ASRangeController previously enqueued display of individual nodes by
adding their views to the hierarchy, wrapping each `-addSubview:` call
in an explicit CATransaction to force displays to occur in order. This
hack is no longer necessary -- kill it.
Postpone manual display until a future release when it can be called on any thread. Provide the current node manual display logic as a category on ASDisplayNode only available for ASRangeController. Deprecate -displayImmediately.
Rename the ASDisplayNode property to match its _ASDisplayLayer
counterpart -- `displaySuspended` is more succinct and is a more
plausible name for a Cocoa BOOL property.
Added a sample project that will demonstrate how to manually display nodes. Removed the UIWindow hack that coupled display of nodes with Core Animation transactions.
Most UITableViewCell properties aren't useful in conjunction with
ASCellNode -- the system's UIView properties are unsupported for
performance reasons, and properties that configure them (e.g., content
indentation) don't affect custom node hierarchies. This patch adds
support to _ASTableViewCell for the properties that *are* useful.
r=scottg
(1) We can't size nodes without a delegate, and if our owning controller
has been deallocated, our delegate will be nil. Handle this more
gracefully.
(2) Our teardown code needs to be executed on the main thread, but it's
conceivable that we might hit refcount 0 on a background queue. Force
deallocation to occur on the main thread.
Closes#27.
Fixes:
- Usage of UIScreen in -[ASDisplayNode init]
(the offending individual will be prosecuted)
- #38: Proper teardown of nodes owned by ASTableView / ASRangeController
- #34: Fix infinite recursion in very rare subclassing scenario
- #30: Avoid animating cell and section additions to ASTableView
- #19: Set a more reasonable default for maximum display concurrency
r=nadi
ASDisplayNode and several subclasses had previously cleared memory-heavy
objects like the backing store and text layout manager when the node's
view
or layer is removed from a visible heirarchy. This works great in any
system
that uses a "working range", where exiting the range removes the node
from
the hierarchy and reclaiming memory at that time is important.
However, for
standard UIViewController patterns (unused in Paper), this behavior
causes
highly undesirable thrashing (leading to visible flashes & wasteful
re-rendering of content).
After this change, node subclasses should implement -reclaimMemory if
they
need to perform any other cleanup besides backing store destruction
when they
leave a working range or other scenario where memory reduction is
valuable.
To trigger this behavior, calling code should use
-recursivelyReclaimMemory.
r=nadi
Introduce `ASTableView`, a UITableView subclass that uses `ASCellNode`
instead of UITableViewCell. Add working range support via
`ASRangeController`, which observes the visible range, maintains a
working range, and handles most ASDK machinery. ASRangeController is
loosely-enough coupled that it should be easily adapted to
UICollectionView if that's desired in the future.
Notable considerations in the ASRangeController architecture:
* There's no sense rewriting UITableView -- the real win comes from
using nodes instead of UITableViewCells (easily parallelisable
computation, large number of cells vs. few table views, etc.). So,
use a UITableView with empty cells, using UITableViewCell's
contentView as a host for arbitrary node hierarchies.
* Instead of lazy-loading cells the instant they're needed by
UITableView, load them in advance. Preload a substantial number of
nodes in the direction of scroll, as well as a small buffer in the
other direction.
* Maintain compatibility with UITableView's API, with one primary change
-- consumer code yields configured ASCellNodes, not UITableViewCells.
* Don't use -tableView:heightForRowAtIndexPath:. Nodes already compute
their preferred sizes and cache results for use at layout-time, so
ASTableView uses their calculatedSizes directly.
* Corollary: ASTableView is only aware of nodes that have been sized.
This means that, if a cell appears onscreen, it has layout data and
can display a "realistic placeholder", e.g. by making its subnodes'
background colour grey.
Other improvements:
* Remove dead references and update headers (fixes#7, #20).
* Rename `-[ASDisplayNode sizeToFit:]` to `-measure:` and fix
`constrainedSizeForCalulatedSize` typo (fixes#15).
* Rename `-willAppear` and `-didDisappear` to `-willEnterHierarchy` and
`-didExitHierarchy`. Remove `-willDisappear` -- it was redundant, and
there was no counterpart `-didAppear`.
* Rename `viewLoaded` to `nodeLoaded`.
