Shuffle & Cleanup Stuff (#3080)

Source/Layout/ASStackLayoutSpec.h

@@ -0,0 +1,110 @@
+//
+//  ASStackLayoutSpec.h
+//  AsyncDisplayKit
+//
+//  Copyright (c) 2014-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/ASLayoutSpec.h>
+#import <AsyncDisplayKit/ASStackLayoutDefines.h>
+
+NS_ASSUME_NONNULL_BEGIN
+
+/**
+ A simple layout spec that stacks a list of children vertically or horizontally.
+
+ - All children are initially laid out with the an infinite available size in the stacking direction.
+ - In the other direction, this spec's constraint is passed.
+ - The children's sizes are summed in the stacking direction.
+   - If this sum is less than this spec's minimum size in stacking direction, children with flexGrow are flexed.
+   - If it is greater than this spec's maximum size in the stacking direction, children with flexShrink are flexed.
+   - If, even after flexing, the sum is still greater than this spec's maximum size in the stacking direction,
+     justifyContent determines how children are laid out.
+
+ For example:
+ 
+ - Suppose stacking direction is Vertical, min-width=100, max-width=300, min-height=200, max-height=500.
+ - All children are laid out with min-width=100, max-width=300, min-height=0, max-height=INFINITY.
+ - If the sum of the childrens' heights is less than 200, children with flexGrow are flexed larger.
+ - If the sum of the childrens' heights is greater than 500, children with flexShrink are flexed smaller.
+   Each child is shrunk by `((sum of heights) - 500)/(number of flexShrink-able children)`.
+ - If the sum of the childrens' heights is greater than 500 even after flexShrink-able children are flexed,
+   justifyContent determines how children are laid out.
+ */
+@interface ASStackLayoutSpec : ASLayoutSpec
+
+/** 
+ Specifies the direction children are stacked in. If horizontalAlignment and verticalAlignment were set, 
+ they will be resolved again, causing justifyContent and alignItems to be updated accordingly
+ */
+@property (nonatomic, assign) ASStackLayoutDirection direction;
+/** The amount of space between each child. */
+@property (nonatomic, assign) CGFloat spacing;
+/** 
+ Specifies how children are aligned horizontally. Depends on the stack direction, setting the alignment causes either
+ justifyContent or alignItems to be updated. The alignment will remain valid after future direction changes.
+ Thus, it is preferred to those properties
+ */
+@property (nonatomic, assign) ASHorizontalAlignment horizontalAlignment;
+/** 
+ Specifies how children are aligned vertically. Depends on the stack direction, setting the alignment causes either
+ justifyContent or alignItems to be updated. The alignment will remain valid after future direction changes.
+ Thus, it is preferred to those properties
+ */
+@property (nonatomic, assign) ASVerticalAlignment verticalAlignment;
+/** The amount of space between each child. Defaults to ASStackLayoutJustifyContentStart */
+@property (nonatomic, assign) ASStackLayoutJustifyContent justifyContent;
+/** Orientation of children along cross axis. Defaults to ASStackLayoutAlignItemsStretch */
+@property (nonatomic, assign) ASStackLayoutAlignItems alignItems;
+//TODO documentation. Defaults to ASStackLayoutFlexWrapNoWrap
+@property (nonatomic, assign) ASStackLayoutFlexWrap flexWrap;
+//TODO documentation. Defaults to ASStackLayoutAlignContentStart
+@property (nonatomic, assign) ASStackLayoutAlignContent alignContent;
+
+- (instancetype)init;
+
+/**
+ @param direction The direction of the stack view (horizontal or vertical)
+ @param spacing The spacing between the children
+ @param justifyContent If no children are flexible, this describes how to fill any extra space
+ @param alignItems Orientation of the children along the cross axis
+ @param children ASLayoutElement children to be positioned.
+ */
++ (instancetype)stackLayoutSpecWithDirection:(ASStackLayoutDirection)direction
+                                     spacing:(CGFloat)spacing
+                              justifyContent:(ASStackLayoutJustifyContent)justifyContent
+                                  alignItems:(ASStackLayoutAlignItems)alignItems
+                                    children:(NSArray<id<ASLayoutElement>> *)children AS_WARN_UNUSED_RESULT;
+
+/**
+ @param direction The direction of the stack view (horizontal or vertical)
+ @param spacing The spacing between the children
+ @param justifyContent If no children are flexible, this describes how to fill any extra space
+ @param alignItems Orientation of the children along the cross axis
+ @param children ASLayoutElement children to be positioned.
+ TODO documentation flex wrap and align content
+ */
++ (instancetype)stackLayoutSpecWithDirection:(ASStackLayoutDirection)direction
+                                     spacing:(CGFloat)spacing
+                              justifyContent:(ASStackLayoutJustifyContent)justifyContent
+                                  alignItems:(ASStackLayoutAlignItems)alignItems
+                                    flexWrap:(ASStackLayoutFlexWrap)flexWrap
+                                alignContent:(ASStackLayoutAlignContent)alignContent
+                                    children:(NSArray<id<ASLayoutElement>> *)children AS_WARN_UNUSED_RESULT;
+
+/**
+ * @return A stack layout spec with direction of ASStackLayoutDirectionVertical
+ **/
++ (instancetype)verticalStackLayoutSpec AS_WARN_UNUSED_RESULT;
+
+/**
+ * @return A stack layout spec with direction of ASStackLayoutDirectionHorizontal
+ **/
++ (instancetype)horizontalStackLayoutSpec AS_WARN_UNUSED_RESULT;
+
+@end
+
+NS_ASSUME_NONNULL_END