version1.m

-(void)someBigMethod {
  // create a screenshot
  CALayer * screenLayer = [[[[[UIApplication sharedApplication] keyWindow] rootViewController] view] layer];
  CGFloat const shotScale = ([[UIScreen mainScreen] scale] / 2.0);
  UIGraphicsBeginImageContextWithOptions(screenLayer.bounds.size, YES, shotScale);
  [screenLayer renderInContext:UIGraphicsGetCurrentContext()];
  UIImage * screenshot = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();

  // put the screenshot in a layer
  CALayer * bgLayer = [[CALayer alloc] init];
  bgLayer.contentsScale = shotScale;
  bgLayer.rasterizationScale = shotScale;
  bgLayer.opaque=YES;
  bgLayer.bounds = CGRectMake(0, 0, screenshot.size.width, screenshot.size.height);
  bgLayer.contents = (id) screenshot.CGImage;
  
  // lots more lines to do more stuff
}

version2.m

-(void)someBigMethod {
  UIImage* screenshot = createScreenshot();
  CALayer * bgLayer = putScreenshotInALayer(screenshot);
  // lots more 1 line function calls
}

// with a bunch of private helper methods that each do one thing like

-(UIImage*)createScreenshot {
  CALayer * screenLayer = [[[[[UIApplication sharedApplication] keyWindow] rootViewController] view] layer];
  CGFloat const shotScale = ([[UIScreen mainScreen] scale] / 2.0);
  UIGraphicsBeginImageContextWithOptions(screenLayer.bounds.size, YES, shotScale);
  [screenLayer renderInContext:UIGraphicsGetCurrentContext()];
  UIImage * screenshot = UIGraphicsGetImageFromCurrentImageContext();
  UIGraphicsEndImageContext();
  return screenshot;
}

-(CALayer*)putScreenshotInALayer(UIImage *)screenshot {
  CALayer * bgLayer = [[CALayer alloc] init];
  bgLayer.contentsScale = shotScale;
  bgLayer.rasterizationScale = shotScale;
  bgLayer.opaque=YES;
  bgLayer.bounds = CGRectMake(0, 0, screenshot.size.width, screenshot.size.height);
  bgLayer.contents = (id) screenshot.CGImage;
  return bgLayer;
}