IOS7 字体变化

enum {   NSLineBreakByWordWrapping = 0,   NSLineBreakByCharWrapping,   NSLineBreakByClipping,   NSLineBreakByTruncatingHead,   NSLineBreakByTruncatingTail,   NSLineBreakByTruncatingMiddle};typedef NSUInteger NSLineBreakModetypedef enum {   UILineBreakModeWordWrap = 0,   UILineBreakModeCharacterWrap,   UILineBreakModeClip,   UILineBreakModeHeadTruncation,   UILineBreakModeTailTruncation,   UILineBreakModeMiddleTruncation,} UILineBreakMode;

连接：https://developer.apple.com/library/ios/documentation/uikit/reference/NSString_UIKit_Additions/Reference/Reference.html