Add support for fractional font sizes (microsoft#14013)

After this commit a user may specify fractional font sizes.
Support was only implemented for AtlasEngine however.
DxEngine continues to use rounded (integer) font sizes.

Closes microsoft#6678

## Validation Steps Performed
* Install a bitmap font that requires fractional font sizes
  (e.g. Terminus TTF, https://files.ax86.net/terminus-ttf/)
* Set font size to something integer (e.g. 14pt)
  Glyphs are blurry ✅
* Set font size to something fractional (e.g. 13.5pt)
  Glyphs are crisp ✅

doc/cascadia/profiles.schema.json

@@ -244,7 +244,7 @@
           "default": 12,
           "description": "Size of the font in points.",
           "minimum": 1,
-          "type": "integer"
+          "type": "number"
         },
         "weight": {
           "default": "normal",
@@ -2252,7 +2252,7 @@
           "default": 12,
           "description": "[deprecated] Define 'size' within the 'font' object instead.",
           "minimum": 1,
-          "type": "integer",
+          "type": "number",
           "deprecated": true
         },
         "fontWeight": {

src/cascadia/PublicTerminalCore/HwndTerminal.cpp

@@ -169,7 +169,7 @@ static bool RegisterTermClass(HINSTANCE hInstance) noexcept
 }
 
 HwndTerminal::HwndTerminal(HWND parentHwnd) :
-    _desiredFont{ L"Consolas", 0, DEFAULT_FONT_WEIGHT, { 0, 14 }, CP_UTF8 },
+    _desiredFont{ L"Consolas", 0, DEFAULT_FONT_WEIGHT, 14, CP_UTF8 },
     _actualFont{ L"Consolas", 0, DEFAULT_FONT_WEIGHT, { 0, 14 }, CP_UTF8, false },
     _uiaProvider{ nullptr },
     _currentDpi{ USER_DEFAULT_SCREEN_DPI },
@@ -799,7 +799,7 @@ void _stdcall TerminalSetTheme(void* terminal, TerminalTheme theme, LPCWSTR font
 
     publicTerminal->_terminal->SetCursorStyle(static_cast<DispatchTypes::CursorStyle>(theme.CursorStyle));
 
-    publicTerminal->_desiredFont = { fontFamily, 0, DEFAULT_FONT_WEIGHT, { 0, fontSize }, CP_UTF8 };
+    publicTerminal->_desiredFont = { fontFamily, 0, DEFAULT_FONT_WEIGHT, static_cast<float>(fontSize), CP_UTF8 };
     publicTerminal->_UpdateFont(newDpi);
 
     // When the font changes the terminal dimensions need to be recalculated since the available row and column

src/cascadia/TerminalControl/ControlCore.cpp

@@ -95,7 +95,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
                              Control::IControlAppearance unfocusedAppearance,
                              TerminalConnection::ITerminalConnection connection) :
         _connection{ connection },
-        _desiredFont{ DEFAULT_FONT_FACE, 0, DEFAULT_FONT_WEIGHT, { 0, DEFAULT_FONT_SIZE }, CP_UTF8 },
+        _desiredFont{ DEFAULT_FONT_FACE, 0, DEFAULT_FONT_WEIGHT, DEFAULT_FONT_SIZE, CP_UTF8 },
         _actualFont{ DEFAULT_FONT_FACE, 0, DEFAULT_FONT_WEIGHT, { 0, DEFAULT_FONT_SIZE }, CP_UTF8, false }
     {
         _EnsureStaticInitialization();
@@ -859,15 +859,15 @@ namespace winrt::Microsoft::Terminal::Control::implementation
     // - fontSize: The size of the font.
     // Return Value:
     // - Returns true if you need to call _refreshSizeUnderLock().
-    bool ControlCore::_setFontSizeUnderLock(int fontSize)
+    bool ControlCore::_setFontSizeUnderLock(float fontSize)
     {
         // Make sure we have a non-zero font size
-        const auto newSize = std::max(fontSize, 1);
+        const auto newSize = std::max(fontSize, 1.0f);
         const auto fontFace = _settings->FontFace();
         const auto fontWeight = _settings->FontWeight();
-        _actualFont = { fontFace, 0, fontWeight.Weight, { 0, newSize }, CP_UTF8, false };
+        _desiredFont = { fontFace, 0, fontWeight.Weight, newSize, CP_UTF8 };
+        _actualFont = { fontFace, 0, fontWeight.Weight, _desiredFont.GetEngineSize(), CP_UTF8, false };
         _actualFontFaceName = { fontFace };
-        _desiredFont = { _actualFont };
 
         const auto before = _actualFont.GetSize();
         _updateFont();
@@ -893,11 +893,11 @@ namespace winrt::Microsoft::Terminal::Control::implementation
     // - Adjust the font size of the terminal control.
     // Arguments:
     // - fontSizeDelta: The amount to increase or decrease the font size by.
-    void ControlCore::AdjustFontSize(int fontSizeDelta)
+    void ControlCore::AdjustFontSize(float fontSizeDelta)
     {
         const auto lock = _terminal->LockForWriting();
 
-        if (_setFontSizeUnderLock(_desiredFont.GetEngineSize().Y + fontSizeDelta))
+        if (_setFontSizeUnderLock(_desiredFont.GetFontSize() + fontSizeDelta))
         {
             _refreshSizeUnderLock();
         }
@@ -1211,10 +1211,14 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         return static_cast<uint16_t>(_actualFont.GetWeight());
     }
 
-    til::size ControlCore::FontSizeInDips() const
+    winrt::Windows::Foundation::Size ControlCore::FontSizeInDips() const
     {
-        const til::size fontSize{ _actualFont.GetSize() };
-        return fontSize.scale(til::math::rounding, 1.0f / ::base::saturated_cast<float>(_compositionScale));
+        const auto fontSize = _actualFont.GetSize();
+        const auto scale = 1.0f / static_cast<float>(_compositionScale);
+        return {
+            fontSize.width * scale,
+            fontSize.height * scale,
+        };
     }
 
     TerminalConnection::ConnectionState ControlCore::ConnectionState() const

src/cascadia/TerminalControl/ControlCore.h

@@ -76,10 +76,10 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         void SizeChanged(const double width, const double height);
         void ScaleChanged(const double scale);
 
-        void AdjustFontSize(int fontSizeDelta);
+        void AdjustFontSize(float fontSizeDelta);
         void ResetFontSize();
         FontInfo GetFont() const;
-        til::size FontSizeInDips() const;
+        winrt::Windows::Foundation::Size FontSizeInDips() const;
 
         winrt::Windows::Foundation::Size FontSize() const noexcept;
         winrt::hstring FontFaceName() const noexcept;
@@ -282,7 +282,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         std::unique_ptr<til::throttled_func_trailing<>> _updatePatternLocations;
         std::shared_ptr<ThrottledFuncTrailing<Control::ScrollPositionChangedArgs>> _updateScrollBar;
 
-        bool _setFontSizeUnderLock(int fontSize);
+        bool _setFontSizeUnderLock(float fontSize);
         void _updateFont(const bool initialUpdate = false);
         void _refreshSizeUnderLock();
         void _updateSelectionUI();

src/cascadia/TerminalControl/ControlCore.idl

@@ -105,7 +105,7 @@ namespace Microsoft.Terminal.Control
         void ClearHoveredCell();
 
         void ResetFontSize();
-        void AdjustFontSize(Int32 fontSizeDelta);
+        void AdjustFontSize(Single fontSizeDelta);
         void SizeChanged(Double width, Double height);
         void ScaleChanged(Double scale);
 

src/cascadia/TerminalControl/ControlInteractivity.cpp

@@ -301,7 +301,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
                 const auto touchdownPoint = *_singleClickTouchdownPos;
                 const auto dx = pixelPosition.X - touchdownPoint.X;
                 const auto dy = pixelPosition.Y - touchdownPoint.Y;
-                const auto w = fontSizeInDips.width;
+                const auto w = fontSizeInDips.Width;
                 const auto distanceSquared = dx * dx + dy * dy;
                 const auto maxDistanceSquared = w * w / 16; // (w / 4)^2
 
@@ -337,16 +337,16 @@ namespace winrt::Microsoft::Terminal::Control::implementation
             const auto fontSizeInDips{ _core->FontSizeInDips() };
 
             // Get the difference between the point we've dragged to and the start of the touch.
-            const auto dy = static_cast<double>(newTouchPoint.Y - anchor.Y);
+            const auto dy = static_cast<float>(newTouchPoint.Y - anchor.Y);
 
             // Start viewport scroll after we've moved more than a half row of text
-            if (std::abs(dy) > (fontSizeInDips.height / 2.0))
+            if (std::abs(dy) > (fontSizeInDips.Height / 2.0f))
             {
                 // Multiply by -1, because moving the touch point down will
                 // create a positive delta, but we want the viewport to move up,
                 // so we'll need a negative scroll amount (and the inverse for
                 // panning down)
-                const auto numRows = dy / -fontSizeInDips.height;
+                const auto numRows = dy / -fontSizeInDips.Height;
 
                 const auto currentOffset = _core->ScrollOffset();
                 const auto newValue = numRows + currentOffset;
@@ -459,7 +459,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
     //   scrolling event.
     // Arguments:
     // - mouseDelta: the mouse wheel delta that triggered this event.
-    void ControlInteractivity::_mouseTransparencyHandler(const double mouseDelta)
+    void ControlInteractivity::_mouseTransparencyHandler(const int32_t mouseDelta) const
     {
         // Transparency is on a scale of [0.0,1.0], so only increment by .01.
         const auto effectiveDelta = mouseDelta < 0 ? -.01 : .01;
@@ -471,9 +471,9 @@ namespace winrt::Microsoft::Terminal::Control::implementation
     //   event.
     // Arguments:
     // - mouseDelta: the mouse wheel delta that triggered this event.
-    void ControlInteractivity::_mouseZoomHandler(const double mouseDelta)
+    void ControlInteractivity::_mouseZoomHandler(const int32_t mouseDelta) const
     {
-        const auto fontDelta = mouseDelta < 0 ? -1 : 1;
+        const auto fontDelta = mouseDelta < 0 ? -1.0f : 1.0f;
         _core->AdjustFontSize(fontDelta);
     }
 
@@ -483,7 +483,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
     // - mouseDelta: the mouse wheel delta that triggered this event.
     // - pixelPosition: the location of the mouse during this event
     // - isLeftButtonPressed: true iff the left mouse button was pressed during this event.
-    void ControlInteractivity::_mouseScrollHandler(const double mouseDelta,
+    void ControlInteractivity::_mouseScrollHandler(const int32_t mouseDelta,
                                                    const Core::Point pixelPosition,
                                                    const bool isLeftButtonPressed)
     {

src/cascadia/TerminalControl/ControlInteractivity.h

@@ -132,9 +132,9 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         unsigned int _numberOfClicks(Core::Point clickPos, Timestamp clickTime);
         void _updateSystemParameterSettings() noexcept;
 
-        void _mouseTransparencyHandler(const double mouseDelta);
-        void _mouseZoomHandler(const double mouseDelta);
-        void _mouseScrollHandler(const double mouseDelta,
+        void _mouseTransparencyHandler(const int32_t mouseDelta) const;
+        void _mouseZoomHandler(const int32_t mouseDelta) const;
+        void _mouseScrollHandler(const int32_t mouseDelta,
                                  const Core::Point terminalPosition,
                                  const bool isLeftButtonPressed);
 

src/cascadia/TerminalControl/IControlSettings.idl

@@ -36,7 +36,7 @@ namespace Microsoft.Terminal.Control
         Boolean UseAtlasEngine { get; };
 
         String FontFace { get; };
-        Int32 FontSize { get; };
+        Single FontSize { get; };
         Windows.UI.Text.FontWeight FontWeight { get; };
         String Padding { get; };
         Windows.Foundation.Collections.IMap<String, UInt32> FontFeatures { get; };

src/cascadia/TerminalControl/TermControl.cpp

@@ -1517,7 +1517,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
     // - Adjust the font size of the terminal control.
     // Arguments:
     // - fontSizeDelta: The amount to increase or decrease the font size by.
-    void TermControl::AdjustFontSize(int fontSizeDelta)
+    void TermControl::AdjustFontSize(float fontSizeDelta)
     {
         _core.AdjustFontSize(fontSizeDelta);
     }
@@ -2082,8 +2082,8 @@ namespace winrt::Microsoft::Terminal::Control::implementation
         //      The family is only used to determine if the font is truetype or
         //      not, but DX doesn't use that info at all.
         //      The Codepage is additionally not actually used by the DX engine at all.
-        FontInfo actualFont = { fontFace, 0, fontWeight.Weight, { 0, fontSize }, CP_UTF8, false };
-        FontInfoDesired desiredFont = { actualFont };
+        FontInfoDesired desiredFont{ fontFace, 0, fontWeight.Weight, fontSize, CP_UTF8 };
+        FontInfo actualFont{ fontFace, 0, fontWeight.Weight, desiredFont.GetEngineSize(), CP_UTF8, false };
 
         // Create a DX engine and initialize it with our font and DPI. We'll
         // then use it to measure how much space the requested rows and columns

src/cascadia/TerminalControl/TermControl.h

@@ -82,7 +82,7 @@ namespace winrt::Microsoft::Terminal::Control::implementation
 
         void ScrollViewport(int viewTop);
 
-        void AdjustFontSize(int fontSizeDelta);
+        void AdjustFontSize(float fontSizeDelta);
         void ResetFontSize();
         til::point GetFontSize() const;
 

src/cascadia/TerminalControl/TermControl.idl

@@ -71,7 +71,7 @@ namespace Microsoft.Terminal.Control
 
         void SearchMatch(Boolean goForward);
 
-        void AdjustFontSize(Int32 fontSizeDelta);
+        void AdjustFontSize(Single fontSizeDelta);
         void ResetFontSize();
 
         void ToggleShaderEffects();

src/cascadia/TerminalSettingsEditor/Appearances.idl

@@ -34,7 +34,7 @@ namespace Microsoft.Terminal.Settings.Editor
         IHostedInWindow WindowRoot; // necessary to send the right HWND into the file picker dialogs.
 
         OBSERVABLE_PROJECTED_APPEARANCE_SETTING(String, FontFace);
-        OBSERVABLE_PROJECTED_APPEARANCE_SETTING(Int32, FontSize);
+        OBSERVABLE_PROJECTED_APPEARANCE_SETTING(Single, FontSize);
         OBSERVABLE_PROJECTED_APPEARANCE_SETTING(Windows.UI.Text.FontWeight, FontWeight);
 
         OBSERVABLE_PROJECTED_APPEARANCE_SETTING(String, ColorSchemeName);

src/cascadia/TerminalSettingsModel/ActionArgs.h

@@ -117,7 +117,7 @@ private:
 
 ////////////////////////////////////////////////////////////////////////////////
 #define ADJUST_FONT_SIZE_ARGS(X) \
-    X(int32_t, Delta, "delta", false, 0)
+    X(float, Delta, "delta", false, 0)
 
 ////////////////////////////////////////////////////////////////////////////////
 #define SEND_INPUT_ARGS(X) \

src/cascadia/TerminalSettingsModel/ActionArgs.idl

@@ -187,7 +187,7 @@ namespace Microsoft.Terminal.Settings.Model
 
     [default_interface] runtimeclass AdjustFontSizeArgs : IActionArgs
     {
-        Int32 Delta { get; };
+        Single Delta { get; };
     };
 
     [default_interface] runtimeclass SendInputArgs : IActionArgs

src/cascadia/TerminalSettingsModel/CascadiaSettingsSerialization.cpp

@@ -1110,8 +1110,9 @@ void CascadiaSettings::WriteSettingsToDisk()
 
     // write current settings to current settings file
     Json::StreamWriterBuilder wbuilder;
-    wbuilder.settings_["indentation"] = "    ";
     wbuilder.settings_["enableYAMLCompatibility"] = true; // suppress spaces around colons
+    wbuilder.settings_["indentation"] = "    ";
+    wbuilder.settings_["precision"] = 6; // prevent values like 1.1000000000000001
 
     FILETIME lastWriteTime{};
     const auto styledString{ Json::writeString(wbuilder, ToJson()) };

src/cascadia/TerminalSettingsModel/FontConfig.idl

@@ -16,7 +16,7 @@ namespace Microsoft.Terminal.Settings.Model
         Microsoft.Terminal.Settings.Model.Profile SourceProfile { get; };
 
         INHERITABLE_FONT_SETTING(String, FontFace);
-        INHERITABLE_FONT_SETTING(Int32, FontSize);
+        INHERITABLE_FONT_SETTING(Single, FontSize);
         INHERITABLE_FONT_SETTING(Windows.UI.Text.FontWeight, FontWeight);
 
         INHERITABLE_FONT_SETTING(Windows.Foundation.Collections.IMap<String COMMA UInt32>, FontFeatures);

src/cascadia/TerminalSettingsModel/MTSMSettings.h

@@ -96,7 +96,7 @@ Author(s):
 
 #define MTSM_FONT_SETTINGS(X)                                                          \
     X(hstring, FontFace, "face", DEFAULT_FONT_FACE)                                    \
-    X(int32_t, FontSize, "size", DEFAULT_FONT_SIZE)                                    \
+    X(float, FontSize, "size", DEFAULT_FONT_SIZE)                                      \
     X(winrt::Windows::UI::Text::FontWeight, FontWeight, "weight", DEFAULT_FONT_WEIGHT) \
     X(IFontAxesMap, FontAxes, "axes")                                                  \
     X(IFontFeatureMap, FontFeatures, "features")

src/cascadia/TerminalSettingsModel/TerminalSettings.h

@@ -121,7 +121,7 @@ namespace winrt::Microsoft::Terminal::Settings::Model::implementation
         INHERITABLE_SETTING(Model::TerminalSettings, double, Opacity, UseAcrylic() ? 0.5 : 1.0);
         INHERITABLE_SETTING(Model::TerminalSettings, hstring, Padding, DEFAULT_PADDING);
         INHERITABLE_SETTING(Model::TerminalSettings, hstring, FontFace, DEFAULT_FONT_FACE);
-        INHERITABLE_SETTING(Model::TerminalSettings, int32_t, FontSize, DEFAULT_FONT_SIZE);
+        INHERITABLE_SETTING(Model::TerminalSettings, float, FontSize, DEFAULT_FONT_SIZE);
 
         INHERITABLE_SETTING(Model::TerminalSettings, winrt::Windows::UI::Text::FontWeight, FontWeight);
         INHERITABLE_SETTING(Model::TerminalSettings, IFontAxesMap, FontAxes);

src/cascadia/inc/ControlProperties.h

@@ -57,7 +57,7 @@
     X(bool, UseAcrylic, false)                                                                                                                           \
     X(winrt::hstring, Padding, DEFAULT_PADDING)                                                                                                          \
     X(winrt::hstring, FontFace, L"Consolas")                                                                                                             \
-    X(int32_t, FontSize, DEFAULT_FONT_SIZE)                                                                                                              \
+    X(float, FontSize, DEFAULT_FONT_SIZE)                                                                                                                \
     X(winrt::Windows::UI::Text::FontWeight, FontWeight)                                                                                                  \
     X(IFontFeatureMap, FontFeatures)                                                                                                                     \
     X(IFontAxesMap, FontAxes)                                                                                                                            \

src/renderer/atlas/AtlasEngine.api.cpp

@@ -561,6 +561,7 @@ void AtlasEngine::_resolveFontMetrics(const wchar_t* requestedFaceName, const Fo
 {
     const auto requestedFamily = fontInfoDesired.GetFamily();
     auto requestedWeight = fontInfoDesired.GetWeight();
+    auto fontSize = fontInfoDesired.GetFontSize();
     auto requestedSize = fontInfoDesired.GetEngineSize();
 
     if (!requestedFaceName)
@@ -573,6 +574,7 @@ void AtlasEngine::_resolveFontMetrics(const wchar_t* requestedFaceName, const Fo
     }
     if (!requestedSize.Y)
     {
+        fontSize = 12.0f;
         requestedSize = { 0, 12 };
     }
     if (!requestedWeight)
@@ -614,8 +616,8 @@ void AtlasEngine::_resolveFontMetrics(const wchar_t* requestedFaceName, const Fo
     // Point sizes are commonly treated at a 72 DPI scale
     // (including by OpenType), whereas DirectWrite uses 96 DPI.
     // Since we want the height in px we multiply by the display's DPI.
-    const auto fontSizeInDIP = requestedSize.Y / 72.0f * 96.0f;
-    const auto fontSizeInPx = requestedSize.Y / 72.0f * _api.dpi;
+    const auto fontSizeInDIP = fontSize / 72.0f * 96.0f;
+    const auto fontSizeInPx = fontSize / 72.0f * _api.dpi;
 
     const auto designUnitsPerPx = fontSizeInPx / static_cast<float>(metrics.designUnitsPerEm);
     const auto ascent = static_cast<float>(metrics.ascent) * designUnitsPerPx;
@@ -662,7 +664,7 @@ void AtlasEngine::_resolveFontMetrics(const wchar_t* requestedFaceName, const Fo
     // Our cells can't overlap each other so we additionally clamp the bottom line to be inside the cell boundaries.
     doubleUnderlinePosBottom = std::min(doubleUnderlinePosBottom, lineHeight - thinLineWidth);
 
-    const auto cellWidth = gsl::narrow<u16>(std::roundf(advanceWidth));
+    const auto cellWidth = gsl::narrow<u16>(std::lroundf(advanceWidth));
     const auto cellHeight = gsl::narrow<u16>(lineHeight);
 
     {
@@ -675,8 +677,7 @@ void AtlasEngine::_resolveFontMetrics(const wchar_t* requestedFaceName, const Fo
             // The coordSizeUnscaled parameter to SetFromEngine is used for API functions like GetConsoleFontSize.
             // Since clients expect that settings the font height to Y yields back a font height of Y,
             // we're scaling the X relative/proportional to the actual cellWidth/cellHeight ratio.
-            // The code below uses a poor form of integer rounding.
-            requestedSize.X = (requestedSize.Y * cellWidth + cellHeight / 2) / cellHeight;
+            requestedSize.X = gsl::narrow_cast<til::CoordType>(std::lroundf(fontSize / cellHeight * cellWidth));
         }
 
         fontInfo.SetFromEngine(requestedFaceName, requestedFamily, requestedWeight, false, coordSize, requestedSize);