iOS基于 UILabel实现文字添加描边功能

- (void)drawTextInRect:(CGRect)rect {   CGSize shadowOffset = self.shadowOffset;  UIColor *textColor = self.textColor;    CGContextRef c = UIGraphicsGetCurrentContext();   CGContextSetLineWidth(c, 1);   CGContextSetLineJoin(c, kCGLineJoinRound);    CGContextSetTextDrawingMode(c, kCGTextStroke);   self.textColor = [UIColor whiteColor];   [super drawTextInRect:rect];   CGContextSetTextDrawingMode(c, kCGTextFill);   self.textColor = textColor;   self.shadowOffset = CGSizeMake(0, 0);   [super drawTextInRect:rect];    self.shadowOffset = shadowOffset; }