Fix the compatibility with UIView transition

Actually this is not the good design, but at least a workaround

Author: dreampiggy

SDWebImageSwiftUI/Classes/AnimatedImage.swift

@@ -275,9 +275,8 @@ public struct AnimatedImage : PlatformViewRepresentable {
                 self.imageModel.placeholderView?.isHidden = false
                 self.imageHandler.failureBlock?(error ?? NSError())
             }
-            // Finished loading
-            configureView(view, context: context)
-            layoutView(view, context: context)
+            // Finished loading, async
+            finishUpdateView(view, context: context, image: image)
         }
     }
 
@@ -310,6 +309,8 @@ public struct AnimatedImage : PlatformViewRepresentable {
         #endif
         context.coordinator.imageLoading.imageName = name
         view.wrapped.image = image
+        // Finished loading, sync
+        finishUpdateView(view, context: context, image: image)
     }
 
     private func updateViewForData(_ data: Data?, view: AnimatedImageViewWrapper, context: Context) {
@@ -323,6 +324,8 @@ public struct AnimatedImage : PlatformViewRepresentable {
         }
         context.coordinator.imageLoading.imageData = data
         view.wrapped.image = image
+        // Finished loading, sync
+        finishUpdateView(view, context: context, image: image)
     }
 
     private func updateViewForURL(_ url: URL?, view: AnimatedImageViewWrapper, context: Context) {
@@ -347,6 +350,8 @@ public struct AnimatedImage : PlatformViewRepresentable {
             setupIndicator(view, context: context)
             loadImage(view, context: context)
         }
+        // Finished loading, sync
+        finishUpdateView(view, context: context, image: view.wrapped.image)
     }
 
     func updateView(_ view: AnimatedImageViewWrapper, context: Context) {
@@ -364,9 +369,6 @@ public struct AnimatedImage : PlatformViewRepresentable {
             break // impossible
         }
 
-        // Finished loading
-        configureView(view, context: context)
-        layoutView(view, context: context)
         if let viewUpdateBlock = imageHandler.viewUpdateBlock {
             viewUpdateBlock(view.wrapped, context)
         }
@@ -384,6 +386,17 @@ public struct AnimatedImage : PlatformViewRepresentable {
         }
     }
 
+    func finishUpdateView(_ view: AnimatedImageViewWrapper, context: Context, image: PlatformImage?) {
+        // Finished loading
+        if let imageSize = image?.size {
+            view.imageSize = imageSize
+        } else {
+            view.imageSize = nil
+        }
+        configureView(view, context: context)
+        layoutView(view, context: context)
+    }
+    
     func layoutView(_ view: AnimatedImageViewWrapper, context: Context) {
         // AspectRatio && ContentMode
         #if os(macOS)

SDWebImageSwiftUI/Classes/ImageViewWrapper.swift

@@ -20,6 +20,7 @@ public class AnimatedImageViewWrapper : PlatformView {
     var interpolationQuality = CGInterpolationQuality.default
     var shouldAntialias = false
     var resizingMode: Image.ResizingMode?
+    var imageSize: CGSize?
 
     public override func draw(_ rect: CGRect) {
         #if os(macOS)
@@ -49,20 +50,27 @@ public class AnimatedImageViewWrapper : PlatformView {
 
     public override var intrinsicContentSize: CGSize {
         /// Match the behavior of SwiftUI.Image, only when image is resizable, use the super implementation to calculate size
-        let imageSize = wrapped.intrinsicContentSize
+        var contentSize = wrapped.intrinsicContentSize
+        /// Sometimes, like during the transaction, the wrapped.image == nil, which cause contentSize invalid
+        /// Use image size as backup
+        /// TODO: This mixed use of UIKit/SwiftUI animation will cause visial issue because the intrinsicContentSize during animation may be changed
+        if let imageSize = imageSize {
+            if contentSize != imageSize {
+                contentSize = imageSize
+            }
+        }
         if let _ = resizingMode {
             /// Keep aspect ratio
-            let noIntrinsicMetric = AnimatedImageViewWrapper.noIntrinsicMetric
-            if (imageSize.width > 0 && imageSize.height > 0) {
-                let ratio = imageSize.width / imageSize.height
+            if contentSize.width > 0 && contentSize.height > 0 {
+                let ratio = contentSize.width / contentSize.height
                 let size = CGSize(width: ratio, height: 1)
                 return size
             } else {
-                return CGSize(width: noIntrinsicMetric, height: noIntrinsicMetric)
+                return contentSize
             }
         } else {
             /// Not resizable, always use image size, like SwiftUI.Image
-            return imageSize
+            return contentSize
         }
     }