Fastest way to take screenShot of UIView

Question

I've searched a lot but only found two methods to take screen shot of UIView. first renderInContext: I've used it in a way

CGContextRef context = [self createBitmapContextOfSize:CGSizeMake(nImageWidth, nImageHeight)];
CGAffineTransform flipVertical = CGAffineTransformMake(1, 0, 0, -1, 0, nImageHeight);
CGContextConcatCTM(context, flipVertical);
[self.layer setBackgroundColor:[UIColor clearColor].CGColor];
[self.layer renderInContext:context];
CGImageRef cgImage = CGBitmapContextCreateImage(context);
UIImage* background = [UIImage imageWithCGImage: cgImage];
CGImageRelease(cgImage);

Second drawViewHierarchyInRect: which I've used as

UIImage *background = nil;

UIGraphicsBeginImageContextWithOptions (self.bounds.size, NO, self.window.screen.scale);

if ([self respondsToSelector:@selector(drawViewHierarchyInRect:afterScreenUpdates:)])
{
    [self drawViewHierarchyInRect:self.bounds afterScreenUpdates:YES];   
}
background = UIGraphicsGetImageFromCurrentImageContext();

UIGraphicsEndImageContext();

I know that the second one is faster than first and it work for me for iPhone because the view has low size. but when I capturing from iPad the video become jerky. Can Any body tell me faster way of taking screen shot. any help would be highly appreciated

Answer 1

Regarding performance, the Apple Docs state the following:

In addition to -drawViewHierarchyInRect:afterScreenUpdates:, UIView now provides another two snapshot related methods, -snapshotViewAfterScreenUpdates: and -resizableSnapshotViewFromRect:afterScreenUpdates:withCapInsets:. UIScreen also has -snapshotViewAfterScreenUpdates:.

Unlike UIView's -drawViewHierarchyInRect:afterScreenUpdates:, these methods return a UIView object. If you are looking for a new snapshot view, use one of these methods. It will be more efficient than calling -drawViewHierarchyInRect:afterScreenUpdates: to render the view contents into a bitmap image yourself. You can use the returned view as a visual stand-in for the current view/screen in your app. For example, you might use a snapshot view for animations where updating a large view hierarchy might be expensive.

Answer 2

There is a third method for taking a snapshot that is much much quicker than either of these but it returns a UIView.

- (UIView *)snapshotViewAfterScreenUpdates:(BOOL)afterUpdates

If you are just using the snapshot to place as a background "image" etc... then I'd use this instead.

However, this is only available for iOS8.

To use it just do...

UIView *snapshotView = [someView snapshotViewAfterScreenUpdates:YES];