CATransform3D

gistfile1.cs

/// <summary>
		/// Sets the anchor point and translates the view so that it stays in its current position.
/// Normally, changing the anchor point also adjusts the view's position.
		/// </summary>
		/// <param name='oView'>the view whose anchor point has to be modified</param>
		/// <param name='oNewAnchorPoint'>the new anchor point</param>
		public void SetAnchorPointAndTranslate(PointF oNewAnchorPoint )
		{
			UIView oView = this;
    		PointF oNewPoint = new PointF(oView.Bounds.Width * oNewAnchorPoint.X, oView.Bounds.Height * oNewAnchorPoint.Y);
    		PointF oOldPoint = new PointF(oView.Bounds.Width * oView.Layer.AnchorPoint.X, oView.Bounds.Height * oView.Layer.AnchorPoint.Y);
    		
			oNewPoint = oView.Transform.TransformPoint(oNewPoint);
    		oOldPoint = oView.Transform.TransformPoint(oOldPoint);

    		PointF oPosition = new PointF(oView.Layer.Position.X - oOldPoint.X + oNewPoint.X, oView.Layer.Position.Y - oOldPoint.Y + oNewPoint.Y);

    		oView.Layer.Position = oPosition;
    		oView.Layer.AnchorPoint = oNewAnchorPoint;
		}

/// <summary>
		/// Moves a tile view from left to right or right to left.
		/// </summary>
		/// <param name='iIndex'>zero based index of the tile to move</param>
		/// <param name='eDir'>move left or right?</param>
		/// <param name='bAnimate'>TRUE to animate the movement</param>
private void MoveTileView(int iIndex, UISwipeGestureRecognizerDirection eDir, bool bAnimate)
		{
			TileViewBase oView = this.VisibleTileViews[iIndex];
			
			// Anchor point of the animated layer will be adjusted to rotate along the edges of the view and not the center.
			// Changing the anchor point however affects the view's position. This means the changed anchor point has
			// to be compensated.
			if(eDir == UISwipeGestureRecognizerDirection.Left
			   && oView.ViewPosition == TileViewBase.VIEW_POSITION.Center)
			{
				// If swiping left and the view is currently in center, the anchor point goes to the left edge.
				oView.SetAnchorPointAndTranslate(new PointF(0, 0.5f));
			}
			
			if(eDir == UISwipeGestureRecognizerDirection.Right
			   && oView.ViewPosition == TileViewBase.VIEW_POSITION.Center)
			{
				// If swiping right and the view is currently in center, the anchor point goes to the right edge.
				oView.SetAnchorPointAndTranslate(new PointF(1, 0.5f));
			}
			
			// If the views are pushed aside, apply a small X offset to prevent them from sticking on top of each other.
			float fOffsetX;
			if(eDir == UISwipeGestureRecognizerDirection.Left)
			{
				fOffsetX = iIndex * TILE_DISTANCE;
			}
			else
			{
				fOffsetX = (iIndex - (this.VisibleTileViews.Length - 1)) * TILE_DISTANCE;
			}
			
			// Prepare transformation to rotate view around Y axis and translate to the left or right border of the screen.
			float fAnimDir = eDir == UISwipeGestureRecognizerDirection.Left ? -1 : 1;
			// TODO: Uncomment if CATransform3D no longer crashes as it does in MT 5.2.10
			CATransform3D oTransform3D = CATransform3D.Identity;
			oTransform3D.m34 = 1.0f / -400;
			oTransform3D = oTransform3D.Translate(fAnimDir * TILE_TRANSLATION_X + fOffsetX, 0, 0);
			oTransform3D = oTransform3D.Rotate(fAnimDir * (-70f) * (float)Math.PI / 180f, 0, 1, 0);	
			
			
			// Animate the transformation of the current view.
			UIView.Animate(
				bAnimate ? ANIM_CHANGE_VIEW_SECS : 0,
				0f,
				UIViewAnimationOptions.CurveEaseOut,
				delegate
				{
					// Check in what direction the swipe was going (left or right).
					switch(eDir)
					{
						case UISwipeGestureRecognizerDirection.Left:
							// Swipe left. If view is centered, move to left. 
							// If view is right, move to center.
							if(oView.ViewPosition == TileViewBase.VIEW_POSITION.Center)
							{
								oView.Layer.Transform = oTransform3D;
								oView.ViewPosition = TileViewBase.VIEW_POSITION.Left;
							}
							else if(oView.ViewPosition == TileViewBase.VIEW_POSITION.Right)
							{
								CATransform3D oTransformCenter = CATransform3D.Identity;
								oView.Layer.Transform = oTransformCenter;
								oView.ViewPosition = TileViewBase.VIEW_POSITION.Center;
							}
							break;
					
						case UISwipeGestureRecognizerDirection.Right:
							// Swipe right. If view is centered, move to right. 
							// If view is left, move to center.
							if(oView.ViewPosition == TileViewBase.VIEW_POSITION.Center)
							{
								oView.Layer.Transform = oTransform3D;
								oView.ViewPosition = TileViewBase.VIEW_POSITION.Right;
							}
							else if(oView.ViewPosition== TileViewBase.VIEW_POSITION.Left)
							{
								CATransform3D oTransformCenter = CATransform3D.Identity;
								oView.Layer.Transform = oTransformCenter;
								oView.ViewPosition = TileViewBase.VIEW_POSITION.Center;
							}
							break;
					}
				
					if(oView.ViewPosition == TileViewBase.VIEW_POSITION.Center)
					{
						oView.Alpha = 1f;
						oView.UserInteractionEnabled = true;
						oView.EnableShadow(true);
					}
					else
					{
						oView.Alpha = 0.7f;
						oView.UserInteractionEnabled = false;
						oView.EnableShadow(false);
					}
				},
				delegate
				{
				}
			);
		}