Add support for customizing font fallback (#16821)

This adds support for specifying more than one font family using a
syntax that is similar to CSS' `font-family` property.
The implementation is straight-forward and is effectively
just a wrapper around `IDWriteFontFallbackBuilder`.

Closes #2664

## PR Checklist
* Font fallback
  * Write "「猫」"
  * Use "Consolas" and remember the shape of the glyphs
  * Use "Consolas, MS Gothic" and check that it changed ✅
* Settings UI autocompletion
  * It completes ✅
  * It filters ✅
  * It recognizes commas and starts a new name ✅
* All invalid font names are listed in the warning message ✅

---------

Co-authored-by: Dustin L. Howett <duhowett@microsoft.com>

.github/actions/spelling/expect/expect.txt

@@ -1155,6 +1155,7 @@ NOCONTEXTHELP
 NOCOPYBITS
 NODUP
 noexcepts
+NOFONT
 NOINTEGRALHEIGHT
 NOINTERFACE
 NOLINKINFO

src/cascadia/TerminalControl/ControlCore.cpp

@@ -336,6 +336,11 @@ namespace winrt::Microsoft::Terminal::Control::implementation
             _renderEngine = std::make_unique<::Microsoft::Console::Render::AtlasEngine>();
             _renderer->AddRenderEngine(_renderEngine.get());
 
+            // Hook up the warnings callback as early as possible so that we catch everything.
+            _renderEngine->SetWarningCallback([this](HRESULT hr, wil::zwstring_view parameter) {
+                _rendererWarning(hr, parameter);
+            });
+
             // Initialize our font with the renderer
             // We don't have to care about DPI. We'll get a change message immediately if it's not 96
             // and react accordingly.
@@ -371,12 +376,6 @@ namespace winrt::Microsoft::Terminal::Control::implementation
 
             _terminal->CreateFromSettings(*_settings, *_renderer);
 
-            // IMPORTANT! Set this callback up sooner than later. If we do it
-            // after Enable, then it'll be possible to paint the frame once
-            // _before_ the warning handler is set up, and then warnings from
-            // the first paint will be ignored!
-            _renderEngine->SetWarningCallback(std::bind(&ControlCore::_rendererWarning, this, std::placeholders::_1));
-
             // Tell the render engine to notify us when the swap chain changes.
             // We do this after we initially set the swapchain so as to avoid
             // unnecessary callbacks (and locking problems)
@@ -1024,18 +1023,6 @@ namespace winrt::Microsoft::Terminal::Control::implementation
             LOG_IF_FAILED(_renderEngine->UpdateFont(_desiredFont, _actualFont, featureMap, axesMap));
         }
 
-        // If the actual font isn't what was requested...
-        if (_actualFont.GetFaceName() != _desiredFont.GetFaceName())
-        {
-            // Then warn the user that we picked something because we couldn't find their font.
-            // Format message with user's choice of font and the font that was chosen instead.
-            const winrt::hstring message{ fmt::format(std::wstring_view{ RS_(L"NoticeFontNotFound") },
-                                                      _desiredFont.GetFaceName(),
-                                                      _actualFont.GetFaceName()) };
-            auto noticeArgs = winrt::make<NoticeEventArgs>(NoticeLevel::Warning, message);
-            RaiseNotice.raise(*this, std::move(noticeArgs));
-        }
-
         const auto actualNewSize = _actualFont.GetSize();
         FontSizeChanged.raise(*this, winrt::make<FontSizeChangedArgs>(actualNewSize.width, actualNewSize.height));
     }
@@ -1724,9 +1711,9 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         }
     }
 
-    void ControlCore::_rendererWarning(const HRESULT hr)
+    void ControlCore::_rendererWarning(const HRESULT hr, wil::zwstring_view parameter)
     {
-        RendererWarning.raise(*this, winrt::make<RendererWarningArgs>(hr));
+        RendererWarning.raise(*this, winrt::make<RendererWarningArgs>(hr, winrt::hstring{ parameter }));
     }
 
     winrt::fire_and_forget ControlCore::_renderEngineSwapChainChanged(const HANDLE sourceHandle)

src/cascadia/TerminalControl/ControlCore.h

@@ -390,7 +390,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         winrt::Windows::System::DispatcherQueueTimer _midiAudioSkipTimer{ nullptr };
 
 #pragma region RendererCallbacks
-        void _rendererWarning(const HRESULT hr);
+        void _rendererWarning(const HRESULT hr, wil::zwstring_view parameter);
         winrt::fire_and_forget _renderEngineSwapChainChanged(const HANDLE handle);
         void _rendererBackgroundColorChanged();
         void _rendererTabColorChanged();

src/cascadia/TerminalControl/EventArgs.h

@@ -148,12 +148,14 @@ namespace winrt::Microsoft::Terminal::Control::implementation
     struct RendererWarningArgs : public RendererWarningArgsT<RendererWarningArgs>
     {
     public:
-        RendererWarningArgs(const uint64_t hr) :
-            _Result(hr)
+        RendererWarningArgs(const HRESULT hr, winrt::hstring parameter) :
+            _Result{ hr },
+            _Parameter{ std::move(parameter) }
         {
         }
 
-        WINRT_PROPERTY(uint64_t, Result);
+        WINRT_PROPERTY(HRESULT, Result);
+        WINRT_PROPERTY(winrt::hstring, Parameter);
     };
 
     struct TransparencyChangedEventArgs : public TransparencyChangedEventArgsT<TransparencyChangedEventArgs>

src/cascadia/TerminalControl/EventArgs.idl

@@ -77,7 +77,8 @@ namespace Microsoft.Terminal.Control
 
     runtimeclass RendererWarningArgs
     {
-        UInt64 Result { get; };
+        HRESULT Result { get; };
+        String Parameter { get; };
     }
 
     runtimeclass TransparencyChangedEventArgs

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

@@ -213,6 +213,14 @@ Please either install the missing font or choose another one.</value>
     <value>Renderer encountered an unexpected error: {0}</value>
     <comment>{0} is an error code.</comment>
   </data>
+  <data name="RendererErrorFontNotFound" xml:space="preserve">
+    <value>Unable to find the following fonts: {0}. Please either install them or choose different fonts.</value>
+    <comment>{Locked="{0}"} This is a warning dialog shown when the user selects a font that isn't installed.</comment>
+  </data>
+  <data name="RendererErrorOther" xml:space="preserve">
+    <value>Renderer encountered an unexpected error: {0:#010x} {1}</value>
+    <comment>{Locked="{0:#010x}","{1}"} {0:#010x} is a placeholder for a Windows error code (e.g. 0x88985002). {1} is the corresponding message.</comment>
+  </data>
   <data name="TermControlReadOnly" xml:space="preserve">
     <value>Read-only mode is enabled.</value>
   </data>

src/cascadia/TerminalControl/TermControl.cpp

@@ -991,36 +991,45 @@ namespace winrt::Microsoft::Terminal::Control::implementation
     // - hr: an  HRESULT describing the warning
     // Return Value:
     // - <none>
-    winrt::fire_and_forget TermControl::_RendererWarning(IInspectable /*sender*/,
-                                                         Control::RendererWarningArgs args)
+    winrt::fire_and_forget TermControl::_RendererWarning(IInspectable /*sender*/, Control::RendererWarningArgs args)
     {
-        const auto hr = static_cast<HRESULT>(args.Result());
-
         auto weakThis{ get_weak() };
         co_await wil::resume_foreground(Dispatcher());
 
-        if (auto control{ weakThis.get() })
+        const auto control = weakThis.get();
+        if (!control)
         {
-            winrt::hstring message;
-            if (HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND) == hr ||
-                HRESULT_FROM_WIN32(ERROR_PATH_NOT_FOUND) == hr)
-            {
-                message = winrt::hstring{ fmt::format(std::wstring_view{ RS_(L"PixelShaderNotFound") },
-                                                      (_focused ? _core.FocusedAppearance() : _core.UnfocusedAppearance()).PixelShaderPath()) };
-            }
-            else if (D2DERR_SHADER_COMPILE_FAILED == hr)
-            {
-                message = winrt::hstring{ fmt::format(std::wstring_view{ RS_(L"PixelShaderCompileFailed") }) };
-            }
-            else
-            {
-                message = winrt::hstring{ fmt::format(std::wstring_view{ RS_(L"UnexpectedRendererError") },
-                                                      hr) };
-            }
+            co_return;
+        }
 
-            auto noticeArgs = winrt::make<NoticeEventArgs>(NoticeLevel::Warning, std::move(message));
-            control->RaiseNotice.raise(*control, std::move(noticeArgs));
+        const auto hr = args.Result();
+        const auto parameter = args.Parameter();
+        winrt::hstring message;
+
+        switch (hr)
+        {
+        case HRESULT_FROM_WIN32(ERROR_FILE_NOT_FOUND):
+        case HRESULT_FROM_WIN32(ERROR_PATH_NOT_FOUND):
+            message = winrt::hstring{ fmt::format(std::wstring_view{ RS_(L"PixelShaderNotFound") }, parameter) };
+            break;
+        case D2DERR_SHADER_COMPILE_FAILED:
+            message = winrt::hstring{ fmt::format(std::wstring_view{ RS_(L"PixelShaderCompileFailed") }) };
+            break;
+        case DWRITE_E_NOFONT:
+            message = winrt::hstring{ fmt::format(std::wstring_view{ RS_(L"RendererErrorFontNotFound") }, parameter) };
+            break;
+        default:
+        {
+            wchar_t buf[512];
+            const auto len = FormatMessageW(FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, nullptr, hr, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), &buf[0], ARRAYSIZE(buf), nullptr);
+            const std::wstring_view msg{ &buf[0], len };
+            message = winrt::hstring{ fmt::format(std::wstring_view{ RS_(L"RendererErrorOther") }, hr, msg) };
+            break;
         }
+        }
+
+        auto noticeArgs = winrt::make<NoticeEventArgs>(NoticeLevel::Warning, std::move(message));
+        control->RaiseNotice.raise(*control, std::move(noticeArgs));
     }
 
     void TermControl::_AttachDxgiSwapChainToXaml(HANDLE swapChainHandle)