Swiftgram/examples/CustomCollectionView-Swift/Sample/ImageCellNode.swift

//
//  ImageCellNode.swift
//  Sample
//
//  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.
//  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
//
//  Unless required by applicable law or agreed to in writing, software
//  distributed under the License is distributed on an "AS IS" BASIS,
//  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//  See the License for the specific language governing permissions and
//  limitations under the License.
//

import UIKit
import AsyncDisplayKit

class ImageCellNode: ASCellNode {
  let imageNode = ASImageNode()
  required init(with image : UIImage) {
    super.init()
    imageNode.image = image
    self.addSubnode(self.imageNode)
  }

  override func layoutSpecThatFits(_ constrainedSize: ASSizeRange) -> ASLayoutSpec {
    var imageRatio: CGFloat = 0.5
    if imageNode.image != nil {
      imageRatio = (imageNode.image?.size.height)! / (imageNode.image?.size.width)!
    }
    
    let imagePlace = ASRatioLayoutSpec(ratio: imageRatio, child: imageNode)
    
    let stackLayout = ASStackLayoutSpec.horizontal()
    stackLayout.justifyContent = .start
    stackLayout.alignItems = .start
    stackLayout.style.flexShrink = 1.0
    stackLayout.children = [imagePlace]
    
    return  ASInsetLayoutSpec(insets: UIEdgeInsets.zero, child: stackLayout)
  }
  
}