Dropdown menu animation

MenuCustomAnimationDelegate.h

//
//  MenuCustomAnimationDelegate.h
//  
//
//  Created by Ankit Aggarwal on 25/05/15.
//  Copyright (c) 2015 Ankit Aggarwal. All rights reserved.
//

#import <UIKit/UIKit.h>

@interface MenuCustomAnimationDelegate : NSObject <UIViewControllerAnimatedTransitioning, UIViewControllerTransitioningDelegate>

@property (nonatomic, strong) UIImage *snapshot;
@property (nonatomic, assign) BOOL reverse;

@end

MenuCustomAnimationDelegate.m

//
//  MenuCustomAnimationDelegate.m
//  
//
//  Created by Ankit Aggarwal on 25/05/15.
//  Copyright (c) 2015 Ankit Aggarwal. All rights reserved.
//

#import "MenuCustomAnimationDelegate.h"
#import "MenuViewController.h"

@implementation MenuCustomAnimationDelegate

- (id <UIViewControllerAnimatedTransitioning>)animationControllerForPresentedController:(UIViewController *)presented presentingController:(UIViewController *)presenting sourceController:(UIViewController *)source
{
    return self;
}

- (id <UIViewControllerAnimatedTransitioning>)animationControllerForDismissedController:(UIViewController *)dismissed
{
    self.reverse = YES;
    return self;
}

- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext {
    
    if(self.reverse == NO)
        [self animationForPresenting:transitionContext];
    else
        [self animationForDismissal:transitionContext];
}

- (void)animationForPresenting:(id<UIViewControllerContextTransitioning>)transitionContext {
    
    MenuViewController *toViewController = (id)[transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    UIView *containerView = [transitionContext containerView];
    NSTimeInterval duration = [self transitionDuration:transitionContext];
    
    UIImageView *imageView = toViewController.imageView;
    imageView.image = self.snapshot;
    
    [containerView addSubview:toViewController.view];
    imageView.transform = CGAffineTransformMakeTranslation(0, - [UIScreen mainScreen].bounds.size.width * (5.0/4));
    
    [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleLightContent animated:YES];
    
    [UIView animateWithDuration:duration delay:0 usingSpringWithDamping:0.6 initialSpringVelocity:0.3 options:0 animations:^{
        imageView.transform = CGAffineTransformIdentity;
    } completion:^(BOOL finished) {
        [transitionContext completeTransition:!transitionContext.transitionWasCancelled];
    }];
}

- (void)animationForDismissal:(id<UIViewControllerContextTransitioning>)transitionContext {
    
    MenuViewController *fromViewController = (id)[transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
    UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    UIView *containerView = [transitionContext containerView];
    NSTimeInterval duration = [self transitionDuration:transitionContext];
    
    UIImageView *imageView = fromViewController.imageView;
    
    [containerView insertSubview:toViewController.view belowSubview:fromViewController.view];
    toViewController.view.alpha = 1;
    
    [[UIApplication sharedApplication] setStatusBarStyle:UIStatusBarStyleDefault animated:YES];
    
    [UIView animateWithDuration:duration delay:0 usingSpringWithDamping:0.8 initialSpringVelocity:0.3 options:0 animations:^{
        imageView.transform = CGAffineTransformMakeTranslation(0, - [UIScreen mainScreen].bounds.size.width * (5.0/4));
    } completion:^(BOOL finished) {
        [transitionContext completeTransition:!transitionContext.transitionWasCancelled];
    }];
}

- (NSTimeInterval)transitionDuration:(id<UIViewControllerContextTransitioning>)transitionContext {
    return self.reverse ? 0.3 : 0.3;
}

@end