gistfile1.m

@interface UIWindow (resize)
-(void)_adjustSizeClassesAndResizeWindowToFrame:(CGRect)frame;
@end

typedef enum _UICustomRes
{
	UICustomResiPadTwoThirds,
	UICustomResiPadHalf,
	UICustomResiPadOneThird,
	UICustomResiPhone47,
	UICustomResiPhone55,
	UICustomResNone
	
} UICustomRes;

UICustomRes _forceResizeState = UICustomResNone;

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions
{
	UITapGestureRecognizer *resizeTapGesture = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(_forceResize:)];
	resizeTapGesture.numberOfTouchesRequired = 3;
	[self.window addGestureRecognizer:resizeTapGesture];

	return YES;
}

-(void)_forceResize:(UITapGestureRecognizer *)sender
{
	switch (_forceResizeState)
	{
		case UICustomResiPadTwoThirds:
			[self.window _adjustSizeClassesAndResizeWindowToFrame:CGRectMake(0, 0, 704, 768)];
			break;
		case UICustomResiPadHalf:
			[self.window _adjustSizeClassesAndResizeWindowToFrame:CGRectMake(0, 0, 512, 768)];
			break;
		case UICustomResiPadOneThird:
			[self.window _adjustSizeClassesAndResizeWindowToFrame:CGRectMake(0, 0, 320, 768)];
			break;
		case UICustomResiPhone47:
			[self.window _adjustSizeClassesAndResizeWindowToFrame:CGRectMake(0, 0, 375, 667)];
			break;
		case UICustomResiPhone55:
			[self.window _adjustSizeClassesAndResizeWindowToFrame:CGRectMake(0, 0, 414, 736)];
			break;
		case UICustomResNone:
			[self.window _adjustSizeClassesAndResizeWindowToFrame:CGRectMake(0, 0, 1024, 768)];
			break;
		default:
			break;
	}
	
	_forceResizeState++;
	
	if (_forceResizeState > UICustomResNone)
		_forceResizeState = UICustomResiPadTwoThirds;
}