iOS-全屏截图、view生成图片、scrollView生成长图

1. 全屏截图

+ (UIImage *)snapshotScreen {
    UIWindow *window = [UIApplication sharedApplication].keyWindow;
    UIGraphicsBeginImageContextWithOptions(window.bounds.size, NO, [UIScreen mainScreen].scale);
    [window.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

2. view生成图片

+ (UIImage *)snapshotWithView:(UIView *)view {
    UIGraphicsBeginImageContextWithOptions(view.bounds.size, NO, [UIScreen mainScreen].scale);
    [view.layer renderInContext:UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();
    return image;
}

2. scrollView生成长图

+ (UIImage *)snapshotWithScrollView:(UIScrollView *)scrollView {
    CGPoint savedContentOffset = scrollView.contentOffset;
    CGRect savedFrame = scrollView.frame;
    
    scrollView.contentOffset = CGPointZero;
    scrollView.frame = CGRectMake(0, 0, scrollView.contentSize.width, scrollView.contentSize.height);

    UIGraphicsBeginImageContextWithOptions(scrollView.contentSize, NO, [UIScreen mainScreen].scale);
    [scrollView.layer renderInContext: UIGraphicsGetCurrentContext()];
    UIImage *image = UIGraphicsGetImageFromCurrentImageContext();
    UIGraphicsEndImageContext();

    scrollView.contentOffset = savedContentOffset;
    scrollView.frame = savedFrame;
    
    return image;
}