iOS 15 fixes

Packages/ComposeUI/Sources/ComposeUI/Views/ComposeView.swift

@@ -116,6 +116,8 @@ public struct NavigationTitlePreferenceKey: PreferenceKey {
 
 private struct ToolbarActions: ToolbarContent {
     @ObservedObject var draft: Draft
+    // Prior to iOS 16, the toolbar content doesn't seem to have access
+    // to the environment form the containing view.
     let controller: ComposeController
     
     var body: some ToolbarContent {

Packages/ComposeUI/Sources/ComposeUI/Views/NewMainTextView.swift

@@ -8,6 +8,8 @@
 import SwiftUI
 
 struct NewMainTextView: View {
+    static var minHeight: CGFloat { 150 }
+    
     @Binding var value: String
     @FocusState.Binding var focusedField: FocusableField?
     @State private var becomeFirstResponder = true
@@ -16,6 +18,7 @@ struct NewMainTextView: View {
         NewMainTextViewRepresentable(value: $value, becomeFirstResponder: $becomeFirstResponder)
             .focused($focusedField, equals: .body)
             .modifier(FocusedInputModifier())
+            .modifier(HeightExpandingModifier(minHeight: Self.minHeight))
             .overlay(alignment: .topLeading) {
                 if value.isEmpty {
                     PlaceholderView()
@@ -34,6 +37,9 @@ private struct NewMainTextViewRepresentable: UIViewRepresentable {
     @Environment(\.composeUIConfig.useTwitterKeyboard) private var useTwitterKeyboard
     // TODO: test textSelectionStartsAtBeginning
     @Environment(\.composeUIConfig.textSelectionStartsAtBeginning) private var textSelectionStartsAtBeginning
+    #if !os(visionOS)
+    @Environment(\.textViewContentHeight) @Binding private var textViewContentHeight
+    #endif
     
     func makeUIView(context: Context) -> UITextView {
         let view: UITextView
@@ -86,6 +92,16 @@ private struct NewMainTextViewRepresentable: UIViewRepresentable {
                 becomeFirstResponder = false
             }
         }
+        
+        #if !os(visionOS)
+        if #unavailable(iOS 16.0) {
+            DispatchQueue.main.async {
+                let targetSize = CGSize(width: uiView.bounds.width, height: UIView.layoutFittingCompressedSize.height)
+                let fittingSize = uiView.systemLayoutSizeFitting(targetSize, withHorizontalFittingPriority: .required, verticalFittingPriority: .defaultHigh)
+                textViewContentHeight = fittingSize.height
+            }
+        }
+        #endif
     }
     
     func makeCoordinator() -> WrappedTextViewCoordinator {
@@ -96,12 +112,11 @@ private struct NewMainTextViewRepresentable: UIViewRepresentable {
         return coordinator
     }
     
-    // TODO: fallback for this on iOS 15
     @available(iOS 16.0, *)
     func sizeThatFits(_ proposal: ProposedViewSize, uiView: UIViewType, context: Context) -> CGSize? {
         let width = proposal.width ?? 10
         let size = uiView.sizeThatFits(CGSize(width: width, height: 0))
-        return CGSize(width: width, height: max(150, size.height))
+        return CGSize(width: width, height: max(NewMainTextView.minHeight, size.height))
     }
 }
 
@@ -261,3 +276,38 @@ private struct PlaceholderView: View {
             .allowsHitTesting(false)
     }
 }
+
+#if !os(visionOS)
+@available(iOS, obsoleted: 16.0)
+private struct HeightExpandingModifier: ViewModifier {
+    let minHeight: CGFloat
+    
+    @State private var height: CGFloat?
+    private var effectiveHeight: CGFloat {
+        height.map { max($0, minHeight) } ?? minHeight
+    }
+    
+    func body(content: Content) -> some View {
+        if #available(iOS 16.0, *) {
+            content
+        } else {
+            content
+                .frame(height: effectiveHeight)
+                .environment(\.textViewContentHeight, $height)
+        }
+    }
+}
+
+@available(iOS, obsoleted: 16.0)
+private struct TextViewContentHeightKey: EnvironmentKey {
+    static var defaultValue: Binding<CGFloat?> { .constant(nil) }
+}
+
+@available(iOS, obsoleted: 16.0)
+private extension EnvironmentValues {
+    var textViewContentHeight: Binding<CGFloat?> {
+        get { self[TextViewContentHeightKey.self] }
+        set { self[TextViewContentHeightKey.self] = newValue }
+    }
+}
+#endif