Implement ConEmu's OSC 9;4 to set the taskbar progress indicator

src/cascadia/TerminalApp/Tab.cpp

@@ -185,6 +185,7 @@ namespace winrt::TerminalApp::implementation
         if (lastFocusedControl)
         {
             lastFocusedControl.Focus(FocusState::Programmatic);
+            lastFocusedControl.SendTaskbarProgressEvent();
         }
     }
 

src/cascadia/TerminalControl/TermControl.cpp

@@ -76,7 +76,9 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
         _lastMouseClickTimestamp{},
         _lastMouseClickPos{},
         _selectionNeedsToBeCopied{ false },
-        _searchBox{ nullptr }
+        _searchBox{ nullptr },
+        _taskbarState{ 0 },
+        _taskbarProgress{ 0 }
     {
         _EnsureStaticInitialization();
         InitializeComponent();
@@ -2277,15 +2279,17 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
     }
 
     // Method Description:
-    // - Sends an event (which will be caught by TerminalPage and forwarded to AppHost after)
+    // - Sets our internal knowledge of the taskbar's state and progress, then
+    //   sends an event (which will be caught by TerminalPage and forwarded to AppHost after)
     //   to set the progress indicator on the taskbar
     // Arguments:
     // - state: the state with which to set the progress indicator
     // - progress: the progress with which to set the progress indicator (only used if state is 1)
     void TermControl::_SetTaskbarProgress(const size_t state, const size_t progress)
     {
-        auto setTaskbarProgressArgs = winrt::make_self<SetTaskbarProgressEventArgs>(state, progress);
-        _setTaskbarProgressHandlers(*this, *setTaskbarProgressArgs);
+        _taskbarState = state;
+        _taskbarProgress = progress;
+        SendTaskbarProgressEvent();
     }
 
     hstring TermControl::Title()
@@ -3034,6 +3038,15 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
         return coreColor.has_value() ? Windows::Foundation::IReference<winrt::Windows::UI::Color>(coreColor.value()) : nullptr;
     }
 
+    // Method Description:
+    // - Sends an event (which will be caught by TerminalPage and forwarded to AppHost after)
+    //   to set the progress indicator on the taskbar
+    void TermControl::SendTaskbarProgressEvent()
+    {
+        auto setTaskbarProgressArgs = winrt::make_self<SetTaskbarProgressEventArgs>(_taskbarState, _taskbarProgress);
+        _setTaskbarProgressHandlers(*this, *setTaskbarProgressArgs);
+    }
+
     // -------------------------------- WinRT Events ---------------------------------
     // Winrt events need a method for adding a callback to the event and removing the callback.
     // These macros will define them both for you.

src/cascadia/TerminalControl/TermControl.h

@@ -156,6 +156,8 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
 
         Windows::Foundation::IReference<winrt::Windows::UI::Color> TabColor() noexcept;
 
+        void SendTaskbarProgressEvent();
+
         // clang-format off
         // -------------------------------- WinRT Events ---------------------------------
         DECLARE_EVENT(TitleChanged,             _titleChangedHandlers,              TerminalControl::TitleChangedEventArgs);
@@ -232,6 +234,9 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
         // Track the last hyperlink ID we hovered over
         uint16_t _lastHoveredId;
 
+        size_t _taskbarState;
+        size_t _taskbarProgress;
+
         using Timestamp = uint64_t;
 
         // imported from WinUser

src/cascadia/TerminalControl/TermControl.idl

@@ -97,6 +97,8 @@ namespace Microsoft.Terminal.TerminalControl
         void SendInput(String input);
         void ToggleRetroEffect();
 
+        void SendTaskbarProgressEvent();
+
         Windows.Foundation.IReference<Windows.UI.Color> TabColor { get; };
         event Windows.Foundation.TypedEventHandler<Object, Object> TabColorChanged;
     }

src/cascadia/WindowsTerminal/IslandWindow.cpp

@@ -530,18 +530,21 @@ void IslandWindow::SetTaskbarProgress(const size_t state, const size_t progress)
             break;
         case 1:
             // sets the progress value to value given by the 'progress' parameter
+            _taskbar->SetProgressState(_window.get(), TBPF_NORMAL);
             _taskbar->SetProgressValue(_window.get(), progress, 100);
             break;
         case 2:
             // sets the progress indicator to an error state
             _taskbar->SetProgressState(_window.get(), TBPF_ERROR);
+            _taskbar->SetProgressValue(_window.get(), progress, 100);
             break;
         case 3:
             // sets the progress indicator to an indeterminate state
             _taskbar->SetProgressState(_window.get(), TBPF_INDETERMINATE);
         case 4:
             // sets the progress indicator to a pause state
             _taskbar->SetProgressState(_window.get(), TBPF_PAUSED);
+            _taskbar->SetProgressValue(_window.get(), progress, 100);
         default:
             break;
         }