Create screenshot in iOS. [Objective-C,ios,xcode]

gistfile1.m

CGSize screenSize = [[UIScreen mainScreen] applicationFrame].size;

CGColorSpaceRef colorSpaceRef = CGColorSpaceCreateDeviceRGB();

CGContextRef ctx = CGBitmapContextCreate(nil, screenSize.width, screenSize.height, 8, 4*(int)screenSize.width, colorSpaceRef, kCGImageAlphaPremultipliedLast);

CGContextTranslateCTM(ctx, 0.0, screenSize.height);
CGContextScaleCTM(ctx, 1.0, -1.0);

[(CALayer*)self.view.layer renderInContext:ctx];

CGImageRef cgImage = CGBitmapContextCreateImage(ctx);
UIImage *image = [UIImage imageWithCGImage:cgImage];
CGImageRelease(cgImage);

CGContextRelease(ctx);
//UIImage *image can be used for saving for file, or to be placed in some UIImageView or wathever...
[UIImageJPEGRepresentation(image, 1.0) writeToFile:@"screen.jpg" atomically:NO];