UIGraphic

UIGraphic
这里有一篇纯正的分享文章 https://www.jianshu.com/p/494c57f49479

1. 向图片中添加文字, 类似水印

- (UIImage *)addText:(NSString *)string toImage:(UIImage *)image withTextFontSize:(NSInteger)fontSize fontColor:(UIColor *)fontColor {
    UIGraphicsBeginImageContext(image.size);
    [image drawAtPoint:CGPointZero];
    NSMutableDictionary *attributDic = [NSMutableDictionary dictionary];
    attributDic[NSForegroundColorAttributeName] = fontColor;
    attributDic[NSFontAttributeName] = [UIFont systemFontOfSize:fontSize];
    [string drawAtPoint:CGPointMake(20, 20) withAttributes:attributDic];
    UIImage *resultImage = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return resultImage;
}

调用该方法:

- (void)viewDidLoad {
    [super viewDidLoad];
    UIImage *picImage = [UIImage imageNamed:@"pic"];
    self.logoImageView.image = [self addText:@"Github Peyton" toImage:picImage withTextFontSize:25 fontColor:[UIColor blackColor]];
}

效果:

11524110791_.pic.jpg