2015-07-12 17:27:44 +07:00

92 lines
3.3 KiB
Objective-C

/*
* 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 <UIKit/UIKit.h>
#import <AsyncDisplayKit/ASAssert.h>
#import <AsyncDisplayKit/ASLayoutable.h>
extern CGPoint const CGPointNull;
extern BOOL CGPointIsNull(CGPoint point);
/** Represents a computed immutable layout tree. */
@interface ASLayout : NSObject
@property (nonatomic, weak, readonly) id<ASLayoutable> layoutableObject;
@property (nonatomic, readonly) CGSize size;
/**
* Position in parent. Default to CGPointNull.
*
* @discussion When being used as a sublayout, this property must not equal CGPointNull.
*/
@property (nonatomic, readwrite) CGPoint position;
/**
* Array of ASLayouts. Each must have a valid non-null position.
*/
@property (nonatomic, readonly) NSArray *sublayouts;
/**
* Initializer.
*
* @param layoutableObject The backing ASLayoutable object.
*
* @param size The size of this layout.
*
* @param position The posiion of this layout within its parent (if available).
*
* @param sublayouts Sublayouts belong to the new layout.
*/
+ (instancetype)newWithLayoutableObject:(id<ASLayoutable>)layoutableObject
size:(CGSize)size
position:(CGPoint)position
sublayouts:(NSArray *)sublayouts;
/**
* Convenience initializer that has CGPointNull position.
* Best used by ASDisplayNode subclasses that are manually creating a layout for -calculateLayoutThatFits:,
* or for ASLayoutSpec subclasses that are referencing the "self" level in the layout tree,
* or for creating a sublayout of which the position is yet to be determined.
*
* @param layoutableObject The backing ASLayoutable object.
*
* @param size The size of this layout.
*
* @param sublayouts Sublayouts belong to the new layout.
*/
+ (instancetype)newWithLayoutableObject:(id<ASLayoutable>)layoutableObject
size:(CGSize)size
sublayouts:(NSArray *)sublayouts;
/**
* Convenience that has CGPointNull position and no sublayouts.
* Best used for creating a layout that has no sublayouts, and is either a root one
* or a sublayout of which the position is yet to be determined.
*
* @param layoutableObject The backing ASLayoutable object.
*
* @param size The size of this layout.
*/
+ (instancetype)newWithLayoutableObject:(id<ASLayoutable>)layoutableObject size:(CGSize)size;
/**
* @abstract Evaluates a given predicate block against each object in the receiving layout tree
* and returns a new, 1-level deep layout containing the objects for which the predicate block returns true.
*
* @param predicateBlock The block is applied to a layout to be evaluated.
* The block takes 1 argument: evaluatedLayout - the layout to be evaluated.
* The block returns YES if evaluatedLayout evaluates to true, otherwise NO.
*
* @return A new, 1-level deep layout containing the layouts for which the predicate block returns true.
*/
- (ASLayout *)flattenedLayoutUsingPredicateBlock:(BOOL (^)(ASLayout *evaluatedLayout))predicateBlock;
@end