Another reactions experiment

submodules/MessageReactionListUI/Sources/MessageReactionListLoadingPlaceholder.swift

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+import Foundation
+import AsyncDisplayKit
+import Display
+import TelegramPresentationData
+import TelegramCore
+
+final class MessageReactionListLoadingPlaceholder: ASDisplayNode {
+    private let theme: PresentationTheme
+    private let itemHeight: CGFloat
+    private let itemImage: UIImage?
+    
+    private let backgroundNode: ASDisplayNode
+    private let separatorNode: ASDisplayNode
+    private let highlightNode: ASImageNode
+    private var itemNodes: [ASImageNode] = []
+    
+    init(theme: PresentationTheme, itemHeight: CGFloat) {
+        self.theme = theme
+        self.itemHeight = itemHeight
+        
+        self.backgroundNode = ASDisplayNode()
+        self.backgroundNode.backgroundColor = UIColor(white: 0.92, alpha: 1.0)
+        
+        self.separatorNode = ASDisplayNode()
+        self.separatorNode.backgroundColor = theme.list.itemPlainSeparatorColor
+        
+        self.highlightNode = ASImageNode()
+        self.highlightNode.displaysAsynchronously = false
+        self.highlightNode.displayWithoutProcessing = true
+        
+        let leftInset: CGFloat = 15.0
+        let avatarSize: CGFloat = 40.0
+        let avatarSpacing: CGFloat = 11.0
+        let contentWidth: CGFloat = 4.0
+        let contentHeight: CGFloat = 14.0
+        let rightInset: CGFloat = 54.0
+        self.itemImage = generateImage(CGSize(width: leftInset + avatarSize + avatarSpacing + contentWidth + rightInset, height: itemHeight), rotatedContext: { size, context in
+            context.setFillColor(theme.actionSheet.opaqueItemBackgroundColor.cgColor)
+            context.fill(CGRect(origin: CGPoint(), size: size))
+            context.setFillColor(theme.list.itemPlainSeparatorColor.cgColor)
+            context.fill(CGRect(origin: CGPoint(), size: CGSize(width: size.width, height: UIScreenPixel)))
+            context.setBlendMode(.copy)
+            context.setFillColor(UIColor.clear.cgColor)
+            context.fillEllipse(in: CGRect(origin: CGPoint(x: leftInset, y: floor((itemHeight - avatarSize) / 2.0)), size: CGSize(width: avatarSize, height: avatarSize)))
+            let contentOrigin = leftInset + avatarSize + avatarSpacing
+            context.fill(CGRect(origin: CGPoint(x: contentOrigin, y: floor((size.height - contentHeight) / 2.0)), size: CGSize(width: size.width - contentOrigin - rightInset, height: contentHeight)))
+        })?.stretchableImage(withLeftCapWidth: Int(leftInset + avatarSize + avatarSpacing + 1), topCapHeight: 0)
+        
+        super.init()
+        
+        self.addSubnode(self.backgroundNode)
+        self.addSubnode(self.highlightNode)
+        self.addSubnode(self.separatorNode)
+    }
+    
+    func updateLayout(size: CGSize) {
+        self.backgroundNode.frame = CGRect(origin: CGPoint(), size: size)
+        
+        var verticalOffset: CGFloat = 0.0
+        var index = 0
+        while verticalOffset < size.height - 1.0 {
+            if self.itemNodes.count >= index {
+                let itemNode = ASImageNode()
+                itemNode.image = self.itemImage
+                self.itemNodes.append(itemNode)
+                self.addSubnode(itemNode)
+            }
+            self.itemNodes[index].frame = CGRect(origin: CGPoint(x: 0.0, y: verticalOffset), size: CGSize(width: size.width, height: self.itemHeight))
+            verticalOffset += self.itemHeight
+            index += 1
+        }
+        self.separatorNode.frame = CGRect(origin: CGPoint(x: 0.0, y: verticalOffset), size: CGSize(width: size.width, height: UIScreenPixel))
+        if index < self.itemNodes.count {
+            for i in index ..< self.itemNodes.count {
+                self.itemNodes[i].removeFromSupernode()
+            }
+            self.itemNodes.removeLast(self.itemNodes.count - index)
+        }
+    }
+}