TrailingPosition.h

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/*
 * Copyright (c) Meta Platforms, Inc. and affiliates.
 *
 * This source code is licensed under the MIT license found in the
 * LICENSE file in the root directory of this source tree.
 */
 
#pragma once
 
#include <yoga/Yoga.h>
#include <yoga/algorithm/FlexDirection.h>
#include <yoga/event/event.h>
#include <yoga/node/Node.h>
 
namespace facebook::yoga {
 
// Given an offset to an edge, returns the offset to the opposite edge on the
// same axis. This assumes that the width/height of both nodes is determined at
// this point.
inline float getPositionOfOppositeEdge(
    float position,
    FlexDirection axis,
    const yoga::Node* const containingNode,
    const yoga::Node* const node) {
  return containingNode->getLayout().measuredDimension(dimension(axis)) -
      node->getLayout().measuredDimension(dimension(axis)) - position;
}
 
inline void setChildTrailingPosition(
    const yoga::Node* const node,
    yoga::Node* const child,
    const FlexDirection axis) {
  child->setLayoutPosition(
      getPositionOfOppositeEdge(
          child->getLayout().position(flexStartEdge(axis)), axis, node, child),
      flexEndEdge(axis));
}
 
inline bool needsTrailingPosition(const FlexDirection axis) {
  return axis == FlexDirection::RowReverse ||
      axis == FlexDirection::ColumnReverse;
}
 
} // namespace facebook::yoga