Add support for soft fonts in the DX renderer (#13362)

## Summary of the Pull Request

This PR adds support for downloadable soft fonts in the DirectX
renderer, potentially enabling them to be used in Windows Terminal.

## References

Soft fonts were first implemented in conhost (with the GDI renderer) in
PR #10011.

## PR Checklist
* [ ] Closes #xxx
* [x] CLA signed.
* [ ] Tests added/passed
* [ ] Documentation updated.
* [ ] Schema updated.
* [ ] I've discussed this with core contributors already. If not
checked, I'm ready to accept this work might be rejected in favor of a
different grand plan. Issue number where discussion took place: #xxx

## Detailed Description of the Pull Request / Additional comments

The way the DirectX implementation works is by building up a bitmap
containing all of the glyphs, and then drawing an appropriate subsection
of that bitmap for each character that needs to be rendered. The current
text color is applied with a color matrix effect, and the glyphs are
automatically scaled up to the current font size with a scaling effect.

By default the scaling uses a high quality cubic interpolation, which
gives it a smoother antialiased effect. But if the *Text antialiasing*
option is configured as *Aliased*, we use a simpler nearest-neighbor
interpolation, which more closely matches the rendering of the original
GDI implementation.

## Validation Steps Performed

I've manually tested the renderer in conhost with the `UseDx` registry
entry. I've also tested in Windows Terminal using the experimental
passthrough mode.

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

@@ -292,6 +292,7 @@ codeproject
 coinit
 COLLECTIONURI
 colorizing
+COLORMATRIX
 colororacle
 colorref
 colorscheme

src/renderer/dx/CustomTextRenderer.cpp

@@ -238,10 +238,10 @@ using namespace Microsoft::Console::Render;
 // - firstPass - true if we're being called before the text is drawn, false afterwards.
 // Return Value:
 // - S_FALSE if we did nothing, S_OK if we successfully painted, otherwise an appropriate HRESULT
-[[nodiscard]] HRESULT _drawCursor(gsl::not_null<ID2D1DeviceContext*> d2dContext,
-                                  D2D1_RECT_F textRunBounds,
-                                  const DrawingContext& drawingContext,
-                                  const bool firstPass)
+[[nodiscard]] HRESULT CustomTextRenderer::DrawCursor(gsl::not_null<ID2D1DeviceContext*> d2dContext,
+                                                     D2D1_RECT_F textRunBounds,
+                                                     const DrawingContext& drawingContext,
+                                                     const bool firstPass)
 try
 {
     if (!drawingContext.cursorInfo.has_value())
@@ -374,7 +374,7 @@ try
         // =   =      =====
         // =====      =====
         //
-        // Then, outside of _drawCursor, the glyph is drawn:
+        // Then, outside of DrawCursor, the glyph is drawn:
         //
         // EMPTY BOX  FILLED BOX
         // ==A==      ==A==
@@ -556,7 +556,7 @@ CATCH_RETURN()
 
     d2dContext->FillRectangle(rect, drawingContext->backgroundBrush);
 
-    RETURN_IF_FAILED(_drawCursor(d2dContext.Get(), rect, *drawingContext, true));
+    RETURN_IF_FAILED(DrawCursor(d2dContext.Get(), rect, *drawingContext, true));
 
     // GH#5098: If we're rendering with cleartype text, we need to always render
     // onto an opaque background. If our background _isn't_ opaque, then we need
@@ -746,7 +746,7 @@ CATCH_RETURN()
                                             clientDrawingEffect));
     }
 
-    RETURN_IF_FAILED(_drawCursor(d2dContext.Get(), rect, *drawingContext, false));
+    RETURN_IF_FAILED(DrawCursor(d2dContext.Get(), rect, *drawingContext, false));
 
     return S_OK;
 }

src/renderer/dx/CustomTextRenderer.h

@@ -112,6 +112,11 @@ namespace Microsoft::Console::Render
 
         [[nodiscard]] HRESULT STDMETHODCALLTYPE EndClip(void* clientDrawingContext) noexcept;
 
+        [[nodiscard]] static HRESULT DrawCursor(gsl::not_null<ID2D1DeviceContext*> d2dContext,
+                                                D2D1_RECT_F textRunBounds,
+                                                const DrawingContext& drawingContext,
+                                                const bool firstPass);
+
     private:
         [[nodiscard]] HRESULT _FillRectangle(void* clientDrawingContext,
                                              IUnknown* clientDrawingEffect,

src/renderer/dx/DxRenderer.cpp

@@ -881,6 +881,8 @@ void DxEngine::_ReleaseDeviceResources() noexcept
 
         _d2dBitmap.Reset();
 
+        _softFont.Reset();
+
         if (nullptr != _d2dDeviceContext.Get() && _isPainting)
         {
             _d2dDeviceContext->EndDraw();
@@ -1689,12 +1691,22 @@ try
     // Calculate positioning of our origin.
     const auto origin = (coord * _fontRenderData->GlyphCell()).to_d2d_point();
 
-    // Create the text layout
-    RETURN_IF_FAILED(_customLayout->Reset());
-    RETURN_IF_FAILED(_customLayout->AppendClusters(clusters));
+    if (_usingSoftFont)
+    {
+        // We need to reset the clipping rect applied by the CustomTextRenderer,
+        // since the soft font will want to set its own clipping rect.
+        RETURN_IF_FAILED(_customRenderer->EndClip(_drawingContext.get()));
+        RETURN_IF_FAILED(_softFont.Draw(*_drawingContext, clusters, origin.x, origin.y));
+    }
+    else
+    {
+        // Create the text layout
+        RETURN_IF_FAILED(_customLayout->Reset());
+        RETURN_IF_FAILED(_customLayout->AppendClusters(clusters));
 
-    // Layout then render the text
-    RETURN_IF_FAILED(_customLayout->Draw(_drawingContext.get(), _customRenderer.Get(), origin.x, origin.y));
+        // Layout then render the text
+        RETURN_IF_FAILED(_customLayout->Draw(_drawingContext.get(), _customRenderer.Get(), origin.x, origin.y));
+    }
 
     return S_OK;
 }
@@ -1933,8 +1945,9 @@ CATCH_RETURN()
 [[nodiscard]] HRESULT DxEngine::UpdateDrawingBrushes(const TextAttribute& textAttributes,
                                                      const RenderSettings& renderSettings,
                                                      const gsl::not_null<IRenderData*> /*pData*/,
-                                                     const bool /*usingSoftFont*/,
+                                                     const bool usingSoftFont,
                                                      const bool isSettingDefaultBrushes) noexcept
+try
 {
     const auto [colorForeground, colorBackground] = renderSettings.GetAttributeColorsWithAlpha(textAttributes);
 
@@ -1951,6 +1964,12 @@ CATCH_RETURN()
     _d2dBrushForeground->SetColor(_foregroundColor);
     _d2dBrushBackground->SetColor(_backgroundColor);
 
+    _usingSoftFont = usingSoftFont;
+    if (_usingSoftFont)
+    {
+        _softFont.SetColor(_foregroundColor);
+    }
+
     // If this flag is set, then we need to update the default brushes too and the swap chain background.
     if (isSettingDefaultBrushes)
     {
@@ -1990,6 +2009,7 @@ CATCH_RETURN()
 
     return S_OK;
 }
+CATCH_RETURN();
 
 // Routine Description:
 // - Updates the font used for drawing
@@ -2021,7 +2041,8 @@ try
     // Prepare the text layout.
     _customLayout = WRL::Make<CustomTextLayout>(_fontRenderData.get());
 
-    return S_OK;
+    // Inform the soft font of the new cell size so it can scale appropriately.
+    return _softFont.SetTargetSize(_fontRenderData->GlyphCell());
 }
 CATCH_RETURN();
 
@@ -2233,6 +2254,7 @@ try
     {
         _antialiasingMode = antialiasingMode;
         _recreateDeviceRequested = true;
+        LOG_IF_FAILED(_softFont.SetAntialiasing(antialiasingMode != D2D1_TEXT_ANTIALIAS_MODE_ALIASED));
         LOG_IF_FAILED(InvalidateAll());
     }
 }
@@ -2275,6 +2297,24 @@ void DxEngine::UpdateHyperlinkHoveredId(const uint16_t hoveredId) noexcept
     _hyperlinkHoveredId = hoveredId;
 }
 
+// Routine Description:
+// - This method will replace the active soft font with the given bit pattern.
+// Arguments:
+// - bitPattern - An array of scanlines representing all the glyphs in the font.
+// - cellSize - The cell size for an individual glyph.
+// - centeringHint - The horizontal extent that glyphs are offset from center.
+// Return Value:
+// - S_OK if successful. E_FAIL if there was an error.
+HRESULT DxEngine::UpdateSoftFont(const gsl::span<const uint16_t> bitPattern,
+                                 const til::size cellSize,
+                                 const size_t centeringHint) noexcept
+try
+{
+    _softFont.SetFont(bitPattern, cellSize, _fontRenderData->GlyphCell(), centeringHint);
+    return S_OK;
+}
+CATCH_RETURN();
+
 // Method Description:
 // - Informs this render engine about certain state for this frame at the
 //   beginning of this frame. We'll use it to get information about the cursor

src/renderer/dx/DxRenderer.hpp

@@ -27,6 +27,7 @@
 #include "CustomTextLayout.h"
 #include "CustomTextRenderer.h"
 #include "DxFontRenderData.h"
+#include "DxSoftFont.h"
 
 #include "../../types/inc/Viewport.hpp"
 
@@ -91,6 +92,10 @@ namespace Microsoft::Console::Render
 
         [[nodiscard]] HRESULT ScrollFrame() noexcept override;
 
+        [[nodiscard]] HRESULT UpdateSoftFont(const gsl::span<const uint16_t> bitPattern,
+                                             const til::size cellSize,
+                                             const size_t centeringHint) noexcept override;
+
         [[nodiscard]] HRESULT PrepareRenderInfo(const RenderFrameInfo& info) noexcept override;
 
         [[nodiscard]] HRESULT ResetLineTransform() noexcept override;
@@ -204,6 +209,8 @@ namespace Microsoft::Console::Render
         ::Microsoft::WRL::ComPtr<ID2D1StrokeStyle> _hyperlinkStrokeStyle;
 
         std::unique_ptr<DxFontRenderData> _fontRenderData;
+        DxSoftFont _softFont;
+        bool _usingSoftFont;
 
         D2D1_STROKE_STYLE_PROPERTIES _strokeStyleProperties;
         D2D1_STROKE_STYLE_PROPERTIES _dashStrokeStyleProperties;