让图片只拉伸最中心的那一像素

#import "MMMyLotteryViewController.h"


@interface MMMyLotteryViewController ()

@property (weak, nonatomic) IBOutlet UIButton *loginBtn;

@end


@implementation MMMyLotteryViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    
    //解决自动布局下图片拉伸导致边缘模糊的问题
    UIImage *bacImage = self.loginBtn.currentBackgroundImage;
    //让图片只拉伸最中心的那一像素，得到新图片
    bacImage = [bacImage stretchableImageWithLeftCapWidth:bacImage.size.width*0.5 topCapHeight:bacImage.size.height*0.5];
    //将新图片设置回去
    [self.loginBtn setBackgroundImage:bacImage forState:UIControlStateNormal];
}

@end