[0.82] Enables word-extension during drag after a double-click selection (#15640)

* enables word-extension during drag after a double-click selection

* yarn lint:fix and format

* Change files

Author: iamAbhi-916

change/react-native-windows-3c6ddb8b-a7f5-4d43-a953-7461a9bc110c.json

@@ -0,0 +1,7 @@
+{
+  "type": "prerelease",
+  "comment": "enables word-extension during drag after a double-click selection",
+  "packageName": "react-native-windows",
+  "email": "74712637+iamAbhi-916@users.noreply.github.com",
+  "dependentChangeType": "patch"
+}

vnext/Microsoft.ReactNative/Fabric/Composition/ParagraphComponentView.cpp

@@ -548,6 +548,7 @@ void ParagraphComponentView::ClearSelection() noexcept {
   m_selectionStart = std::nullopt;
   m_selectionEnd = std::nullopt;
   m_isSelecting = false;
+  m_isWordSelecting = false;
   if (hadSelection) {
     // Clears selection highlight
     DrawText();
@@ -598,7 +599,13 @@ void ParagraphComponentView::OnPointerPressed(
 
     if (isDoubleClick) {
       SelectWordAtPosition(*charPosition);
-      m_isSelecting = false;
+      if (m_selectionStart && m_selectionEnd) {
+        m_isWordSelecting = true;
+        m_wordAnchorStart = *m_selectionStart;
+        m_wordAnchorEnd = *m_selectionEnd;
+        m_isSelecting = true;
+        CapturePointer(args.Pointer());
+      }
     } else {
       // Single-click: start drag selection
       m_selectionStart = charPosition;
@@ -640,10 +647,28 @@ void ParagraphComponentView::OnPointerMoved(
   facebook::react::Point localPt{position.X, position.Y};
   std::optional<int32_t> charPosition = GetClampedTextPosition(localPt);
 
-  if (charPosition && charPosition != m_selectionEnd) {
-    m_selectionEnd = charPosition;
-    DrawText();
-    args.Handled(true);
+  if (charPosition) {
+    if (m_isWordSelecting) {
+      // Extend selection by whole words
+      auto [wordStart, wordEnd] = GetWordBoundariesAtPosition(*charPosition);
+
+      if (*charPosition < m_wordAnchorStart) {
+        m_selectionStart = wordStart;
+        m_selectionEnd = m_wordAnchorEnd;
+      } else if (*charPosition >= m_wordAnchorEnd) {
+        m_selectionStart = m_wordAnchorStart;
+        m_selectionEnd = wordEnd;
+      } else {
+        m_selectionStart = m_wordAnchorStart;
+        m_selectionEnd = m_wordAnchorEnd;
+      }
+      DrawText();
+      args.Handled(true);
+    } else if (charPosition != m_selectionEnd) {
+      m_selectionEnd = charPosition;
+      DrawText();
+      args.Handled(true);
+    }
   }
 }
 
@@ -667,6 +692,7 @@ void ParagraphComponentView::OnPointerReleased(
   }
 
   m_isSelecting = false;
+  m_isWordSelecting = false;
 
   ReleasePointerCapture(args.Pointer());
 
@@ -691,6 +717,7 @@ void ParagraphComponentView::OnPointerCaptureLost() noexcept {
   // Pointer capture was lost stop any active selection drag
   if (m_isSelecting) {
     m_isSelecting = false;
+    m_isWordSelecting = false;
 
     if (!m_selectionStart || !m_selectionEnd || *m_selectionStart == *m_selectionEnd) {
       m_selectionStart = std::nullopt;
@@ -741,12 +768,17 @@ void ParagraphComponentView::CopySelectionToClipboard() noexcept {
   winrt::Windows::ApplicationModel::DataTransfer::Clipboard::SetContent(dataPackage);
 }
 
-void ParagraphComponentView::SelectWordAtPosition(int32_t charPosition) noexcept {
+std::pair<int32_t, int32_t> ParagraphComponentView::GetWordBoundariesAtPosition(int32_t charPosition) noexcept {
   const std::wstring utf16Text{facebook::react::WindowsTextLayoutManager::GetTransformedText(m_attributedStringBox)};
   const int32_t textLength = static_cast<int32_t>(utf16Text.length());
 
-  if (utf16Text.empty() || charPosition < 0 || charPosition >= textLength) {
-    return;
+  if (utf16Text.empty() || charPosition < 0) {
+    return {0, 0};
+  }
+
+  charPosition = std::min(charPosition, textLength - 1);
+  if (charPosition < 0) {
+    return {0, 0};
   }
 
   int32_t wordStart = charPosition;
@@ -779,6 +811,12 @@ void ParagraphComponentView::SelectWordAtPosition(int32_t charPosition) noexcept
     }
   }
 
+  return {wordStart, wordEnd};
+}
+
+void ParagraphComponentView::SelectWordAtPosition(int32_t charPosition) noexcept {
+  auto [wordStart, wordEnd] = GetWordBoundariesAtPosition(charPosition);
+
   if (wordEnd > wordStart) {
     SetSelection(wordStart, wordEnd);
     DrawText();

vnext/Microsoft.ReactNative/Fabric/Composition/ParagraphComponentView.h

@@ -98,6 +98,7 @@ struct ParagraphComponentView : ParagraphComponentViewT<ParagraphComponentView,
   void CopySelectionToClipboard() noexcept;
 
   void SelectWordAtPosition(int32_t charPosition) noexcept;
+  std::pair<int32_t, int32_t> GetWordBoundariesAtPosition(int32_t charPosition) noexcept;
 
   void ShowContextMenu() noexcept;
 
@@ -114,6 +115,11 @@ struct ParagraphComponentView : ParagraphComponentViewT<ParagraphComponentView,
   std::optional<int32_t> m_selectionEnd;
   bool m_isSelecting{false};
 
+  // Double click + drag selection
+  bool m_isWordSelecting{false};
+  int32_t m_wordAnchorStart{0};
+  int32_t m_wordAnchorEnd{0};
+
   // Double-click detection
   std::chrono::steady_clock::time_point m_lastClickTime{};
   std::optional<int32_t> m_lastClickPosition;