shadowOffset 具体解释

x向右为正，y向下为正

1.y<0

UILabel *label=[[UILabelalloc]
initWithFrame:CGRectMake(40,40,
250,50)];

label.backgroundColor=[UIColorclearColor];

label.textColor=[UIColorredColor];

label.text=@"和合谷";

label.shadowColor=[UIColorblueColor];

label.shadowOffset=CGSizeMake(0, -3);

执行结果为：

第二.y>0

UILabel *label=[[UILabelalloc]
initWithFrame:CGRectMake(40,40,
250,50)];

label.backgroundColor=[UIColorclearColor];

label.textColor=[UIColorredColor];

label.text=@"和合谷";

label.shadowColor=[UIColorblueColor];

label.shadowOffset=CGSizeMake(0,3);

第三、x>0

UILabel *label=[[UILabelalloc]
initWithFrame:CGRectMake(40,40,
250,50)];

label.backgroundColor=[UIColorclearColor];

label.textColor=[UIColorredColor];

label.text=@"和合谷";

label.shadowColor=[UIColorblueColor];

label.shadowOffset=CGSizeMake(3,0);

[self.viewaddSubview:label];

结果：

watermark/2/text/aHR0cDovL2Jsb2cuY3Nkbi5uZXQvcmljaGFyZF9ydWZlbmc=/font/5a6L5L2T/fontsize/400/fill/I0JBQkFCMA==/dissolve/70/gravity/SouthEast" alt="">

第四、x<0

UILabel *label=[[UILabelalloc]
initWithFrame:CGRectMake(40,40,
250,50)];

label.backgroundColor=[UIColorclearColor];

label.textColor=[UIColorredColor];

label.text=@"和合谷";

label.shadowColor=[UIColorblueColor];

label.shadowOffset=CGSizeMake(-3,0);