Introduce toggleBlockSelection action (#13219)

## Summary of the Pull Request
This introduced the `toggleBlockSelection` action to allow users to create a block selection using only the keyboard. This is not bound to any keys by default, however it is added to the command palette.

## References
#4993 - Epic
#5804 - Spec

## Validation Steps Performed
- [X] Mark mode always starts in line selection mode
- [X] Mouse selections are always in line selection mode by default
- [X] Can toggle block selection for an existing selection (regardless of how it was created)
- [X] The selection is copied properly (aka, no rendering issues)

src/cascadia/TerminalApp/AppActionHandlers.cpp

@@ -1053,4 +1053,14 @@ namespace winrt::TerminalApp::implementation
             args.Handled(true);
         }
     }
+
+    void TerminalPage::_HandleToggleBlockSelection(const IInspectable& /*sender*/,
+                                                   const ActionEventArgs& args)
+    {
+        if (const auto& control{ _GetActiveControl() })
+        {
+            const auto handled = control.ToggleBlockSelection();
+            args.Handled(handled);
+        }
+    }
 }

src/cascadia/TerminalControl/ControlCore.cpp

@@ -1015,6 +1015,18 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         _renderer->TriggerSelection();
     }
 
+    bool ControlCore::ToggleBlockSelection()
+    {
+        auto lock = _terminal->LockForWriting();
+        if (_terminal->IsSelectionActive())
+        {
+            _terminal->SetBlockSelection(!_terminal->IsBlockSelection());
+            _renderer->TriggerSelection();
+            return true;
+        }
+        return false;
+    }
+
     void ControlCore::ToggleMarkMode()
     {
         auto lock = _terminal->LockForWriting();

src/cascadia/TerminalControl/ControlCore.h

@@ -82,6 +82,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         void PasteText(const winrt::hstring& hstr);
         bool CopySelectionToClipboard(bool singleLine, const Windows::Foundation::IReference<CopyFormat>& formats);
         void SelectAll();
+        bool ToggleBlockSelection();
         void ToggleMarkMode();
         bool IsInMarkMode() const;
 

src/cascadia/TerminalControl/ControlCore.idl

@@ -66,6 +66,7 @@ namespace Microsoft.Terminal.Control
         void SendInput(String text);
         void PasteText(String text);
         void SelectAll();
+        Boolean ToggleBlockSelection();
         void ToggleMarkMode();
         void ClearBuffer(ClearBufferType clearType);
         Boolean IsInMarkMode();

src/cascadia/TerminalControl/TermControl.cpp

@@ -1859,6 +1859,11 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         _core.SelectAll();
     }
 
+    bool TermControl::ToggleBlockSelection()
+    {
+        return _core.ToggleBlockSelection();
+    }
+
     void TermControl::ToggleMarkMode()
     {
         _core.ToggleMarkMode();

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();
+        bool ToggleBlockSelection();
         void ToggleMarkMode();
         void Close();
         Windows::Foundation::Size CharacterDimensions() const;

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();
+        Boolean ToggleBlockSelection();
         void ToggleMarkMode();
         void ClearBuffer(ClearBufferType clearType);
         void Close();

src/cascadia/TerminalCore/TerminalSelection.cpp

@@ -258,6 +258,7 @@ void Terminal::ToggleMarkMode()
         _selection->end = cursorPos;
         _selection->pivot = cursorPos;
         _markMode = true;
+        _blockSelection = false;
     }
 }
 

src/cascadia/TerminalSettingsModel/ActionAndArgs.cpp

@@ -77,6 +77,7 @@ 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 ToggleBlockSelectionKey{ "toggleBlockSelection" };
 
 static constexpr std::string_view ActionKey{ "action" };
 
@@ -390,6 +391,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
                 { ShortcutAction::RestoreLastClosed, RS_(L"RestoreLastClosedCommandKey") },
                 { ShortcutAction::SelectAll, RS_(L"SelectAllCommandKey") },
                 { ShortcutAction::MarkMode, RS_(L"MarkModeCommandKey") },
+                { ShortcutAction::ToggleBlockSelection, RS_(L"ToggleBlockSelectionCommandKey") },
             };
         }();
 

src/cascadia/TerminalSettingsModel/AllShortcutActions.h

@@ -90,7 +90,8 @@
     ON_ALL_ACTIONS(AdjustOpacity)          \
     ON_ALL_ACTIONS(RestoreLastClosed)      \
     ON_ALL_ACTIONS(SelectAll)              \
-    ON_ALL_ACTIONS(MarkMode)
+    ON_ALL_ACTIONS(MarkMode)               \
+    ON_ALL_ACTIONS(ToggleBlockSelection)
 
 #define ALL_SHORTCUT_ACTIONS_WITH_ARGS             \
     ON_ALL_ACTIONS_WITH_ARGS(AdjustFontSize)       \

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

@@ -529,4 +529,7 @@
     <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>
+  <data name="ToggleBlockSelectionCommandKey" xml:space="preserve">
+    <value>Toggle block selection</value>
+  </data>
 </root>

src/cascadia/TerminalSettingsModel/defaults.json

@@ -386,6 +386,7 @@
         { "command": "paste", "keys": "shift+insert" },
         { "command": "selectAll", "keys": "ctrl+shift+a" },
         { "command": "markMode", "keys": "ctrl+shift+m" },
+        { "command": "toggleBlockSelection" },
 
         // Scrollback
         { "command": "scrollDown", "keys": "ctrl+shift+down" },