Comments on: Saving a view as an image.

By: DaveF

DaveF — Thu, 05 Aug 2010 00:14:45 +0000

Awesome snippet Skylar. One thing is that I’m using this code on an iPad application in landscape orientation and the resulting screengrab is in portrait mode. I know I could just alter the image itself but is there a cleaner way to get the image at the correct orientation?

By: DanCreek

DanCreek — Mon, 29 Mar 2010 01:31:56 +0000

Thanks for the memory leak tip Andrew. You just saved me hours of troubleshooting.

By: Skylar

Skylar — Thu, 14 Jan 2010 09:36:40 +0000

Good catch, I have not updated the sample code attached to post. Honestly, this is such a simple post that I simply forgot that I had attached any downloadable source code. I will update the download link at some indeterminate date in the future.

Thanks!

[WORDPRESS HASHCASH] The poster sent us ‘0 which is not a hashcash value.

By: nglayton

nglayton — Sat, 09 Jan 2010 17:15:39 +0000

did the source attached to the post get updated. I can’t tell, I don’t see any of the lines talked about in the source code. Was there a 3rd change not posted ?

By: Andrew Ash

Andrew Ash — Sun, 20 Dec 2009 20:56:02 +0000

Thanks Skylar, CGImageRelease seems to be the way to go there.

By: Skylar

Skylar — Sun, 20 Dec 2009 08:22:59 +0000

Thanks for the catch. That’s the problem with writing up a quick tutorial without testing it, you sometimes forget releases : )

In the future though, you might want to use CGImageRelease instead of CFRelease. According to Apple, the two are equivalent, except CGImageRelease won’t throw an error if the image is NULL.

[WORDPRESS HASHCASH] The poster sent us ‘0 which is not a hashcash value.

By: Andrew Ash

Andrew Ash — Sun, 20 Dec 2009 07:58:05 +0000

I’ve been struggling with a memory leak in an iPhone app, and I think I’ve traced it down to using the takeScreenshot method you have above. The relevant line is this:

UIImage *screenshot = [UIImage imageWithCGImage:UIGetScreenImage()];

This line calls UIGetScreenImage(), which returns a CGImageRef, and uses that reference to create a UIImage. The problem I think is in what is done with the CGImageRef. It seems that UIGetScreenImage expects you to release the CGImageRef yourself, using CGRelease. Replacing the above line of code with the following lines fixed a massive memory leak I had:

CGImageRef screenshotCG = UIGetScreenImage();
UIImage *screenshot = [UIImage imageWithCGImage:screenshotCG];
CFRelease(screenshotCG);

Credit where credit is due — I had the idea to check this from a code snippet at:
http://netsharc.wordpress.com/2008/12/25/iphone-dev-creating-a-full-screen-camera-preview/