Objective-C: Capture screenshot of all views within custom frame - ios

Question

I have a game where users can create custom levels and upload them to my server for other users to play and I want to get a screenshot of the "action area" before the user tests his/her level to upload to my server as sort of a "preview image".
I know how to get a screenshot of the entire view, but I want to define it to a custom frame. Consider the following image:
I want to just take a screenshot of the area in red, the "action area." Can I achieve this?

Answer 1

Just you need to make a rect of the area you want to be captured and pass the rect in the method.
Swift 3.x :
extension UIView {
func imageSnapshot() -> UIImage {
return self.imageSnapshotCroppedToFrame(frame: nil)
}
func imageSnapshotCroppedToFrame(frame: CGRect?) -> UIImage {
let scaleFactor = UIScreen.main.scale
UIGraphicsBeginImageContextWithOptions(bounds.size, false, scaleFactor)
self.drawHierarchy(in: bounds, afterScreenUpdates: true)
var image: UIImage = UIGraphicsGetImageFromCurrentImageContext()!
UIGraphicsEndImageContext()
if let frame = frame {
let scaledRect = frame.applying(CGAffineTransform(scaleX: scaleFactor, y: scaleFactor))
if let imageRef = image.cgImage!.cropping(to: scaledRect) {
image = UIImage(cgImage: imageRef)
}
}
return image
}
}
//How to call :
imgview.image = self.view.imageSnapshotCroppedToFrame(frame: CGRect.init(x: 0, y: 0, width: 320, height: 100))
Objective C :
-(UIImage *)captureScreenInRect:(CGRect)captureFrame
{
CALayer *layer;
layer = self.view.layer;
UIGraphicsBeginImageContext(self.view.bounds.size);
CGContextClipToRect (UIGraphicsGetCurrentContext(),captureFrame);
[layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *screenImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return screenImage;
}
//How to call :
imgView.image = [self captureScreenInRect:CGRectMake(0, 0, 320, 100)];

Answer 2

- (UIImage *) getScreenShot {
UIWindow *keyWindow = [[UIApplication sharedApplication] keyWindow];
CGRect rect = [keyWindow bounds];
UIGraphicsBeginImageContext(rect.size);
CGContextRef context = UIGraphicsGetCurrentContext();
[keyWindow.layer renderInContext:context];
UIImage *img = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
return img;
}