Add 'submodules/AsyncDisplayKit/' from commit '02bedc12816e251ad71777f9d2578329b6d2bef6'

git-subtree-dir: submodules/AsyncDisplayKit
git-subtree-mainline: d06f423e0e
git-subtree-split: 02bedc1281

submodules/AsyncDisplayKit/examples/CustomCollectionView/Sample/MosaicCollectionLayoutDelegate.m

@@ -0,0 +1,167 @@
+//
+//  MosaicCollectionLayoutDelegate.m
+//  Texture
+//
+//  Copyright (c) Pinterest, Inc.  All rights reserved.
+//  Licensed under Apache 2.0: http://www.apache.org/licenses/LICENSE-2.0
+//
+
+#import "MosaicCollectionLayoutDelegate.h"
+#import "MosaicCollectionLayoutInfo.h"
+#import "ImageCellNode.h"
+
+#import <AsyncDisplayKit/ASCollectionElement.h>
+
+@implementation MosaicCollectionLayoutDelegate {
+  // Read-only properties
+  MosaicCollectionLayoutInfo *_info;
+}
+
+- (instancetype)initWithNumberOfColumns:(NSInteger)numberOfColumns headerHeight:(CGFloat)headerHeight
+{
+  self = [super init];
+  if (self != nil) {
+    _info = [[MosaicCollectionLayoutInfo alloc] initWithNumberOfColumns:numberOfColumns
+                                                           headerHeight:headerHeight
+                                                          columnSpacing:10.0
+                                                          sectionInsets:UIEdgeInsetsMake(10.0, 10.0, 10.0, 10.0)
+                                                       interItemSpacing:UIEdgeInsetsMake(10.0, 0, 10.0, 0)];
+  }
+  return self;
+}
+
+- (ASScrollDirection)scrollableDirections
+{
+  ASDisplayNodeAssertMainThread();
+  return ASScrollDirectionVerticalDirections;
+}
+
+- (id)additionalInfoForLayoutWithElements:(ASElementMap *)elements
+{
+  ASDisplayNodeAssertMainThread();
+  return _info;
+}
+
++ (ASCollectionLayoutState *)calculateLayoutWithContext:(ASCollectionLayoutContext *)context
+{
+  CGFloat layoutWidth = context.viewportSize.width;
+  ASElementMap *elements = context.elements;
+  CGFloat top = 0;
+  MosaicCollectionLayoutInfo *info = (MosaicCollectionLayoutInfo *)context.additionalInfo;
+  
+  NSMapTable<ASCollectionElement *, UICollectionViewLayoutAttributes *> *attrsMap = [NSMapTable elementToLayoutAttributesTable];
+  NSMutableArray *columnHeights = [NSMutableArray array];
+  
+  NSInteger numberOfSections = [elements numberOfSections];
+  for (NSUInteger section = 0; section < numberOfSections; section++) {
+    NSInteger numberOfItems = [elements numberOfItemsInSection:section];
+    
+    top += info.sectionInsets.top;
+    
+    if (info.headerHeight > 0) {
+      NSIndexPath *indexPath = [NSIndexPath indexPathForItem:0 inSection:section];
+      ASCollectionElement *element = [elements supplementaryElementOfKind:UICollectionElementKindSectionHeader
+                                                              atIndexPath:indexPath];
+      UICollectionViewLayoutAttributes *attrs = [UICollectionViewLayoutAttributes layoutAttributesForSupplementaryViewOfKind:UICollectionElementKindSectionHeader
+                                                                                                               withIndexPath:indexPath];
+      
+      ASSizeRange sizeRange = [self _sizeRangeForHeaderOfSection:section withLayoutWidth:layoutWidth info:info];
+      CGSize size = [element.node layoutThatFits:sizeRange].size;
+      CGRect frame = CGRectMake(info.sectionInsets.left, top, size.width, size.height);
+      
+      attrs.frame = frame;
+      [attrsMap setObject:attrs forKey:element];
+      top = CGRectGetMaxY(frame);
+    }
+    
+    [columnHeights addObject:[NSMutableArray array]];
+    for (NSUInteger idx = 0; idx < info.numberOfColumns; idx++) {
+      [columnHeights[section] addObject:@(top)];
+    }
+    
+    CGFloat columnWidth = [self _columnWidthForSection:section withLayoutWidth:layoutWidth info:info];
+    for (NSUInteger idx = 0; idx < numberOfItems; idx++) {
+      NSUInteger columnIndex = [self _shortestColumnIndexInSection:section withColumnHeights:columnHeights];
+      NSIndexPath *indexPath = [NSIndexPath indexPathForItem:idx inSection:section];
+      ASCollectionElement *element = [elements elementForItemAtIndexPath:indexPath];
+      UICollectionViewLayoutAttributes *attrs = [UICollectionViewLayoutAttributes layoutAttributesForCellWithIndexPath:indexPath];
+      
+      ASSizeRange sizeRange = [self _sizeRangeForItem:element.node atIndexPath:indexPath withLayoutWidth:layoutWidth info:info];
+      CGSize size = [element.node layoutThatFits:sizeRange].size;
+      CGPoint position = CGPointMake(info.sectionInsets.left + (columnWidth + info.columnSpacing) * columnIndex,
+                                     [columnHeights[section][columnIndex] floatValue]);
+      CGRect frame = CGRectMake(position.x, position.y, size.width, size.height);
+      
+      attrs.frame = frame;
+      [attrsMap setObject:attrs forKey:element];
+      // TODO Profile and avoid boxing if there are significant retain/release overheads
+      columnHeights[section][columnIndex] = @(CGRectGetMaxY(frame) + info.interItemSpacing.bottom);
+    }
+    
+    NSUInteger columnIndex = [self _tallestColumnIndexInSection:section withColumnHeights:columnHeights];
+    top = [columnHeights[section][columnIndex] floatValue] - info.interItemSpacing.bottom + info.sectionInsets.bottom;
+    
+    for (NSUInteger idx = 0; idx < [columnHeights[section] count]; idx++) {
+      columnHeights[section][idx] = @(top);
+    }
+  }
+  
+  CGFloat contentHeight = [[[columnHeights lastObject] firstObject] floatValue];
+  CGSize contentSize = CGSizeMake(layoutWidth, contentHeight);
+  return [[ASCollectionLayoutState alloc] initWithContext:context
+                                              contentSize:contentSize
+                           elementToLayoutAttributesTable:attrsMap];
+}
+
++ (CGFloat)_columnWidthForSection:(NSUInteger)section withLayoutWidth:(CGFloat)layoutWidth info:(MosaicCollectionLayoutInfo *)info
+{
+  return ([self _widthForSection:section withLayoutWidth:layoutWidth info:info] - ((info.numberOfColumns - 1) * info.columnSpacing)) / info.numberOfColumns;
+}
+
++ (CGFloat)_widthForSection:(NSUInteger)section withLayoutWidth:(CGFloat)layoutWidth info:(MosaicCollectionLayoutInfo *)info
+{
+  return layoutWidth - info.sectionInsets.left - info.sectionInsets.right;
+}
+
++ (ASSizeRange)_sizeRangeForItem:(ASCellNode *)item atIndexPath:(NSIndexPath *)indexPath withLayoutWidth:(CGFloat)layoutWidth info:(MosaicCollectionLayoutInfo *)info
+{
+  CGFloat itemWidth = [self _columnWidthForSection:indexPath.section withLayoutWidth:layoutWidth info:info];
+  if ([item isKindOfClass:[ImageCellNode class]]) {
+    return ASSizeRangeMake(CGSizeMake(itemWidth, 0), CGSizeMake(itemWidth, CGFLOAT_MAX));
+  } else {
+    return ASSizeRangeMake(CGSizeMake(itemWidth, itemWidth)); // In kShowUICollectionViewCells = YES mode, make those cells itemWidth x itemWidth.
+  }
+}
+
++ (ASSizeRange)_sizeRangeForHeaderOfSection:(NSInteger)section withLayoutWidth:(CGFloat)layoutWidth info:(MosaicCollectionLayoutInfo *)info
+{
+  return ASSizeRangeMake(CGSizeMake(0, info.headerHeight), CGSizeMake([self _widthForSection:section withLayoutWidth:layoutWidth info:info], info.headerHeight));
+}
+
++ (NSUInteger)_tallestColumnIndexInSection:(NSUInteger)section withColumnHeights:(NSArray *)columnHeights
+{
+  __block NSUInteger index = 0;
+  __block CGFloat tallestHeight = 0;
+  [columnHeights[section] enumerateObjectsUsingBlock:^(NSNumber *height, NSUInteger idx, BOOL *stop) {
+    if (height.floatValue > tallestHeight) {
+      index = idx;
+      tallestHeight = height.floatValue;
+    }
+  }];
+  return index;
+}
+
++ (NSUInteger)_shortestColumnIndexInSection:(NSUInteger)section withColumnHeights:(NSArray *)columnHeights
+{
+  __block NSUInteger index = 0;
+  __block CGFloat shortestHeight = CGFLOAT_MAX;
+  [columnHeights[section] enumerateObjectsUsingBlock:^(NSNumber *height, NSUInteger idx, BOOL *stop) {
+    if (height.floatValue < shortestHeight) {
+      index = idx;
+      shortestHeight = height.floatValue;
+    }
+  }];
+  return index;
+}
+
+@end