinite chess board

Question

Hello.
for example i want to create an infinite chess board for iphone.
i want to scale it as i want and to ho throw it up, down, left and right.
in what way can i make it? what class to use?
i think UIScrollView, but how? i do not have an image, because it must be infinite
and then i want to add figures to this chess board. for example if user tap on a cell a figure appears.

Answer 1

Hi Mywa, and welcome to the Dev Forums!
I'll try to outline a solution, but I doubt anyone is going to code it for you in a forum, so you'll need some iPhone development experience. As a minimum, make sure you know exactly how the [PageControl|http://developer.apple.com/library/ios/#samplecode/PageControl/Int roduction/Intro.html] sample app works, and have a good understanding of the Tiling example in the [ScrollViewSuite|http://developer.apple.com/library/ios/#samplecode/ScrollViewS uite/Introduction/Intro.html%23//apple_ref/doc/uid/DTS40008904]. It would also help if you're familiar with most of the content in the Scroll View Programming Guide for iOS.
I would start the project by obtaining a 320 x 320 image of your chess board (e.g. a slice of the board containing 8 x 8 squares, each 40 x 40 pixels). For now, you can just package the image as a single UIImageView object in a xib file (later on we might replace this with a custom subclass of UIView which draws either blank or populated squares, but let's do the basics first).
In your board controller's viewDidLoad method, create 9 of these objects, setting the frames to make 3 rows of 3 squares each, and add the 9 objects to a 320 x 320 scrollview so that only the central object is visible. Then set the scroll view's [contentSize|http://developer.apple.com/library/ios/documentation/UIKit/Referen ce/UIScrollViewClass/Reference/UIScrollView.html#//appleref/doc/uid/TP40006922-CH3-SW20] property to 960 x 960 and make sure you can scroll horizontally and vertically to the edges of the grid.
Once you get that part working, you're ready to expand the contentSize and write the code which removes and adds the 320 x 320 image view objects as needed. This is where you'll need to understand the sample apps I recommended. Basically, after each scrolling movement your controller logic needs to decide which image view objects can be released (or recycled), and which grid positions need a new (or reused) image view. The game is to always have an image view ready before any part of an empty grid position becomes visible.
For best performance, the image view objects should be placed in a "reuse" queue when they're removed from the superview, then pulled off the queue as needed, just as cells are managed by UITableView. But the reuse queue is only an optimization, so I would save it for later. For now, I would just release and create. The important thing is to make sure you never need to have very many more than 9 image view objects in memory at any time.
Once you have your "infinite" board operating correctly, you're ready to decide how to store the position of each piece, and how to draw the pieces on the visible squares. If the number of pieces is likely to exceed 1000, you might find the data storage to be more challenging than the drawing, because you'll need to locate pieces fast enough to keep up with scrolling. If the number of 8 x 8 board segments is to be considered infinite, you might not want to store the data for all 64 squares of every segment that's ever been visible. In that case you'll need a "sparse array" that only includes info on populated squares, i.e. one element for each piece instead of one element for each location. I think William gave you some good advice on what data structures to use for this. At some point you might also consider a database to implement your sparse array.
That's probably the best I can do to get you started. I would advise against trying to design all the details ahead of time. E.g., I don't expect you to reply with "Ok, but how do I actually draw the pieces?" until you've got the board working. And I don't expect you to ask how to draw the board until you've become good friends with the recommended sample apps. But once you're seriously into the sample code, we might be able to help with questions like: "I'm trying to calculate which view objects are visible as shown in the layoutSubviews method of [3Tiling/Classes/TiledScrollView.m|http://developer.apple.com/library/ios/sampleco de/ScrollViewSuite/Listings/3_Tiling_Classes_TiledScrollView_m.html#//apple_ref/ doc/uid/DTS40008904-3_Tiling_Classes_TiledScrollView_m-DontLinkElementID26], but ... ". Ok?
\- Ray