precalculate

src/cascadia/TerminalCore/ColorFix.cpp

@@ -232,6 +232,11 @@ void ColorFix::_ToRGB()
 // - The foreground color after performing any necessary changes to make it more perceivable
 COLORREF ColorFix::GetPerceivableColor(COLORREF fg, COLORREF bg)
 {
+    // If the colors are the same, don't do any adjusting
+    if (fg == bg)
+    {
+        return fg;
+    }
     ColorFix backLab(bg);
     ColorFix frontLab(fg);
     double de1 = GetDeltaE(frontLab, backLab);

src/cascadia/TerminalCore/Terminal.cpp

@@ -9,6 +9,7 @@
 #include "../../inc/argb.h"
 #include "../../types/inc/utils.hpp"
 #include "../../types/inc/colorTable.hpp"
+#include "ColorFix.hpp"
 
 #include <winrt/Microsoft.Terminal.Core.h>
 
@@ -182,6 +183,7 @@ void Terminal::UpdateAppearance(const ICoreAppearance& appearance)
     {
         _colorTable.at(i) = til::color{ appearance.GetColorTableEntry(i) };
     }
+    _MakeAdjustedColorMap();
 
     CursorType cursorShape = CursorType::VerticalBar;
     switch (appearance.CursorShape())
@@ -1276,3 +1278,15 @@ const size_t Microsoft::Terminal::Core::Terminal::GetTaskbarProgress() const noe
 {
     return _taskbarProgress;
 }
+
+void Terminal::_MakeAdjustedColorMap()
+{
+    // for each pair of <fg, bg>, map it to the adjusted fg
+    for (const auto fg : _colorTable)
+    {
+        for (const auto bg : _colorTable)
+        {
+            _adjustedColorMap[std::pair<COLORREF, COLORREF>(fg, bg)] = ColorFix::GetPerceivableColor(fg, bg);
+        }
+    }
+}

src/cascadia/TerminalCore/Terminal.hpp

@@ -370,6 +370,9 @@ private:
 
     void _NotifyTerminalCursorPositionChanged() noexcept;
 
+    std::map<std::pair<COLORREF, COLORREF>, COLORREF> _adjustedColorMap;
+    void _MakeAdjustedColorMap();
+
 #pragma region TextSelection
     // These methods are defined in TerminalSelection.cpp
     std::vector<SMALL_RECT> _GetSelectionRects() const noexcept;

src/cascadia/TerminalCore/terminalrenderdata.cpp

@@ -4,7 +4,6 @@
 #include "pch.h"
 #include "Terminal.hpp"
 #include <DefaultSettings.h>
-#include "ColorFix.hpp"
 
 using namespace Microsoft::Terminal::Core;
 using namespace Microsoft::Console::Types;
@@ -54,6 +53,10 @@ std::pair<COLORREF, COLORREF> Terminal::GetAttributeColors(const TextAttribute&
         _screenReversed,
         _blinkingState.IsBlinkingFaint(),
         _intenseIsBright);
+    if (_perceptualColorNudging && _adjustedColorMap.find(colors) != _adjustedColorMap.end())
+    {
+        colors.first = _adjustedColorMap.at(colors);
+    }
     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.
@@ -61,16 +64,7 @@ std::pair<COLORREF, COLORREF> Terminal::GetAttributeColors(const TextAttribute&
     {
         colors.second |= 0xff000000;
     }
-    std::pair<COLORREF, COLORREF> result;
-    if (_perceptualColorNudging)
-    {
-        result = std::pair<COLORREF, COLORREF>(ColorFix::GetPerceivableColor(colors.first, colors.second), colors.second);
-    }
-    else
-    {
-        result = colors;
-    }
-    return result;
+    return colors;
 }
 
 COORD Terminal::GetCursorPosition() const noexcept