feat: comment view open animation (#322)

Author: wesleynw

Splajompy/Extensions/View.swift

@@ -0,0 +1,8 @@
+import SwiftUI
+
+extension View {
+  @ViewBuilder
+  func modify(@ViewBuilder _ fn: (Self) -> some View) -> some View {
+    fn(self)
+  }
+}

Splajompy/Extensions/Zoomable.swift

@@ -169,11 +169,6 @@
   }
 
   extension View {
-    @ViewBuilder
-    fileprivate func modify(@ViewBuilder _ fn: (Self) -> some View) -> some View {
-      fn(self)
-    }
-
     @ViewBuilder
     fileprivate func animatableTransformEffect(_ transform: CGAffineTransform)
       -> some View

Splajompy/Posts/PostView.swift

@@ -41,6 +41,7 @@ struct PostView: View {
   var onPostPinned: () -> Void
   var onPostUnpinned: () -> Void
 
+  @Namespace private var namespace
   @State private var isShowingComments = false
   @State private var isReporting = false
   @State private var showReportAlert = false
@@ -88,6 +89,15 @@ struct PostView: View {
     .padding(.horizontal, 16)
     .sheet(isPresented: $isShowingComments) {
       CommentsView(postId: post.post.postId, postManager: postManager)
+        .modify {
+          #if os(iOS)
+            if #available(iOS 18, *) {
+              $0.navigationTransition(
+                .zoom(sourceID: "comments", in: namespace)
+              )
+            }
+          #endif
+        }
     }
     .alert("Post Reported", isPresented: $showReportAlert) {
       Button("OK") {}
@@ -244,7 +254,10 @@ struct PostView: View {
                 }
               }
 
-              Button(role: .destructive, action: { showDeleteConfirmation = true }) {
+              Button(
+                role: .destructive,
+                action: { showDeleteConfirmation = true }
+              ) {
                 Label("Delete", systemImage: "trash")
                   .foregroundColor(.red)
               }
@@ -307,6 +320,11 @@ struct PostView: View {
         }
         .buttonStyle(.plain)
         .sensoryFeedback(.impact, trigger: isShowingComments)
+        .modify {
+          if #available(iOS 18, *) {
+            $0.matchedTransitionSource(id: "comments", in: namespace)
+          }
+        }
 
         Divider()
           .padding(.vertical, 5)