Adds ASCollectionViewLayoutController and convenience CGRect/ASScrollDirection functions. Fixes default collection view range tuning parameters for Preload and Render ranges; values were flipped.

AsyncDisplayKit.xcodeproj/project.pbxproj

@@ -147,6 +147,10 @@
 		205F0E121B371BD7007741D0 /* ASScrollDirection.m in Sources */ = {isa = PBXBuildFile; fileRef = 205F0E111B371BD7007741D0 /* ASScrollDirection.m */; };
 		205F0E191B37339C007741D0 /* ASAbstractLayoutController.h in Headers */ = {isa = PBXBuildFile; fileRef = 205F0E171B37339C007741D0 /* ASAbstractLayoutController.h */; settings = {ATTRIBUTES = (Public, ); }; };
 		205F0E1A1B37339C007741D0 /* ASAbstractLayoutController.mm in Sources */ = {isa = PBXBuildFile; fileRef = 205F0E181B37339C007741D0 /* ASAbstractLayoutController.mm */; };
+		205F0E1D1B373A2C007741D0 /* ASCollectionViewLayoutController.h in Headers */ = {isa = PBXBuildFile; fileRef = 205F0E1B1B373A2C007741D0 /* ASCollectionViewLayoutController.h */; settings = {ATTRIBUTES = (Public, ); }; };
+		205F0E1E1B373A2C007741D0 /* ASCollectionViewLayoutController.mm in Sources */ = {isa = PBXBuildFile; fileRef = 205F0E1C1B373A2C007741D0 /* ASCollectionViewLayoutController.mm */; };
+		205F0E211B376416007741D0 /* CGRect+ASConvenience.h in Headers */ = {isa = PBXBuildFile; fileRef = 205F0E1F1B376416007741D0 /* CGRect+ASConvenience.h */; };
+		205F0E221B376416007741D0 /* CGRect+ASConvenience.m in Sources */ = {isa = PBXBuildFile; fileRef = 205F0E201B376416007741D0 /* CGRect+ASConvenience.m */; };
 		242995D31B29743C00090100 /* ASBasicImageDownloaderTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 242995D21B29743C00090100 /* ASBasicImageDownloaderTests.m */; };
 		2911485C1A77147A005D0878 /* ASControlNodeTests.m in Sources */ = {isa = PBXBuildFile; fileRef = 2911485B1A77147A005D0878 /* ASControlNodeTests.m */; };
 		291B63FB1AA53A7A000A71B3 /* ASScrollDirection.h in Headers */ = {isa = PBXBuildFile; fileRef = 296A0A311A951715005ACEAA /* ASScrollDirection.h */; settings = {ATTRIBUTES = (Public, ); }; };
@@ -329,6 +333,10 @@
 		205F0E111B371BD7007741D0 /* ASScrollDirection.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ASScrollDirection.m; sourceTree = "<group>"; };
 		205F0E171B37339C007741D0 /* ASAbstractLayoutController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASAbstractLayoutController.h; sourceTree = "<group>"; };
 		205F0E181B37339C007741D0 /* ASAbstractLayoutController.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASAbstractLayoutController.mm; sourceTree = "<group>"; };
+		205F0E1B1B373A2C007741D0 /* ASCollectionViewLayoutController.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASCollectionViewLayoutController.h; sourceTree = "<group>"; };
+		205F0E1C1B373A2C007741D0 /* ASCollectionViewLayoutController.mm */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.objcpp; path = ASCollectionViewLayoutController.mm; sourceTree = "<group>"; };
+		205F0E1F1B376416007741D0 /* CGRect+ASConvenience.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = "CGRect+ASConvenience.h"; sourceTree = "<group>"; };
+		205F0E201B376416007741D0 /* CGRect+ASConvenience.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = "CGRect+ASConvenience.m"; sourceTree = "<group>"; };
 		242995D21B29743C00090100 /* ASBasicImageDownloaderTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ASBasicImageDownloaderTests.m; sourceTree = "<group>"; };
 		2911485B1A77147A005D0878 /* ASControlNodeTests.m */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.objc; path = ASControlNodeTests.m; sourceTree = "<group>"; };
 		292C59991A956527007E5DD6 /* ASLayoutRangeType.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = ASLayoutRangeType.h; sourceTree = "<group>"; };
@@ -554,6 +562,8 @@
 				054963481A1EA066000F8E56 /* ASBasicImageDownloader.mm */,
 				299DA1A71A828D2900162D41 /* ASBatchContext.h */,
 				299DA1A81A828D2900162D41 /* ASBatchContext.mm */,
+				205F0E1B1B373A2C007741D0 /* ASCollectionViewLayoutController.h */,
+				205F0E1C1B373A2C007741D0 /* ASCollectionViewLayoutController.mm */,
 				464052191A3F83C40061C0BA /* ASDataController.h */,
 				4640521A1A3F83C40061C0BA /* ASDataController.mm */,
 				05A6D05819D0EB64002DD95E /* ASDealloc2MainObject.h */,
@@ -590,6 +600,8 @@
 				058D09F3195D050800B7D73C /* ASTextNodeWordKerner.h */,
 				058D09F4195D050800B7D73C /* ASTextNodeWordKerner.m */,
 				058D0A12195D050800B7D73C /* ASThread.h */,
+				205F0E1F1B376416007741D0 /* CGRect+ASConvenience.h */,
+				205F0E201B376416007741D0 /* CGRect+ASConvenience.m */,
 				058D09F5195D050800B7D73C /* NSMutableAttributedString+TextKitAdditions.h */,
 				058D09F6195D050800B7D73C /* NSMutableAttributedString+TextKitAdditions.m */,
 				058D09F7195D050800B7D73C /* Transactions */,
@@ -728,6 +740,7 @@
 				6BDC61F61979037800E50D21 /* AsyncDisplayKit.h in Headers */,
 				058D0A6D195D05EC00B7D73C /* _ASAsyncTransactionGroup.h in Headers */,
 				058D0A6E195D05EC00B7D73C /* _ASAsyncTransactionGroup.m in Headers */,
+				205F0E1D1B373A2C007741D0 /* ASCollectionViewLayoutController.h in Headers */,
 				058D0A6F195D05EC00B7D73C /* UIView+ASConvenience.h in Headers */,
 				058D0A70195D05EC00B7D73C /* UIView+ASConvenience.m in Headers */,
 				058D0A82195D060300B7D73C /* ASAssert.h in Headers */,
@@ -754,6 +767,7 @@
 				058D0A79195D05F900B7D73C /* ASDisplayNode+DebugTiming.mm in Headers */,
 				058D0A7A195D05F900B7D73C /* ASDisplayNode+UIViewBridge.mm in Headers */,
 				2967F9E21AB0A5190072E4AB /* ASBasicImageDownloaderInternal.h in Headers */,
+				205F0E211B376416007741D0 /* CGRect+ASConvenience.h in Headers */,
 				058D0A7B195D05F900B7D73C /* ASDisplayNodeInternal.h in Headers */,
 				058D0A7C195D05F900B7D73C /* ASImageNode+CGExtras.h in Headers */,
 				058D0A7D195D05F900B7D73C /* ASImageNode+CGExtras.m in Headers */,
@@ -932,6 +946,7 @@
 				058D0A1E195D050800B7D73C /* ASTextNodeShadower.m in Sources */,
 				058D0A18195D050800B7D73C /* _ASDisplayLayer.mm in Sources */,
 				058D0A2C195D050800B7D73C /* ASSentinel.m in Sources */,
+				205F0E221B376416007741D0 /* CGRect+ASConvenience.m in Sources */,
 				205F0E1A1B37339C007741D0 /* ASAbstractLayoutController.mm in Sources */,
 				464052211A3F83C40061C0BA /* ASDataController.mm in Sources */,
 				299DA1AA1A828D2900162D41 /* ASBatchContext.mm in Sources */,
@@ -969,6 +984,7 @@
 				0516FA411A1563D200B4EBED /* ASMultiplexImageNode.mm in Sources */,
 				058D0A16195D050800B7D73C /* ASImageNode.mm in Sources */,
 				058D0A29195D050800B7D73C /* ASDisplayNode+DebugTiming.mm in Sources */,
+				205F0E1E1B373A2C007741D0 /* ASCollectionViewLayoutController.mm in Sources */,
 				058D0A22195D050800B7D73C /* _ASAsyncTransaction.m in Sources */,
 				055F1A3919ABD413004DAFF1 /* ASRangeController.mm in Sources */,
 				296A0A2F1A9516B2005ACEAA /* ASBatchFetching.m in Sources */,

AsyncDisplayKit/ASCollectionView.mm

@@ -9,7 +9,7 @@
 #import "ASCollectionView.h"
 
 #import "ASAssert.h"
-#import "ASFlowLayoutController.h"
+#import "ASCollectionViewLayoutController.h"
 #import "ASRangeController.h"
 #import "ASDataController.h"
 #import "ASDisplayNodeInternal.h"
@@ -109,7 +109,7 @@ static BOOL _isInterceptedSelector(SEL sel)
 
   ASDataController *_dataController;
   ASRangeController *_rangeController;
-  ASFlowLayoutController *_layoutController;
+  ASCollectionViewLayoutController *_layoutController;
 
   BOOL _performingBatchUpdates;
   NSMutableArray *_batchUpdateBlocks;
@@ -143,9 +143,7 @@ static BOOL _isInterceptedSelector(SEL sel)
   asyncDataFetchingEnabled = NO;
 
   ASDisplayNodeAssert([layout asdk_isFlowLayout], @"only flow layouts are currently supported");
-
+  _layoutController = [[ASCollectionViewLayoutController alloc] initWithCollectionView:self];
-  ASFlowLayoutDirection direction = (((UICollectionViewFlowLayout *)layout).scrollDirection == UICollectionViewScrollDirectionHorizontal) ? ASFlowLayoutDirectionHorizontal : ASFlowLayoutDirectionVertical;
-  _layoutController = [[ASFlowLayoutController alloc] initWithScrollOption:direction];
 
   _rangeController = [[ASRangeController alloc] init];
   _rangeController.delegate = self;
@@ -379,14 +377,14 @@ static BOOL _isInterceptedSelector(SEL sel)
   ASScrollDirection scrollableDirections = [self scrollableDirections];
   
   if (ASScrollDirectionContainsHorizontalDirection(scrollableDirections)) { // Can scroll horizontally.
-    if (scrollVelocity.x > 0) {
+    if (scrollVelocity.x >= 0) {
       direction |= ASScrollDirectionRight;
     } else {
       direction |= ASScrollDirectionLeft;
     }
   }
   if (ASScrollDirectionContainsVerticalDirection(scrollableDirections)) { // Can scroll vertically.
-    if (scrollVelocity.y > 0) {
+    if (scrollVelocity.y >= 0) {
       direction |= ASScrollDirectionDown;
     } else {
       direction |= ASScrollDirectionUp;
@@ -493,7 +491,7 @@ static BOOL _isInterceptedSelector(SEL sel)
 {
   CGSize restrainedSize = self.bounds.size;
 
-  if (_layoutController.layoutDirection == ASFlowLayoutDirectionHorizontal) {
+  if (ASScrollDirectionContainsHorizontalDirection([self scrollableDirections])) {
     restrainedSize.width = FLT_MAX;
   } else {
     restrainedSize.height = FLT_MAX;

AsyncDisplayKit/Details/ASAbstractLayoutController.mm

@@ -8,9 +8,7 @@
 
 #import "ASAbstractLayoutController.h"
 
-#include <map>
 #include <vector>
-#include <cassert>
 
 #import "ASAssert.h"
 
@@ -29,13 +27,13 @@
   
   _tuningParameters = std::vector<ASRangeTuningParameters>(ASLayoutRangeTypeCount);
   _tuningParameters[ASLayoutRangeTypePreload] = {
-    .leadingBufferScreenfuls = 2,
-    .trailingBufferScreenfuls = 1
-  };
-  _tuningParameters[ASLayoutRangeTypeRender] = {
     .leadingBufferScreenfuls = 3,
     .trailingBufferScreenfuls = 2
   };
+  _tuningParameters[ASLayoutRangeTypeRender] = {
+    .leadingBufferScreenfuls = 2,
+    .trailingBufferScreenfuls = 1
+  };
   
   return self;
 }

AsyncDisplayKit/Details/ASCollectionViewLayoutController.h

@@ -0,0 +1,18 @@
+/* Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <AsyncDisplayKit/ASAbstractLayoutController.h>
+#import <AsyncDisplayKit/ASBaseDefines.h>
+
+@class ASCollectionView;
+
+@interface ASCollectionViewLayoutController : ASAbstractLayoutController
+
+- (instancetype)initWithCollectionView:(ASCollectionView *)collectionView;
+
+@end

AsyncDisplayKit/Details/ASCollectionViewLayoutController.mm

@@ -0,0 +1,153 @@
+/* Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "ASCollectionViewLayoutController.h"
+
+#include <vector>
+
+#import "ASAssert.h"
+#import "ASCollectionView.h"
+#import "CGRect+ASConvenience.h"
+
+struct ASDirectionalScreenfulBuffer {
+  CGFloat positiveDirection; // Positive relative to iOS Core Animation layer coordinate space.
+  CGFloat negativeDirection;
+};
+typedef struct ASDirectionalScreenfulBuffer ASDirectionalScreenfulBuffer;
+
+ASDirectionalScreenfulBuffer ASDirectionalScreenfulBufferHorizontal(ASScrollDirection scrollDirection,
+                                                                    ASRangeTuningParameters rangeTuningParameters) {
+  ASDirectionalScreenfulBuffer horizontalBuffer = {0, 0};
+  BOOL movingRight = ASScrollDirectionContainsRight(scrollDirection);
+  horizontalBuffer.positiveDirection = movingRight ? rangeTuningParameters.leadingBufferScreenfuls :
+                                                     rangeTuningParameters.trailingBufferScreenfuls;
+  horizontalBuffer.negativeDirection = movingRight ? rangeTuningParameters.trailingBufferScreenfuls :
+                                                     rangeTuningParameters.leadingBufferScreenfuls;
+  return horizontalBuffer;
+}
+
+ASDirectionalScreenfulBuffer ASDirectionalScreenfulBufferVertical(ASScrollDirection scrollDirection,
+                                                                  ASRangeTuningParameters rangeTuningParameters) {
+  ASDirectionalScreenfulBuffer verticalBuffer = {0, 0};
+  BOOL movingDown = ASScrollDirectionContainsDown(scrollDirection);
+  verticalBuffer.positiveDirection = movingDown ? rangeTuningParameters.leadingBufferScreenfuls :
+                                                  rangeTuningParameters.trailingBufferScreenfuls;
+  verticalBuffer.negativeDirection = movingDown ? rangeTuningParameters.trailingBufferScreenfuls :
+                                                  rangeTuningParameters.leadingBufferScreenfuls;
+  return verticalBuffer;
+}
+
+struct ASRangeGeometry {
+  CGRect rangeBounds;
+  CGRect updateBounds;
+};
+typedef struct ASRangeGeometry ASRangeGeometry;
+
+
+#pragma mark -
+#pragma mark ASCollectionViewLayoutController
+
+@interface ASCollectionViewLayoutController () {
+  ASCollectionView * __weak _collectionView;
+  std::vector<CGRect> _updateRangeBoundsIndexedByRangeType;
+}
+@end
+
+@implementation ASCollectionViewLayoutController
+
+- (instancetype)initWithCollectionView:(ASCollectionView *)collectionView {
+  if (!(self = [super init])) {
+    return nil;
+  }
+  _collectionView = collectionView;
+  _updateRangeBoundsIndexedByRangeType = std::vector<CGRect>(ASLayoutRangeTypeCount);
+  return self;
+}
+
+#pragma mark -
+#pragma mark Index Paths in Range
+
+- (NSSet *)indexPathsForScrolling:(ASScrollDirection)scrollDirection
+                     viewportSize:(CGSize)viewportSize
+                        rangeType:(ASLayoutRangeType)rangeType {
+  ASRangeGeometry rangeGeometry = [self rangeGeometryWithScrollDirection:scrollDirection
+                                                          collectionView:_collectionView
+                                                   rangeTuningParameters:[self tuningParametersForRangeType:rangeType]];
+  _updateRangeBoundsIndexedByRangeType[rangeType] = rangeGeometry.updateBounds;
+  return [self indexPathsForItemsWithinRangeBounds:rangeGeometry.rangeBounds collectionView:_collectionView];
+}
+
+- (ASRangeGeometry)rangeGeometryWithScrollDirection:(ASScrollDirection)scrollDirection
+                                     collectionView:(ASCollectionView *)collectionView
+                              rangeTuningParameters:(ASRangeTuningParameters)rangeTuningParameters {
+  CGRect rangeBounds = collectionView.bounds;
+  CGRect updateBounds = collectionView.bounds;
+  ASScrollDirection scrollableDirections = [collectionView scrollableDirections];
+  
+  BOOL canScrollHorizontally = ASScrollDirectionContainsHorizontalDirection(scrollableDirections);
+  if (canScrollHorizontally) {
+    ASDirectionalScreenfulBuffer horizontalBuffer = ASDirectionalScreenfulBufferHorizontal(scrollDirection,
+                                                                                           rangeTuningParameters);
+    rangeBounds = asdk_CGRectExpandHorizontally(rangeBounds,
+                                                horizontalBuffer.negativeDirection,
+                                                horizontalBuffer.positiveDirection);
+    // Update bounds is at most 95% of the next/previous screenful and at least half of tuning parameter value.
+    updateBounds = asdk_CGRectExpandHorizontally(updateBounds,
+                                                 MIN(horizontalBuffer.negativeDirection * 0.5, 0.95),
+                                                 MIN(horizontalBuffer.positiveDirection * 0.5, 0.95));
+  }
+  
+  BOOL canScrollVertically = ASScrollDirectionContainsVerticalDirection(scrollableDirections);
+  if (canScrollVertically) {
+    ASDirectionalScreenfulBuffer verticalBuffer = ASDirectionalScreenfulBufferVertical(scrollDirection,
+                                                                                       rangeTuningParameters);
+    rangeBounds = asdk_CGRectExpandVertically(rangeBounds,
+                                              verticalBuffer.negativeDirection,
+                                              verticalBuffer.positiveDirection);
+    // Update bounds is at most 95% of the next/previous screenful and at least half of tuning parameter value.
+    updateBounds = asdk_CGRectExpandVertically(updateBounds,
+                                               MIN(verticalBuffer.negativeDirection * 0.5, 0.95),
+                                               MIN(verticalBuffer.positiveDirection * 0.5, 0.95));
+  }
+
+  return {rangeBounds, updateBounds};
+}
+
+- (NSSet *)indexPathsForItemsWithinRangeBounds:(CGRect)rangeBounds collectionView:(ASCollectionView *)collectionView {
+  NSMutableSet *indexPathSet = [[NSMutableSet alloc] init];
+  NSArray *layoutAttributes = [collectionView.collectionViewLayout layoutAttributesForElementsInRect:rangeBounds];
+  for (UICollectionViewLayoutAttributes *la in layoutAttributes) {
+    [indexPathSet addObject:la.indexPath];
+  }
+  return indexPathSet;
+}
+
+#pragma mark -
+#pragma mark Should Update Range
+
+- (BOOL)shouldUpdateForVisibleIndexPaths:(NSArray *)indexPaths
+                            viewportSize:(CGSize)viewportSize
+                               rangeType:(ASLayoutRangeType)rangeType {
+  CGRect updateRangeBounds = _updateRangeBoundsIndexedByRangeType[rangeType];
+  if (CGRectIsEmpty(updateRangeBounds)) {
+    return YES;
+  }
+  
+  CGRect currentBounds = _collectionView.bounds;
+  if (CGRectIsEmpty(currentBounds)) {
+    currentBounds = CGRectMake(0, 0, viewportSize.width, viewportSize.height);
+  }
+  
+  if (CGRectContainsRect(updateRangeBounds, currentBounds)) {
+    return NO;
+  } else {
+    return YES;
+  }
+}
+
+@end

AsyncDisplayKit/Details/ASScrollDirection.h

@@ -26,4 +26,9 @@ ASDISPLAYNODE_EXTERN_C_BEGIN
 BOOL ASScrollDirectionContainsVerticalDirection(ASScrollDirection scrollDirection);
 BOOL ASScrollDirectionContainsHorizontalDirection(ASScrollDirection scrollDirection);
 
+BOOL ASScrollDirectionContainsRight(ASScrollDirection scrollDirection);
+BOOL ASScrollDirectionContainsLeft(ASScrollDirection scrollDirection);
+BOOL ASScrollDirectionContainsUp(ASScrollDirection scrollDirection);
+BOOL ASScrollDirectionContainsDown(ASScrollDirection scrollDirection);
+
 ASDISPLAYNODE_EXTERN_C_END

AsyncDisplayKit/Details/ASScrollDirection.m

@@ -18,3 +18,19 @@ BOOL ASScrollDirectionContainsVerticalDirection(ASScrollDirection scrollDirectio
 BOOL ASScrollDirectionContainsHorizontalDirection(ASScrollDirection scrollDirection) {
   return (scrollDirection & ASScrollDirectionHorizontalDirections) != 0;
 }
+
+BOOL ASScrollDirectionContainsRight(ASScrollDirection scrollDirection) {
+  return (scrollDirection & ASScrollDirectionRight) != 0;
+}
+
+BOOL ASScrollDirectionContainsLeft(ASScrollDirection scrollDirection) {
+  return (scrollDirection & ASScrollDirectionLeft) != 0;
+}
+
+BOOL ASScrollDirectionContainsUp(ASScrollDirection scrollDirection) {
+  return (scrollDirection & ASScrollDirectionUp) != 0;
+}
+
+BOOL ASScrollDirectionContainsDown(ASScrollDirection scrollDirection) {
+  return (scrollDirection & ASScrollDirectionDown) != 0;
+}

AsyncDisplayKit/Details/CGRect+ASConvenience.h

@@ -0,0 +1,18 @@
+/* Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import <CoreGraphics/CoreGraphics.h>
+
+#import "ASBaseDefines.h"
+
+ASDISPLAYNODE_EXTERN_C_BEGIN
+
+CGRect asdk_CGRectExpandHorizontally(CGRect rect, CGFloat negativeMultiplier, CGFloat positiveMultiplier);
+CGRect asdk_CGRectExpandVertically(CGRect rect, CGFloat negativeMultiplier, CGFloat positiveMultiplier);
+
+ASDISPLAYNODE_EXTERN_C_END

AsyncDisplayKit/Details/CGRect+ASConvenience.m

@@ -0,0 +1,31 @@
+/* Copyright (c) 2015-present, Facebook, Inc.
+ * All rights reserved.
+ *
+ * This source code is licensed under the BSD-style license found in the
+ * LICENSE file in the root directory of this source tree. An additional grant
+ * of patent rights can be found in the PATENTS file in the same directory.
+ */
+
+#import "CGRect+ASConvenience.h"
+
+CGRect asdk_CGRectExpandHorizontally(CGRect rect, CGFloat negativeMultiplier, CGFloat positiveMultiplier) {
+  CGFloat negativeDirectionWidth = negativeMultiplier * rect.size.width;
+  CGFloat positiveDirectionWidth = positiveMultiplier * rect.size.width;
+  CGFloat width = negativeDirectionWidth + rect.size.width + positiveDirectionWidth;
+  CGFloat originX = rect.origin.x - negativeDirectionWidth;
+  return CGRectMake(originX,
+                    rect.origin.y,
+                    width,
+                    rect.size.height);
+}
+
+CGRect asdk_CGRectExpandVertically(CGRect rect, CGFloat negativeMultiplier, CGFloat positiveMultiplier) {
+  CGFloat negativeDirectionHeight = negativeMultiplier * rect.size.height;
+  CGFloat positiveDirectionHeight = positiveMultiplier * rect.size.height;
+  CGFloat height = negativeDirectionHeight + rect.size.height + positiveDirectionHeight;
+  CGFloat originY = rect.origin.y - negativeDirectionHeight;
+  return CGRectMake(rect.origin.x,
+                    originY,
+                    rect.size.width,
+                    height);
+}