public override void AnimateTransition(IUIViewControllerContextTransitioning transitionContext)
        {
            var fromViewController = transitionContext.GetViewControllerForKey(UITransitionContext.FromViewControllerKey);
            var toViewController   = transitionContext.GetViewControllerForKey(UITransitionContext.ToViewControllerKey);

            UIView containerView = transitionContext.ContainerView;

            var fromView = transitionContext.GetViewFor(UITransitionContext.FromViewKey);
            var toView   = transitionContext.GetViewFor(UITransitionContext.ToViewKey);

            fromView.Frame = transitionContext.GetInitialFrameForViewController(fromViewController);
            toView.Frame   = transitionContext.GetFinalFrameForViewController(toViewController);

            fromView.Alpha = 1f;
            toView.Alpha   = 0f;

            containerView.AddSubview(toView);
            var transitionDuration = TransitionDuration(transitionContext);

            UIView.Animate(transitionDuration, 0, UIViewAnimationOptions.TransitionNone, () => {
                fromView.Alpha = 0f;
                toView.Alpha   = 1f;
            }, () => {
                bool wasCancel = transitionContext.TransitionWasCancelled;
                transitionContext.CompleteTransition(!wasCancel);
            }
                           );
        }
        protected override void AnimatePresentingInContext(IUIViewControllerContextTransitioning transitioningContext, UIViewController originatingController, UIViewController destinationController)
        {
            CGRect fromVCrect = transitioningContext.GetInitialFrameForViewController(originatingController);
            CGRect toVCRect   = fromVCrect;

            toVCRect.Y = (nfloat)(toVCRect.Size.Height - this.InitialY);

            destinationController.View.Frame = toVCRect;
            UIView container = transitioningContext.ContainerView;
            UIView imageView = new UIImageView(DummyImage);

            destinationController.View.AddSubview(imageView);

            container.AddSubview(originatingController.View);
            container.AddSubview(destinationController.View);

            UIView.Animate(AnimationDuration, () =>
            {
                destinationController.View.Frame = fromVCrect;
                imageView.Alpha = 0.0f;
            },
                           () =>
            {
                imageView.RemoveFromSuperview();
                if (transitioningContext.TransitionWasCancelled)
                {
                    transitioningContext.CompleteTransition(false);
                }
                else
                {
                    transitioningContext.CompleteTransition(true);
                }
            });
        }
		public override void AnimateTransition (IUIViewControllerContextTransitioning transitionContext,
		                                        UIViewController fromViewController, UIViewController toViewController,
		                                        UIView fromView, UIView toView)
		{
			UIView containerView = transitionContext.ContainerView;
			containerView.AddSubview (toView);
			containerView.SendSubviewToBack (toView);

			var transform = CATransform3D.Identity;
			transform.m34 = -0.002f;
			containerView.Layer.SublayerTransform = transform;

			var initialFrame = transitionContext.GetInitialFrameForViewController (fromViewController);
			fromView.Frame = initialFrame;
			toView.Frame = initialFrame;

			List<UIView> toViewSnapshots = CreateSnapshots (toView, true);
			UIView flippedSectionOfToView = toViewSnapshots [Reverse ? 0 : 1];

			List<UIView> fromViewSnapshots = CreateSnapshots (fromView, false);
			UIView flippedSectionOfFromView = fromViewSnapshots [Reverse ? 1 : 0];

			flippedSectionOfFromView = AddShadowToView (flippedSectionOfFromView, !Reverse);
			UIView flippedSectionOfFromViewShadow = flippedSectionOfFromView.Subviews [1];
			flippedSectionOfFromViewShadow.Alpha = 0f;

			flippedSectionOfToView = AddShadowToView (flippedSectionOfToView, Reverse);
			UIView flippedSectionOfToViewShadow = flippedSectionOfToView.Subviews [1];
			flippedSectionOfToViewShadow.Alpha = 1f;

			// change the anchor point so that the view rotate around the correct edge
			UpdateAnchorPointAndOffset (new CGPoint (Reverse ? 0f : 1f, 0.5f), flippedSectionOfFromView);
			UpdateAnchorPointAndOffset (new CGPoint (Reverse ? 1f : 0f, 0.5f), flippedSectionOfToView);

			flippedSectionOfToView.Layer.Transform = Rotate (Reverse ? (float)Math.PI / 2 : -(float)Math.PI / 2);
			double duration = TransitionDuration (transitionContext);

			Action animations = () => {
				UIView.AddKeyframeWithRelativeStartTime (0.0, 0.5, () => {
					flippedSectionOfFromView.Layer.Transform = Rotate (Reverse ? -(float)Math.PI / 2 : (float)Math.PI / 2);
					flippedSectionOfFromViewShadow.Alpha = 1f;
				});

				UIView.AddKeyframeWithRelativeStartTime (0.5, 0.5, () => {
					flippedSectionOfToView.Layer.Transform = Rotate (Reverse ? 0.001f : -0.001f);
					flippedSectionOfToViewShadow.Alpha = 0f;
				});
			};

			UIView.AnimateKeyframes (duration, 0.0, UIViewKeyframeAnimationOptions.CalculationModeLinear, animations, (finished) => {
				if (transitionContext.TransitionWasCancelled) {
					RemoveOtherViews (fromView);
				} else {
					RemoveOtherViews (toView);
				}

				transitionContext.CompleteTransition (!transitionContext.TransitionWasCancelled);
			});
		}
        public void AnimateTransition(IUIViewControllerContextTransitioning transitionContext)
        {
            var fromViewController = transitionContext.GetViewControllerForKey(UITransitionContext.FromViewControllerKey);
            var toViewController   = transitionContext.GetViewControllerForKey(UITransitionContext.ToViewControllerKey);

            UIView containerView = transitionContext.ContainerView;

            var  toView       = transitionContext.GetViewFor(UITransitionContext.ToViewKey);
            var  fromView     = transitionContext.GetViewFor(UITransitionContext.FromViewKey);
            bool isPresenting = (fromViewController == PresentingViewController);

            var fromViewFinalFrame = transitionContext.GetFinalFrameForViewController(fromViewController);
            var toViewInitialFrame = transitionContext.GetInitialFrameForViewController(toViewController);

            var toViewFinalFrame = transitionContext.GetFinalFrameForViewController(toViewController);

            if (toView != null)
            {
                containerView.AddSubview(toView);
            }

            if (isPresenting)
            {
                toViewInitialFrame.X    = containerView.Bounds.GetMinX();
                toViewInitialFrame.Y    = containerView.Bounds.GetMaxY();
                toViewInitialFrame.Size = toViewFinalFrame.Size;

                toView.Frame = toViewInitialFrame;
            }
            else
            {
                fromView.Frame.Offset(0f, fromView.Frame.Height);
                fromViewFinalFrame = new CGRect(fromView.Frame.X, fromView.Frame.Y + fromView.Frame.Height, fromViewFinalFrame.Width, fromViewFinalFrame.Height);
            }

            double transitionDuration = TransitionDuration(transitionContext);

            UIView.Animate(transitionDuration, 0, UIViewAnimationOptions.TransitionNone, () => {
                if (isPresenting)
                {
                    toView.Frame = toViewFinalFrame;
                }
                else
                {
                    fromView.Frame = fromViewFinalFrame;
                }
            }, () => {
                bool wasCancelled = transitionContext.TransitionWasCancelled;
                transitionContext.CompleteTransition(!wasCancelled);
            }
                           );
        }
Ejemplo n.º 5
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        public void AnimateTransition(IUIViewControllerContextTransitioning transitionContext)
        {
            var toController      = transitionContext.GetViewControllerForKey(UITransitionContext.ToViewControllerKey);
            var fromController    = transitionContext.GetViewControllerForKey(UITransitionContext.FromViewControllerKey);
            var animationDuration = TransitionDuration(transitionContext);

            if (presenting)
            {
                transitionContext.ContainerView.AddSubview(toController.View);

                var finalFrame = transitionContext.GetFinalFrameForViewController(toController);

                var frame = new CGRect(finalFrame.Location, finalFrame.Size);
                frame.Offset(0.0f, transitionContext.ContainerView.Frame.Height - 20);
                toController.View.Frame = frame;
                toController.View.Alpha = 0.5f;

                AnimationExtensions.Animate(animationDuration, Curves.CardInCurve, () =>
                {
                    toController.View.Frame = finalFrame;
                    toController.View.Alpha = 1.0f;
                },
                                            () => transitionContext.CompleteTransition(!transitionContext.TransitionWasCancelled));
            }
            else
            {
                var initialFrame = transitionContext.GetInitialFrameForViewController(fromController);
                initialFrame.Offset(0.0f, transitionContext.ContainerView.Frame.Height);
                var finalFrame = initialFrame;

                if (transitionContext.IsInteractive)
                {
                    UIView.Animate(
                        animationDuration,
                        () => fromController.View.Frame = finalFrame,
                        () => transitionContext.CompleteTransition(!transitionContext.TransitionWasCancelled)
                        );
                }
                else
                {
                    AnimationExtensions.Animate(animationDuration, Curves.CardOutCurve, () =>
                    {
                        fromController.View.Frame = finalFrame;
                        fromController.View.Alpha = 0.5f;
                    },
                                                () => transitionContext.CompleteTransition(!transitionContext.TransitionWasCancelled));
                }
            }
        }
Ejemplo n.º 6
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        public override void AnimateTransition(IUIViewControllerContextTransitioning transitionContext)
        {
            var toViewController   = GetViewController(transitionContext, UITransitionContext.ToViewControllerKey);
            var fromViewController = GetViewController(transitionContext, UITransitionContext.FromViewControllerKey);

            UIView fromView = fromViewController.View;
            UIView toView   = toViewController.View;


            UIView containerView = transitionContext.ContainerView;

            containerView.AddSubview(toView);

            // Add a perspective transform
            var transform = CATransform3D.Identity;

            transform.m34 = -0.002f;
            containerView.Layer.SublayerTransform = transform;

            // Give both VCs the same start frame
            CGRect initialFrame = transitionContext.GetInitialFrameForViewController(fromViewController);

            fromView.Frame = initialFrame;
            toView.Frame   = initialFrame;

            float factor = Reverse ? 1f : -1f;

            // flip the to VC halfway round - hiding it
            toView.Layer.Transform = GetRotation(factor * -(float)Math.PI / 2);
            double duration = TransitionDuration(transitionContext);

            Action animations = () =>
            {
                UIView.AddKeyframeWithRelativeStartTime(0.0, 0.5, () =>
                {
                    fromView.Layer.Transform = GetRotation(factor * (float)Math.PI / 2);
                });

                UIView.AddKeyframeWithRelativeStartTime(0.5, 0.5, () =>
                {
                    toView.Layer.Transform = GetRotation(0f);
                });
            };

            UIView.AnimateKeyframes(duration, 0.0, UIViewKeyframeAnimationOptions.CalculationModeLinear, animations, (finished) =>
            {
                transitionContext.CompleteTransition(!transitionContext.TransitionWasCancelled);
            });
        }
        public override void AnimateTransition(IUIViewControllerContextTransitioning transitionContext)
        {
            var fromViewController = transitionContext.GetViewControllerForKey(UITransitionContext.FromViewControllerKey);
            var toViewController   = transitionContext.GetViewControllerForKey(UITransitionContext.ToViewControllerKey);

            UIView containerView = transitionContext.ContainerView;

            var fromView = transitionContext.GetViewFor(UITransitionContext.FromViewKey);
            var toView   = transitionContext.GetViewFor(UITransitionContext.ToViewKey);

            var fromFrame = transitionContext.GetInitialFrameForViewController(fromViewController);
            var toFrame   = transitionContext.GetFinalFrameForViewController(toViewController);

            var offset = new CGVector(0f, 0f);

            if (targetEdge == UIRectEdge.Left)
            {
                offset = new CGVector(-1f, 0f);
            }
            else if (targetEdge == UIRectEdge.Right)
            {
                offset = new CGVector(1f, 0f);
            }

            fromView.Frame = fromFrame;

            CGRect auxFrame = toFrame;

            auxFrame.Offset(toFrame.Width * offset.dx * -1f, toFrame.Height * offset.dy * -1f);
            toView.Frame = auxFrame;

            containerView.AddSubview(toView);

            var duration = TransitionDuration(transitionContext);

            UIView.Animate(duration, 0, UIViewAnimationOptions.TransitionNone, () => {
                var fromFrameAux = fromFrame;
                fromFrameAux.Offset(fromFrame.Width * offset.dx, fromFrame.Height * offset.dy);
                fromView.Frame = fromFrameAux;

                toView.Frame = toFrame;
            }, () => {
                transitionContext.CompleteTransition(!transitionContext.TransitionWasCancelled);
            }
                           );
        }
        public override void AnimateTransition(IUIViewControllerContextTransitioning transitionContext, 
		                                        UIViewController fromViewController, UIViewController toViewController, 
		                                        UIView fromView, UIView toView)
        {
            UIView containerView = transitionContext.ContainerView;
            containerView.AddSubview (toView);

            // Add a perspective transform
            var transform = CATransform3D.Identity;
            transform.m34 = -0.002f;
            containerView.Layer.SublayerTransform = transform;

            // Give both VCs the same start frame
            RectangleF initialFrame = transitionContext.GetInitialFrameForViewController (fromViewController);
            fromView.Frame = initialFrame;
            toView.Frame = initialFrame;

            float factor = Reverse ? 1f : -1f;

            // flip the to VC halfway round - hiding it
            toView.Layer.Transform = Rotate (factor * -(float)Math.PI / 2);
            double duration = TransitionDuration (transitionContext);

            NSAction animations = () => {
                UIView.AddKeyframeWithRelativeStartTime (0.0, 0.5, () => {
                    fromView.Layer.Transform = Rotate (factor * (float)Math.PI / 2);
                });

                UIView.AddKeyframeWithRelativeStartTime (0.5, 0.5, () => {
                    toView.Layer.Transform = Rotate (0f);
                });
            };

            UIView.AnimateKeyframes (duration, 0.0, UIViewKeyframeAnimationOptions.CalculationModeLinear, animations, (finished) => {
                transitionContext.CompleteTransition (!transitionContext.TransitionWasCancelled);
            });
        }
        public override void AnimateTransition(IUIViewControllerContextTransitioning transitionContext,
                                               UIViewController fromViewController, UIViewController toViewController,
                                               UIView fromView, UIView toView)
        {
            UIView containerView = transitionContext.ContainerView;

            containerView.AddSubview(toView);
            containerView.SendSubviewToBack(toView);

            var transform = CATransform3D.Identity;

            transform.m34 = -0.002f;
            containerView.Layer.SublayerTransform = transform;

            var initialFrame = transitionContext.GetInitialFrameForViewController(fromViewController);

            fromView.Frame = initialFrame;
            toView.Frame   = initialFrame;

            List <UIView> toViewSnapshots        = CreateSnapshots(toView, true);
            UIView        flippedSectionOfToView = toViewSnapshots [Reverse ? 0 : 1];

            List <UIView> fromViewSnapshots        = CreateSnapshots(fromView, false);
            UIView        flippedSectionOfFromView = fromViewSnapshots [Reverse ? 1 : 0];

            flippedSectionOfFromView = AddShadowToView(flippedSectionOfFromView, !Reverse);
            UIView flippedSectionOfFromViewShadow = flippedSectionOfFromView.Subviews [1];

            flippedSectionOfFromViewShadow.Alpha = 0f;

            flippedSectionOfToView = AddShadowToView(flippedSectionOfToView, Reverse);
            UIView flippedSectionOfToViewShadow = flippedSectionOfToView.Subviews [1];

            flippedSectionOfToViewShadow.Alpha = 1f;

            // change the anchor point so that the view rotate around the correct edge
            UpdateAnchorPointAndOffset(new CGPoint(Reverse ? 0f : 1f, 0.5f), flippedSectionOfFromView);
            UpdateAnchorPointAndOffset(new CGPoint(Reverse ? 1f : 0f, 0.5f), flippedSectionOfToView);

            flippedSectionOfToView.Layer.Transform = Rotate(Reverse ? (float)Math.PI / 2 : -(float)Math.PI / 2);
            double duration = TransitionDuration(transitionContext);

            Action animations = () => {
                UIView.AddKeyframeWithRelativeStartTime(0.0, 0.5, () => {
                    flippedSectionOfFromView.Layer.Transform = Rotate(Reverse ? -(float)Math.PI / 2 : (float)Math.PI / 2);
                    flippedSectionOfFromViewShadow.Alpha     = 1f;
                });

                UIView.AddKeyframeWithRelativeStartTime(0.5, 0.5, () => {
                    flippedSectionOfToView.Layer.Transform = Rotate(Reverse ? 0.001f : -0.001f);
                    flippedSectionOfToViewShadow.Alpha     = 0f;
                });
            };

            UIView.AnimateKeyframes(duration, 0.0, UIViewKeyframeAnimationOptions.CalculationModeLinear, animations, (finished) => {
                if (transitionContext.TransitionWasCancelled)
                {
                    RemoveOtherViews(fromView);
                }
                else
                {
                    RemoveOtherViews(toView);
                }

                transitionContext.CompleteTransition(!transitionContext.TransitionWasCancelled);
            });
        }
Ejemplo n.º 10
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        public override void AnimateTransition(IUIViewControllerContextTransitioning transitionContext)
        {
            var    fromViewController = transitionContext.GetViewControllerForKey(UITransitionContext.FromViewControllerKey);
            var    toViewController   = transitionContext.GetViewControllerForKey(UITransitionContext.ToViewControllerKey);
            UIView containerView      = transitionContext.ContainerView;

            var fromView = transitionContext.GetViewFor(UITransitionContext.FromViewKey);
            var toView   = transitionContext.GetViewFor(UITransitionContext.ToViewKey);

            fromView.Frame = transitionContext.GetInitialFrameForViewController(fromViewController);
            toView.Frame   = transitionContext.GetFinalFrameForViewController(toViewController);
            bool isPush = Array.IndexOf(toViewController.NavigationController.ViewControllers, toViewController) > Array.IndexOf(fromViewController.NavigationController.ViewControllers, fromViewController);

            containerView.AddSubview(toView);

            // TODO
            UIImage fromViewSnapshot;
            var     toViewSnapshot = new UIImage();

            UIGraphics.BeginImageContextWithOptions(containerView.Bounds.Size, true, containerView.Window.Screen.Scale);
            fromView.DrawViewHierarchy(containerView.Bounds, false);
            fromViewSnapshot = UIGraphics.GetImageFromCurrentImageContext();
            UIGraphics.EndImageContext();

            CoreFoundation.DispatchQueue.MainQueue.DispatchAsync(() => {
                UIGraphics.BeginImageContextWithOptions(containerView.Bounds.Size, true, containerView.Window.Screen.Scale);
                toView.DrawViewHierarchy(containerView.Bounds, false);
                toViewSnapshot = UIGraphics.GetImageFromCurrentImageContext();
                UIGraphics.EndImageContext();
            });

            var transitionContainer = new UIView(containerView.Bounds)
            {
                Opaque          = true,
                BackgroundColor = UIColor.Black
            };

            containerView.AddSubview(transitionContainer);

            CATransform3D t = CATransform3D.Identity;

            t.m34 = 1f / -900f;
            transitionContainer.Layer.SublayerTransform = t;

            // The size and number of slices is a function of the width.
            var sliceSize         = Math.Round(transitionContainer.Frame.Width / 10f);
            var horizontalSileces = Math.Ceiling(transitionContainer.Frame.Width / sliceSize);
            var verticalSlices    = Math.Ceiling(transitionContainer.Frame.Height / sliceSize);

            // transitionSpacing controls the transition duration for each slice.
            // Higher values produce longer animations with multiple slices having
            // their animations 'in flight' simultaneously.
            float transitionSpacing  = 160f;
            var   transitionDuration = TransitionDuration(transitionContext);

            nfloat dx = isPush ? transitionContainer.Bounds.GetMaxY() - transitionContainer.Bounds.GetMinX()
                                                                : transitionContainer.Bounds.GetMinX() - transitionContainer.Bounds.GetMaxX();

            nfloat dy = isPush ? transitionContainer.Bounds.GetMaxY() - transitionContainer.Bounds.GetMinY() :
                        transitionContainer.Bounds.GetMinY() - transitionContainer.Bounds.GetMaxY();

            var transitionVector = new CGVector(dx, dy);

            var transitionVectorLength = (nfloat)Math.Sqrt(transitionVector.dx * transitionVector.dx + transitionVector.dy * transitionVector.dy);
            var transitionUnitVector   = new CGVector(transitionVector.dx / transitionVectorLength, transitionVector.dy / new nfloat(transitionVectorLength));

            for (int y = 0; y < verticalSlices; y++)
            {
                for (int x = 0; x < horizontalSileces; x++)
                {
                    var fromContentLayer = new CALayer {
                        Frame = new CGRect(x + sliceSize * -1f, y * sliceSize * -1f, containerView.Bounds.Width, containerView.Bounds.Height),
                        RasterizationScale = fromViewSnapshot.CurrentScale,
                        Contents           = fromViewSnapshot.CGImage
                    };

                    var toContentLayer = new CALayer();
                    toContentLayer.Frame = new CGRect(x * sliceSize * -1f, y * sliceSize * -1f, containerView.Bounds.Width, containerView.Bounds.Height);

                    CoreFoundation.DispatchQueue.MainQueue.DispatchAsync(() => {
                        bool wereActionDisabled      = CATransaction.DisableActions;
                        CATransaction.DisableActions = true;

                        toContentLayer.RasterizationScale = toViewSnapshot.CurrentScale;
                        toContentLayer.Contents           = toViewSnapshot.CGImage;

                        CATransaction.DisableActions = wereActionDisabled;
                    });

                    var toCheckboardSquareView = new UIView {
                        Frame  = new CGRect(x * sliceSize, y * sliceSize, sliceSize, sliceSize),
                        Opaque = false
                    };

                    toCheckboardSquareView.Layer.MasksToBounds = true;
                    toCheckboardSquareView.Layer.DoubleSided   = false;
                    toCheckboardSquareView.Layer.Transform     = CATransform3D.MakeRotation(NMath.PI, 0f, 1f, 0f);
                    toCheckboardSquareView.Layer.AddSublayer(toContentLayer);

                    var fromCheckboardSquareView = new UIView {
                        Frame  = new CGRect(x * sliceSize, y * sliceSize, sliceSize, sliceSize),
                        Opaque = false
                    };

                    fromCheckboardSquareView.Layer.MasksToBounds = true;
                    fromCheckboardSquareView.Layer.DoubleSided   = false;
                    fromCheckboardSquareView.Layer.Transform     = CATransform3D.Identity;
                    fromCheckboardSquareView.Layer.AddSublayer(fromContentLayer);

                    transitionContainer.AddSubview(toCheckboardSquareView);
                    transitionContainer.AddSubview(fromCheckboardSquareView);
                }
            }

            int sliceAnimationsPending = 0;

            for (int y = 0; y < verticalSlices; y++)
            {
                for (int x = 0; x < horizontalSileces; x++)
                {
                    double toIndex = y * horizontalSileces * 2f + (x * 2);
                    UIView toCheckboardSquareView = transitionContainer.Subviews[(int)toIndex];

                    double fromIndex = y * horizontalSileces * 2f + (x * 2 + 1);
                    UIView fromCheckboardSquareView = transitionContainer.Subviews[(int)fromIndex];

                    CGVector sliceOriginVector;

                    if (isPush)
                    {
                        sliceOriginVector = new CGVector(fromCheckboardSquareView.Frame.GetMinX() - transitionContainer.Bounds.GetMinX(), fromCheckboardSquareView.Frame.GetMinY() - transitionContainer.Bounds.GetMinY());
                    }
                    else
                    {
                        sliceOriginVector = new CGVector(fromCheckboardSquareView.Frame.GetMaxX() - transitionContainer.Bounds.GetMaxX(), fromCheckboardSquareView.Frame.GetMaxY() - transitionContainer.Bounds.GetMaxY());
                    }

                    // Project sliceOriginVector onto transitionVector.
                    nfloat dot        = sliceOriginVector.dx * transitionVector.dx + sliceOriginVector.dy * transitionVector.dy;
                    var    projection = new CGVector(transitionUnitVector.dx * dot / transitionVectorLength, transitionUnitVector.dy * dot / transitionVectorLength);

                    // Compute the length of the projection.
                    var projectionLength = NMath.Sqrt(projection.dx * projection.dx + projection.dy * projection.dy);

                    double startTime = projectionLength / (transitionVectorLength + transitionSpacing) * transitionDuration;
                    double duration  = ((projectionLength + transitionSpacing) / (transitionVectorLength + transitionSpacing) * transitionDuration) - startTime;

                    sliceAnimationsPending++;

                    UIView.Animate(duration, startTime, UIViewAnimationOptions.TransitionNone, () => {
                        toCheckboardSquareView.Layer.Transform   = CATransform3D.Identity;
                        fromCheckboardSquareView.Layer.Transform = CATransform3D.MakeRotation(NMath.PI, 0f, 1f, 0f);
                    }, () => {
                        if (--sliceAnimationsPending == 0)
                        {
                            bool wasCancelled = transitionContext.TransitionWasCancelled;
                            transitionContainer.RemoveFromSuperview();
                            transitionContext.CompleteTransition(!wasCancelled);
                        }
                    }
                                   );
                }
            }
        }
        public override void AnimateTransition(IUIViewControllerContextTransitioning transitionContext)
        {
            var fromViewController = transitionContext.GetViewControllerForKey(UITransitionContext.FromViewControllerKey);
            var toViewController   = transitionContext.GetViewControllerForKey(UITransitionContext.ToViewControllerKey);

            UIView containerView = transitionContext.ContainerView;
            var    fromView      = transitionContext.GetViewFor(UITransitionContext.FromViewKey);
            var    toView        = transitionContext.GetViewFor(UITransitionContext.ToViewKey);

            bool isPresenting = (toViewController.PresentingViewController == fromViewController);

            var fromFrame = transitionContext.GetInitialFrameForViewController(fromViewController);
            var toFrame   = transitionContext.GetFinalFrameForViewController(toViewController);

            var offset = new CGVector(0f, 0f);

            switch (targetEdge)
            {
            case UIRectEdge.Top:
                offset = new CGVector(0f, 1f);
                break;

            case UIRectEdge.Bottom:
                offset = new CGVector(0f, -1f);
                break;

            case UIRectEdge.Left:
                offset = new CGVector(1f, 0f);
                break;

            case UIRectEdge.Right:
                offset = new CGVector(-1, 0);
                break;

            default:
                offset = new CGVector(0f, 0f);
                // TODO: error
                break;
            }

            if (isPresenting)
            {
                fromView.Frame = fromFrame;
                toView.Frame   = new CGRect(toFrame.X + (toFrame.Size.Width * offset.dx * -1), toFrame.Y + (toFrame.Size.Height * offset.dy * -1), toFrame.Size.Width, toFrame.Size.Height);
            }
            else
            {
                fromView.Frame = fromFrame;
                toView.Frame   = toFrame;
            }

            if (isPresenting)
            {
                containerView.AddSubview(toView);
            }
            else
            {
                containerView.InsertSubviewBelow(toView, fromView);
            }

            var duration = TransitionDuration(transitionContext);

            UIView.Animate(duration, 0, UIViewAnimationOptions.TransitionNone, () => {
                toView.Frame = isPresenting ?
                               toFrame : new CGRect(fromFrame.X + (fromFrame.Size.Width * offset.dx), fromFrame.Y + (fromFrame.Size.Height * offset.dy), fromFrame.Size.Width, fromFrame.Size.Height);
            }, () => {
                bool wasCancel = transitionContext.TransitionWasCancelled;

                if (wasCancel)
                {
                    toView.RemoveFromSuperview();
                    transitionContext.CompleteTransition(!wasCancel);
                }
            });
        }