获取带有emoji的字符串宽度和高度

// 得到带有emoji string
长度和宽度
+ (CGSize) calculateEnojiStringSizeWithString:(NSString *) content font:(UIFont *)
font constraintStringWidth:(CGFloat)stirngWidth
{
    NSMutableParagraphStyle *paragraphStyle = [[NSMutableParagraphStyle
alloc]init];
    paragraphStyle.lineBreakMode =
NSLineBreakByWordWrapping;
    NSDictionary *attributes =
@{NSFontAttributeName:font,
NSParagraphStyleAttributeName:paragraphStyle.copy};
    [paragraphStyle release];
    CGSize contentSize = [content
boundingRectWithSize:CGSizeMake(stirngWidth,
MAXFLOAT) options:NSStringDrawingUsesLineFragmentOrigin
                                                         
attributes:attributes
                                                            
context:nil].size;
    return contentSize;

}