tdf#147999: Fix canvas font width for fallback fonts on Windows

For some reason we are getting the wrong font width for fallback fonts, which
results in rendering them squished. This happens only with VCL canvas, but not
with DX one, so it shows when hardware acceleration is disabled (either
explicitly or implicitly when Skia is enabled).

Change-Id: I5a45b1c1d68f4c6e6dd6b43371602af3330a7cd3
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/154272
Tested-by: Jenkins
Reviewed-by: خالد حسني <khaled@libreoffice.org>

canvas/source/vcl/canvasfont.cxx

@@ -47,7 +47,8 @@ namespace vclcanvas
                       Size( 0, ::basegfx::fround(rFontRequest.CellSize) ) ) ),
         maFontRequest( rFontRequest ),
         mpRefDevice( &rDevice ),
-        mpOutDevProvider( rOutDevProvider )
+        mpOutDevProvider( rOutDevProvider ),
+        maFontMatrix( rFontMatrix )
     {
         maFont->SetAlignment( ALIGN_BASELINE );
         maFont->SetCharSet( (rFontRequest.FontDescription.IsSymbolFont==css::util::TriState_YES) ? RTL_TEXTENCODING_SYMBOL : RTL_TEXTENCODING_UNICODE );
@@ -63,27 +64,7 @@ namespace vclcanvas
         maFont->SetLanguage( LanguageTag::convertToLanguageType( rFontRequest.Locale, false));
 
         // adjust to stretched/shrunk font
-        if( !::rtl::math::approxEqual( rFontMatrix.m00, rFontMatrix.m11) )
-        {
-            OutputDevice& rOutDev( rOutDevProvider->getOutDev() );
-
-            const bool bOldMapState( rOutDev.IsMapModeEnabled() );
-            rOutDev.EnableMapMode(false);
-
-            const Size aSize = rOutDev.GetFontMetric( *maFont ).GetFontSize();
-
-            const double fDividend( rFontMatrix.m10 + rFontMatrix.m11 );
-            double fStretch = rFontMatrix.m00 + rFontMatrix.m01;
-
-            if( !::basegfx::fTools::equalZero( fDividend) )
-                fStretch /= fDividend;
-
-            const ::tools::Long nNewWidth = ::basegfx::fround( aSize.Width() * fStretch );
-
-            maFont->SetAverageFontWidth( nNewWidth );
-
-            rOutDev.EnableMapMode(bOldMapState);
-        }
+        tools::setupFontWidth(rFontMatrix, maFont.get(), rOutDevProvider->getOutDev());
 
         sal_uInt32 nEmphasisMark = 0;
 
@@ -172,6 +153,13 @@ namespace vclcanvas
     {
         return *maFont;
     }
+
+    const css::geometry::Matrix2D& CanvasFont::getFontMatrix() const
+    {
+        SolarMutexGuard aGuard;
+
+        return maFontMatrix;
+    }
 }
 
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */

canvas/source/vcl/canvasfont.hxx

@@ -75,11 +75,14 @@ namespace vclcanvas
 
         vcl::Font const & getVCLFont() const;
 
+        const css::geometry::Matrix2D& getFontMatrix() const;
+
     private:
         ::canvas::vcltools::VCLObject<vcl::Font>                          maFont;
         css::rendering::FontRequest                                       maFontRequest;
         css::uno::Reference< css::rendering::XGraphicDevice>              mpRefDevice;
         OutDevProviderSharedPtr                                           mpOutDevProvider;
+        css::geometry::Matrix2D                                           maFontMatrix;
     };
 
 }

canvas/source/vcl/impltools.cxx

@@ -135,6 +135,33 @@ namespace vclcanvas::tools
             return true;
         }
 
+        void setupFontWidth(const css::geometry::Matrix2D& rFontMatrix,
+                            vcl::Font&                     rFont,
+                            OutputDevice&                  rOutDev)
+        {
+            rFont.SetFontSize(Size(0, rFont.GetFontHeight()));
+
+            if (!::rtl::math::approxEqual(rFontMatrix.m00, rFontMatrix.m11))
+            {
+                const bool bOldMapState(rOutDev.IsMapModeEnabled());
+                rOutDev.EnableMapMode(false);
+
+                const Size aSize = rOutDev.GetFontMetric(rFont).GetFontSize();
+
+                const double fDividend(rFontMatrix.m10 + rFontMatrix.m11);
+                double fStretch = rFontMatrix.m00 + rFontMatrix.m01;
+
+                if (!::basegfx::fTools::equalZero(fDividend))
+                    fStretch /= fDividend;
+
+                const ::tools::Long nNewWidth = ::basegfx::fround(aSize.Width() * fStretch);
+
+                rFont.SetAverageFontWidth(nNewWidth);
+
+                rOutDev.EnableMapMode(bOldMapState);
+            }
+        }
+
         bool isRectangle( const ::tools::PolyPolygon& rPolyPoly )
         {
             // exclude some cheap cases first

canvas/source/vcl/impltools.hxx

@@ -60,6 +60,7 @@ namespace com::sun::star::geometry
     struct RealPoint2D;
     struct RealSize2D;
     struct RealRectangle2D;
+    struct Matrix2D;
 }
 
 namespace com::sun::star::rendering
@@ -88,6 +89,10 @@ namespace vclcanvas
                                  const css::rendering::RenderState&    renderState,
                                  ::OutputDevice const &                rOutDev );
 
+        void setupFontWidth(const css::geometry::Matrix2D& rFontMatrix,
+                            vcl::Font&                     rFont,
+                            OutputDevice&                  rOutDev);
+
         /** Predicate, to determine whether polygon is actually an axis-aligned rectangle
 
             @return true, if the polygon is a rectangle.

canvas/source/vcl/textlayout.cxx

@@ -350,6 +350,14 @@ namespace vclcanvas
     {
         SolarMutexGuard aGuard;
 
+#ifdef _WIN32
+        // tdf#147999
+        // On Windows we get the wrong font width for fallback fonts unless we setup again here.
+        vcl::Font aFont(rOutDev.GetFont());
+        tools::setupFontWidth(mpFont->getFontMatrix(), aFont, rOutDev);
+        rOutDev.SetFont(aFont);
+#endif
+
         setupLayoutMode( rOutDev, mnTextDirection );
 
         if( maLogicalAdvancements.hasElements() )