void UpdateCoverImage(ItemView aCover)
{
UIImage coverImage;
if (coverImages.TryGetValue (aCover.Number, out coverImage)){
if (coverImageHeights.ContainsKey (aCover.Number))
aCover.SetImage (coverImage, coverImageHeights [aCover.Number], kReflectionFraction);
} else {
aCover.SetImage (defaultImage, defaultImageHeight, kReflectionFraction);
if (dataSource != null)
dataSource.RequestImage (this, aCover.Number);
}
}
void SetupInitialState()
{
if (dataSource != null)
defaultImage = dataSource.GetDefaultImage ();
scrollView = new UIScrollView (Frame) {
UserInteractionEnabled = false,
MultipleTouchEnabled = false,
AutoresizingMask = UIViewAutoresizing.FlexibleHeight | UIViewAutoresizing.FlexibleWidth
};
AddSubview (scrollView);
MultipleTouchEnabled = false;
UserInteractionEnabled = true;
AutosizesSubviews = true;
Layer.Position = new System.Drawing.PointF ((float)(Frame.Size.Width / 2), (float)(Frame.Height / 2));
// Initialize the visible and selected cover range.
lowerVisibleCover = upperVisibleCover = -1;
selectedCoverView = null;
// Set up transforms
UpdateTransforms ();
// Set some perspective
var sublayerTransform = CATransform3D.Identity;
sublayerTransform.m34 = -0.01f;
scrollView.Layer.SublayerTransform = sublayerTransform;
Bounds = Frame;
}
void LayoutCover(ItemView aCover, int selectedIndex, bool animated)
{
int coverNumber = aCover.Number;
CATransform3D newTransform;
float newZPosition = sideCoverPosition;
PointF newPosition = new PointF (halfScreenWidth + aCover.HorizontalPosition, halfScreenHeight + aCover.VerticalPosition);
if (coverNumber < selectedIndex){
newPosition.X -= centerCoverOffset;
newTransform = leftTransform;
} else if (coverNumber > selectedIndex){
newPosition.X += centerCoverOffset;
newTransform = rightTransform;
} else {
newZPosition = 0;
newTransform = CATransform3D.Identity;
}
if (animated){
BeginAnimations (null);
SetAnimationCurve (UIViewAnimationCurve.EaseOut);
SetAnimationBeginsFromCurrentState (true); // fixed typo Curren -> Current
}
aCover.Layer.Transform = newTransform;
aCover.Layer.ZPosition = newZPosition;
aCover.Layer.Position = newPosition;
if (animated)
CommitAnimations ();
}
ItemView CoverForIndex(int index)
{
var coverView = DequeueReusableCover ();
if (coverView == null)
coverView = new ItemView (this, System.Drawing.RectangleF.Empty);
coverView.Number = index;
return coverView;
}
public void SetSelectedCover(int newSelectedCover)
{
if (selectedCoverView != null && (newSelectedCover == selectedCoverView.Number))
return;
int newLowerBound = Math.Max (0, newSelectedCover - kCoverBuffer);
int newUpperBound = Math.Min (numberOfImages - 1, newSelectedCover + kCoverBuffer);
if (selectedCoverView == null){
// Allocate and display covers from newLower to newUYpper bounds.
for (int i = newLowerBound; i <= newUpperBound; i++){
var cover = CoverForIndex (i);
onscreenCovers [i] = cover;
UpdateCoverImage (cover);
scrollView.Layer.AddSublayer (cover.Layer);
LayoutCover (cover, newSelectedCover, false);
}
lowerVisibleCover = newLowerBound;
upperVisibleCover = newUpperBound;
selectedCoverView = onscreenCovers [newSelectedCover];
return;
}
// Check to see if the new and current ranges overlap
if ((newLowerBound > upperVisibleCover) || (newUpperBound < lowerVisibleCover)){
// They do not overlap at all
// This does not animate -- assuming it's programmatically set from view controller.
// Recycle all onscreen covers.
for (int i = lowerVisibleCover; i <= upperVisibleCover; i++){
var cover = onscreenCovers [i];
offscreenCovers.Push (cover);
cover.RemoveFromSuperview ();
onscreenCovers.Remove (i);
}
// Move all available covers to new location
for (int i = newLowerBound; i <= newUpperBound; i++){
var cover = CoverForIndex (i);
onscreenCovers [i] = cover;
UpdateCoverImage (cover);
scrollView.Layer.AddSublayer (cover.Layer);
}
lowerVisibleCover = newLowerBound;
upperVisibleCover = newUpperBound;
selectedCoverView = onscreenCovers [newSelectedCover];
LayoutCovers (newSelectedCover, newLowerBound, newUpperBound);
return;
} else if (newSelectedCover > selectedCoverView.Number){
for (int i = lowerVisibleCover; i < newLowerBound; i++){
var cover = onscreenCovers [i];
if (upperVisibleCover < newUpperBound){
// Tack it on right side
upperVisibleCover++;
cover.Number = upperVisibleCover;
UpdateCoverImage (cover);
onscreenCovers [cover.Number] = cover;
LayoutCover (cover, newSelectedCover, false);
} else {
// Recycle this cover
offscreenCovers.Push (cover);
cover.RemoveFromSuperview ();
}
onscreenCovers.Remove (i);
}
lowerVisibleCover = newLowerBound;
// Add in any missing covers on the right up to the newUpperBound.
for (int i = upperVisibleCover+1; i <= newUpperBound; i++){
var cover = CoverForIndex (i);
onscreenCovers [i] = cover;
UpdateCoverImage (cover);
scrollView.Layer.AddSublayer (cover.Layer);
LayoutCover (cover, newSelectedCover, false);
}
upperVisibleCover = newUpperBound;
} else {
// Move covers that are now out of range on the right to the left side.
// but only if appropriate (within the range set by newLoweBound).
for (int i = upperVisibleCover; i > newUpperBound; i--){
var cover = onscreenCovers [i];
if (lowerVisibleCover > newLowerBound){
// Tack it on the left
lowerVisibleCover--;
cover.Number = lowerVisibleCover;
UpdateCoverImage (cover);
onscreenCovers [lowerVisibleCover] = cover;
LayoutCover (cover, newSelectedCover, false);
} else {
// Recycle this cover
offscreenCovers.Push (cover);
cover.RemoveFromSuperview ();
}
}
upperVisibleCover = newUpperBound;
// Add in any missing covers on the left down to the newLowerBound
for (int i = lowerVisibleCover - 1; i >= newLowerBound; i--){
var cover = CoverForIndex (i);
onscreenCovers [i] = cover;
UpdateCoverImage (cover);
scrollView.Layer.AddSublayer (cover.Layer);
LayoutCover (cover, newSelectedCover, false);
}
lowerVisibleCover = newLowerBound;
}
if (selectedCoverView.Number > newSelectedCover)
LayoutCovers (newSelectedCover, newSelectedCover, selectedCoverView.Number);
else if (newSelectedCover > selectedCoverView.Number)
LayoutCovers (newSelectedCover, selectedCoverView.Number, newSelectedCover);
selectedCoverView = onscreenCovers [newSelectedCover];
}
public void SetSelectedCover(int newSelectedCover)
{
if (selectedCoverView != null && (newSelectedCover == selectedCoverView.Number))
{
return;
}
int newLowerBound = Math.Max(0, newSelectedCover - kCoverBuffer);
int newUpperBound = Math.Min(numberOfImages - 1, newSelectedCover + kCoverBuffer);
if (selectedCoverView == null)
{
// Allocate and display covers from newLower to newUYpper bounds.
for (int i = newLowerBound; i <= newUpperBound; i++)
{
var cover = CoverForIndex(i);
onscreenCovers [i] = cover;
UpdateCoverImage(cover);
scrollView.Layer.AddSublayer(cover.Layer);
LayoutCover(cover, newSelectedCover, false);
}
lowerVisibleCover = newLowerBound;
upperVisibleCover = newUpperBound;
selectedCoverView = onscreenCovers [newSelectedCover];
return;
}
// Check to see if the new and current ranges overlap
if ((newLowerBound > upperVisibleCover) || (newUpperBound < lowerVisibleCover))
{
// They do not overlap at all
// This does not animate -- assuming it's programmatically set from view controller.
// Recycle all onscreen covers.
for (int i = lowerVisibleCover; i <= upperVisibleCover; i++)
{
var cover = onscreenCovers [i];
offscreenCovers.Push(cover);
cover.RemoveFromSuperview();
onscreenCovers.Remove(i);
}
// Move all available covers to new location
for (int i = newLowerBound; i <= newUpperBound; i++)
{
var cover = CoverForIndex(i);
onscreenCovers [i] = cover;
UpdateCoverImage(cover);
scrollView.Layer.AddSublayer(cover.Layer);
}
lowerVisibleCover = newLowerBound;
upperVisibleCover = newUpperBound;
selectedCoverView = onscreenCovers [newSelectedCover];
LayoutCovers(newSelectedCover, newLowerBound, newUpperBound);
return;
}
else if (newSelectedCover > selectedCoverView.Number)
{
for (int i = lowerVisibleCover; i < newLowerBound; i++)
{
var cover = onscreenCovers [i];
if (upperVisibleCover < newUpperBound)
{
// Tack it on right side
upperVisibleCover++;
cover.Number = upperVisibleCover;
UpdateCoverImage(cover);
onscreenCovers [cover.Number] = cover;
LayoutCover(cover, newSelectedCover, false);
}
else
{
// Recycle this cover
offscreenCovers.Push(cover);
cover.RemoveFromSuperview();
}
onscreenCovers.Remove(i);
}
lowerVisibleCover = newLowerBound;
// Add in any missing covers on the right up to the newUpperBound.
for (int i = upperVisibleCover + 1; i <= newUpperBound; i++)
{
var cover = CoverForIndex(i);
onscreenCovers [i] = cover;
UpdateCoverImage(cover);
scrollView.Layer.AddSublayer(cover.Layer);
LayoutCover(cover, newSelectedCover, false);
}
upperVisibleCover = newUpperBound;
}
else
{
// Move covers that are now out of range on the right to the left side.
// but only if appropriate (within the range set by newLoweBound).
for (int i = upperVisibleCover; i > newUpperBound; i--)
{
var cover = onscreenCovers [i];
if (lowerVisibleCover > newLowerBound)
{
// Tack it on the left
lowerVisibleCover--;
cover.Number = lowerVisibleCover;
UpdateCoverImage(cover);
onscreenCovers [lowerVisibleCover] = cover;
LayoutCover(cover, newSelectedCover, false);
}
else
{
// Recycle this cover
offscreenCovers.Push(cover);
cover.RemoveFromSuperview();
}
}
upperVisibleCover = newUpperBound;
// Add in any missing covers on the left down to the newLowerBound
for (int i = lowerVisibleCover - 1; i >= newLowerBound; i--)
{
var cover = CoverForIndex(i);
onscreenCovers [i] = cover;
UpdateCoverImage(cover);
scrollView.Layer.AddSublayer(cover.Layer);
LayoutCover(cover, newSelectedCover, false);
}
lowerVisibleCover = newLowerBound;
}
if (selectedCoverView.Number > newSelectedCover)
{
LayoutCovers(newSelectedCover, newSelectedCover, selectedCoverView.Number);
}
else if (newSelectedCover > selectedCoverView.Number)
{
LayoutCovers(newSelectedCover, selectedCoverView.Number, newSelectedCover);
}
selectedCoverView = onscreenCovers [newSelectedCover];
}
