UILabel

/******label随字体改变宽度******/
+ (CGSize)sizeWithString:(NSString *)string font:(UIFont *)font{
CGRect rect = [string boundingRectWithSize:CGSizeMake(CGFLOAT_MAX, CGFLOAT_MAX)//限制最大高度
options:NSStringDrawingTruncatesLastVisibleLine | NSStringDrawingUsesFontLeading |NSStringDrawingUsesLineFragmentOrigin//采用换行模式
attributes:@{NSFontAttributeName: font}//传入的字体字典
context:nil];
return rect.size;
}

UILabel

原文：http://www.cnblogs.com/conan0919/p/5592922.html