Make textContainerInset easier to customize

Author: mshibanami

Example/Example (Shared)/ContentView.swift

@@ -13,6 +13,7 @@ struct ContentView: View {
     @State var text2 = ""
     @State var text3 = "Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua."
     @State var text4 = ""
+    @State var text5 = "I have greater horizontal padding than the others."
 
     var body: some View {
         ScrollView {
@@ -73,6 +74,17 @@ struct ContentView: View {
                     .autocapitalizationType(.none)
                 }
 #endif
+                ExampleSection("Customized textContentInset") {
+                    ResizingTextView(
+                        text: $text5,
+                        placeholder: ""
+                    )
+#if os(macOS)
+                    .textContainerInset(CGSize(width: 40, height: 10))
+#elseif os(iOS)
+                    .textContainerInset(UIEdgeInsets(top: 0, left: 40, bottom: 0, right: 40))
+#endif
+                }
             }
             .scenePadding()
         }

Sources/ResizingTextView/ResizingTextView.swift

@@ -207,6 +207,12 @@ public extension ResizingTextView {
         newSelf.font = font
         return newSelf
     }
+    
+    func textContainerInset(_ inset: CGSize?) -> Self {
+        var newSelf = self
+        newSelf.textContainerInset = inset
+        return newSelf
+    }
 
 #elseif os(iOS)
     func foregroundColor(_ color: UIColor) -> Self {
@@ -226,5 +232,11 @@ public extension ResizingTextView {
         newSelf.autocapitalizationType = autocapitalizationType
         return newSelf
     }
+    
+    func textContainerInset(_ inset: UIEdgeInsets?) -> Self {
+        var newSelf = self
+        newSelf.textContainerInset = inset
+        return newSelf
+    }
 #endif
 }

Sources/ResizingTextView/TextView (AppKit).swift

@@ -52,7 +52,6 @@ struct TextView: NSViewRepresentable {
 
     func makeNSView(context: Context) -> TextEnclosingScrollView {
         let textView = CustomTextView()
-        textView.textContainerInset = textContainerInset
         textView.delegate = context.coordinator
         textView.isRichText = false
         textView.allowsUndo = true
@@ -130,6 +129,9 @@ struct TextView: NSViewRepresentable {
         if textView.isSelectable != isSelectable {
             textView.isSelectable = isSelectable
         }
+        if textView.textContainerInset != textContainerInset {
+            textView.textContainerInset = textContainerInset
+        }
         if textView.textContainer?.maximumNumberOfLines != lineLimit {
             textView.textContainer?.maximumNumberOfLines = lineLimit
         }

Sources/ResizingTextView/TextView (UIKit).swift

@@ -6,6 +6,9 @@ import UIKit
 
 struct TextView: UIViewRepresentable {
     static let defaultForegroundColor = Color(UIColor.label)
+    
+    /// HACK: In iOS 17, the last sentence of a non-editable text may not be drawn if the textContainerInset is `.zero`. To avoid it, we add this default value to the insets.
+    private static let defaultTextContainerInset = UIEdgeInsets(top: 0.00000001, left: 0.00000001, bottom: 0.00000001, right: 0.00000001)
 
     @Binding private var text: String
     private var isEditable: Bool
@@ -17,7 +20,7 @@ struct TextView: UIViewRepresentable {
     private var canHaveNewLineCharacters: Bool
     private var width: CGFloat?
     private var autocapitalizationType: UITextAutocapitalizationType
-    private var textContainerInset: UIEdgeInsets
+    private var textContainerInset: UIEdgeInsets?
 
     init(
         _ text: Binding<String>,
@@ -31,7 +34,7 @@ struct TextView: UIViewRepresentable {
         autocapitalizationType: UITextAutocapitalizationType,
         textContainerInset: UIEdgeInsets?
     ) {
-        self._text = text
+        _text = text
         self.isEditable = isEditable
         self.isScrollable = isScrollable
         self.isSelectable = isSelectable
@@ -40,10 +43,7 @@ struct TextView: UIViewRepresentable {
         self.font = font
         self.canHaveNewLineCharacters = canHaveNewLineCharacters
         self.autocapitalizationType = autocapitalizationType
-        
-        // HACK: In iOS 17, the last sentence of a non-editable text may not be drawn if the textContainerInset is `.zero`. To avoid it, we add this default value to the insets.
-        let defaultTextContainerInset = UIEdgeInsets(top: 0.00000001, left: 0.00000001, bottom: 0.00000001, right: 0.00000001)
-        self.textContainerInset = textContainerInset ?? defaultTextContainerInset
+        self.textContainerInset = textContainerInset
     }
 
     func makeUIView(context: Context) -> CustomTextView {
@@ -84,6 +84,10 @@ struct TextView: UIViewRepresentable {
         if view.autocapitalizationType != autocapitalizationType {
             view.autocapitalizationType = autocapitalizationType
         }
+        let textContainerInset = textContainerInset ?? Self.defaultTextContainerInset
+        if view.textContainerInset != textContainerInset {
+            view.textContainerInset = textContainerInset
+        }
         if lineLimit > 0 {
             if view.textContainer.lineBreakMode != .byTruncatingTail {
                 view.textContainer.lineBreakMode = .byTruncatingTail