How do I center a number in a circle? - objective-c

Question

I'm trying to produce a set of custom page numbers. The current page number will be displayed. The others will simply be open circles.
Using the code below, I'm getting the desired results - except, with the new text attributes in iOS7, I cannot figure out how to center the number.
Any help will be appreciated.
Original iOS6 code:
[pageNumber drawInRect:CGRectMake(x,(self.frame.size.height-_currentPageDiameter)/2-1,_currentPageDiameter,_currentPageDiameter) withFont:[UIFont systemFontOfSize:_currentPageDiameter-2] lineBreakMode:UILineBreakModeCharacterWrap alignment:NSTextAlignmentCenter];
My iOS7 code:
NSString *pageNumber = [NSString stringWithFormat:#"%i", i+1];
CGContextSetFillColorWithColor(myContext, [[UIColor whiteColor] CGColor]);
UIFont* font = [UIFont systemFontOfSize:_currentPageDiameter-2];
NSDictionary *attrs = #{ NSForegroundColorAttributeName : [UIColor whiteColor],
NSFontAttributeName : font,
NSTextEffectAttributeName : NSTextEffectLetterpressStyle};
CGRect r = CGRectMake(x,(self.frame.size.height-_currentPageDiameter)/2-1,_currentPageDiameter,_currentPageDiameter);
[pageNumber drawInRect:r withAttributes:attrs];

Answer 1

The property you're missing for center alignment is defined the following way. I also added the line break mode you had defined on the iOS6 code:
NSMutableParagraphStyle *paragrapStyle = [[NSMutableParagraphStyle alloc] init];
paragrapStyle.alignment = NSTextAlignmentCenter;
paragrapStyle.lineBreakMode = NSLineBreakByCharWrapping;
You just place them in the attributes dictionary under the key:
NSArray *attrs = #{
NSParagraphStyleAttributeName : paragraphStyle,
...
};