Abstract GetTextForClipboard() for UIA (#4578)

## Summary of the Pull Request
`GetTextForClipboard` already exists in the TextBuffer. It makes sense to use that for UIA as well. This changes the behavior or `GetText()` such that it does not remove leading/trailing whitespace anymore. That is more of an expected behavior.

## References
This also contributes to...
- #4509: UIA Box Selection
- #2447: UIA Signaling for Selection
- #1354: UIA support for Wide Glyphs
Now that the expansion occurs at before render-time, the selection anchors are an accurate representation of what is selected. We just need to move GetText to the TextBuffer. Then we can have those three issues just rely on code from the text buffer. This also means ConHost gets some of this stuff for free 😀

## Detailed Description of the Pull Request / Additional comments
- `TextBuffer::GetTextForClipboard()` --> `GetText()`
- `TextBuffer::GetText()` no longer requires GetForegroundColor/GetBackgroundColor. If either of these are not defined, we return a `TextAndColor` with only the `text` field populated.
- renamed a few parameters for copying text to the clipboard for clarity
- Updated `UiaTextRange::GetText()` to use `TextBuffer::GetText()`

## Validation Steps Performed
Manual tests for UIA using accessibility insights and Windows Terminal's copy action (w/ and w/out shift)

Added tests as well.

src/buffer/out/textBuffer.cpp

@@ -1364,26 +1364,30 @@ void TextBuffer::_ExpandTextRow(SMALL_RECT& textRow) const
 // Routine Description:
 // - Retrieves the text data from the selected region and presents it in a clipboard-ready format (given little post-processing).
 // Arguments:
-// - lineSelection - true if entire line is being selected. False otherwise (box selection)
-// - trimTrailingWhitespace - setting flag removes trailing whitespace at the end of each row in selection
-// - selectionRects - the selection regions from which the data will be extracted from the buffer
-// - GetForegroundColor - function used to map TextAttribute to RGB COLORREF for foreground color
-// - GetBackgroundColor - function used to map TextAttribute to RGB COLORREF for foreground color
+// - includeCRLF - inject CRLF pairs to the end of each line
+// - trimTrailingWhitespace - remove the trailing whitespace at the end of each line
+// - textRects - the rectangular regions from which the data will be extracted from the buffer (i.e.: selection rects)
+// - GetForegroundColor - function used to map TextAttribute to RGB COLORREF for foreground color. If null, only extract the text.
+// - GetBackgroundColor - function used to map TextAttribute to RGB COLORREF for background color. If null, only extract the text.
 // Return Value:
 // - The text, background color, and foreground color data of the selected region of the text buffer.
-const TextBuffer::TextAndColor TextBuffer::GetTextForClipboard(const bool lineSelection,
-                                                               const bool trimTrailingWhitespace,
-                                                               const std::vector<SMALL_RECT>& selectionRects,
-                                                               std::function<COLORREF(TextAttribute&)> GetForegroundColor,
-                                                               std::function<COLORREF(TextAttribute&)> GetBackgroundColor) const
+const TextBuffer::TextAndColor TextBuffer::GetText(const bool includeCRLF,
+                                                   const bool trimTrailingWhitespace,
+                                                   const std::vector<SMALL_RECT>& selectionRects,
+                                                   std::function<COLORREF(TextAttribute&)> GetForegroundColor,
+                                                   std::function<COLORREF(TextAttribute&)> GetBackgroundColor) const
 {
     TextAndColor data;
+    const bool copyTextColor = GetForegroundColor && GetBackgroundColor;
 
     // preallocate our vectors to reduce reallocs
     size_t const rows = selectionRects.size();
     data.text.reserve(rows);
-    data.FgAttr.reserve(rows);
-    data.BkAttr.reserve(rows);
+    if (copyTextColor)
+    {
+        data.FgAttr.reserve(rows);
+        data.BkAttr.reserve(rows);
+    }
 
     // for each row in the selection
     for (UINT i = 0; i < rows; i++)
@@ -1402,60 +1406,73 @@ const TextBuffer::TextAndColor TextBuffer::GetTextForClipboard(const bool lineSe
 
         // preallocate to avoid reallocs
         selectionText.reserve(gsl::narrow<size_t>(highlight.Width()) + 2); // + 2 for \r\n if we munged it
-        selectionFgAttr.reserve(gsl::narrow<size_t>(highlight.Width()) + 2);
-        selectionBkAttr.reserve(gsl::narrow<size_t>(highlight.Width()) + 2);
+        if (copyTextColor)
+        {
+            selectionFgAttr.reserve(gsl::narrow<size_t>(highlight.Width()) + 2);
+            selectionBkAttr.reserve(gsl::narrow<size_t>(highlight.Width()) + 2);
+        }
 
         // copy char data into the string buffer, skipping trailing bytes
         while (it)
         {
             const auto& cell = *it;
-            auto cellData = cell.TextAttr();
-            COLORREF const CellFgAttr = GetForegroundColor(cellData);
-            COLORREF const CellBkAttr = GetBackgroundColor(cellData);
 
             if (!cell.DbcsAttr().IsTrailing())
             {
                 selectionText.append(cell.Chars());
-                for (const wchar_t wch : cell.Chars())
+
+                if (copyTextColor)
                 {
-                    selectionFgAttr.push_back(CellFgAttr);
-                    selectionBkAttr.push_back(CellBkAttr);
+                    auto cellData = cell.TextAttr();
+                    COLORREF const CellFgAttr = GetForegroundColor(cellData);
+                    COLORREF const CellBkAttr = GetBackgroundColor(cellData);
+                    for (const wchar_t wch : cell.Chars())
+                    {
+                        selectionFgAttr.push_back(CellFgAttr);
+                        selectionBkAttr.push_back(CellBkAttr);
+                    }
                 }
             }
 #pragma warning(suppress : 26444)
             // TODO GH 2675: figure out why there's custom construction/destruction happening here
             it++;
         }
 
-        // trim trailing spaces if SHIFT key not held
+        const bool forcedWrap = GetRowByOffset(iRow).GetCharRow().WasWrapForced();
+
         if (trimTrailingWhitespace)
         {
-            const ROW& Row = GetRowByOffset(iRow);
-
-            // FOR LINE SELECTION ONLY: if the row was wrapped, don't remove the spaces at the end.
-            if (!lineSelection || !Row.GetCharRow().WasWrapForced())
+            // if the row was NOT wrapped...
+            if (!forcedWrap)
             {
+                // remove the spaces at the end (aka trim the trailing whitespace)
                 while (!selectionText.empty() && selectionText.back() == UNICODE_SPACE)
                 {
                     selectionText.pop_back();
-                    selectionFgAttr.pop_back();
-                    selectionBkAttr.pop_back();
+                    if (copyTextColor)
+                    {
+                        selectionFgAttr.pop_back();
+                        selectionBkAttr.pop_back();
+                    }
                 }
             }
+        }
 
-            // apply CR/LF to the end of the final string, unless we're the last line.
-            // a.k.a if we're earlier than the bottom, then apply CR/LF.
-            if (i < selectionRects.size() - 1)
+        // apply CR/LF to the end of the final string, unless we're the last line.
+        // a.k.a if we're earlier than the bottom, then apply CR/LF.
+        if (includeCRLF && i < selectionRects.size() - 1)
+        {
+            // if the row was NOT wrapped...
+            if (!forcedWrap)
             {
-                // FOR LINE SELECTION ONLY: if the row was wrapped, do not apply CR/LF.
-                // a.k.a. if the row was NOT wrapped, then we can assume a CR/LF is proper
-                // always apply \r\n for box selection
-                if (!lineSelection || !GetRowByOffset(iRow).GetCharRow().WasWrapForced())
-                {
-                    COLORREF const Blackness = RGB(0x00, 0x00, 0x00); // cant see CR/LF so just use black FG & BK
+                // then we can assume a CR/LF is proper
+                selectionText.push_back(UNICODE_CARRIAGERETURN);
+                selectionText.push_back(UNICODE_LINEFEED);
 
-                    selectionText.push_back(UNICODE_CARRIAGERETURN);
-                    selectionText.push_back(UNICODE_LINEFEED);
+                if (copyTextColor)
+                {
+                    // cant see CR/LF so just use black FG & BK
+                    COLORREF const Blackness = RGB(0x00, 0x00, 0x00);
                     selectionFgAttr.push_back(Blackness);
                     selectionFgAttr.push_back(Blackness);
                     selectionBkAttr.push_back(Blackness);
@@ -1465,8 +1482,11 @@ const TextBuffer::TextAndColor TextBuffer::GetTextForClipboard(const bool lineSe
         }
 
         data.text.emplace_back(std::move(selectionText));
-        data.FgAttr.emplace_back(std::move(selectionFgAttr));
-        data.BkAttr.emplace_back(std::move(selectionBkAttr));
+        if (copyTextColor)
+        {
+            data.FgAttr.emplace_back(std::move(selectionFgAttr));
+            data.BkAttr.emplace_back(std::move(selectionBkAttr));
+        }
     }
 
     return data;

src/buffer/out/textBuffer.hpp

@@ -145,11 +145,11 @@ class TextBuffer final
         std::vector<std::vector<COLORREF>> BkAttr;
     };
 
-    const TextAndColor GetTextForClipboard(const bool lineSelection,
-                                           const bool trimTrailingWhitespace,
-                                           const std::vector<SMALL_RECT>& selectionRects,
-                                           std::function<COLORREF(TextAttribute&)> GetForegroundColor,
-                                           std::function<COLORREF(TextAttribute&)> GetBackgroundColor) const;
+    const TextAndColor GetText(const bool lineSelection,
+                               const bool trimTrailingWhitespace,
+                               const std::vector<SMALL_RECT>& textRects,
+                               std::function<COLORREF(TextAttribute&)> GetForegroundColor = nullptr,
+                               std::function<COLORREF(TextAttribute&)> GetBackgroundColor = nullptr) const;
 
     static std::string GenHTML(const TextAndColor& rows,
                                const int fontHeightPoints,

src/cascadia/TerminalApp/TerminalPage.cpp

@@ -1345,7 +1345,7 @@ namespace winrt::TerminalApp::implementation
     bool TerminalPage::_CopyText(const bool trimTrailingWhitespace)
     {
         const auto control = _GetActiveControl();
-        return control.CopySelectionToClipboard(trimTrailingWhitespace);
+        return control.CopySelectionToClipboard(!trimTrailingWhitespace);
     }
 
     // Method Description:

src/cascadia/TerminalControl/TermControl.cpp

@@ -903,7 +903,7 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
                 }
                 else
                 {
-                    CopySelectionToClipboard(!shiftEnabled);
+                    CopySelectionToClipboard(shiftEnabled);
                 }
             }
         }
@@ -1028,7 +1028,7 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
                 // If the terminal was unfocused AND a click-drag selection happened, copy to clipboard.
                 if (!_unfocusedClickPos || (_unfocusedClickPos && _isClickDragSelection))
                 {
-                    CopySelectionToClipboard(!shiftEnabled);
+                    CopySelectionToClipboard(shiftEnabled);
                 }
             }
         }
@@ -1661,17 +1661,16 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
     //     Windows Clipboard (CascadiaWin32:main.cpp).
     // - CopyOnSelect does NOT clear the selection
     // Arguments:
-    // - trimTrailingWhitespace: enable removing any whitespace from copied selection
-    //    and get text to appear on separate lines.
-    bool TermControl::CopySelectionToClipboard(bool trimTrailingWhitespace)
+    // - collapseText: collapse all of the text to one line
+    bool TermControl::CopySelectionToClipboard(bool collapseText)
     {
         // no selection --> nothing to copy
         if (_terminal == nullptr || !_terminal->IsSelectionActive())
         {
             return false;
         }
         // extract text from buffer
-        const auto bufferData = _terminal->RetrieveSelectedTextFromBuffer(trimTrailingWhitespace);
+        const auto bufferData = _terminal->RetrieveSelectedTextFromBuffer(collapseText);
 
         // convert text: vector<string> --> string
         std::wstring textData;

src/cascadia/TerminalControl/TermControl.h

@@ -63,7 +63,7 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
         hstring Title();
         hstring GetProfileName() const;
 
-        bool CopySelectionToClipboard(bool trimTrailingWhitespace);
+        bool CopySelectionToClipboard(bool collapseText);
         void PasteTextFromClipboard();
         void Close();
         Windows::Foundation::Size CharacterDimensions() const;

src/cascadia/TerminalControl/TermControl.idl

@@ -52,7 +52,7 @@ namespace Microsoft.Terminal.TerminalControl
 
         String Title { get; };
 
-        Boolean CopySelectionToClipboard(Boolean trimTrailingWhitespace);
+        Boolean CopySelectionToClipboard(Boolean collapseText);
         void PasteTextFromClipboard();
         void Close();
         Windows.Foundation.Size CharacterDimensions { get; };

src/cascadia/TerminalCore/TerminalSelection.cpp

@@ -16,15 +16,15 @@ using namespace Microsoft::Terminal::Core;
  *                  |-position where we double-clicked
  *                 _|_
  *               |word|
- *                |--| 
+ *                |--|
  *  start & pivot-|  |-end
  *
  *     2. Drag your mouse down a line
  *
- *                    
- *  start & pivot-|__________ 
+ *
+ *  start & pivot-|__________
  *             __|word_______|
- *            |______| 
+ *            |______|
  *                  |
  *                  |-end & mouse position
  *
@@ -33,7 +33,7 @@ using namespace Microsoft::Terminal::Core;
  *                  |-start & mouse position
  *                  |________
  *             ____|   ______|
- *            |___w|ord           
+ *            |___w|ord
  *                |-end & pivot
  *
  *    The pivot never moves until a new selection is created. It ensures that that cell will always be selected.
@@ -250,20 +250,21 @@ void Terminal::ClearSelection()
 // Method Description:
 // - get wstring text from highlighted portion of text buffer
 // Arguments:
-// - trimTrailingWhitespace: enable removing any whitespace from copied selection
-//    and get text to appear on separate lines.
+// - collapseText: collapse all of the text to one line
 // Return Value:
 // - wstring text from buffer. If extended to multiple lines, each line is separated by \r\n
-const TextBuffer::TextAndColor Terminal::RetrieveSelectedTextFromBuffer(bool trimTrailingWhitespace) const
+const TextBuffer::TextAndColor Terminal::RetrieveSelectedTextFromBuffer(bool collapseText) const
 {
+    const auto selectionRects = _GetSelectionRects();
+
     std::function<COLORREF(TextAttribute&)> GetForegroundColor = std::bind(&Terminal::GetForegroundColor, this, std::placeholders::_1);
     std::function<COLORREF(TextAttribute&)> GetBackgroundColor = std::bind(&Terminal::GetBackgroundColor, this, std::placeholders::_1);
 
-    return _buffer->GetTextForClipboard(!_blockSelection,
-                                        trimTrailingWhitespace,
-                                        _GetSelectionRects(),
-                                        GetForegroundColor,
-                                        GetBackgroundColor);
+    return _buffer->GetText(!collapseText,
+                            !collapseText,
+                            selectionRects,
+                            GetForegroundColor,
+                            GetBackgroundColor);
 }
 
 // Method Description:

src/host/ut_host/ClipboardTests.cpp

@@ -84,10 +84,8 @@ class ClipboardTests
         selection.emplace_back(SMALL_RECT{ 0, 2, 14, 2 });
         selection.emplace_back(SMALL_RECT{ 0, 3, 8, 3 });
 
-        return Clipboard::Instance().RetrieveTextFromBuffer(screenInfo,
-                                                            fLineSelection,
-                                                            selection)
-            .text;
+        const auto& buffer = screenInfo.GetTextBuffer();
+        return buffer.GetText(true, fLineSelection, selection).text;
     }
 
 #pragma prefast(push)