Add support for the "blink" graphic rendition attribute

.github/actions/spell-check/expect/expect.txt

@@ -857,6 +857,7 @@ GETAUTOHIDEBAREX
 GETCARETWIDTH
 getch
 getchar
+GETCLIENTAREAANIMATION
 GETCOMMANDHISTORY
 GETCOMMANDHISTORYLENGTH
 GETCONSOLEINPUT

src/buffer/out/TextAttribute.cpp

@@ -88,16 +88,18 @@ bool TextAttribute::IsLegacy() const noexcept
 // - defaultFgColor: the default foreground color rgb value.
 // - defaultBgColor: the default background color rgb value.
 // - reverseScreenMode: true if the screen mode is reversed.
+// - blinkingIsFaint: true if blinking should be interpreted as faint.
 // Return Value:
 // - the foreground and background colors that should be displayed.
 std::pair<COLORREF, COLORREF> TextAttribute::CalculateRgbColors(const gsl::span<const COLORREF> colorTable,
                                                                 const COLORREF defaultFgColor,
                                                                 const COLORREF defaultBgColor,
-                                                                const bool reverseScreenMode) const noexcept
+                                                                const bool reverseScreenMode,
+                                                                const bool blinkingIsFaint) const noexcept
 {
     auto fg = _foreground.GetColor(colorTable, defaultFgColor, IsBold());
     auto bg = _background.GetColor(colorTable, defaultBgColor);
-    if (IsFaint())
+    if (IsFaint() || (IsBlinking() && blinkingIsFaint))
     {
         fg = (fg >> 1) & 0x7F7F7F; // Divide foreground color components by two.
     }

src/buffer/out/TextAttribute.hpp

@@ -69,7 +69,8 @@ class TextAttribute final
     std::pair<COLORREF, COLORREF> CalculateRgbColors(const gsl::span<const COLORREF> colorTable,
                                                      const COLORREF defaultFgColor,
                                                      const COLORREF defaultBgColor,
-                                                     const bool reverseScreenMode = false) const noexcept;
+                                                     const bool reverseScreenMode = false,
+                                                     const bool blinkingIsFaint = false) const noexcept;
 
     bool IsLeadingByte() const noexcept;
     bool IsTrailingByte() const noexcept;

src/cascadia/TerminalControl/TermControl.cpp

@@ -72,6 +72,7 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
         _actualFont{ DEFAULT_FONT_FACE, 0, DEFAULT_FONT_WEIGHT, { 0, DEFAULT_FONT_SIZE }, CP_UTF8, false },
         _touchAnchor{ std::nullopt },
         _cursorTimer{},
+        _blinkTimer{},
         _lastMouseClickTimestamp{},
         _lastMouseClickPos{},
         _selectionNeedsToBeCopied{ false },
@@ -721,6 +722,24 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
                 _cursorTimer = std::nullopt;
             }
 
+            // Set up blinking attributes
+            BOOL animationsEnabled = TRUE;
+            SystemParametersInfoW(SPI_GETCLIENTAREAANIMATION, 0, &animationsEnabled, 0);
+            if (animationsEnabled && blinkTime != INFINITE)
+            {
+                // Create a timer
+                DispatcherTimer blinkTimer;
+                blinkTimer.Interval(std::chrono::milliseconds(blinkTime));
+                blinkTimer.Tick({ get_weak(), &TermControl::_BlinkTimerTick });
+                blinkTimer.Start();
+                _blinkTimer.emplace(std::move(blinkTimer));
+            }
+            else
+            {
+                // The user has disabled blinking
+                _blinkTimer = std::nullopt;
+            }
+
             // import value from WinUser (convert from milli-seconds to micro-seconds)
             _multiClickTimer = GetDoubleClickTime() * 1000;
 
@@ -1777,6 +1796,11 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
             _cursorTimer.value().Start();
         }
 
+        if (_blinkTimer.has_value())
+        {
+            _blinkTimer.value().Start();
+        }
+
         _UpdateSystemParameterSettings();
     }
 
@@ -1822,6 +1846,11 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
             _cursorTimer.value().Stop();
             _terminal->SetCursorOn(false);
         }
+
+        if (_blinkTimer.has_value())
+        {
+            _blinkTimer.value().Stop();
+        }
     }
 
     // Method Description:
@@ -2035,6 +2064,22 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
         _terminal->SetCursorOn(!_terminal->IsCursorOn());
     }
 
+    // Method Description:
+    // - Toggle the blinking rendition state when called by the blink timer.
+    // Arguments:
+    // - sender: not used
+    // - e: not used
+    void TermControl::_BlinkTimerTick(Windows::Foundation::IInspectable const& /* sender */,
+                                      Windows::Foundation::IInspectable const& /* e */)
+    {
+        if (!_closing)
+        {
+            auto& renderTarget = *_renderer;
+            auto& blinkingState = _terminal->GetBlinkingState();
+            blinkingState.ToggleBlinkingRendition(renderTarget);
+        }
+    }
+
     // Method Description:
     // - Sets selection's end position to match supplied cursor position, e.g. while mouse dragging.
     // Arguments:

src/cascadia/TerminalControl/TermControl.h

@@ -201,6 +201,7 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
         std::optional<wchar_t> _leadingSurrogate;
 
         std::optional<Windows::UI::Xaml::DispatcherTimer> _cursorTimer;
+        std::optional<Windows::UI::Xaml::DispatcherTimer> _blinkTimer;
 
         // If this is set, then we assume we are in the middle of panning the
         //      viewport via touch input.
@@ -251,6 +252,7 @@ namespace winrt::Microsoft::Terminal::TerminalControl::implementation
         void _HyperlinkHandler(const std::wstring_view uri);
 
         void _CursorTimerTick(Windows::Foundation::IInspectable const& sender, Windows::Foundation::IInspectable const& e);
+        void _BlinkTimerTick(Windows::Foundation::IInspectable const& sender, Windows::Foundation::IInspectable const& e);
         void _SetEndSelectionPointAtCursor(Windows::Foundation::Point const& cursorPosition);
         void _SendInputToConnection(const winrt::hstring& wstr);
         void _SendInputToConnection(std::wstring_view wstr);

src/cascadia/TerminalCore/Terminal.cpp

@@ -1036,3 +1036,8 @@ const std::optional<til::color> Terminal::GetTabColor() const noexcept
 {
     return _tabColor;
 }
+
+BlinkingState& Terminal::GetBlinkingState() const noexcept
+{
+    return _blinkingState;
+}

src/cascadia/TerminalCore/Terminal.hpp

@@ -6,7 +6,7 @@
 #include <conattrs.hpp>
 
 #include "../../buffer/out/textBuffer.hpp"
-#include "../../renderer/inc/IRenderData.hpp"
+#include "../../renderer/inc/BlinkingState.hpp"
 #include "../../terminal/parser/StateMachine.hpp"
 #include "../../terminal/input/terminalInput.hpp"
 
@@ -187,6 +187,8 @@ class Microsoft::Terminal::Core::Terminal final :
 
     const std::optional<til::color> GetTabColor() const noexcept;
 
+    Microsoft::Console::Render::BlinkingState& GetBlinkingState() const noexcept;
+
 #pragma region TextSelection
     // These methods are defined in TerminalSelection.cpp
     enum class SelectionExpansionMode
@@ -224,6 +226,7 @@ class Microsoft::Terminal::Core::Terminal final :
     COLORREF _defaultBg;
     CursorType _defaultCursorShape;
     bool _screenReversed;
+    mutable Microsoft::Console::Render::BlinkingState _blinkingState;
 
     bool _snapOnInput;
     bool _altGrAliasing;

src/cascadia/TerminalCore/TerminalDispatchGraphics.cpp

@@ -132,6 +132,7 @@ bool TerminalDispatch::SetGraphicsRendition(const gsl::span<const DispatchTypes:
             attr.SetItalic(false);
             break;
         case BlinkOrXterm256Index:
+        case RapidBlink: // We just interpret rapid blink as an alias of blink.
             attr.SetBlinking(true);
             break;
         case Steady:

src/cascadia/TerminalCore/terminalrenderdata.cpp

@@ -52,10 +52,12 @@ const TextAttribute Terminal::GetDefaultBrushColors() noexcept
 
 std::pair<COLORREF, COLORREF> Terminal::GetAttributeColors(const TextAttribute& attr) const noexcept
 {
+    _blinkingState.RecordBlinkingUsage(attr);
     auto colors = attr.CalculateRgbColors({ _colorTable.data(), _colorTable.size() },
                                           _defaultFg,
                                           _defaultBg,
-                                          _screenReversed);
+                                          _screenReversed,
+                                          _blinkingState.IsBlinkingFaint());
     colors.first |= 0xff000000;
     // We only care about alpha for the default BG (which enables acrylic)
     // If the bg isn't the default bg color, or reverse video is enabled, make it fully opaque.

src/host/CursorBlinker.cpp

@@ -28,6 +28,12 @@ void CursorBlinker::UpdateSystemMetrics()
 {
     // This can be -1 in a TS session
     _uCaretBlinkTime = ServiceLocator::LocateSystemConfigurationProvider()->GetCaretBlinkTime();
+
+    // If animations are disabled, or the blink rate is infinite, blinking is not allowed.
+    BOOL animationsEnabled = TRUE;
+    SystemParametersInfoW(SPI_GETCLIENTAREAANIMATION, 0, &animationsEnabled, 0);
+    auto& blinkingState = ServiceLocator::LocateGlobals().getConsoleInformation().GetBlinkingState();
+    blinkingState.SetBlinkingAllowed(animationsEnabled && _uCaretBlinkTime != INFINITE);
 }
 
 void CursorBlinker::SettingsChanged()
@@ -53,7 +59,8 @@ void CursorBlinker::FocusStart()
 }
 
 // Routine Description:
-// - This routine is called when the timer in the console with the focus goes off.  It blinks the cursor.
+// - This routine is called when the timer in the console with the focus goes off.
+//   It blinks the cursor and also toggles the rendition of any blinking attributes.
 // Arguments:
 // - ScreenInfo - reference to screen info structure.
 // Return Value:
@@ -109,7 +116,7 @@ void CursorBlinker::TimerRoutine(SCREEN_INFORMATION& ScreenInfo)
     if (cursor.GetDelay())
     {
         cursor.SetDelay(false);
-        goto DoScroll;
+        goto DoBlinkingRenditionAndScroll;
     }
 
     // Don't blink the cursor for remote sessions.
@@ -118,7 +125,7 @@ void CursorBlinker::TimerRoutine(SCREEN_INFORMATION& ScreenInfo)
          (!cursor.IsBlinkingAllowed())) &&
         cursor.IsOn())
     {
-        goto DoScroll;
+        goto DoBlinkingRenditionAndScroll;
     }
 
     // Blink only if the cursor isn't turned off via the API
@@ -127,6 +134,9 @@ void CursorBlinker::TimerRoutine(SCREEN_INFORMATION& ScreenInfo)
         cursor.SetIsOn(!cursor.IsOn());
     }
 
+DoBlinkingRenditionAndScroll:
+    gci.GetBlinkingState().ToggleBlinkingRendition(ScreenInfo.GetRenderTarget());
+
 DoScroll:
     Scrolling::s_ScrollIfNecessary(ScreenInfo);
 }

src/host/consoleInformation.cpp

@@ -12,6 +12,7 @@
 #include "..\types\inc\convert.hpp"
 
 using Microsoft::Console::Interactivity::ServiceLocator;
+using Microsoft::Console::Render::BlinkingState;
 using Microsoft::Console::VirtualTerminal::VtIo;
 
 CONSOLE_INFORMATION::CONSOLE_INFORMATION() :
@@ -222,7 +223,8 @@ InputBuffer* const CONSOLE_INFORMATION::GetActiveInputBuffer() const
 // - the default foreground color of the console.
 COLORREF CONSOLE_INFORMATION::GetDefaultForeground() const noexcept
 {
-    return Settings::CalculateDefaultForeground();
+    const auto fg = GetDefaultForegroundColor();
+    return fg != INVALID_COLOR ? fg : GetColorTableEntry(LOBYTE(GetFillAttribute()) & FG_ATTRS);
 }
 
 // Method Description:
@@ -236,7 +238,25 @@ COLORREF CONSOLE_INFORMATION::GetDefaultForeground() const noexcept
 // - the default background color of the console.
 COLORREF CONSOLE_INFORMATION::GetDefaultBackground() const noexcept
 {
-    return Settings::CalculateDefaultBackground();
+    const auto bg = GetDefaultBackgroundColor();
+    return bg != INVALID_COLOR ? bg : GetColorTableEntry((LOBYTE(GetFillAttribute()) & BG_ATTRS) >> 4);
+}
+
+// Method Description:
+// - Get the colors of a particular text attribute, using our color table,
+//      and our configured default attributes.
+// Arguments:
+// - attr: the TextAttribute to retrieve the foreground color of.
+// Return Value:
+// - The color values of the attribute's foreground and background.
+std::pair<COLORREF, COLORREF> CONSOLE_INFORMATION::LookupAttributeColors(const TextAttribute& attr) const noexcept
+{
+    _blinkingState.RecordBlinkingUsage(attr);
+    return attr.CalculateRgbColors(Get256ColorTable(),
+                                   GetDefaultForeground(),
+                                   GetDefaultBackground(),
+                                   IsScreenReversed(),
+                                   _blinkingState.IsBlinkingFaint());
 }
 
 // Method Description:
@@ -355,6 +375,17 @@ Microsoft::Console::CursorBlinker& CONSOLE_INFORMATION::GetCursorBlinker() noexc
     return _blinker;
 }
 
+// Method Description:
+// - return a reference to the console's blinking state.
+// Arguments:
+// - <none>
+// Return Value:
+// - a reference to the console's blinking state.
+BlinkingState& CONSOLE_INFORMATION::GetBlinkingState() const noexcept
+{
+    return _blinkingState;
+}
+
 // Method Description:
 // - Generates a CHAR_INFO for this output cell, using the TextAttribute
 //      GetLegacyAttributes method to generate the legacy style attributes.

src/host/server.h

@@ -28,6 +28,7 @@ Revision History:
 #include "..\server\WaitQueue.h"
 
 #include "..\host\RenderData.hpp"
+#include "..\renderer\inc\BlinkingState.hpp"
 
 // clang-format off
 // Flags flags
@@ -125,6 +126,7 @@ class CONSOLE_INFORMATION :
 
     COLORREF GetDefaultForeground() const noexcept;
     COLORREF GetDefaultBackground() const noexcept;
+    std::pair<COLORREF, COLORREF> LookupAttributeColors(const TextAttribute& attr) const noexcept;
 
     void SetTitle(const std::wstring_view newTitle);
     void SetTitlePrefix(const std::wstring& newTitlePrefix);
@@ -141,6 +143,7 @@ class CONSOLE_INFORMATION :
     friend class SCREEN_INFORMATION;
     friend class CommonState;
     Microsoft::Console::CursorBlinker& GetCursorBlinker() noexcept;
+    Microsoft::Console::Render::BlinkingState& GetBlinkingState() const noexcept;
 
     CHAR_INFO AsCharInfo(const OutputCellView& cell) const noexcept;
 
@@ -157,6 +160,7 @@ class CONSOLE_INFORMATION :
 
     Microsoft::Console::VirtualTerminal::VtIo _vtIo;
     Microsoft::Console::CursorBlinker _blinker;
+    mutable Microsoft::Console::Render::BlinkingState _blinkingState;
 };
 
 #define ConsoleLocked() (ServiceLocator::LocateGlobals()->getConsoleInformation()->ConsoleLock.OwningThread == NtCurrentTeb()->ClientId.UniqueThread)

src/host/settings.cpp

@@ -831,51 +831,6 @@ bool Settings::GetUseDx() const noexcept
     return _fUseDx;
 }
 
-// Method Description:
-// - Return the default foreground color of the console. If the settings are
-//      configured to have a default foreground color (separate from the color
-//      table), this will return that value. Otherwise it will return the value
-//      from the colortable corresponding to our default legacy attributes.
-// Arguments:
-// - <none>
-// Return Value:
-// - the default foreground color of the console.
-COLORREF Settings::CalculateDefaultForeground() const noexcept
-{
-    const auto fg = GetDefaultForegroundColor();
-    return fg != INVALID_COLOR ? fg : GetColorTableEntry(LOBYTE(_wFillAttribute) & FG_ATTRS);
-}
-
-// Method Description:
-// - Return the default background color of the console. If the settings are
-//      configured to have a default background color (separate from the color
-//      table), this will return that value. Otherwise it will return the value
-//      from the colortable corresponding to our default legacy attributes.
-// Arguments:
-// - <none>
-// Return Value:
-// - the default background color of the console.
-COLORREF Settings::CalculateDefaultBackground() const noexcept
-{
-    const auto bg = GetDefaultBackgroundColor();
-    return bg != INVALID_COLOR ? bg : GetColorTableEntry((LOBYTE(_wFillAttribute) & BG_ATTRS) >> 4);
-}
-
-// Method Description:
-// - Get the colors of a particular text attribute, using our color table,
-//      and our configured default attributes.
-// Arguments:
-// - attr: the TextAttribute to retrieve the foreground color of.
-// Return Value:
-// - The color values of the attribute's foreground and background.
-std::pair<COLORREF, COLORREF> Settings::LookupAttributeColors(const TextAttribute& attr) const noexcept
-{
-    return attr.CalculateRgbColors(Get256ColorTable(),
-                                   CalculateDefaultForeground(),
-                                   CalculateDefaultBackground(),
-                                   _fScreenReversed);
-}
-
 bool Settings::GetCopyColor() const noexcept
 {
     return _fCopyColor;