在UIButton标题上居中图片

有一个自定义UIButton，占了视图的四分之一，我想要在按钮标题上设置一张图片，居中设置。

代码：

CGRect imageFrame= CGRectMake(0, 0, 80, 80);
UIEdgeInsets imageInset = UIEdgeInsetsMake(0, 0, 30, 0);
UIEdgeInsets titleInset = UIEdgeInsetsMake(80, 0, 0, 0);

btnSideSettings = [UIButton buttonWithType:UIButtonTypeCustom];
btnSideSettings.frame = settingsFrame;
[btnSideSettings setImage:[UIImage imageNamed:@"btnSideSettings"] forState:UIControlStateNormal];
btnSideSettings.imageView.frame = imageFrame;
btnSideSettings.imageEdgeInsets = imageInset;
btnSideSettings.titleEdgeInsets = titleInset;
btnSideSettings.titleLabel.textAlignment = NSTextAlignmentCenter;
[btnSideSettings setTitle:@"Settings" forState:UIControlStateNormal];

结果：

如果注释掉添加图片，标题就会居中。

请明白人指点一下，谢谢。

可以换种方式来实现 。我这里的方式是用UIImageView 来倒圆角实现 .注意这里要导入一个库

#import <QuartzCore/QuartzCore.h>

UIImage *image=[UIImage imageNamed:@"btnSideSettings"];
UIImageView *imgView=[[UIImageView alloc] initWithImage:image];

/////给imgView进行圆形遮罩
imgView.layer.masksToBound=YES;  ////required
imgView.layer.cornerRadius=imgView.frame.size.width/2;  /////radiu is a half of imageview's width

如果在图片上有点击动作可用手势来实现 。