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

74 lines
2.9 KiB
Objective-C

//
// ASStackUnpositionedLayout.h
// 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 <vector>
#import <AsyncDisplayKit/ASLayout.h>
#import <AsyncDisplayKit/ASStackLayoutSpecUtilities.h>
#import <AsyncDisplayKit/ASStackLayoutSpec.h>
/** The threshold that determines if a violation has actually occurred. */
AS_EXTERN CGFloat const kViolationEpsilon;
struct ASStackLayoutSpecChild {
/** The original source child. */
id<ASLayoutElement> element;
/** Style object of element. */
ASLayoutElementStyle *style;
/** Size object of the element */
ASLayoutElementSize size;
};
struct ASStackLayoutSpecItem {
/** The original source child. */
ASStackLayoutSpecChild child;
/** The proposed layout or nil if no is calculated yet. */
ASLayout *layout;
};
struct ASStackUnpositionedLine {
/** The set of proposed children in this line, each contains child layout, not yet positioned. */
std::vector<ASStackLayoutSpecItem> items;
/** The total size of the children in the stack dimension, including all spacing. */
CGFloat stackDimensionSum;
/** The size in the cross dimension */
CGFloat crossSize;
/** The baseline of the stack which baseline aligned children should align to */
CGFloat baseline;
};
/** Represents a set of stack layout children that have their final layout computed, but are not yet positioned. */
struct ASStackUnpositionedLayout {
/** The set of proposed lines, each contains child layouts, not yet positioned. */
const std::vector<ASStackUnpositionedLine> lines;
/**
* In a single line stack (e.g no wrao), this is the total size of the children in the stack dimension, including all spacing.
* In a multi-line stack, this is the largest stack dimension among lines.
*/
const CGFloat stackDimensionSum;
const CGFloat crossDimensionSum;
/** Given a set of children, computes the unpositioned layouts for those children. */
static ASStackUnpositionedLayout compute(const std::vector<ASStackLayoutSpecChild> &children,
const ASStackLayoutSpecStyle &style,
const ASSizeRange &sizeRange,
const BOOL concurrent);
static CGFloat baselineForItem(const ASStackLayoutSpecStyle &style,
const ASStackLayoutSpecItem &l);
static CGFloat computeStackViolation(const CGFloat stackDimensionSum,
const ASStackLayoutSpecStyle &style,
const ASSizeRange &sizeRange);
static CGFloat computeCrossViolation(const CGFloat crossDimensionSum,
const ASStackLayoutSpecStyle &style,
const ASSizeRange &sizeRange);
};