* Introduce ASCollectionViewLayout
- `ASCollectionViewLayout` is an async `UICollectionViewLayout` that encapsulates its layout calculation logic into a separate thread-safe object which can be used ahead of time and/or on multiple threads.
- `ASDataController` now can prepare for a new layout resulted from a change set before `ASCollectionView` even knows about it. By the time the change set it ready to be consumed by `ASCollectionView`, its new layout is also ready.
- New `ASCollectionViewLayoutCalculating` protocol that is simple and generic enough that many types of calculators can be built on top. `ASCollectionViewLayoutSpecCalculator` conforms to `ASCollectionViewLayoutCalculating` protocol and can be backed by any layout spec (e.g `ASStackLayoutSpec`, `PIMasonryLayoutSpec`, etc). We can even build a `ASCollectionViewLayoutYogaCalculator` that uses Yoga internally.
- A built-in `ASCollectionViewFlowLayoutCalculator` that is a subclass of `ASCollectionViewLayoutSpecCalculator` and uses a multi-threaded multi-line `ASStackLayoutSpec` internally. The result is a performant and thread-safe flow layout calculator.
- Finally, `ASCollectionViewLayout` can be subclassed to handle a specific type of calculator with optimizations implemented based on the knowledge of such calculator. For example, `ASCollectionViewFlowLayout` can have a highly optimized implementation of `-layoutAttributesForElementsInRect:`.
Protocolize layout calculator providing and consuming
Add flex wrap documentation
Add a `multithreaded` flag to ASStackLayoutSpec that forces it to dispatch even if it's off main
- Update ASCollectionViewFlowLayoutSpecCalculator to use that flag.
Minor change in ASCollectionViewLayout
Implement Mosaic layout calculator
Minor change
Fix project file
Rename and fix project file
Skip fetching constrained size only if a layout calculator is available
Update examples/ASCollectionView
Remove unnecessary change in ASTableView
Address comments
Rename collection view calculator protocols
Minor changes after rebasing with master
Add ASLegacyCollectionLayoutCalculator for backward compatibility
Remove ASCollectionLayoutSpecCalculator
Remove ASLegacyCollectionLayoutCalculator
Introduce ASCollectionLayout
- A wrapper object that contains content size and an element to rect table.
- Collection layout calculators to return this new object instead of an ASLayout.
Before adding a content cache
Finishing hooking up ASCollectionLayoutDataSource to ASCollectionNode
Stash
Finish ASCollectionLayout
Rough impl of ASCollectionFlowLayout
Revert changes in CustomCollectionView example
Move ASRectTable back to Private
* Rename ASCollectionContentAttributes to ASCollectionLayoutState
* Address other comments
* Introduce ASCollectionLayoutDelegate and make ASCollectionLayout private
* Address comments
* API tweaks:
- Replace `-layoutContextWithElementMap:` in ASCollectionLayoutDelegate with `-additionalInfoForLayoutWithElements:`. The returned object is then stored in ASCollectionLayoutContext for later lookups.
- ASCollectionLayoutContext has no public initializer.
- ASDataControllerLayoutDelegate no longer requires a context of type ASCollectionLayoutContext but simply an `id`. This helps decouple ASDataController and ASCollectionLayout.
- Rename `elementMap` to `elements`.
- Rename `visibleMap` to `visibleElements`.
- Other minor changes.
* Rename ASCGSizeHash to ASHashFromCGSize
* Make sure to call super in -[ASCollectionLayout prepareLayout]
* Update example/ASCollectionView to use ASCollectionFlowLayoutDelegate
* Remove unnecessary change
Although we may not want to support this property long-term, there are some usages of it
that are difficult to avoid. Specifically because the complexity it adds is both low,
and contained to a small area of the code that would be easy to remove it, it would be
great to support this.
The usage relates to apps that require the Interop protocol, and are architected to expect
a few methods / protocols being implemented on the UICollectionView class itself. It does
not directly override ASCollectionView behaviors. So hypothetically, it would also work
if it were possible to set ASCollectionView's superclass.
Instead, the app is making its own subclass descend from ASCollectionView and use the interop
APIs, even in environments where there are no ASCellNodes ever returned.
