Merge pull request #127 from facebook/manual-display

Add -[ASDisplayNode display].

.gitignore

@@ -22,3 +22,5 @@ docs/htdocs
 docs/.sass-cache
 
 *.swp
+
+*.lock

AsyncDisplayKit/ASDisplayNode.h

@@ -294,6 +294,19 @@
  */
 @property (nonatomic, assign) BOOL shouldRasterizeDescendants;
 
+/**
+ * @abstract Calls -setNeedsDisplay and -displayIfNeeded on the node's backing store.
+ *
+ * @note This method must be called on the main thread but there are plans to allow this on any thread.
+ */
+- (void)display;
+
+/**
+ * @abstract Call -display on the node and recursively on all subnodes, forcing the entire node hierarchy to be
+ * displayed.
+ */
+- (void)recursivelyDisplay;
+
 /** 
  * @abstract Display the node's view/layer immediately on the current thread, bypassing the background thread rendering.
  */

AsyncDisplayKit/ASDisplayNode.mm

@@ -437,6 +437,33 @@ void ASDisplayNodePerformBlockOnMainThread(void (^block)())
   _contentsScaleForDisplay = contentsScaleForDisplay;
 }
 
+- (void)display
+{
+  ASDisplayNodeAssertMainThread();
+  ASDisplayNodeAssert(self.nodeLoaded, @"backing store must be loaded before calling -display");
+
+  // rendering a backing store requires a node be laid out
+  [self __layout];
+
+  CALayer *layer = [self isLayerBacked] ? self.layer : self.view.layer;
+
+  if (layer.contents) {
+    return;
+  }
+
+  [layer setNeedsDisplay];
+  [layer displayIfNeeded];
+}
+
+- (void)recursivelyDisplay
+{
+  for (ASDisplayNode *node in self.subnodes) {
+    [node recursivelyDisplay];
+  }
+
+  [self display];
+}
+
 - (void)displayImmediately
 {
   ASDisplayNodeAssertMainThread();

AsyncDisplayKit/Details/ASRangeController.mm

@@ -91,22 +91,6 @@
   return sizingQueue;
 }
 
-+ (UIView *)workingView
-{
-  // we add nodes' views to this invisible window to start async rendering
-  static UIWindow *workingWindow = nil;
-  static dispatch_once_t onceToken;
-  dispatch_once(&onceToken, ^{
-    workingWindow = [[UIWindow alloc] initWithFrame:CGRectZero];
-    workingWindow.windowLevel = UIWindowLevelNormal - 1000;
-    workingWindow.userInteractionEnabled = NO;
-    workingWindow.clipsToBounds = YES;
-    workingWindow.hidden = YES;
-  });
-
-  return workingWindow;
-}
-
 
 #pragma mark -
 #pragma mark Helpers.
@@ -191,47 +175,51 @@ static BOOL ASRangeIsValid(NSRange range)
   NSInteger index = [self indexForIndexPath:node.asyncdisplaykit_indexPath];
   if (NSLocationInRange(index, _workingRange)) {
     // move the node's view to the working range area, so its rendering persists
-    [self moveNodeToWorkingView:node];
+    [self addNodeToWorkingRange:node];
   } else {
     // this node isn't in the working range, remove it from the view hierarchy
-    [self removeNodeFromWorkingView:node];
+    [self removeNodeFromWorkingRange:node];
   }
 }
 
-- (void)removeNodeFromWorkingView:(ASCellNode *)node
+- (void)removeNodeFromWorkingRange:(ASCellNode *)node
 {
   ASDisplayNodeAssertMainThread();
   ASDisplayNodeAssert(node, @"invalid argument");
 
   [node recursiveSetPreventOrCancelDisplay:YES];
   [node.view removeFromSuperview];
-  
+
   // since this class usually manages large or infinite data sets, the working range
   // directly bounds memory usage by requiring redrawing any content that falls outside the range.
   [node recursivelyReclaimMemory];
-  
+
   [_workingIndexPaths removeObject:node.asyncdisplaykit_indexPath];
 }
 
-- (void)moveNodeToWorkingView:(ASCellNode *)node
+- (void)addNodeToWorkingRange:(ASCellNode *)node
 {
   ASDisplayNodeAssertMainThread();
   ASDisplayNodeAssert(node, @"invalid argument");
 
-  [self moveNode:node toView:[ASRangeController workingView]];
+  // if node is in the working range it should not actively be in view
+  [node.view removeFromSuperview];
+
+  [node recursivelyDisplay];
+
   [_workingIndexPaths addObject:node.asyncdisplaykit_indexPath];
 }
 
 - (void)moveNode:(ASCellNode *)node toView:(UIView *)view
 {
   ASDisplayNodeAssertMainThread();
-  ASDisplayNodeAssert(node && view, @"invalid argument, did you mean -removeNodeFromWorkingView:?");
+  ASDisplayNodeAssert(node && view, @"invalid argument, did you mean -removeNodeFromWorkingRange:?");
 
   // use an explicit transaction to force CoreAnimation to display nodes in the order they are added.
   [CATransaction begin];
 
   [view addSubview:node.view];
-  
+
   [CATransaction commit];
 }
 
@@ -481,7 +469,7 @@ static NSRange ASCalculateWorkingRange(ASRangeTuningParameters params, ASScrollD
                                            _nodeSizes,
                                            [_delegate rangeControllerViewportSize:self]);
   }
-  
+
   [self setWorkingRange:workingRange];
 }
 
@@ -504,7 +492,7 @@ static NSRange ASCalculateWorkingRange(ASRangeTuningParameters params, ASScrollD
   for (NSIndexPath *indexPath in removedIndexPaths) {
     ASCellNode *node = [self sizedNodeForIndexPath:indexPath];
     ASDisplayNodeAssert(node, @"an unsized node should never have entered the working range");
-    [self removeNodeFromWorkingView:node];
+    [self removeNodeFromWorkingRange:node];
   }
 
   // add nodes that have entered the working range (i.e., those that are in the new working range but not the old one)
@@ -513,7 +501,7 @@ static NSRange ASCalculateWorkingRange(ASRangeTuningParameters params, ASScrollD
     // if a node in the working range is still sizing, the sizing logic will add it to the working range for us later
     ASCellNode *node = [self sizedNodeForIndexPath:indexPath];
     if (node) {
-      [self moveNodeToWorkingView:node];
+      [self addNodeToWorkingRange:node];
     } else {
       ASDisplayNodeAssert(_sizedNodeCount != _totalNodeCount, @"logic error");
     }