NSMutableAttributedString *attrString = [[NSMutableAttributedString alloc]initWithString:@"我是富文本"];

//字体

[attrString addAttribute:NSFontAttributeName

                      value:[UIFont systemFontOfSize:12.0]

                      range:NSMakeRange(0, 2)];

//粗细 负为实体，正为中空

[attrString addAttribute:NSStrokeWidthAttributeName

                           value:@(-3)

                           range:NSMakeRange(0, attrString.length)];

//颜色

[attrString addAttribute:NSForegroundColorAttributeName

                      value:[UIColor redColor]

                      range:NSMakeRange(0, attrString.length)];

[labelInstance setAttributedText:attrString];