iPhone: Get camera preview

Question

I\'d like to get the image that is being displayed on the UIImagePickerController when user uses the camera. And when I get I want to process the image and display instead

Answer 1

This one is also working quite good. Use it when the camera preview is open:

UIImage *viewImage = [[(id)objc_getClass("PLCameraController") 
                      performSelector:@selector(sharedInstance)] 
                      performSelector:@selector(_createPreviewImage)];

But as far as I found out it brings the same results than the following solution which takes a 'screenshot' of the current screen:

extern CGImageRef UIGetScreenImage();

CGImageRef cgoriginal = UIGetScreenImage();
CGImageRef cgimg = CGImageCreateWithImageInRect(cgoriginal, rect);            
UIImage *viewImage = [UIImage imageWithCGImage:cgimg];    
CGImageRelease(cgoriginal);                
CGImageRelease(cgimg);  

A problem I didn't still find a fix for is, how can one get the camera image very fast without any overlays?

Answer 2

The unofficial call is:

UIGetScreenImage()

which you declare above the @implementation as:

extern CGImageRef UIGetScreenImage();

There may be a documented way to do this in 3.1, but I'm not sure. If not, please please file a Radar with Apple asking them to make some kind of screen grab access public!!!

That uses your same AppleID you log in to the iPhone development portal with.

Update: This call is not yet documented, but Apple explicitly has given the OK to use it with App Store apps.

Answer 3

at least for now, there's no way to do this. (certainly no official documented way, and as far as I know nobody's figured out an unofficial way either.)

the camera preview data is being drawn by the OS in some way that bypasses the normal graphics methods.