Poker Real Time Odds on Mac OS X: Part 2

The continuing story of creating a tool called SeeingStars, offering real time odds for PokerStars. Read part 1 here.

If you are an Objective-C programmer, I’m going to give you enough code to get the basics working in this series of articles. If you are not a programmer at all, you probably won’t enjoy much of what follows. Important to note is that I seldom code in Objective-C, so my code isn’t always idiomatic for Objective-C and may have obvious bugs. Please point this out in the comments so I can learn.

Here’s the basic strategy:

1. Find the top-most PokerStars poker table window, if any
2. If no such window exists go to step 7
3. Grab a screenshot of the window
4. Determine the player’s hole cards and the community cards using some form of screen scraping/OCR
5. Calculate the % chance of winning, assuming the villains have random hands
6. Display the % chance of winning
7. Wait a second or so
8. Go back to step 1

The hardest bit for me will be step 4, which is determining the player’s hole cards and the community cards. I already have a fair idea how to do the other steps.

First, a timer will achieve the “wait a second or so” of step 7 and 8:

- (IBAction)startRepeatingTimer:sender {
    [NSTimer scheduledTimerWithTimeInterval:1.0
                                     target:self selector:@selector(targetMethod:)
                                   userInfo:[self userInfo] repeats:YES];
}

- (void)targetMethod:(NSTimer *)theTimer {
    NSDictionary *windowDictionary = [[PokerRoomController alloc] findPokerStarsTableWindows];
    if (windowDictionary != nil) {
        NSString *title = [windowDictionary objectForKey:@"kCGWindowName"];
        NSLog(@"title = %@", title);
    }
}

Is one second a reasonable time, that balances snappy updates with low CPU load? I don’t know. I’ll know later in the story. But for now, it is an adequate starting point. I tend to go for “good enough” solutions until I have evidence that the solution is not good. I’ll address performance issues as they arise.

Now for step 1 – find the top-most PokerStars window. There’s a handy function to find all the windows open on your Mac, introduced in Mac OS X 10.5 (Leopard). It is called CGWindowListCopyWindowInfo. It is part of Quartz Window Services. It returns a key-value dictionary of information for each window. Conveniently it returns windows ordered from top to bottom; the front-most window is first in the array of dictionaries. “Normal” windows have a layer of 0.

- (NSDictionary *)findFrontNormalWindow {
    NSArray *windowList = (__bridge NSArray *) 
        CGWindowListCopyWindowInfo(kCGWindowListOptionOnScreenOnly, kCGNullWindowID);
    for (NSDictionary *dictionary in windowList) {
        NSNumber *windowLayer = [dictionary objectForKey:@"kCGWindowLayer"];
        if ([windowLayer isEqualToNumber:[NSNumber numberWithInt:0]]) {
            return dictionary;
        }
    }
    return nil;
}

Now we need to make sure the front-most window is a PokerStars table window. For Poker Copilot, I’ve created a set of heuristics to determine this as follows. If all the following are true, then this is a PokerStars table window:

• Does the window owner name start with PokerStars? This “start with” clause allows this approach to work with PokerStarsES, PokerStarsFR, PokerStarsEU, etc?
• Does the window name NOT include “Tournament Buy-in”?
• Does the window name NOT include “Chat”?
• Does the window name NOT include “Cashier”?
• Does the window name NOT include “PokerStars Lobby”?
• Does the window name include at least one hyphens?
• If the window name contains exactly two hyphens, Is the window’s aspect ratio (width/height) NOT 1.45 +/- 0.01? (That excludes the hand replayer window).
• Does the window name include “Logged In as”?

I’ve sneakily left out a couple of obscure edge cases from that list. Hey, it’s taken four years to build up this knowledge for Poker Copilot; I’m not going to give all my secrets away!

- (BOOL)isTableWindow:(NSString *)title bounds:(CGRect)bounds {
    BOOL buyinWindow = [title rangeOfString:@"Tournament Buy-in"].location == 0;
    BOOL chatWindow = [title rangeOfString:@"Chat"].location == 0;
    BOOL cashierWindow = [title rangeOfString:@"Cashier"].location == 0;
    BOOL lobbyWindow = [title rangeOfString:@"PokerStars Lobby"].location == 0;
    BOOL hasHyphens = [[title componentsSeparatedByString:@"-"] count] - 1 > 1;
    double aspectRatio = bounds.size.width / (bounds.size.height - 22);
    double epsilon = fabs(1.45 - aspectRatio);
    NSUInteger count = [[title componentsSeparatedByString:@"-"] count] - 1;
    BOOL isReplayerWindow = count == 2 && epsilon < 0.01;
    BOOL hasLoggedIn = ([title rangeOfString:@"Logged In as"].location != NSNotFound);
    return !buyinWindow &&
        !chatWindow &&
        !lobbyWindow &&
        !cashierWindow &&
        !isReplayerWindow &&
        hasHyphens &&
        hasLoggedIn;
}

@implementation PokerRoomController {
}

- (NSDictionary *)findPokerStarsTableWindows {
    NSDictionary *windowDictionary = [self findFrontNormalWindow];
    if (windowDictionary == nil) {
        return nil;
    }
    NSString *windowOwnerName = [windowDictionary objectForKey:@"kCGWindowOwnerName"];
    if ([windowOwnerName rangeOfString:@"PokerStars"].location != 0) {
        return nil;
    }
    NSString *title = [windowDictionary objectForKey:@"kCGWindowName"];
    CGRect bounds;
    CGRectMakeWithDictionaryRepresentation(
        (__bridge CFDictionaryRef) 
        ([windowDictionary objectForKey:@"kCGWindowBounds"]), &bounds);
    if (!([self isTableWindow:title bounds:bounds])) {
        return nil;
    }
    return windowDictionary;
}

- (NSDictionary *)findFrontNormalWindow {
    NSArray *windowList = (__bridge NSArray *) 
        CGWindowListCopyWindowInfo(kCGWindowListOptionOnScreenOnly, kCGNullWindowID);
    for (NSDictionary *dictionary in windowList) {
        NSNumber *windowLayer = [dictionary objectForKey:@"kCGWindowLayer"];
        if ([windowLayer isEqualToNumber:[NSNumber numberWithInt:0]]) {
            return dictionary;
        }
    }
    return nil;
}

- (BOOL)isTableWindow:(NSString *)title bounds:(CGRect)bounds {
    BOOL buyinWindow = [title rangeOfString:@"Tournament Buy-in"].location == 0;
    BOOL chatWindow = [title rangeOfString:@"Chat"].location == 0;
    BOOL cashierWindow = [title rangeOfString:@"Cashier"].location == 0;
    BOOL lobbyWindow = [title rangeOfString:@"PokerStars Lobby"].location == 0;
    BOOL hasHyphens = [[title componentsSeparatedByString:@"-"] count] - 1 > 1;
    double aspectRatio = bounds.size.width / (bounds.size.height - 22);
    double epsilon = fabs(1.45 - aspectRatio);
    NSUInteger count = [[title componentsSeparatedByString:@"-"] count] - 1;
    BOOL isReplayerWindow = count == 2 && epsilon < 0.01;
    BOOL hasLoggedIn = ([title rangeOfString:@"Logged In as"].location != NSNotFound);
    return !buyinWindow &&
        !chatWindow &&
        !lobbyWindow &&
        !cashierWindow &&
        !isReplayerWindow &&
        hasHyphens &&
        hasLoggedIn;
}

@end