Swiftgram/Source/Layout/ASLayoutSpec.h
Michael Schneider 82b7806473 [Layout] Remove finalLayoutElement (#96)
* Remove finalLayoutElement

* Add changelog

* Remove some documentation
2017-05-03 10:45:01 -07:00

114 lines
4.4 KiB
Objective-C

//
// ASLayoutSpec.h
// Texture
//
// 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 /ASDK-Licenses directory of this source tree. An additional
// grant of patent rights can be found in the PATENTS file in the same directory.
//
// Modifications to this file made after 4/13/2017 are: Copyright (c) 2017-present,
// Pinterest, Inc. Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
#import <AsyncDisplayKit/ASLayoutElement.h>
#import <AsyncDisplayKit/ASAsciiArtBoxCreator.h>
#import <AsyncDisplayKit/ASObjectDescriptionHelpers.h>
NS_ASSUME_NONNULL_BEGIN
/**
* A layout spec is an immutable object that describes a layout, loosely inspired by React.
*/
@interface ASLayoutSpec : NSObject <ASLayoutElement, ASLayoutElementStylability, NSFastEnumeration>
/**
* Creation of a layout spec should only happen by a user in layoutSpecThatFits:. During that method, a
* layout spec can be created and mutated. Once it is passed back to ASDK, the isMutable flag will be
* set to NO and any further mutations will cause an assert.
*/
@property (nonatomic, assign) BOOL isMutable;
/**
* First child within the children's array.
*
* @discussion Every ASLayoutSpec must act on at least one child. The ASLayoutSpec base class takes the
* responsibility of holding on to the spec children. Some layout specs, like ASInsetLayoutSpec,
* only require a single child.
*
* For layout specs that require a known number of children (ASBackgroundLayoutSpec, for example)
* a subclass should use this method to set the "primary" child. It can then use setChild:atIndex:
* to set any other required children. Ideally a subclass would hide this from the user, and use the
* setChild:atIndex: internally. For example, ASBackgroundLayoutSpec exposes a "background"
* property that behind the scenes is calling setChild:atIndex:.
*/
@property (nullable, strong, nonatomic) id<ASLayoutElement> child;
/**
* An array of ASLayoutElement children
*
* @discussion Every ASLayoutSpec must act on at least one child. The ASLayoutSpec base class takes the
* reponsibility of holding on to the spec children. Some layout specs, like ASStackLayoutSpec,
* can take an unknown number of children. In this case, the this method should be used.
* For good measure, in these layout specs it probably makes sense to define
* setChild: and setChild:forIdentifier: methods to do something appropriate or to assert.
*/
@property (nullable, strong, nonatomic) NSArray<id<ASLayoutElement>> *children;
@end
/**
* An ASLayoutSpec subclass that can wrap one or more ASLayoutElement and calculates the layout based on the
* sizes of the children. If multiple children are provided the size of the biggest child will be used to for
* size of this layout spec.
*/
@interface ASWrapperLayoutSpec : ASLayoutSpec
/*
* Returns an ASWrapperLayoutSpec object with the given layoutElement as child.
*/
+ (instancetype)wrapperWithLayoutElement:(id<ASLayoutElement>)layoutElement AS_WARN_UNUSED_RESULT;
/*
* Returns an ASWrapperLayoutSpec object with the given layoutElements as children.
*/
+ (instancetype)wrapperWithLayoutElements:(NSArray<id<ASLayoutElement>> *)layoutElements AS_WARN_UNUSED_RESULT;
/*
* Returns an ASWrapperLayoutSpec object initialized with the given layoutElement as child.
*/
- (instancetype)initWithLayoutElement:(id<ASLayoutElement>)layoutElement AS_WARN_UNUSED_RESULT;
/*
* Returns an ASWrapperLayoutSpec object initialized with the given layoutElements as children.
*/
- (instancetype)initWithLayoutElements:(NSArray<id<ASLayoutElement>> *)layoutElements AS_WARN_UNUSED_RESULT;
/*
* Init not available for ASWrapperLayoutSpec
*/
- (instancetype)init __unavailable;
@end
@interface ASLayoutSpec (Debugging) <ASLayoutElementAsciiArtProtocol, ASDebugNameProvider>
/**
* Used by other layout specs to create ascii art debug strings
*/
+ (NSString *)asciiArtStringForChildren:(NSArray *)children parentName:(NSString *)parentName direction:(ASStackLayoutDirection)direction;
+ (NSString *)asciiArtStringForChildren:(NSArray *)children parentName:(NSString *)parentName;
@end
@interface ASLayoutSpec (Deprecated)
ASLayoutElementStyleForwardingDeclaration
@end
NS_ASSUME_NONNULL_END