Eliminate more transient allocations: Titles and invalid rectangles and bitmap runs and utf8 conversions (#8621)

## References
* See also #8617 

## PR Checklist
* [x] Supports #3075
* [x] I work here.
* [x] Manual test.

## Detailed Description of the Pull Request / Additional comments

### Window Title Generation
Every time the renderer checks the title, it's doing two bad things that
I've fixed:
1. It's assembling the prefix to the full title doing a concatenation.
   No one ever gets just the prefix ever after it is set besides the
   concat. So instead of storing prefix and the title, I store the
   assembled prefix + title and the bare title.
2. A copy must be made because it was returning `std::wstring` instead
   of `std::wstring&`. Now it returns the ref.

### Dirty Area Return
Every time the renderer checks the dirty area, which is sometimes
multiple times per pass (regular text printing, again for selection,
etc.), a vector is created off the heap to return the rectangles. The
consumers only ever iterate this data. Now we return a span over a
rectangle or rectangles that the engine must store itself.
1. For some renderers, it's always a constant 1 element. They update
   that 1 element when dirty is queried and return it in the span with a
   span size of 1.
2. For other renderers with more complex behavior, they're already
   holding a cached vector of rectangles. Now it's effectively giving
   out the ref to those in the span for iteration.

### Bitmap Runs
The `til::bitmap` used a `std::optional<std::vector<til::rectangle>>`
inside itself to cache its runs and would clear the optional when the
runs became invalidated. Unfortunately doing `.reset()` to clear the
optional will destroy the underlying vector and have it release its
memory. We know it's about to get reallocated again, so we're just going
to make it a `std::pmr::vector` and give it a memory pool. 

The alternative solution here was to use a `bool` and
`std::vector<til::rectangle>` and just flag when the vector was invalid,
but that was honestly more code changes and I love excuses to try out
PMR now.

Also, instead of returning the ref to the vector... I'm just returning a
span now. Everyone just iterates it anyway, may as well not share the
implementation detail.

### UTF-8 conversions
When testing with Terminal and looking at the `conhost.exe`'s PTY
renderer, it spends a TON of allocation time on converting all the
UTF-16 stuff inside to UTF-8 before it sends it out the PTY. This was
because `ConvertToA` was allocating a string inside itself and returning
it just to have it freed after printing and looping back around again...
as a PTY does.

The change here is to use `til::u16u8` that accepts a buffer out
parameter so the caller can just hold onto it.

## Validation Steps Performed
- [x] `big.txt` in conhost.exe (GDI renderer)
- [x] `big.txt` in Terminal (DX, PTY renderer)
- [x] Ensure WDDM and BGFX build under Razzle with this change.

src/cascadia/TerminalCore/Terminal.hpp

@@ -182,7 +182,7 @@ public:
     void SelectNewRegion(const COORD coordStart, const COORD coordEnd) override;
     const COORD GetSelectionAnchor() const noexcept override;
     const COORD GetSelectionEnd() const noexcept override;
-    const std::wstring GetConsoleTitle() const noexcept override;
+    const std::wstring_view GetConsoleTitle() const noexcept override;
     void ColorSelection(const COORD coordSelectionStart, const COORD coordSelectionEnd, const TextAttribute) override;
 #pragma endregion
 

src/cascadia/TerminalCore/terminalrenderdata.cpp

@@ -215,7 +215,7 @@ void Terminal::SelectNewRegion(const COORD coordStart, const COORD coordEnd)
     SetSelectionEnd(realCoordEnd, SelectionExpansionMode::Cell);
 }
 
-const std::wstring Terminal::GetConsoleTitle() const noexcept
+const std::wstring_view Terminal::GetConsoleTitle() const noexcept
 try
 {
     if (_title.has_value())

src/host/consoleInformation.cpp

@@ -24,6 +24,8 @@ CONSOLE_INFORMATION::CONSOLE_INFORMATION() :
     // ExeAliasList initialized below
     _OriginalTitle(),
     _Title(),
+    _Prefix(),
+    _TitleAndPrefix(),
     _LinkTitle(),
     Flags(0),
     PopupCount(0),
@@ -115,7 +117,12 @@ ULONG CONSOLE_INFORMATION::GetCSRecursionCount()
     try
     {
         gci.SetTitle(title);
-        gci.SetOriginalTitle(std::wstring(TranslateConsoleTitle(gci.GetTitle().c_str(), TRUE, FALSE)));
+
+        // TranslateConsoleTitle must have a null terminated string.
+        // This should only happen once on startup so the copy shouldn't be costly
+        // but could be eliminated by rewriting TranslateConsoleTitle.
+        const std::wstring nullTerminatedTitle{ gci.GetTitle() };
+        gci.SetOriginalTitle(std::wstring(TranslateConsoleTitle(nullTerminatedTitle.c_str(), TRUE, FALSE)));
     }
     catch (...)
     {
@@ -269,6 +276,7 @@ std::pair<COLORREF, COLORREF> CONSOLE_INFORMATION::LookupAttributeColors(const T
 void CONSOLE_INFORMATION::SetTitle(const std::wstring_view newTitle)
 {
     _Title = std::wstring{ newTitle.begin(), newTitle.end() };
+    _TitleAndPrefix = _Prefix + _Title;
 
     auto* const pRender = ServiceLocator::LocateGlobals().pRender;
     if (pRender)
@@ -284,9 +292,10 @@ void CONSOLE_INFORMATION::SetTitle(const std::wstring_view newTitle)
 // - newTitlePrefix: The new value to use for the title prefix
 // Return Value:
 // - <none>
-void CONSOLE_INFORMATION::SetTitlePrefix(const std::wstring& newTitlePrefix)
+void CONSOLE_INFORMATION::SetTitlePrefix(const std::wstring_view newTitlePrefix)
 {
-    _TitlePrefix = newTitlePrefix;
+    _Prefix = newTitlePrefix;
+    _TitleAndPrefix = _Prefix + _Title;
 
     auto* const pRender = ServiceLocator::LocateGlobals().pRender;
     if (pRender)
@@ -302,7 +311,7 @@ void CONSOLE_INFORMATION::SetTitlePrefix(const std::wstring& newTitlePrefix)
 // - originalTitle: The new value to use for the console's original title
 // Return Value:
 // - <none>
-void CONSOLE_INFORMATION::SetOriginalTitle(const std::wstring& originalTitle)
+void CONSOLE_INFORMATION::SetOriginalTitle(const std::wstring_view originalTitle)
 {
     _OriginalTitle = originalTitle;
 }
@@ -314,7 +323,7 @@ void CONSOLE_INFORMATION::SetOriginalTitle(const std::wstring& originalTitle)
 // - linkTitle: The new value to use for the console's link title
 // Return Value:
 // - <none>
-void CONSOLE_INFORMATION::SetLinkTitle(const std::wstring& linkTitle)
+void CONSOLE_INFORMATION::SetLinkTitle(const std::wstring_view linkTitle)
 {
     _LinkTitle = linkTitle;
 }
@@ -324,8 +333,8 @@ void CONSOLE_INFORMATION::SetLinkTitle(const std::wstring& linkTitle)
 // Arguments:
 // - <none>
 // Return Value:
-// - a reference to the console's title.
+// - the console's title.
-const std::wstring& CONSOLE_INFORMATION::GetTitle() const noexcept
+const std::wstring_view CONSOLE_INFORMATION::GetTitle() const noexcept
 {
     return _Title;
 }
@@ -336,10 +345,10 @@ const std::wstring& CONSOLE_INFORMATION::GetTitle() const noexcept
 // Arguments:
 // - <none>
 // Return Value:
-// - a new wstring containing the combined prefix and title.
+// - the combined prefix and title.
-const std::wstring CONSOLE_INFORMATION::GetTitleAndPrefix() const
+const std::wstring_view CONSOLE_INFORMATION::GetTitleAndPrefix() const
 {
-    return _TitlePrefix + _Title;
+    return _TitleAndPrefix;
 }
 
 // Method Description:
@@ -347,8 +356,8 @@ const std::wstring CONSOLE_INFORMATION::GetTitleAndPrefix() const
 // Arguments:
 // - <none>
 // Return Value:
-// - a reference to the console's original title.
+// - the console's original title.
-const std::wstring& CONSOLE_INFORMATION::GetOriginalTitle() const noexcept
+const std::wstring_view CONSOLE_INFORMATION::GetOriginalTitle() const noexcept
 {
     return _OriginalTitle;
 }
@@ -358,8 +367,8 @@ const std::wstring& CONSOLE_INFORMATION::GetOriginalTitle() const noexcept
 // Arguments:
 // - <none>
 // Return Value:
-// - a reference to the console's link title.
+// - the console's link title.
-const std::wstring& CONSOLE_INFORMATION::GetLinkTitle() const noexcept
+const std::wstring_view CONSOLE_INFORMATION::GetLinkTitle() const noexcept
 {
     return _LinkTitle;
 }

src/host/getset.cpp

@@ -1660,33 +1660,21 @@ void DoSrvPrivateRefreshWindow(_In_ const SCREEN_INFORMATION& screenInfo)
         }
 
         // Get the appropriate title and length depending on the mode.
-        const wchar_t* pwszTitle;
+        const std::wstring_view storedTitle = isOriginal ? gci.GetOriginalTitle() : gci.GetTitle();
-        size_t cchTitleLength;
-
-        if (isOriginal)
-        {
-            pwszTitle = gci.GetOriginalTitle().c_str();
-            cchTitleLength = gci.GetOriginalTitle().length();
-        }
-        else
-        {
-            pwszTitle = gci.GetTitle().c_str();
-            cchTitleLength = gci.GetTitle().length();
-        }
 
         // Always report how much space we would need.
-        needed = cchTitleLength;
+        needed = storedTitle.size();
 
         // If we have a pointer to receive the data, then copy it out.
         if (title.has_value())
         {
-            HRESULT const hr = StringCchCopyNW(title->data(), title->size(), pwszTitle, cchTitleLength);
+            HRESULT const hr = StringCchCopyNW(title->data(), title->size(), storedTitle.data(), storedTitle.size());
 
             // Insufficient buffer is allowed. If we return a partial string, that's still OK by historical/compat standards.
             // Just say how much we managed to return.
             if (SUCCEEDED(hr) || STRSAFE_E_INSUFFICIENT_BUFFER == hr)
             {
-                written = std::min(title->size(), cchTitleLength);
+                written = std::min(title->size(), storedTitle.size());
             }
         }
         return S_OK;

src/host/renderData.cpp

@@ -318,7 +318,7 @@ const bool RenderData::IsGridLineDrawingAllowed() noexcept
 // - Retrieves the title information to be displayed in the frame/edge of the window
 // Return Value:
 // - String with title information
-const std::wstring RenderData::GetConsoleTitle() const noexcept
+const std::wstring_view RenderData::GetConsoleTitle() const noexcept
 {
     const CONSOLE_INFORMATION& gci = ServiceLocator::LocateGlobals().getConsoleInformation();
     return gci.GetTitleAndPrefix();

src/host/renderData.hpp

@@ -54,7 +54,7 @@ public:
 
     const bool IsGridLineDrawingAllowed() noexcept override;
 
-    const std::wstring GetConsoleTitle() const noexcept override;
+    const std::wstring_view GetConsoleTitle() const noexcept override;
 
     const std::wstring GetHyperlinkUri(uint16_t id) const noexcept override;
     const std::wstring GetHyperlinkCustomId(uint16_t id) const noexcept override;

src/host/server.h

@@ -129,13 +129,13 @@ public:
     std::pair<COLORREF, COLORREF> LookupAttributeColors(const TextAttribute& attr) const noexcept;
 
     void SetTitle(const std::wstring_view newTitle);
-    void SetTitlePrefix(const std::wstring& newTitlePrefix);
+    void SetTitlePrefix(const std::wstring_view newTitlePrefix);
-    void SetOriginalTitle(const std::wstring& originalTitle);
+    void SetOriginalTitle(const std::wstring_view originalTitle);
-    void SetLinkTitle(const std::wstring& linkTitle);
+    void SetLinkTitle(const std::wstring_view linkTitle);
-    const std::wstring& GetTitle() const noexcept;
+    const std::wstring_view GetTitle() const noexcept;
-    const std::wstring& GetOriginalTitle() const noexcept;
+    const std::wstring_view GetOriginalTitle() const noexcept;
-    const std::wstring& GetLinkTitle() const noexcept;
+    const std::wstring_view GetLinkTitle() const noexcept;
-    const std::wstring GetTitleAndPrefix() const;
+    const std::wstring_view GetTitleAndPrefix() const;
 
     [[nodiscard]] static NTSTATUS AllocateConsole(const std::wstring_view title);
     // MSFT:16886775 : get rid of friends
@@ -152,7 +152,8 @@ public:
 private:
     CRITICAL_SECTION _csConsoleLock; // serialize input and output using this
     std::wstring _Title;
-    std::wstring _TitlePrefix; // Eg Select, Mark - things that we manually prepend to the title.
+    std::wstring _Prefix; // Eg Select, Mark - things that we manually prepend to the title.
+    std::wstring _TitleAndPrefix;
     std::wstring _OriginalTitle;
     std::wstring _LinkTitle; // Path to .lnk file
     SCREEN_INFORMATION* pCurrentScreenBuffer;

src/host/ut_host/ApiRoutinesTests.cpp

@@ -207,10 +207,12 @@ class ApiRoutinesTests
         CONSOLE_INFORMATION& gci = ServiceLocator::LocateGlobals().getConsoleInformation();
         gci.SetTitle(L"Test window title.");
 
+        const auto title = gci.GetTitle();
+
         int const iBytesNeeded = WideCharToMultiByte(gci.OutputCP,
                                                      0,
-                                                     gci.GetTitle().c_str(),
+                                                     title.data(),
-                                                     -1,
+                                                     gsl::narrow_cast<int>(title.size()),
                                                      nullptr,
                                                      0,
                                                      nullptr,
@@ -221,8 +223,8 @@ class ApiRoutinesTests
 
         VERIFY_WIN32_BOOL_SUCCEEDED(WideCharToMultiByte(gci.OutputCP,
                                                         0,
-                                                        gci.GetTitle().c_str(),
+                                                        title.data(),
-                                                        -1,
+                                                        gsl::narrow_cast<int>(title.size()),
                                                         pszExpected.get(),
                                                         iBytesNeeded,
                                                         nullptr,
@@ -251,10 +253,13 @@ class ApiRoutinesTests
         VERIFY_SUCCEEDED(_pApiRoutines->GetConsoleTitleWImpl(gsl::span<wchar_t>(pwszTitle, ARRAYSIZE(pwszTitle)), cchWritten, cchNeeded));
 
         VERIFY_ARE_NOT_EQUAL(0u, cchWritten);
+
+        const auto title = gci.GetTitle();
+
         // NOTE: W version of API returns string length. A version of API returns buffer length (string + null).
-        VERIFY_ARE_EQUAL(gci.GetTitle().length(), cchWritten);
+        VERIFY_ARE_EQUAL(title.length(), cchWritten);
-        VERIFY_ARE_EQUAL(gci.GetTitle().length(), cchNeeded);
+        VERIFY_ARE_EQUAL(title.length(), cchNeeded);
-        VERIFY_ARE_EQUAL(WEX::Common::String(gci.GetTitle().c_str()), WEX::Common::String(pwszTitle));
+        VERIFY_ARE_EQUAL(WEX::Common::String(title.data(), gsl::narrow_cast<int>(title.size())), WEX::Common::String(pwszTitle));
     }
 
     TEST_METHOD(ApiGetConsoleOriginalTitleA)
@@ -262,10 +267,12 @@ class ApiRoutinesTests
         CONSOLE_INFORMATION& gci = ServiceLocator::LocateGlobals().getConsoleInformation();
         gci.SetOriginalTitle(L"Test original window title.");
 
+        const auto originalTitle = gci.GetOriginalTitle();
+
         int const iBytesNeeded = WideCharToMultiByte(gci.OutputCP,
                                                      0,
-                                                     gci.GetOriginalTitle().c_str(),
+                                                     originalTitle.data(),
-                                                     -1,
+                                                     gsl::narrow_cast<int>(originalTitle.size()),
                                                      nullptr,
                                                      0,
                                                      nullptr,
@@ -276,8 +283,8 @@ class ApiRoutinesTests
 
         VERIFY_WIN32_BOOL_SUCCEEDED(WideCharToMultiByte(gci.OutputCP,
                                                         0,
-                                                        gci.GetOriginalTitle().c_str(),
+                                                        originalTitle.data(),
-                                                        -1,
+                                                        gsl::narrow_cast<int>(originalTitle.size()),
                                                         pszExpected.get(),
                                                         iBytesNeeded,
                                                         nullptr,
@@ -306,10 +313,12 @@ class ApiRoutinesTests
         VERIFY_SUCCEEDED(_pApiRoutines->GetConsoleOriginalTitleWImpl(gsl::span<wchar_t>(pwszTitle, ARRAYSIZE(pwszTitle)), cchWritten, cchNeeded));
 
         VERIFY_ARE_NOT_EQUAL(0u, cchWritten);
+
+        const auto originalTitle = gci.GetOriginalTitle();
         // NOTE: W version of API returns string length. A version of API returns buffer length (string + null).
-        VERIFY_ARE_EQUAL(gci.GetOriginalTitle().length(), cchWritten);
+        VERIFY_ARE_EQUAL(originalTitle.length(), cchWritten);
-        VERIFY_ARE_EQUAL(gci.GetOriginalTitle().length(), cchNeeded);
+        VERIFY_ARE_EQUAL(originalTitle.length(), cchNeeded);
-        VERIFY_ARE_EQUAL(WEX::Common::String(gci.GetOriginalTitle().c_str()), WEX::Common::String(pwszTitle));
+        VERIFY_ARE_EQUAL(WEX::Common::String(originalTitle.data(), gsl::narrow_cast<int>(originalTitle.size())), WEX::Common::String(pwszTitle));
     }
 
     static void s_AdjustOutputWait(const bool fShouldBlock)

src/host/ut_host/VtIoTests.cpp

@@ -355,9 +355,9 @@ public:
         return false;
     }
 
-    const std::wstring GetConsoleTitle() const noexcept override
+    const std::wstring_view GetConsoleTitle() const noexcept override
     {
-        return std::wstring{};
+        return std::wstring_view{};
     }
 
     const bool IsSelectionActive() const override

src/inc/til/bitmap.h

@@ -263,7 +263,7 @@ namespace til // Terminal Implementation Library. Also: "Today I Learned"
                 return const_iterator(_bits, _sz, _sz.area());
             }
 
-            const std::vector<til::rectangle, run_allocator_type>& runs() const
+            const gsl::span<const til::rectangle> runs() const
             {
                 // If we don't have cached runs, rebuild.
                 if (!_runs.has_value())
@@ -271,7 +271,7 @@ namespace til // Terminal Implementation Library. Also: "Today I Learned"
                     _runs.emplace(begin(), end());
                 }
 
-                // Return a reference to the runs.
+                // Return the runs.
                 return _runs.value();
             }
 

src/interactivity/onecore/BgfxEngine.cpp

@@ -230,7 +230,7 @@ BgfxEngine::BgfxEngine(PVOID SharedViewBase, LONG DisplayHeight, LONG DisplayWid
     return S_OK;
 }
 
-std::vector<til::rectangle> BgfxEngine::GetDirtyArea()
+[[nodiscard]] HRESULT BgfxEngine::GetDirtyArea(gsl::span<const til::rectangle>& area) noexcept
 {
     SMALL_RECT r;
     r.Bottom = _displayHeight > 0 ? (SHORT)(_displayHeight - 1) : 0;
@@ -238,7 +238,12 @@ std::vector<til::rectangle> BgfxEngine::GetDirtyArea()
     r.Left = 0;
     r.Right = _displayWidth > 0 ? (SHORT)(_displayWidth - 1) : 0;
 
-    return { r };
+    _dirtyArea = r;
+
+    area = { &_dirtyArea,
+             1 };
+
+    return S_OK;
 }
 
 [[nodiscard]] HRESULT BgfxEngine::GetFontSize(_Out_ COORD* const pFontSize) noexcept
@@ -260,7 +265,7 @@ std::vector<til::rectangle> BgfxEngine::GetDirtyArea()
 // - newTitle: the new string to use for the title of the window
 // Return Value:
 // - S_OK
-[[nodiscard]] HRESULT BgfxEngine::_DoUpdateTitle(_In_ const std::wstring& /*newTitle*/) noexcept
+[[nodiscard]] HRESULT BgfxEngine::_DoUpdateTitle(_In_ const std::wstring_view /*newTitle*/) noexcept
 {
     return S_OK;
 }

src/interactivity/onecore/BgfxEngine.hpp

@@ -67,12 +67,12 @@ namespace Microsoft::Console::Render
 
         [[nodiscard]] HRESULT GetProposedFont(const FontInfoDesired& fiFontInfoDesired, FontInfo& fiFontInfo, int const iDpi) noexcept override;
 
-        std::vector<til::rectangle> GetDirtyArea() override;
+        [[nodiscard]] HRESULT GetDirtyArea(gsl::span<const til::rectangle>& area) noexcept override;
         [[nodiscard]] HRESULT GetFontSize(_Out_ COORD* const pFontSize) noexcept override;
         [[nodiscard]] HRESULT IsGlyphWideByFont(const std::wstring_view glyph, _Out_ bool* const pResult) noexcept override;
 
     protected:
-        [[nodiscard]] HRESULT _DoUpdateTitle(_In_ const std::wstring& newTitle) noexcept override;
+        [[nodiscard]] HRESULT _DoUpdateTitle(_In_ const std::wstring_view newTitle) noexcept override;
 
     private:
         ULONG_PTR _sharedViewBase;
@@ -80,6 +80,7 @@ namespace Microsoft::Console::Render
 
         LONG _displayHeight;
         LONG _displayWidth;
+        til::rectangle _dirtyArea;
 
         COORD _fontSize;
 

src/interactivity/win32/window.cpp

@@ -289,11 +289,17 @@ void Window::_UpdateSystemMetrics() const
             }
         }
 
+        // CreateWindowExW needs a null terminated string, so ensure
+        // title is null terminated in a std::wstring here.
+        // We don't mind the string copy here because making the window
+        // should be infrequent.
+        const std::wstring title{ gci.GetTitle() };
+
         // Attempt to create window
         HWND hWnd = CreateWindowExW(
             CONSOLE_WINDOW_EX_FLAGS,
             CONSOLE_WINDOW_CLASS,
-            gci.GetTitle().c_str(),
+            title.c_str(),
             CONSOLE_WINDOW_FLAGS,
             WI_IsFlagSet(gci.Flags, CONSOLE_AUTO_POSITION) ? CW_USEDEFAULT : rectProposed.left,
             rectProposed.top, // field is ignored if CW_USEDEFAULT was chosen above

src/interactivity/win32/windowproc.cpp

@@ -687,7 +687,10 @@ using namespace Microsoft::Console::Types;
 
     case CM_UPDATE_TITLE:
     {
-        SetWindowTextW(hWnd, gci.GetTitleAndPrefix().c_str());
+        // SetWindowTextW needs null terminated string so assign view to string.
+        const std::wstring titleAndPrefix{ gci.GetTitleAndPrefix() };
+
+        SetWindowTextW(hWnd, titleAndPrefix.c_str());
         break;
     }
 

src/renderer/base/RenderEngineBase.cpp

@@ -13,7 +13,7 @@ RenderEngineBase::RenderEngineBase() :
 {
 }
 
-HRESULT RenderEngineBase::InvalidateTitle(const std::wstring& proposedTitle) noexcept
+HRESULT RenderEngineBase::InvalidateTitle(const std::wstring_view proposedTitle) noexcept
 {
     if (proposedTitle != _lastFrameTitle)
     {
@@ -23,7 +23,7 @@ HRESULT RenderEngineBase::InvalidateTitle(const std::wstring& proposedTitle) noe
     return S_OK;
 }
 
-HRESULT RenderEngineBase::UpdateTitle(const std::wstring& newTitle) noexcept
+HRESULT RenderEngineBase::UpdateTitle(const std::wstring_view newTitle) noexcept
 {
     HRESULT hr = S_FALSE;
     if (newTitle != _lastFrameTitle)

src/renderer/base/renderer.cpp

@@ -467,7 +467,7 @@ void Renderer::TriggerCircling()
 // - <none>
 void Renderer::TriggerTitleChange()
 {
-    const std::wstring newTitle = _pData->GetConsoleTitle();
+    const auto newTitle = _pData->GetConsoleTitle();
     for (IRenderEngine* const pEngine : _rgpEngines)
     {
         LOG_IF_FAILED(pEngine->InvalidateTitle(newTitle));
@@ -483,7 +483,7 @@ void Renderer::TriggerTitleChange()
 // - the HRESULT of the underlying engine's UpdateTitle call.
 HRESULT Renderer::_PaintTitle(IRenderEngine* const pEngine)
 {
-    const std::wstring newTitle = _pData->GetConsoleTitle();
+    const auto newTitle = _pData->GetConsoleTitle();
     return pEngine->UpdateTitle(newTitle);
 }
 
@@ -627,9 +627,10 @@ void Renderer::_PaintBufferOutput(_In_ IRenderEngine* const pEngine)
 
     // This is effectively the number of cells on the visible screen that need to be redrawn.
     // The origin is always 0, 0 because it represents the screen itself, not the underlying buffer.
-    const auto dirtyAreas = pEngine->GetDirtyArea();
+    gsl::span<const til::rectangle> dirtyAreas;
+    LOG_IF_FAILED(pEngine->GetDirtyArea(dirtyAreas));
 
-    for (const auto dirtyRect : dirtyAreas)
+    for (const auto& dirtyRect : dirtyAreas)
     {
         auto dirty = Viewport::FromInclusive(dirtyRect);
 
@@ -1044,7 +1045,10 @@ void Renderer::_PaintOverlay(IRenderEngine& engine,
         // Set it up in a Viewport helper structure and trim it the IME viewport to be within the full console viewport.
         Viewport viewConv = Viewport::FromInclusive(srCaView);
 
-        for (SMALL_RECT srDirty : engine.GetDirtyArea())
+        gsl::span<const til::rectangle> dirtyAreas;
+        LOG_IF_FAILED(engine.GetDirtyArea(dirtyAreas));
+
+        for (SMALL_RECT srDirty : dirtyAreas)
         {
             // Dirty is an inclusive rectangle, but oddly enough the IME was an exclusive one, so correct it.
             srDirty.Bottom++;
@@ -1101,13 +1105,14 @@ void Renderer::_PaintSelection(_In_ IRenderEngine* const pEngine)
 {
     try
     {
-        auto dirtyAreas = pEngine->GetDirtyArea();
+        gsl::span<const til::rectangle> dirtyAreas;
+        LOG_IF_FAILED(pEngine->GetDirtyArea(dirtyAreas));
 
         // Get selection rectangles
         const auto rectangles = _GetSelectionRects();
         for (auto rect : rectangles)
         {
-            for (auto dirtyRect : dirtyAreas)
+            for (auto& dirtyRect : dirtyAreas)
             {
                 // Make a copy as `TrimToViewport` will manipulate it and
                 // can destroy it for the next dirtyRect to test against.

src/renderer/dx/DxRenderer.cpp

@@ -66,7 +66,8 @@ using namespace Microsoft::Console::Types;
 DxEngine::DxEngine() :
     RenderEngineBase(),
     _invalidateFullRows{ true },
-    _invalidMap{},
+    _pool{ til::pmr::get_default_resource() },
+    _invalidMap{ &_pool },
     _invalidScroll{},
     _allInvalid{ false },
     _firstFrame{ true },
@@ -2087,13 +2088,16 @@ float DxEngine::GetScaling() const noexcept
 // Routine Description:
 // - Gets the area that we currently believe is dirty within the character cell grid
 // Arguments:
-// - <none>
+// - area - Rectangle describing dirty area in characters.
 // Return Value:
-// - Rectangle describing dirty area in characters.
+// - S_OK
-[[nodiscard]] std::vector<til::rectangle> DxEngine::GetDirtyArea()
+[[nodiscard]] HRESULT DxEngine::GetDirtyArea(gsl::span<const til::rectangle>& area) noexcept
+try
 {
-    return _invalidMap.runs();
+    area = _invalidMap.runs();
+    return S_OK;
 }
+CATCH_RETURN();
 
 // Routine Description:
 // - Gets the current font size
@@ -2141,7 +2145,7 @@ CATCH_RETURN();
 // - newTitle: the new string to use for the title of the window
 // Return Value:
 // - S_OK
-[[nodiscard]] HRESULT DxEngine::_DoUpdateTitle(_In_ const std::wstring& /*newTitle*/) noexcept
+[[nodiscard]] HRESULT DxEngine::_DoUpdateTitle(_In_ const std::wstring_view /*newTitle*/) noexcept
 {
     if (_hwndTarget != INVALID_HANDLE_VALUE)
     {

src/renderer/dx/DxRenderer.hpp

@@ -113,7 +113,7 @@ namespace Microsoft::Console::Render
 
         [[nodiscard]] HRESULT GetProposedFont(const FontInfoDesired& fiFontInfoDesired, FontInfo& fiFontInfo, int const iDpi) noexcept override;
 
-        [[nodiscard]] std::vector<til::rectangle> GetDirtyArea() override;
+        [[nodiscard]] HRESULT GetDirtyArea(gsl::span<const til::rectangle>& area) noexcept override;
 
         [[nodiscard]] HRESULT GetFontSize(_Out_ COORD* const pFontSize) noexcept override;
         [[nodiscard]] HRESULT IsGlyphWideByFont(const std::wstring_view glyph, _Out_ bool* const pResult) noexcept override;
@@ -130,7 +130,7 @@ namespace Microsoft::Console::Render
         void UpdateHyperlinkHoveredId(const uint16_t hoveredId) noexcept;
 
     protected:
-        [[nodiscard]] HRESULT _DoUpdateTitle(_In_ const std::wstring& newTitle) noexcept override;
+        [[nodiscard]] HRESULT _DoUpdateTitle(_In_ const std::wstring_view newTitle) noexcept override;
         [[nodiscard]] HRESULT _PaintTerminalEffects() noexcept;
         [[nodiscard]] bool _FullRepaintNeeded() const noexcept;
 
@@ -181,7 +181,8 @@ namespace Microsoft::Console::Render
 
         bool _firstFrame;
         bool _invalidateFullRows;
-        til::bitmap _invalidMap;
+        std::pmr::unsynchronized_pool_resource _pool;
+        til::pmr::bitmap _invalidMap;
         til::point _invalidScroll;
         bool _allInvalid;
 

src/renderer/gdi/gdirenderer.hpp

@@ -66,12 +66,12 @@ namespace Microsoft::Console::Render
                                               _Out_ FontInfo& Font,
                                               const int iDpi) noexcept override;
 
-        [[nodiscard]] std::vector<til::rectangle> GetDirtyArea() override;
+        [[nodiscard]] HRESULT GetDirtyArea(gsl::span<const til::rectangle>& area) noexcept override;
         [[nodiscard]] HRESULT GetFontSize(_Out_ COORD* const pFontSize) noexcept override;
         [[nodiscard]] HRESULT IsGlyphWideByFont(const std::wstring_view glyph, _Out_ bool* const pResult) noexcept override;
 
     protected:
-        [[nodiscard]] HRESULT _DoUpdateTitle(_In_ const std::wstring& newTitle) noexcept override;
+        [[nodiscard]] HRESULT _DoUpdateTitle(_In_ const std::wstring_view newTitle) noexcept override;
 
     private:
         HWND _hwndTargetWindow;
@@ -82,6 +82,7 @@ namespace Microsoft::Console::Render
 
         bool _fPaintStarted;
 
+        til::rectangle _invalidCharacters;
         PAINTSTRUCT _psInvalidData;
         HDC _hdcMemoryContext;
         bool _isTrueTypeFont;

src/renderer/gdi/math.cpp

@@ -12,18 +12,22 @@ using namespace Microsoft::Console::Render;
 // Routine Description:
 // - Gets the size in characters of the current dirty portion of the frame.
 // Arguments:
-// - <none>
+// - area - The character dimensions of the current dirty area of the frame.
-// Return Value:
-// - The character dimensions of the current dirty area of the frame.
 //      This is an Inclusive rect.
-std::vector<til::rectangle> GdiEngine::GetDirtyArea()
+// Return Value:
+// - S_OK or math failure
+[[nodiscard]] HRESULT GdiEngine::GetDirtyArea(gsl::span<const til::rectangle>& area) noexcept
 {
     RECT rc = _psInvalidData.rcPaint;
 
     SMALL_RECT sr = { 0 };
-    LOG_IF_FAILED(_ScaleByFont(&rc, &sr));
+    RETURN_IF_FAILED(_ScaleByFont(&rc, &sr));
 
-    return { sr };
+    _invalidCharacters = sr;
+
+    area = { &_invalidCharacters, 1 };
+
+    return S_OK;
 }
 
 // Routine Description:

src/renderer/gdi/state.cpp

@@ -31,6 +31,7 @@ GdiEngine::GdiEngine() :
     _lastBg(INVALID_COLOR),
     _lastFontItalic(false),
     _fPaintStarted(false),
+    _invalidCharacters{},
     _hfont(nullptr),
     _hfontItalic(nullptr),
     _pool{ til::pmr::get_default_resource() }, // It's important the pool is first so it can be given to the others on construction.
@@ -392,7 +393,7 @@ GdiEngine::~GdiEngine()
 // - newTitle: the new string to use for the title of the window
 // Return Value:
 // -  S_OK if PostMessageW succeeded, otherwise E_FAIL
-[[nodiscard]] HRESULT GdiEngine::_DoUpdateTitle(_In_ const std::wstring& /*newTitle*/) noexcept
+[[nodiscard]] HRESULT GdiEngine::_DoUpdateTitle(_In_ const std::wstring_view /*newTitle*/) noexcept
 {
     // the CM_UPDATE_TITLE handler in windowproc will query the updated title.
     return PostMessageW(_hwndTargetWindow, CM_UPDATE_TITLE, 0, (LPARAM) nullptr) ? S_OK : E_FAIL;

src/renderer/inc/IRenderData.hpp

@@ -64,7 +64,7 @@ namespace Microsoft::Console::Render
         virtual const std::vector<RenderOverlay> GetOverlays() const noexcept = 0;
 
         virtual const bool IsGridLineDrawingAllowed() noexcept = 0;
-        virtual const std::wstring GetConsoleTitle() const noexcept = 0;
+        virtual const std::wstring_view GetConsoleTitle() const noexcept = 0;
 
         virtual const std::wstring GetHyperlinkUri(uint16_t id) const noexcept = 0;
         virtual const std::wstring GetHyperlinkCustomId(uint16_t id) const noexcept = 0;

src/renderer/inc/IRenderEngine.hpp

@@ -71,7 +71,7 @@ namespace Microsoft::Console::Render
         [[nodiscard]] virtual HRESULT InvalidateAll() noexcept = 0;
         [[nodiscard]] virtual HRESULT InvalidateCircling(_Out_ bool* const pForcePaint) noexcept = 0;
 
-        [[nodiscard]] virtual HRESULT InvalidateTitle(const std::wstring& proposedTitle) noexcept = 0;
+        [[nodiscard]] virtual HRESULT InvalidateTitle(const std::wstring_view proposedTitle) noexcept = 0;
 
         [[nodiscard]] virtual HRESULT PrepareRenderInfo(const RenderFrameInfo& info) noexcept = 0;
 
@@ -100,10 +100,10 @@ namespace Microsoft::Console::Render
                                                       _Out_ FontInfo& FontInfo,
                                                       const int iDpi) noexcept = 0;
 
-        virtual std::vector<til::rectangle> GetDirtyArea() = 0;
+        [[nodiscard]] virtual HRESULT GetDirtyArea(gsl::span<const til::rectangle>& area) noexcept = 0;
         [[nodiscard]] virtual HRESULT GetFontSize(_Out_ COORD* const pFontSize) noexcept = 0;
         [[nodiscard]] virtual HRESULT IsGlyphWideByFont(const std::wstring_view glyph, _Out_ bool* const pResult) noexcept = 0;
-        [[nodiscard]] virtual HRESULT UpdateTitle(const std::wstring& newTitle) noexcept = 0;
+        [[nodiscard]] virtual HRESULT UpdateTitle(const std::wstring_view newTitle) noexcept = 0;
     };
 
     inline Microsoft::Console::Render::IRenderEngine::~IRenderEngine() {}

src/renderer/inc/RenderEngineBase.hpp

@@ -34,9 +34,9 @@ namespace Microsoft::Console::Render
         RenderEngineBase& operator=(RenderEngineBase&&) = default;
 
     public:
-        [[nodiscard]] HRESULT InvalidateTitle(const std::wstring& proposedTitle) noexcept override;
+        [[nodiscard]] HRESULT InvalidateTitle(const std::wstring_view proposedTitle) noexcept override;
 
-        [[nodiscard]] HRESULT UpdateTitle(const std::wstring& newTitle) noexcept override;
+        [[nodiscard]] HRESULT UpdateTitle(const std::wstring_view newTitle) noexcept override;
 
         [[nodiscard]] HRESULT PrepareRenderInfo(const RenderFrameInfo& info) noexcept override;
 
@@ -45,7 +45,7 @@ namespace Microsoft::Console::Render
         void WaitUntilCanRender() noexcept override;
 
     protected:
-        [[nodiscard]] virtual HRESULT _DoUpdateTitle(const std::wstring& newTitle) noexcept = 0;
+        [[nodiscard]] virtual HRESULT _DoUpdateTitle(const std::wstring_view newTitle) noexcept = 0;
 
         bool _titleChanged;
         std::wstring _lastFrameTitle;

src/renderer/uia/UiaRenderer.cpp

@@ -427,12 +427,16 @@ CATCH_RETURN();
 // - Gets the area that we currently believe is dirty within the character cell grid
 // - Not currently used by UiaEngine.
 // Arguments:
-// - <none>
+// - area - Rectangle describing dirty area in characters.
 // Return Value:
-// - Rectangle describing dirty area in characters.
+// - S_OK.
-[[nodiscard]] std::vector<til::rectangle> UiaEngine::GetDirtyArea()
+[[nodiscard]] HRESULT UiaEngine::GetDirtyArea(gsl::span<const til::rectangle>& area) noexcept
 {
-    return { Viewport::Empty().ToInclusive() };
+    // Magic static is only valid because any instance of this object has the same behavior.
+    // Use member variable instead if this ever changes.
+    const static til::rectangle empty;
+    area = { &empty, 1 };
+    return S_OK;
 }
 
 // Routine Description:
@@ -465,7 +469,7 @@ CATCH_RETURN();
 // - newTitle: the new string to use for the title of the window
 // Return Value:
 // - S_FALSE
-[[nodiscard]] HRESULT UiaEngine::_DoUpdateTitle(_In_ const std::wstring& /*newTitle*/) noexcept
+[[nodiscard]] HRESULT UiaEngine::_DoUpdateTitle(_In_ const std::wstring_view /*newTitle*/) noexcept
 {
     return S_FALSE;
 }

src/renderer/uia/UiaRenderer.hpp

@@ -69,12 +69,12 @@ namespace Microsoft::Console::Render
 
         [[nodiscard]] HRESULT GetProposedFont(const FontInfoDesired& fiFontInfoDesired, FontInfo& fiFontInfo, int const iDpi) noexcept override;
 
-        [[nodiscard]] std::vector<til::rectangle> GetDirtyArea() override;
+        [[nodiscard]] HRESULT GetDirtyArea(gsl::span<const til::rectangle>& area) noexcept override;
         [[nodiscard]] HRESULT GetFontSize(_Out_ COORD* const pFontSize) noexcept override;
         [[nodiscard]] HRESULT IsGlyphWideByFont(const std::wstring_view glyph, _Out_ bool* const pResult) noexcept override;
 
     protected:
-        [[nodiscard]] HRESULT _DoUpdateTitle(const std::wstring& newTitle) noexcept override;
+        [[nodiscard]] HRESULT _DoUpdateTitle(const std::wstring_view newTitle) noexcept override;
 
     private:
         bool _isEnabled;

src/renderer/vt/XtermEngine.cpp

@@ -57,7 +57,8 @@ XtermEngine::XtermEngine(_In_ wil::unique_hfile hPipe,
     }
     else
     {
-        const auto dirty = GetDirtyArea();
+        gsl::span<const til::rectangle> dirty;
+        RETURN_IF_FAILED(GetDirtyArea(dirty));
 
         // If we have 0 or 1 dirty pieces in the area, set as appropriate.
         Viewport dirtyView = dirty.empty() ? Viewport::Empty() : Viewport::FromInclusive(til::at(dirty, 0));
@@ -540,7 +541,7 @@ CATCH_RETURN();
 // - newTitle: the new string to use for the title of the window
 // Return Value:
 // - S_OK
-[[nodiscard]] HRESULT XtermEngine::_DoUpdateTitle(const std::wstring& newTitle) noexcept
+[[nodiscard]] HRESULT XtermEngine::_DoUpdateTitle(const std::wstring_view newTitle) noexcept
 {
     // inbox telnet uses xterm-ascii as its mode. If we're in ascii mode, don't
     //      do anything, to maintain compatibility.

src/renderer/vt/XtermEngine.hpp

@@ -59,7 +59,7 @@ namespace Microsoft::Console::Render
 
         [[nodiscard]] HRESULT _MoveCursor(const COORD coord) noexcept override;
 
-        [[nodiscard]] HRESULT _DoUpdateTitle(const std::wstring& newTitle) noexcept override;
+        [[nodiscard]] HRESULT _DoUpdateTitle(const std::wstring_view newTitle) noexcept override;
 
 #ifdef UNIT_TESTING
         friend class VtRendererTest;

src/renderer/vt/math.cpp

@@ -13,13 +13,14 @@ using namespace Microsoft::Console::Types;
 // Routine Description:
 // - Gets the size in characters of the current dirty portion of the frame.
 // Arguments:
-// - <none>
+// - area - The character dimensions of the current dirty area of the frame.
+//          This is an Inclusive rect.
 // Return Value:
-// - The character dimensions of the current dirty area of the frame.
+// - S_OK.
-//      This is an Inclusive rect.
+[[nodiscard]] HRESULT VtEngine::GetDirtyArea(gsl::span<const til::rectangle>& area) noexcept
-std::vector<til::rectangle> VtEngine::GetDirtyArea()
 {
-    return _invalidMap.runs();
+    area = _invalidMap.runs();
+    return S_OK;
 }
 
 // Routine Description:

src/renderer/vt/paint.cpp

@@ -598,7 +598,7 @@ using namespace Microsoft::Console::Types;
 // - newTitle: the new string to use for the title of the window
 // Return Value:
 // - S_OK
-[[nodiscard]] HRESULT VtEngine::_DoUpdateTitle(const std::wstring& /*newTitle*/) noexcept
+[[nodiscard]] HRESULT VtEngine::_DoUpdateTitle(const std::wstring_view /*newTitle*/) noexcept
 {
     return S_OK;
 }

src/renderer/vt/state.cpp

@@ -31,7 +31,8 @@ VtEngine::VtEngine(_In_ wil::unique_hfile pipe,
     _hFile(std::move(pipe)),
     _lastTextAttributes(INVALID_COLOR, INVALID_COLOR),
     _lastViewport(initialViewport),
-    _invalidMap(initialViewport.Dimensions()),
+    _pool(til::pmr::get_default_resource()),
+    _invalidMap(initialViewport.Dimensions(), false, &_pool),
     _lastText({ 0 }),
     _scrollDelta({ 0, 0 }),
     _quickReturn(false),
@@ -50,7 +51,10 @@ VtEngine::VtEngine(_In_ wil::unique_hfile pipe,
     _deferredCursorPos{ INVALID_COORDS },
     _inResizeRequest{ false },
     _trace{},
-    _bufferLine{}
+    _bufferLine{},
+    _buffer{},
+    _formatBuffer{},
+    _conversionBuffer{}
 {
 #ifndef UNIT_TESTING
     // When unit testing, we can instantiate a VtEngine without a pipe.
@@ -144,12 +148,8 @@ VtEngine::VtEngine(_In_ wil::unique_hfile pipe,
 // - S_OK or suitable HRESULT error from either conversion or writing pipe.
 [[nodiscard]] HRESULT VtEngine::_WriteTerminalUtf8(const std::wstring_view wstr) noexcept
 {
-    try
+    RETURN_IF_FAILED(til::u16u8(wstr, _conversionBuffer));
-    {
+    return _Write(_conversionBuffer);
-        const auto converted = ConvertToA(CP_UTF8, wstr);
-        return _Write(converted);
-    }
-    CATCH_RETURN();
 }
 
 // Method Description:

src/renderer/vt/tracing.cpp

@@ -145,7 +145,7 @@ void RenderTracing::TraceInvalidateScroll(const til::point scroll) const
 }
 
 void RenderTracing::TraceStartPaint(const bool quickReturn,
-                                    const til::bitmap& invalidMap,
+                                    const til::pmr::bitmap& invalidMap,
                                     const til::rectangle lastViewport,
                                     const til::point scrollDelt,
                                     const bool cursorMoved,

src/renderer/vt/tracing.hpp

@@ -39,7 +39,7 @@ namespace Microsoft::Console::VirtualTerminal
         void TraceTriggerCircling(const bool newFrame) const;
         void TraceInvalidateScroll(const til::point scroll) const;
         void TraceStartPaint(const bool quickReturn,
-                             const til::bitmap& invalidMap,
+                             const til::pmr::bitmap& invalidMap,
                              const til::rectangle lastViewport,
                              const til::point scrollDelta,
                              const bool cursorMoved,

src/renderer/vt/vtrenderer.hpp

@@ -85,7 +85,7 @@ namespace Microsoft::Console::Render
                                               _Out_ FontInfo& Font,
                                               const int iDpi) noexcept override;
 
-        std::vector<til::rectangle> GetDirtyArea() override;
+        [[nodiscard]] HRESULT GetDirtyArea(gsl::span<const til::rectangle>& area) noexcept override;
         [[nodiscard]] HRESULT GetFontSize(_Out_ COORD* const pFontSize) noexcept override;
         [[nodiscard]] HRESULT IsGlyphWideByFont(const std::wstring_view glyph, _Out_ bool* const pResult) noexcept override;
 
@@ -113,12 +113,14 @@ namespace Microsoft::Console::Render
         std::string _buffer;
 
         std::string _formatBuffer;
+        std::string _conversionBuffer;
 
         TextAttribute _lastTextAttributes;
 
         Microsoft::Console::Types::Viewport _lastViewport;
 
-        til::bitmap _invalidMap;
+        std::pmr::unsynchronized_pool_resource _pool;
+        til::pmr::bitmap _invalidMap;
 
         COORD _lastText;
         til::point _scrollDelta;
@@ -222,7 +224,7 @@ namespace Microsoft::Console::Render
         [[nodiscard]] HRESULT _WriteTerminalUtf8(const std::wstring_view str) noexcept;
         [[nodiscard]] HRESULT _WriteTerminalAscii(const std::wstring_view str) noexcept;
 
-        [[nodiscard]] virtual HRESULT _DoUpdateTitle(const std::wstring& newTitle) noexcept override;
+        [[nodiscard]] virtual HRESULT _DoUpdateTitle(const std::wstring_view newTitle) noexcept override;
 
         /////////////////////////// Unit Testing Helpers ///////////////////////////
 #ifdef UNIT_TESTING

src/renderer/wddmcon/WddmConRenderer.cpp

@@ -353,7 +353,7 @@ bool WddmConEngine::IsInitialized()
     return S_OK;
 }
 
-std::vector<til::rectangle> WddmConEngine::GetDirtyArea()
+[[nodiscard]] HRESULT WddmConEngine::GetDirtyArea(gsl::span<const til::rectangle>& area) noexcept
 {
     SMALL_RECT r;
     r.Bottom = _displayHeight > 0 ? (SHORT)(_displayHeight - 1) : 0;
@@ -361,7 +361,12 @@ std::vector<til::rectangle> WddmConEngine::GetDirtyArea()
     r.Left = 0;
     r.Right = _displayWidth > 0 ? (SHORT)(_displayWidth - 1) : 0;
 
-    return { r };
+    _dirtyArea = r;
+
+    area = { &_dirtyArea,
+             1 };
+
+    return S_OK;
 }
 
 RECT WddmConEngine::GetDisplaySize()
@@ -409,7 +414,7 @@ RECT WddmConEngine::GetDisplaySize()
 // - newTitle: the new string to use for the title of the window
 // Return Value:
 // - S_OK
-[[nodiscard]] HRESULT WddmConEngine::_DoUpdateTitle(_In_ const std::wstring& /*newTitle*/) noexcept
+[[nodiscard]] HRESULT WddmConEngine::_DoUpdateTitle(_In_ const std::wstring_view /*newTitle*/) noexcept
 {
     return S_OK;
 }

src/renderer/wddmcon/WddmConRenderer.hpp

@@ -59,12 +59,12 @@ namespace Microsoft::Console::Render
 
         [[nodiscard]] HRESULT GetProposedFont(const FontInfoDesired& fiFontInfoDesired, FontInfo& fiFontInfo, int const iDpi) noexcept override;
 
-        std::vector<til::rectangle> GetDirtyArea() override;
+        [[nodiscard]] HRESULT GetDirtyArea(gsl::span<const til::rectangle>& area) noexcept override;
         [[nodiscard]] HRESULT GetFontSize(_Out_ COORD* const pFontSize) noexcept override;
         [[nodiscard]] HRESULT IsGlyphWideByFont(const std::wstring_view glyph, _Out_ bool* const pResult) noexcept override;
 
     protected:
-        [[nodiscard]] HRESULT _DoUpdateTitle(_In_ const std::wstring& newTitle) noexcept override;
+        [[nodiscard]] HRESULT _DoUpdateTitle(_In_ const std::wstring_view newTitle) noexcept override;
 
     private:
         HANDLE _hWddmConCtx;
@@ -75,6 +75,7 @@ namespace Microsoft::Console::Render
         // Variables
         LONG _displayHeight;
         LONG _displayWidth;
+        til::rectangle _dirtyArea;
 
         PCD_IO_ROW_INFORMATION* _displayState;