element-ios/Riot/Modules/MatrixKit/Animators/MXKAttachmentAnimator.m

/*
 Copyright 2017 Aram Sargsyan
 
 Licensed under the Apache License, Version 2.0 (the "License");
 you may not use this file except in compliance with the License.
 You may obtain a copy of the License at
 
 http://www.apache.org/licenses/LICENSE-2.0
 
 Unless required by applicable law or agreed to in writing, software
 distributed under the License is distributed on an "AS IS" BASIS,
 WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 See the License for the specific language governing permissions and
 limitations under the License.
 */

#import "MXKAttachmentAnimator.h"
#import "MXLog.h"

@interface MXKAttachmentAnimator ()

@property (nonatomic) PhotoBrowserAnimationType animationType;
@property (nonatomic, weak) UIViewController <MXKSourceAttachmentAnimatorDelegate> *sourceViewController;

@end

@implementation MXKAttachmentAnimator

#pragma mark - Lifecycle

- (instancetype)initWithAnimationType:(PhotoBrowserAnimationType)animationType sourceViewController:(UIViewController <MXKSourceAttachmentAnimatorDelegate> *)viewController
{
    self = [self init];
    if (self) {
        self.animationType = animationType;
        self.sourceViewController = viewController;
    }
    return self;
}

#pragma mark - Public

+ (CGRect)aspectFitImage:(UIImage *)image inFrame:(CGRect)targetFrame
{
    // Sanity check
    if (!image)
    {
        MXLogDebug(@"[MXKAttachmentAnimator] aspectFitImage failed: image is nil");
        return CGRectZero;
    }
    
    if (CGSizeEqualToSize(image.size, targetFrame.size))
    {
        return targetFrame;
    }
    
    CGFloat targetWidth = CGRectGetWidth(targetFrame);
    CGFloat targetHeight = CGRectGetHeight(targetFrame);
    CGFloat imageWidth = image.size.width;
    CGFloat imageHeight = image.size.height;
    
    CGFloat factor = MIN(targetWidth/imageWidth, targetHeight/imageHeight);
    
    CGSize finalSize = CGSizeMake(imageWidth * factor, imageHeight * factor);
    CGRect finalFrame = CGRectMake((targetWidth - finalSize.width)/2 + targetFrame.origin.x, (targetHeight - finalSize.height)/2 + targetFrame.origin.y, finalSize.width, finalSize.height);
    
    return finalFrame;
}

#pragma mark - Animations

- (void)animateZoomInAnimation:(id<UIViewControllerContextTransitioning>)transitionContext
{
    //originalImageView
    UIImageView *originalImageView = [self.sourceViewController originalImageView];
    originalImageView.hidden = YES;
    CGRect convertedFrame = [self.sourceViewController convertedFrameForOriginalImageView];
    
    //toViewController
    UIViewController<MXKDestinationAttachmentAnimatorDelegate> *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    toViewController.view.frame = [transitionContext finalFrameForViewController:toViewController];
    [[transitionContext containerView] addSubview:toViewController.view];
    toViewController.view.alpha = 0.0;
    
    //destinationImageView
    UIImageView *destinationImageView = [toViewController finalImageView];
    destinationImageView.hidden = YES;
    
    //transitioningImageView
    UIImageView *transitioningImageView = [[UIImageView alloc] initWithImage:originalImageView.image];
    transitioningImageView.frame = convertedFrame;
    [[transitionContext containerView] addSubview:transitioningImageView];
    CGRect finalFrameForTransitioningView = [[self class] aspectFitImage:originalImageView.image inFrame:toViewController.view.frame];
    
    
    //animation
    [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
        toViewController.view.alpha = 1.0;
        transitioningImageView.frame = finalFrameForTransitioningView;
    } completion:^(BOOL finished) {
        [transitioningImageView removeFromSuperview];
        destinationImageView.hidden = NO;
        originalImageView.hidden = NO;
        [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
    }];
}

- (void)animateZoomOutAnimation:(id<UIViewControllerContextTransitioning>)transitionContext
{
    //fromViewController
    UIViewController<MXKDestinationAttachmentAnimatorDelegate> *fromViewController = [transitionContext viewControllerForKey:UITransitionContextFromViewControllerKey];
    UIImageView *destinationImageView = [fromViewController finalImageView];
    destinationImageView.hidden = YES;
    
    //toViewController
    UIViewController *toViewController = [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
    toViewController.view.frame = [transitionContext finalFrameForViewController:toViewController];
    [[transitionContext containerView] insertSubview:toViewController.view belowSubview:fromViewController.view];
    UIImageView *originalImageView = [self.sourceViewController originalImageView];
    originalImageView.hidden = YES;
    CGRect convertedFrame = [self.sourceViewController convertedFrameForOriginalImageView];
    
    //transitioningImageView
    UIImageView *transitioningImageView = [[UIImageView alloc] initWithImage:destinationImageView.image];
    transitioningImageView.frame = [[self class] aspectFitImage:destinationImageView.image inFrame:destinationImageView.frame];
    [[transitionContext containerView] addSubview:transitioningImageView];
    
    //animation
    [UIView animateWithDuration:[self transitionDuration:transitionContext] animations:^{
        fromViewController.view.alpha = 0.0;
        transitioningImageView.frame = convertedFrame;
    } completion:^(BOOL finished) {
        [transitioningImageView removeFromSuperview];
        destinationImageView.hidden = NO;
        originalImageView.hidden = NO;
        [transitionContext completeTransition:![transitionContext transitionWasCancelled]];
    }];
}

#pragma mark - UIViewControllerAnimatedTransitioning

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

- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext
{
    switch (self.animationType) {
        case PhotoBrowserZoomInAnimation:
            [self animateZoomInAnimation:transitionContext];
            break;
            
        case PhotoBrowserZoomOutAnimation:
            [self animateZoomOutAnimation:transitionContext];
            break;
    }
}


@end