iOS 截图 截取屏幕

// 从view上截图
- (UIImage *)getImage {
    
    UIGraphicsBeginImageContextWithOptions(CGSizeMake(150, 150), NO, 1.0);  //NO，YES 控制是否透明
    [self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    // 生成后的image
    
    return image;
}

// 根据给定得图片，从其指定区域截取一张新得图片
-(UIImage *)getImageFromImage{
    //大图bigImage
    //定义myImageRect，截图的区域
    CGRect myImageRect = CGRectMake(70, 10, 150, 150);
    UIImage* bigImage= [UIImage imageNamed:@"mm.jpg"];
    CGImageRef imageRef = bigImage.CGImage;
    CGImageRef subImageRef = CGImageCreateWithImageInRect(imageRef, myImageRect);
    CGSize size;
    size.width = 150;
    size.height = 150;
    UIGraphicsBeginImageContext(size);
    CGContextRef context = UIGraphicsGetCurrentContext();
    CGContextDrawImage(context, myImageRect, subImageRef);
    UIImage* smallImage = [UIImage imageWithCGImage:subImageRef];
    UIGraphicsEndImageContext();
    return smallImage;
}