Capturing Screen - iphone

Question

I am trying to capture (screen shot) a view. For that I am using a piece of code shown below that saves it to my document directory as a PNG image.
UIGraphicsBeginImageContextWithOptions(highlightViewController.fhView.centerView.frame.size, YES, 1.0);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *screenshot = UIGraphicsGetImageFromCurrentImageContext();
NSArray *paths = NSSearchPathForDirectoriesInDomains(NSDocumentDirectory, NSUserDomainMask, YES);
NSString *documentsDirectory = [paths objectAtIndex:0];
NSString *appFile = [documentsDirectory stringByAppendingPathComponent:#"1.png"];
NSData *imageData = UIImagePNGRepresentation(screenshot);
[imageData writeToFile:appFile atomically:YES];
UIGraphicsEndImageContext();
Question: can I capture part of the view? Because in the above code I can't change the origin (frame). If anyone has other approach to capture a particular part of view please share it.

Answer 1

You could crop the image:
http://iosdevelopertips.com/graphics/how-to-crop-an-image.html
CGRect rect = CGRectMake(0,0,10,10);
CGImageRef imageRef = CGImageCreateWithImageInRect([screenshot CGImage], rect);
UIImage *croppedScreenshot = [UIImage imageWithCGImage:imageRef];
CGImageRelease(imageRef);

Answer 2

Try this code. This surely works as I have implemented it in many of my projects:
- (UIImage *)image
{
if (cachedImage == nil) {
//YOU CAN CHANGE THE FRAME HERE TO WHATEVER YOU WANT TO CAPTURE
CGRect imageFrame = CGRectMake(0, 0, 400, 300);
UIView *imageView = [[UIView alloc] initWithFrame:imageFrame];
[imageView setOpaque:YES];
[imageView setUserInteractionEnabled:NO];
[self renderInView:imageView withTheme:nil];
UIGraphicsBeginImageContext(imageView.bounds.size);
CGContextRef c = UIGraphicsGetCurrentContext();
CGContextGetCTM(c);
CGContextScaleCTM(c, 1, -1);
CGContextTranslateCTM(c, 0, -imageView.bounds.size.height);
[imageView.layer renderInContext:c];
cachedImage = [UIGraphicsGetImageFromCurrentImageContext() retain];
// rescale graph
UIImage* bigImage = UIGraphicsGetImageFromCurrentImageContext();
CGImageRef scaledImage = [self newCGImageFromImage:[bigImage CGImage] scaledToSize:CGSizeMake(100.0f, 75.0f)];
cachedImage = [[UIImage imageWithCGImage:scaledImage] retain];
CGImageRelease(scaledImage);
UIGraphicsEndImageContext();
[imageView release];
}
return cachedImage;
}
I hope this will help you.

Answer 3

See if you can specify the rect like this and then take screenshot.
CGRect requiredRect = CGRectMake(urView.frame.origin.x, urView.frame.origin.y, urView.bounds.size.width, urView.bounds.size.height);
UIGraphicsBeginImageContext(requiredRect.size);
You can alter the origin and see if it works.
If this doesn't work out, you can try cropping the image as mentioned by #mcb

Answer 4

You can use this code
UIGraphicsBeginImageContext(self.view.bounds.size);
[self.view.layer renderInContext:UIGraphicsGetCurrentContext()];
UIImage *viewImage = UIGraphicsGetImageFromCurrentImageContext();
UIGraphicsEndImageContext();
CGRect rect;
rect = CGRectMake(250,61 ,410, 255);
CGImageRef imageRef = CGImageCreateWithImageInRect([viewImage CGImage], rect);
UIImage *img = [UIImage imageWithCGImage:imageRef];
UIImageWriteToSavedPhotosAlbum(img, nil, nil, nil);
CGImageRelease(imageRef);