Swiftgram/submodules/AsyncDisplayKit/Source/ASAbsoluteLayoutSpec.mm
2019-11-11 16:39:27 +04:00

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//
// ASAbsoluteLayoutSpec.mm
// Texture
//
// Copyright (c) Facebook, Inc. and its affiliates. All rights reserved.
// Changes after 4/13/2017 are: Copyright (c) Pinterest, Inc. All rights reserved.
// Licensed under Apache 2.0: http://www.apache.org/licenses/LICENSE-2.0
//
#import "ASAbsoluteLayoutSpec.h"
#import <AsyncDisplayKit/ASCollections.h>
#import <AsyncDisplayKit/ASLayout.h>
#import <AsyncDisplayKit/ASLayoutSpec+Subclasses.h>
#import <AsyncDisplayKit/ASLayoutSpecUtilities.h>
#import <AsyncDisplayKit/ASLayoutElementStylePrivate.h>
#pragma mark - ASAbsoluteLayoutSpec
@implementation ASAbsoluteLayoutSpec
#pragma mark - Class
+ (instancetype)absoluteLayoutSpecWithChildren:(NSArray *)children NS_RETURNS_RETAINED
{
return [[self alloc] initWithChildren:children];
}
+ (instancetype)absoluteLayoutSpecWithSizing:(ASAbsoluteLayoutSpecSizing)sizing children:(NSArray<id<ASLayoutElement>> *)children NS_RETURNS_RETAINED
{
return [[self alloc] initWithSizing:sizing children:children];
}
#pragma mark - Lifecycle
- (instancetype)init
{
return [self initWithChildren:nil];
}
- (instancetype)initWithChildren:(NSArray *)children
{
return [self initWithSizing:ASAbsoluteLayoutSpecSizingDefault children:children];
}
- (instancetype)initWithSizing:(ASAbsoluteLayoutSpecSizing)sizing children:(NSArray<id<ASLayoutElement>> *)children
{
if (!(self = [super init])) {
return nil;
}
_sizing = sizing;
self.children = children;
return self;
}
#pragma mark - ASLayoutSpec
- (ASLayout *)calculateLayoutThatFits:(ASSizeRange)constrainedSize
{
CGSize size = {
ASPointsValidForSize(constrainedSize.max.width) == NO ? ASLayoutElementParentDimensionUndefined : constrainedSize.max.width,
ASPointsValidForSize(constrainedSize.max.height) == NO ? ASLayoutElementParentDimensionUndefined : constrainedSize.max.height
};
NSArray *children = self.children;
ASLayout *rawSublayouts[children.count];
int i = 0;
for (id<ASLayoutElement> child in children) {
CGPoint layoutPosition = child.style.layoutPosition;
CGSize autoMaxSize = {
constrainedSize.max.width - layoutPosition.x,
constrainedSize.max.height - layoutPosition.y
};
const ASSizeRange childConstraint = ASLayoutElementSizeResolveAutoSize(child.style.size, size, {{0,0}, autoMaxSize});
ASLayout *sublayout = [child layoutThatFits:childConstraint parentSize:size];
sublayout.position = layoutPosition;
rawSublayouts[i++] = sublayout;
}
const auto sublayouts = [NSArray<ASLayout *> arrayByTransferring:rawSublayouts count:i];
if (_sizing == ASAbsoluteLayoutSpecSizingSizeToFit || isnan(size.width)) {
size.width = constrainedSize.min.width;
for (ASLayout *sublayout in sublayouts) {
size.width = MAX(size.width, sublayout.position.x + sublayout.size.width);
}
}
if (_sizing == ASAbsoluteLayoutSpecSizingSizeToFit || isnan(size.height)) {
size.height = constrainedSize.min.height;
for (ASLayout *sublayout in sublayouts) {
size.height = MAX(size.height, sublayout.position.y + sublayout.size.height);
}
}
return [ASLayout layoutWithLayoutElement:self size:ASSizeRangeClamp(constrainedSize, size) sublayouts:sublayouts];
}
@end