Introduce Mark Mode (#13053)

## Summary of the Pull Request
Introduces a non-configurable version of mark mode to Windows Terminal. It has the following interactions defined:
- <kbd>ctrl+shift+m</kbd> --> Enter Mark Mode
- when in Mark Mode...
	- <kbd>ESC</kbd> --> Exit Mark Mode
	- arrow keys --> move "start"
	- <kbd>shift</kbd> + arrow keys --> anchor "start", move "end"
	- <kbd>ctrl+a</kbd> --> select all
- when a selection is active...

When in mark mode, the cursor does not blink.

## References
#4993 - [Epic] Keyboard Selection

## PR Checklist
* [X] Closes #715
* [X] Provides a resolution for #11985

## Detailed Description of the Pull Request / Additional comments
- `TermControl`:
	- `TermControl.cpp` just adds logic to prevent the cursor from blinking when in mark mode
- `ControlCore`
	- in the same place we handle quick edit, we add an entry point to mark mode
- `TerminalCore`
	- this leverages `UpdateSelection()` and other quick edit functions to make mark mode happen

## Validation Steps Performed
- [x] Make selection, split pane, close pane
	- NOTE: A similar scenario caused a crash at one point. Really weird. Keep an eye on it.
- [x] Cursor is off when in mark mode
- [x] general movement/selection
- [x] general movement/selection that forces the viewport to move
- [x] In mark mode, selectAll...
	- [x] arrow keys --> move start
	- [x] shift + arrow keys --> move end
- [x] (regardless of mark mode) if selection active, enter --> copy to clipboard

doc/cascadia/profiles.schema.json

@@ -318,6 +318,7 @@
         "moveFocus",
         "movePane",
         "swapPane",
+        "markMode",
         "moveTab",
         "multipleActions",
         "newTab",

src/cascadia/TerminalApp/AppActionHandlers.cpp

@@ -1043,4 +1043,14 @@ namespace winrt::TerminalApp::implementation
             args.Handled(true);
         }
     }
+
+    void TerminalPage::_HandleMarkMode(const IInspectable& /*sender*/,
+                                       const ActionEventArgs& args)
+    {
+        if (const auto& control{ _GetActiveControl() })
+        {
+            control.ToggleMarkMode();
+            args.Handled(true);
+        }
+    }
 }

src/cascadia/TerminalControl/ControlCore.cpp

@@ -390,11 +390,19 @@ namespace winrt::Microsoft::Terminal::Control::implementation
             vkey != VK_SNAPSHOT &&
             keyDown)
         {
+            if (_terminal->IsInMarkMode() && modifiers.IsCtrlPressed() && vkey == 'A')
+            {
+                auto lock = _terminal->LockForWriting();
+                _terminal->SelectAll();
+                _renderer->TriggerSelection();
+                return true;
+            }
+
             // try to update the selection
-            if (const auto updateSlnParams{ ::Terminal::ConvertKeyEventToUpdateSelectionParams(modifiers, vkey) })
+            if (const auto updateSlnParams{ _terminal->ConvertKeyEventToUpdateSelectionParams(modifiers, vkey) })
             {
                 auto lock = _terminal->LockForWriting();
-                _terminal->UpdateSelection(updateSlnParams->first, updateSlnParams->second);
+                _terminal->UpdateSelection(updateSlnParams->first, updateSlnParams->second, modifiers);
                 _renderer->TriggerSelection();
                 return true;
             }
@@ -1002,6 +1010,18 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         _renderer->TriggerSelection();
     }
 
+    void ControlCore::ToggleMarkMode()
+    {
+        auto lock = _terminal->LockForWriting();
+        _terminal->ToggleMarkMode();
+        _renderer->TriggerSelection();
+    }
+
+    bool ControlCore::IsInMarkMode() const
+    {
+        return _terminal->IsInMarkMode();
+    }
+
     // Method Description:
     // - Pre-process text pasted (presumably from the clipboard)
     //   before sending it over the terminal's connection.

src/cascadia/TerminalControl/ControlCore.h

@@ -81,6 +81,8 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         void PasteText(const winrt::hstring& hstr);
         bool CopySelectionToClipboard(bool singleLine, const Windows::Foundation::IReference<CopyFormat>& formats);
         void SelectAll();
+        void ToggleMarkMode();
+        bool IsInMarkMode() const;
 
         void GotFocus();
         void LostFocus();

src/cascadia/TerminalControl/ControlCore.idl

@@ -66,7 +66,9 @@ namespace Microsoft.Terminal.Control
         void SendInput(String text);
         void PasteText(String text);
         void SelectAll();
+        void ToggleMarkMode();
         void ClearBuffer(ClearBufferType clearType);
+        Boolean IsInMarkMode();
 
         void SetHoveredCell(Microsoft.Terminal.Core.Point terminalPosition);
         void ClearHoveredCell();

src/cascadia/TerminalControl/TermControl.cpp

@@ -1137,7 +1137,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         {
             // Manually show the cursor when a key is pressed. Restarting
             // the timer prevents flickering.
-            _core.CursorOn(true);
+            _core.CursorOn(!_core.IsInMarkMode());
             _cursorTimer->Start();
         }
 
@@ -1608,7 +1608,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         if (_cursorTimer)
         {
             // When the terminal focuses, show the cursor immediately
-            _core.CursorOn(true);
+            _core.CursorOn(!_core.IsInMarkMode());
             _cursorTimer->Start();
         }
 
@@ -1859,6 +1859,11 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         _core.SelectAll();
     }
 
+    void TermControl::ToggleMarkMode()
+    {
+        _core.ToggleMarkMode();
+    }
+
     void TermControl::Close()
     {
         if (!_IsClosing())

src/cascadia/TerminalControl/TermControl.h

@@ -38,6 +38,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         bool CopySelectionToClipboard(bool singleLine, const Windows::Foundation::IReference<CopyFormat>& formats);
         void PasteTextFromClipboard();
         void SelectAll();
+        void ToggleMarkMode();
         void Close();
         Windows::Foundation::Size CharacterDimensions() const;
         Windows::Foundation::Size MinimumSize();

src/cascadia/TerminalControl/TermControl.idl

@@ -51,6 +51,7 @@ namespace Microsoft.Terminal.Control
         Boolean CopySelectionToClipboard(Boolean singleLine, Windows.Foundation.IReference<CopyFormat> formats);
         void PasteTextFromClipboard();
         void SelectAll();
+        void ToggleMarkMode();
         void ClearBuffer(ClearBufferType clearType);
         void Close();
         Windows.Foundation.Size CharacterDimensions { get; };

src/cascadia/TerminalCore/Terminal.cpp

@@ -45,6 +45,7 @@ Terminal::Terminal() :
     _snapOnInput{ true },
     _altGrAliasing{ true },
     _blockSelection{ false },
+    _markMode{ false },
     _selection{ std::nullopt },
     _taskbarState{ 0 },
     _taskbarProgress{ 0 },
@@ -1318,7 +1319,7 @@ void Terminal::SetCursorOn(const bool isOn)
 bool Terminal::IsCursorBlinkingAllowed() const noexcept
 {
     const auto& cursor = _activeBuffer().GetCursor();
-    return cursor.IsBlinkingAllowed();
+    return !_markMode && cursor.IsBlinkingAllowed();
 }
 
 // Method Description:

src/cascadia/TerminalCore/Terminal.hpp

@@ -238,11 +238,13 @@ class Microsoft::Terminal::Core::Terminal final :
     void SetSelectionAnchor(const COORD position);
     void SetSelectionEnd(const COORD position, std::optional<SelectionExpansion> newExpansionMode = std::nullopt);
     void SetBlockSelection(const bool isEnabled) noexcept;
-    void UpdateSelection(SelectionDirection direction, SelectionExpansion mode);
+    void UpdateSelection(SelectionDirection direction, SelectionExpansion mode, ControlKeyStates mods);
     void SelectAll();
+    bool IsInMarkMode() const;
+    void ToggleMarkMode();
 
     using UpdateSelectionParams = std::optional<std::pair<SelectionDirection, SelectionExpansion>>;
-    static UpdateSelectionParams ConvertKeyEventToUpdateSelectionParams(const ControlKeyStates mods, const WORD vkey);
+    UpdateSelectionParams ConvertKeyEventToUpdateSelectionParams(const ControlKeyStates mods, const WORD vkey) const;
 
     const TextBuffer::TextAndColor RetrieveSelectedTextFromBuffer(bool trimTrailingWhitespace);
 #pragma endregion
@@ -310,6 +312,7 @@ class Microsoft::Terminal::Core::Terminal final :
     bool _blockSelection;
     std::wstring _wordDelimiters;
     SelectionExpansion _multiClickSelectionMode;
+    bool _markMode;
 #pragma endregion
 
     std::unique_ptr<TextBuffer> _mainBuffer;

src/cascadia/TerminalCore/TerminalSelection.cpp

@@ -235,13 +235,40 @@ void Terminal::SetBlockSelection(const bool isEnabled) noexcept
     _blockSelection = isEnabled;
 }
 
-Terminal::UpdateSelectionParams Terminal::ConvertKeyEventToUpdateSelectionParams(const ControlKeyStates mods, const WORD vkey)
+bool Terminal::IsInMarkMode() const
 {
-    if (mods.IsShiftPressed() && !mods.IsAltPressed())
+    return _markMode;
+}
+
+void Terminal::ToggleMarkMode()
+{
+    if (_markMode)
+    {
+        // Exit Mark Mode
+        ClearSelection();
+    }
+    else
+    {
+        // Enter Mark Mode
+        // NOTE: directly set cursor state. We already should have locked before calling this function.
+        _activeBuffer().GetCursor().SetIsOn(false);
+        const auto cursorPos{ _activeBuffer().GetCursor().GetPosition() };
+        _selection = SelectionAnchors{};
+        _selection->start = cursorPos;
+        _selection->end = cursorPos;
+        _selection->pivot = cursorPos;
+        _markMode = true;
+    }
+}
+
+Terminal::UpdateSelectionParams Terminal::ConvertKeyEventToUpdateSelectionParams(const ControlKeyStates mods, const WORD vkey) const
+{
+    if ((_markMode || mods.IsShiftPressed()) && !mods.IsAltPressed())
     {
         if (mods.IsCtrlPressed())
         {
             // Ctrl + Shift + _
+            // (Mark Mode) Ctrl + _
             switch (vkey)
             {
             case VK_LEFT:
@@ -257,6 +284,7 @@ Terminal::UpdateSelectionParams Terminal::ConvertKeyEventToUpdateSelectionParams
         else
         {
             // Shift + _
+            // (Mark Mode) Just the vkeys
             switch (vkey)
             {
             case VK_HOME:
@@ -281,11 +309,19 @@ Terminal::UpdateSelectionParams Terminal::ConvertKeyEventToUpdateSelectionParams
     return std::nullopt;
 }
 
-void Terminal::UpdateSelection(SelectionDirection direction, SelectionExpansion mode)
+// Method Description:
+// - updates the selection endpoints based on a direction and expansion mode. Primarily used for keyboard selection.
+// Arguments:
+// - direction: the direction to move the selection endpoint in
+// - mode: the type of movement to be performed (i.e. move by word)
+// - mods: the key modifiers pressed when performing this update
+void Terminal::UpdateSelection(SelectionDirection direction, SelectionExpansion mode, ControlKeyStates mods)
 {
     // 1. Figure out which endpoint to update
-    // One of the endpoints is the pivot, signifying that the other endpoint is the one we want to move.
-    const auto movingEnd{ _selection->start == _selection->pivot };
+    // If we're in mark mode, shift dictates whether you are moving the end or not.
+    // Otherwise, we're updating an existing selection, so one of the endpoints is the pivot,
+    //   signifying that the other endpoint is the one we want to move.
+    const auto movingEnd{ _markMode ? mods.IsShiftPressed() : _selection->start == _selection->pivot };
     auto targetPos{ movingEnd ? _selection->end : _selection->start };
 
     // 2. Perform the movement
@@ -307,8 +343,23 @@ void Terminal::UpdateSelection(SelectionDirection direction, SelectionExpansion
 
     // 3. Actually modify the selection
     // NOTE: targetStart doesn't matter here
-    auto targetStart = false;
-    std::tie(_selection->start, _selection->end) = _PivotSelection(targetPos, targetStart);
+    if (_markMode)
+    {
+        // [Mark Mode]
+        // - moveSelectionEnd  --> just move end (i.e. shift + arrow keys)
+        // - !moveSelectionEnd --> move all three (i.e. just use arrow keys)
+        _selection->end = targetPos;
+        if (!movingEnd)
+        {
+            _selection->start = targetPos;
+            _selection->pivot = targetPos;
+        }
+    }
+    else
+    {
+        auto targetStart = false;
+        std::tie(_selection->start, _selection->end) = _PivotSelection(targetPos, targetStart);
+    }
 
     // 4. Scroll (if necessary)
     if (const auto viewport = _GetVisibleViewport(); !viewport.IsInBounds(targetPos))
@@ -473,6 +524,7 @@ void Terminal::_MoveByBuffer(SelectionDirection direction, COORD& pos)
 void Terminal::ClearSelection()
 {
     _selection = std::nullopt;
+    _markMode = false;
 }
 
 // Method Description:

src/cascadia/TerminalSettingsModel/ActionAndArgs.cpp

@@ -76,6 +76,7 @@ static constexpr std::string_view QuitKey{ "quit" };
 static constexpr std::string_view AdjustOpacityKey{ "adjustOpacity" };
 static constexpr std::string_view RestoreLastClosedKey{ "restoreLastClosed" };
 static constexpr std::string_view SelectAllKey{ "selectAll" };
+static constexpr std::string_view MarkModeKey{ "markMode" };
 
 static constexpr std::string_view ActionKey{ "action" };
 
@@ -388,6 +389,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
                 { ShortcutAction::AdjustOpacity, L"" }, // Intentionally omitted, must be generated by GenerateName
                 { ShortcutAction::RestoreLastClosed, RS_(L"RestoreLastClosedCommandKey") },
                 { ShortcutAction::SelectAll, RS_(L"SelectAllCommandKey") },
+                { ShortcutAction::MarkMode, RS_(L"MarkModeCommandKey") },
             };
         }();
 

src/cascadia/TerminalSettingsModel/AllShortcutActions.h

@@ -89,7 +89,8 @@
     ON_ALL_ACTIONS(Quit)                   \
     ON_ALL_ACTIONS(AdjustOpacity)          \
     ON_ALL_ACTIONS(RestoreLastClosed)      \
-    ON_ALL_ACTIONS(SelectAll)
+    ON_ALL_ACTIONS(SelectAll)              \
+    ON_ALL_ACTIONS(MarkMode)
 
 #define ALL_SHORTCUT_ACTIONS_WITH_ARGS             \
     ON_ALL_ACTIONS_WITH_ARGS(AdjustFontSize)       \

src/cascadia/TerminalSettingsModel/Resources/en-US/Resources.resw

@@ -525,4 +525,8 @@
   <data name="SelectAllCommandKey" xml:space="preserve">
     <value>Select all text</value>
   </data>
+  <data name="MarkModeCommandKey" xml:space="preserve">
+    <value>Toggle mark mode</value>
+    <comment>A command that will toggle "mark mode". This is a mode in the application where the user can mark the text by selecting portions of the text.</comment>
+  </data>
 </root>

src/cascadia/TerminalSettingsModel/defaults.json

@@ -385,6 +385,7 @@
         { "command": "paste", "keys": "ctrl+shift+v" },
         { "command": "paste", "keys": "shift+insert" },
         { "command": "selectAll", "keys": "ctrl+shift+a" },
+        { "command": "markMode", "keys": "ctrl+shift+m" },
 
         // Scrollback
         { "command": "scrollDown", "keys": "ctrl+shift+down" },