Update WT's icon at runtime to match high-contrast as applicable

.github/actions/spell-check/dictionary/apis.txt

@@ -3,14 +3,20 @@ ACCESSDENIED
 alignof
 bitfield
 bitfields
-COLORPROPERTY
 CLASSNOTAVAILABLE
+COLORPROPERTY
+CXICON
+CYICON
 environstrings
 EXPCMDFLAGS
 EXPCMDSTATE
 fullkbd
 futex
+GETDESKWALLPAPER
+GETHIGHCONTRAST
 Hashtable
+HIGHCONTRASTON
+HIGHCONTRASTW
 href
 IAsync
 IBind
@@ -25,8 +31,8 @@ IInheritable
 IMap
 IObject
 IStorage
-llabs
 LCID
+llabs
 lround
 LSHIFT
 NCHITTEST
@@ -46,14 +52,14 @@ RSHIFT
 rx
 serializer
 SIZENS
-GETDESKWALLPAPER
-UPDATEINIFILE
 spsc
 STDCPP
 strchr
 syscall
+THEMECHANGED
 tmp
 tx
+UPDATEINIFILE
 userenv
 wcstoui
 XDocument

res/terminal/Generate-TerminalAssets.ps1

@@ -24,6 +24,7 @@ Param(
   [string]$Path,
   [string]$Destination,
   [int[]]$Altforms = (16, 20, 24, 30, 32, 36, 40, 48, 60, 64, 72, 80, 96, 256),
+  [int[]]$Win32IconSizes = (16, 20, 24, 32, 48, 64, 256),
   [switch]$Unplated = $true,
   [float[]]$Scales = (1.0, 1.25, 1.5, 2.0, 4.0),
   [string]$HighContrastPath = "",
@@ -115,6 +116,7 @@ If (-Not [string]::IsNullOrEmpty($Destination)) {
   $TranslatedOutDir = "."
 }
 
+$intermediates = [System.Collections.Concurrent.ConcurrentBag[PSCustomObject]]::new()
 $intermediateFiles = [System.Collections.Concurrent.ConcurrentBag[string]]::new()
 
 # Generate the base icons
@@ -136,6 +138,11 @@ $allSizes | ForEach-Object -Parallel {
   }
 
   ($using:intermediateFiles).Add($intermediateStandardNt)
+  ($using:intermediates).Add([PSCustomObject]@{
+      Contrast = "standard"
+      Size = $sz
+      PathWSL = $intermediateStandardWsl
+  })
 
   If ($svgContrastWsl -Ne $null) {
     $intermediateBlackNt = "$destinationNt\_intermediate.black.$($sz).png"
@@ -158,7 +165,26 @@ $allSizes | ForEach-Object -Parallel {
 
     ($using:intermediateFiles).Add($intermediateBlackNt)
     ($using:intermediateFiles).Add($intermediateWhiteNt)
+    ($using:intermediates).Add([PSCustomObject]@{
+        Contrast = "black"
+        Size = $sz
+        PathWSL = $intermediateBlackWsl
+    })
+    ($using:intermediates).Add([PSCustomObject]@{
+        Contrast = "white"
+        Size = $sz
+        PathWSL = $intermediateWhiteWsl
+    })
+  }
+}
+
+$intermediates | ? { $_.Size -In $Win32IconSizes } | Group-Object Contrast | ForEach-Object -Parallel {
+  $assetName = "terminal.ico"
+  If ($_.Name -Ne "standard") {
+    $assetName = "terminal_contrast-$($_.Name).ico"
   }
+  Write-Host "Producing win32 .ico for contrast=$($_.Name) as $assetName"
+  wsl convert $_.Group.PathWSL "$($using:TranslatedOutDir)/$assetName"
 }
 
 # Once the base icons are done, splat them into the middles of larger canvases.

src/cascadia/WindowsTerminal/IslandWindow.cpp

@@ -5,6 +5,7 @@
 #include "IslandWindow.h"
 #include "../types/inc/Viewport.hpp"
 #include "resource.h"
+#include "icon.h"
 
 extern "C" IMAGE_DOS_HEADER __ImageBase;
 
@@ -147,6 +148,8 @@ void IslandWindow::_HandleCreateWindow(const WPARAM, const LPARAM lParam) noexce
     ShowWindow(_window.get(), nCmdShow);
 
     UpdateWindow(_window.get());
+
+    UpdateWindowIconForActiveMetrics(_window.get());
 }
 
 // Method Description:
@@ -359,6 +362,9 @@ void IslandWindow::OnSize(const UINT width, const UINT height)
             return 0;
         }
         CATCH_LOG();
+    case WM_THEMECHANGED:
+        UpdateWindowIconForActiveMetrics(_window.get());
+        return 0;
     }
 
     // TODO: handle messages here...

src/cascadia/WindowsTerminal/WindowsTerminal.rc

@@ -52,7 +52,20 @@ END
 
 // Icon with lowest ID value placed first to ensure application icon
 // remains consistent on all systems.
+
+#if defined(WT_BRANDING_RELEASE)
 IDI_APPICON             ICON                    "..\\..\\..\\res\\terminal.ico"
+IDI_APPICON_HC_BLACK    ICON                    "..\\..\\..\\res\\terminal\\images\\terminal_contrast-black.ico"
+IDI_APPICON_HC_WHITE    ICON                    "..\\..\\..\\res\\terminal\\images\\terminal_contrast-white.ico"
+#elif defined(WT_BRANDING_PREVIEW)
+IDI_APPICON             ICON                    "..\\..\\..\\res\\terminal\\images-Pre\\terminal.ico"
+IDI_APPICON_HC_BLACK    ICON                    "..\\..\\..\\res\\terminal\\images-Pre\\terminal_contrast-black.ico"
+IDI_APPICON_HC_WHITE    ICON                    "..\\..\\..\\res\\terminal\\images-Pre\\terminal_contrast-white.ico"
+#else
+IDI_APPICON             ICON                    "..\\..\\..\\res\\terminal\\images-Dev\\terminal.ico"
+IDI_APPICON_HC_BLACK    ICON                    "..\\..\\..\\res\\terminal\\images-Dev\\terminal_contrast-black.ico"
+IDI_APPICON_HC_WHITE    ICON                    "..\\..\\..\\res\\terminal\\images-Dev\\terminal_contrast-white.ico"
+#endif
 
 
 /////////////////////////////////////////////////////////////////////////////

src/cascadia/WindowsTerminal/WindowsTerminal.vcxproj

@@ -57,6 +57,7 @@
     <ClCompile Include="AppHost.cpp" />
     <ClCompile Include="IslandWindow.cpp" />
     <ClCompile Include="NonClientIslandWindow.cpp" />
+    <ClCompile Include="icon.cpp" />
   </ItemGroup>
   <ItemGroup>
     <ResourceCompile Include="WindowsTerminal.rc" />

src/cascadia/WindowsTerminal/icon.cpp

@@ -0,0 +1,49 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#include "pch.h"
+#include "resource.h"
+
+static int _GetActiveAppIconResource()
+{
+    auto iconResource{ IDI_APPICON };
+
+    HIGHCONTRASTW hcInfo{};
+    hcInfo.cbSize = sizeof(hcInfo);
+
+    if (SystemParametersInfoW(SPI_GETHIGHCONTRAST, sizeof(hcInfo), &hcInfo, 0))
+    {
+        if (WI_IsFlagSet(hcInfo.dwFlags, HCF_HIGHCONTRASTON))
+        {
+            iconResource = IDI_APPICON_HC_BLACK;
+
+            if (0x00FFFFFF == GetSysColor(COLOR_WINDOW)) // white window color == white high contrast
+            {
+                iconResource = IDI_APPICON_HC_WHITE;
+            }
+        }
+    }
+
+    return iconResource;
+}
+
+void UpdateWindowIconForActiveMetrics(HWND window)
+{
+    auto iconResource{ MAKEINTRESOURCEW(_GetActiveAppIconResource()) };
+
+    // These handles are loaded with LR_SHARED, so they are safe to "leak".
+    HANDLE smallIcon{ LoadImageW(wil::GetModuleInstanceHandle(), iconResource, IMAGE_ICON, GetSystemMetrics(SM_CXSMICON), GetSystemMetrics(SM_CYSMICON), LR_SHARED) };
+    LOG_LAST_ERROR_IF_NULL(smallIcon);
+
+    HANDLE largeIcon{ LoadImageW(wil::GetModuleInstanceHandle(), iconResource, IMAGE_ICON, GetSystemMetrics(SM_CXICON), GetSystemMetrics(SM_CYICON), LR_SHARED) };
+    LOG_LAST_ERROR_IF_NULL(largeIcon);
+
+    if (smallIcon)
+    {
+        SendMessageW(window, WM_SETICON, ICON_SMALL, reinterpret_cast<LPARAM>(smallIcon));
+    }
+    if (largeIcon)
+    {
+        SendMessageW(window, WM_SETICON, ICON_BIG, reinterpret_cast<LPARAM>(largeIcon));
+    }
+}

src/cascadia/WindowsTerminal/icon.h

@@ -0,0 +1,6 @@
+// Copyright (c) Microsoft Corporation.
+// Licensed under the MIT license.
+
+#pragma once
+
+void UpdateWindowIconForActiveMetrics(HWND window);

src/cascadia/WindowsTerminal/resource.h

@@ -3,6 +3,9 @@
 // Used by WindowsTerminal.rc
 //
 #define IDI_APPICON 101
+#define IDI_APPICON_HC_BLACK 102
+#define IDI_APPICON_HC_WHITE 103
+
 #define IDS_ERROR_DIALOG_TITLE 105
 #define IDS_HELP_DIALOG_TITLE 106
 #define IDS_ERROR_ARCHITECTURE_FORMAT 110