components/FeatureHighlight/src/private/MDCFeatureHighlightAnimationController.m

// Copyright 2016-present the Material Components for iOS authors. All Rights Reserved.
//
// 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 "MDCFeatureHighlightAnimationController.h"

#import "MDCFeatureHighlightView+Private.h"

const NSTimeInterval kMDCFeatureHighlightPresentationDuration = 0.35;
const NSTimeInterval kMDCFeatureHighlightDismissalDuration = 0.2;

@implementation MDCFeatureHighlightAnimationController

- (NSTimeInterval)transitionDuration:
    (nullable __unused id<UIViewControllerContextTransitioning>)transitionContext {
  if (self.presenting) {
    return kMDCFeatureHighlightPresentationDuration;
  } else {
    return kMDCFeatureHighlightDismissalDuration;
  }
}

- (void)animateTransition:(id<UIViewControllerContextTransitioning>)transitionContext {
  UIViewController *toViewController =
      [transitionContext viewControllerForKey:UITransitionContextToViewControllerKey];
  UIView *fromView = [transitionContext viewForKey:UITransitionContextFromViewKey];
  UIView *toView = [transitionContext viewForKey:UITransitionContextToViewKey];

  MDCFeatureHighlightView *highlightView = nil;
  if ([fromView isKindOfClass:[MDCFeatureHighlightView class]]) {
    highlightView = (MDCFeatureHighlightView *)fromView;
  } else if ([toView isKindOfClass:[MDCFeatureHighlightView class]]) {
    highlightView = (MDCFeatureHighlightView *)toView;
  }

  if (self.presenting) {
    [transitionContext.containerView addSubview:toView];
    toView.frame = [transitionContext finalFrameForViewController:toViewController];
  }

  NSTimeInterval transitionDuration = [self transitionDuration:transitionContext];

  [highlightView layoutIfNeeded];
  if (self.presenting) {
    [highlightView animateDiscover:transitionDuration];
  } else {
    switch (self.dismissStyle) {
      case MDCFeatureHighlightDismissAccepted:
        [highlightView animateAccepted:transitionDuration];
        break;

      case MDCFeatureHighlightDismissRejected:
        [highlightView animateRejected:transitionDuration];
        break;
    }
  }
  [UIView animateWithDuration:transitionDuration
      delay:0.0
      options:UIViewAnimationOptionBeginFromCurrentState
      animations:^{
        // We have to perform an animation on highlightView in this block or else UIKit
        // will not know we are performing an animation and will call the completion block
        // immediately, causing our CAAnimations to be cut short.
        if (self.presenting) {
          [highlightView layoutAppearing];
        } else {
          [highlightView layoutDisappearing];
        }
      }
      completion:^(__unused BOOL finished) {
        // If we're dismissing, remove the highlight view from the hierarchy
        if (!self.presenting) {
          [fromView removeFromSuperview];
        }
        [transitionContext completeTransition:YES];
      }];
}

@end