WIN OSX Qt5 unify CreateFontSubset code

This is basically just some refactoring. Most interestingly the
MacOS used to work with 257 glyphs. I couldn't find any
explaination for the 256 glyph limit. Sadly the PrintFontManager
is out of scope. That needs more inspection.

Change-Id: Ibfa0e905f5efeb7d4a609884d64b4ed2615a9d3d
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/102688
Reviewed-by: Jan-Marek Glogowski <glogow@fbihome.de>
Tested-by: Jenkins

6 files changed, 152 insertions, 227 deletions

diff --git a/vcl/inc/salgdi.hxx b/vcl/inc/salgdi.hxx
index 9d86421e4e10..3a8fb1700862 100644
--- a/vcl/inc/salgdi.hxx
+++ b/vcl/inc/salgdi.hxx
@@ -57,6 +57,7 @@ namespace basegfx {
 namespace vcl
 {
 class AbstractTrueTypeFont;
+typedef struct TTGlobalFontInfo_ TTGlobalFontInfo;
 }
 
 typedef sal_Unicode sal_Ucs; // TODO: use sal_UCS4 instead of sal_Unicode
@@ -622,6 +623,19 @@ protected:
     static void GetGlyphWidths(const vcl::AbstractTrueTypeFont& rTTF,
                                const PhysicalFontFace& rFontFace, bool bVertical,
                                std::vector<sal_Int32>& rWidths, Ucs2UIntMap& rUnicodeEnc);
+
+    static bool CreateTTFfontSubset(vcl::AbstractTrueTypeFont& aTTF, const OString& rSysPath,
+                                    const bool bVertical, const sal_GlyphId* pGlyphIds,
+                                    const sal_uInt8* pEncoding, sal_Int32* pGlyphWidths,
+                                    int nGlyphCount);
+
+    static bool CreateCFFfontSubset(const unsigned char* pFontBytes, int nByteLength,
+                                    const OString& rSysPath, const sal_GlyphId* pGlyphIds,
+                                    const sal_uInt8* pEncoding, sal_Int32* pGlyphWidths,
+                                    int nGlyphCount, FontSubsetInfo& rInfo);
+
+    static void FillFontSubsetInfo(const vcl::TTGlobalFontInfo& rTTInfo, const OUString& pPSName,
+                                   FontSubsetInfo& rInfo);
 };
 
 bool SalGraphics::IsNativeControlSupported(ControlType eType, ControlPart ePart)
diff --git a/vcl/inc/sft.hxx b/vcl/inc/sft.hxx
index 86cb718809b3..8711364ed46f 100644
--- a/vcl/inc/sft.hxx
+++ b/vcl/inc/sft.hxx
@@ -144,7 +144,7 @@ namespace vcl
 
 /** Return value of GetTTGlobalFontInfo() */
 
-    typedef struct {
+    typedef struct TTGlobalFontInfo_ {
         char *family;             /**< family name                                             */
         sal_Unicode *ufamily;     /**< family name UCS2                                         */
         char *subfamily;          /**< subfamily name                                          */
diff --git a/vcl/qt5/Qt5Graphics_Text.cxx b/vcl/qt5/Qt5Graphics_Text.cxx
index 351bb3023213..de39fc7009b8 100644
--- a/vcl/qt5/Qt5Graphics_Text.cxx
+++ b/vcl/qt5/Qt5Graphics_Text.cxx
@@ -219,7 +219,6 @@ bool Qt5Graphics::CreateFontSubset(const OUString& rToFile, const PhysicalFontFa
                                    const sal_GlyphId* pGlyphIds, const sal_uInt8* pEncoding,
                                    sal_Int32* pGlyphWidths, int nGlyphCount, FontSubsetInfo& rInfo)
 {
-    // prepare the requested file name for writing the font-subset file
     OUString aSysPath;
     if (osl_File_E_None != osl_getSystemPathFromFileURL(rToFile.pData, &aSysPath.pData))
         return false;
@@ -228,23 +227,16 @@ bool Qt5Graphics::CreateFontSubset(const OUString& rToFile, const PhysicalFontFa
     const Qt5FontFace* pQt5FontFace = static_cast<const Qt5FontFace*>(pFontFace);
     const QFont aFont = pQt5FontFace->CreateFont();
     const QRawFont aRawFont(QRawFont::fromFont(aFont));
-    const QFontInfo aFontInfo(aFont);
     const OString aToFile(OUStringToOString(aSysPath, osl_getThreadTextEncoding()));
-    const int nOrigGlyphCount = nGlyphCount;
 
+    // handle CFF-subsetting
     QByteArray aCFFtable = aRawFont.fontTable("CFF ");
     if (!aCFFtable.isEmpty())
-    {
-        FILE* pOutFile = fopen(aToFile.getStr(), "wb");
-        rInfo.LoadFont(FontType::CFF_FONT, reinterpret_cast<const sal_uInt8*>(aCFFtable.data()),
-                       aCFFtable.size());
-        bool bRet = rInfo.CreateFontSubset(FontType::TYPE1_PFB, pOutFile, nullptr, pGlyphIds,
-                                           pEncoding, nGlyphCount, pGlyphWidths);
-        fclose(pOutFile);
-        return bRet;
-    }
+        return SalGraphics::CreateCFFfontSubset(
+            reinterpret_cast<const sal_uInt8*>(aCFFtable.data()), aCFFtable.size(), aToFile,
+            pGlyphIds, pEncoding, pGlyphWidths, nGlyphCount, rInfo);
 
-    // get details about the subsetted font
+    // fill details about the subsetted font
     rInfo.m_nFontType = FontType::SFNT_TTF;
     rInfo.m_aPSName = toOUString(aRawFont.familyName());
     rInfo.m_nCapHeight = aRawFont.capHeight();
@@ -257,49 +249,8 @@ bool Qt5Graphics::CreateFontSubset(const OUString& rToFile, const PhysicalFontFa
     if (GetTTGlobalFontHeadInfo(&aTTF, nXmin, nYmin, nXmax, nYmax, nMacStyleFlags))
         rInfo.m_aFontBBox = tools::Rectangle(Point(nXmin, nYmin), Point(nXmax, nYmax));
 
-    sal_uInt16 aShortIDs[nGlyphCount + 1];
-    sal_uInt8 aTempEncs[nGlyphCount + 1];
-
-    int nNotDef = -1;
-
-    for (int i = 0; i < nGlyphCount; ++i)
-    {
-        aTempEncs[i] = pEncoding[i];
-
-        sal_GlyphId aGlyphId(pGlyphIds[i]);
-        aShortIDs[i] = static_cast<sal_uInt16>(aGlyphId);
-        if (!aGlyphId && nNotDef < 0)
-            nNotDef = i; // first NotDef glyph found
-    }
-
-    if (nNotDef != 0)
-    {
-        // add fake NotDef glyph if needed
-        if (nNotDef < 0)
-            nNotDef = nGlyphCount++;
-        // NotDef glyph must be in pos 0 => swap glyphids
-        aShortIDs[nNotDef] = aShortIDs[0];
-        aTempEncs[nNotDef] = aTempEncs[0];
-        aShortIDs[0] = 0;
-        aTempEncs[0] = 0;
-    }
-
-    std::unique_ptr<sal_uInt16[]> pGlyphMetrics
-        = GetTTSimpleGlyphMetrics(&aTTF, aShortIDs, nGlyphCount, false);
-    if (!pGlyphMetrics)
-        return false;
-
-    sal_uInt16 nNotDefAdv = pGlyphMetrics[0];
-    pGlyphMetrics[0] = pGlyphMetrics[nNotDef];
-    pGlyphMetrics[nNotDef] = nNotDefAdv;
-
-    for (int i = 0; i < nOrigGlyphCount; ++i)
-        pGlyphWidths[i] = pGlyphMetrics[i];
-
-    // write subset into destination file
-    vcl::SFErrCodes nRC
-        = vcl::CreateTTFromTTGlyphs(&aTTF, aToFile.getStr(), aShortIDs, aTempEncs, nGlyphCount);
-    return (nRC == vcl::SFErrCodes::Ok);
+    return SalGraphics::CreateTTFfontSubset(aTTF, aToFile, false /* use FontSelectPattern? */,
+                                            pGlyphIds, pEncoding, pGlyphWidths, nGlyphCount);
 }
 
 const void* Qt5Graphics::GetEmbedFontData(const PhysicalFontFace*, long* /*pDataLen*/)
diff --git a/vcl/quartz/salgdicommon.cxx b/vcl/quartz/salgdicommon.cxx
index c72e8ee5cabd..3f2ec10bbd30 100644
--- a/vcl/quartz/salgdicommon.cxx
+++ b/vcl/quartz/salgdicommon.cxx
@@ -145,7 +145,7 @@ static void AddPolyPolygonToPath( CGMutablePathRef xPath,
 bool AquaSalGraphics::CreateFontSubset( const OUString& rToFile,
                                         const PhysicalFontFace* pFontData,
                                         const sal_GlyphId* pGlyphIds, const sal_uInt8* pEncoding,
-                                        sal_Int32* pGlyphWidths, int nGlyphCount,
+                                        sal_Int32* pGlyphWidths, const int nGlyphCount,
                                         FontSubsetInfo& rInfo )
 {
     // TODO: move more of the functionality here into the generic subsetter code
@@ -153,36 +153,21 @@ bool AquaSalGraphics::CreateFontSubset( const OUString& rToFile,
     // prepare the requested file name for writing the font-subset file
     OUString aSysPath;
     if( osl_File_E_None != osl_getSystemPathFromFileURL( rToFile.pData, &aSysPath.pData ) )
-    {
         return false;
-    }
 
     // get the raw-bytes from the font to be subset
     std::vector<unsigned char> aBuffer;
     bool bCffOnly = false;
     if( !GetRawFontData( pFontData, aBuffer, &bCffOnly ) )
-    {
         return false;
-    }
     const OString aToFile( OUStringToOString( aSysPath,
                                               osl_getThreadTextEncoding()));
 
     // handle CFF-subsetting
-    if( bCffOnly )
-    {
-        // provide the raw-CFF data to the subsetter
-        ByteCount nCffLen = aBuffer.size();
-        rInfo.LoadFont( FontType::CFF_FONT, aBuffer.data(), nCffLen );
-
-        // NOTE: assuming that all glyphids requested on Aqua are fully translated
-
-        // make the subsetter provide the requested subset
-        FILE* pOutFile = fopen( aToFile.getStr(), "wb" );
-        bool bRC = rInfo.CreateFontSubset( FontType::TYPE1_PFB, pOutFile, nullptr,
-                                           pGlyphIds, pEncoding, nGlyphCount, pGlyphWidths );
-        fclose( pOutFile );
-        return bRC;
-    }
+    // NOTE: assuming that all glyphids requested on Aqua are fully translated
+    if (bCffOnly)
+        return SalGraphics::CreateCFFfontSubset(aBuffer.data(), aBuffer.size(), aToFile, pGlyphIds,
+                                                pEncoding, pGlyphWidths, nGlyphCount, rInfo);
 
     // TODO: modernize psprint's horrible fontsubset C-API
     // this probably only makes sense after the switch to another SCM
@@ -190,102 +175,22 @@ bool AquaSalGraphics::CreateFontSubset( const OUString& rToFile,
 
     // prepare data for psprint's font subsetter
     TrueTypeFont* pSftFont = nullptr;
-    SFErrCodes nRC = ::OpenTTFontBuffer( static_cast<void*>(aBuffer.data()), aBuffer.size(), 0, &pSftFont);
-    if( nRC != SFErrCodes::Ok )
-    {
+    if (::OpenTTFontBuffer( static_cast<void*>(aBuffer.data()), aBuffer.size(), 0, &pSftFont)
+            != SFErrCodes::Ok)
         return false;
-    }
+
     // get details about the subsetted font
     TTGlobalFontInfo aTTInfo;
     ::GetTTGlobalFontInfo( pSftFont, &aTTInfo );
-    rInfo.m_nFontType = FontType::SFNT_TTF;
-    rInfo.m_aPSName = OUString( aTTInfo.psname, std::strlen(aTTInfo.psname),
-                                RTL_TEXTENCODING_UTF8 );
-    rInfo.m_aFontBBox = tools::Rectangle( Point( aTTInfo.xMin, aTTInfo.yMin ),
-                                   Point( aTTInfo.xMax, aTTInfo.yMax ) );
-    rInfo.m_nCapHeight = aTTInfo.yMax; // Well ...
-    rInfo.m_nAscent = aTTInfo.winAscent;
-    rInfo.m_nDescent = aTTInfo.winDescent;
-    // mac fonts usually do not have an OS2-table
-    // => get valid ascent/descent values from other tables
-    if( !rInfo.m_nAscent )
-    {
-        rInfo.m_nAscent = +aTTInfo.typoAscender;
-    }
-    if( !rInfo.m_nAscent )
-    {
-        rInfo.m_nAscent = +aTTInfo.ascender;
-    }
-    if( !rInfo.m_nDescent )
-    {
-        rInfo.m_nDescent = +aTTInfo.typoDescender;
-    }
-    if( !rInfo.m_nDescent )
-    {
-        rInfo.m_nDescent = -aTTInfo.descender;
-    }
-
-    // subset glyphs and get their properties
-    // take care that subset fonts require the NotDef glyph in pos 0
-    int nOrigCount = nGlyphCount;
-    sal_uInt16 aShortIDs[ 257 ];
-    sal_uInt8 aTempEncs[ 257 ];
-    int nNotDef = -1;
-
-    assert( (nGlyphCount <= 256 && "too many glyphs for subsetting" ));
-
-    for( int i = 0; i < nGlyphCount; ++i )
-    {
-        aTempEncs[i] = pEncoding[i];
-
-        sal_GlyphId aGlyphId(pGlyphIds[i]);
-        aShortIDs[i] = static_cast<sal_uInt16>( aGlyphId );
-        if( !aGlyphId && nNotDef < 0 )
-        {
-            nNotDef = i; // first NotDef glyph found
-        }
-    }
-
-    if( nNotDef != 0 )
-    {
-        // add fake NotDef glyph if needed
-        if( nNotDef < 0 )
-        {
-            nNotDef = nGlyphCount++;
-        }
-        // NotDef glyph must be in pos 0 => swap glyphids
-        aShortIDs[ nNotDef ] = aShortIDs[0];
-        aTempEncs[ nNotDef ] = aTempEncs[0];
-        aShortIDs[0] = 0;
-        aTempEncs[0] = 0;
-    }
-
-    // TODO: where to get bVertical?
-    const bool bVertical = false;
-
-    // fill the pGlyphWidths array
-    // while making sure that the NotDef glyph is at index==0
-    std::unique_ptr<sal_uInt16[]> pGlyphMetrics = ::GetTTSimpleGlyphMetrics( pSftFont, aShortIDs,
-                                                                     nGlyphCount, bVertical );
-    if( !pGlyphMetrics )
-    {
-        return false;
-    }
-
-    sal_uInt16 nNotDefAdv = pGlyphMetrics[0];
-    pGlyphMetrics[0] = pGlyphMetrics[nNotDef];
-    pGlyphMetrics[nNotDef]  = nNotDefAdv;
-    for( int i = 0; i < nOrigCount; ++i )
-    {
-        pGlyphWidths[i] = pGlyphMetrics[i];
-    }
-    pGlyphMetrics.reset();
+    OUString aPSName(aTTInfo.psname, std::strlen(aTTInfo.psname), RTL_TEXTENCODING_UTF8);
+    FillFontSubsetInfo(aTTInfo, aPSName, rInfo);
 
     // write subset into destination file
-    nRC = ::CreateTTFromTTGlyphs( pSftFont, aToFile.getStr(), aShortIDs,
-                                  aTempEncs, nGlyphCount );
+    bool bRet
+        = SalGraphics::CreateTTFfontSubset(*pSftFont, aToFile, false /* use FontSelectPattern? */,
+                                           pGlyphIds, pEncoding, pGlyphWidths, nGlyphCount);
     ::CloseTTFont(pSftFont);
-    return (nRC == SFErrCodes::Ok);
+    return bRet;
 }
 
 static void alignLinePoint( const SalPoint* i_pIn, float& o_fX, float& o_fY )
diff --git a/vcl/source/gdi/salgdilayout.cxx b/vcl/source/gdi/salgdilayout.cxx
index 777b2b1115e4..5758bfd2acec 100644
--- a/vcl/source/gdi/salgdilayout.cxx
+++ b/vcl/source/gdi/salgdilayout.cxx
@@ -29,6 +29,7 @@
 #endif
 #endif
 #include <PhysicalFontFace.hxx>
+#include <fontsubset.hxx>
 #include <salgdi.hxx>
 #include <salframe.hxx>
 #include <sft.hxx>
@@ -942,4 +943,111 @@ void SalGraphics::GetGlyphWidths(const vcl::AbstractTrueTypeFont& rTTF,
     }
 }
 
+bool SalGraphics::CreateTTFfontSubset(vcl::AbstractTrueTypeFont& rTTF, const OString& rSysPath,
+                                   const bool bVertical, const sal_GlyphId* pGlyphIds,
+                                   const sal_uInt8* pEncoding, sal_Int32* pGlyphWidths,
+                                   const int nOrigGlyphCount)
+{
+    // Multiple questions:
+    // - Why is there a glyph limit?
+    //   MacOS used to handle 257 glyphs...
+    //   Also the much more complex PrintFontManager variant has this limit.
+    //   Also the very first implementation has the limit in
+    //   commit 8789ed701e98031f2a1657ea0dfd6f7a0b050992
+    // - Why doesn't the PrintFontManager care about the fake glpyh? It
+    //   is used on all unx platforms to create the subset font.
+    // - Should the SAL_WARN actually be asserts, like on MacOS?
+    if (nOrigGlyphCount > 256)
+    {
+        SAL_WARN("vcl.fonts", "too many glyphs for subsetting");
+        return false;
+    }
+
+    int nGlyphCount = nOrigGlyphCount;
+    sal_uInt16 aShortIDs[256];
+    sal_uInt8 aTempEncs[256];
+
+    // handle the undefined / first font glyph
+    int nNotDef = -1, i;
+    for (i = 0; i < nGlyphCount; ++i)
+    {
+        aTempEncs[i] = pEncoding[i];
+        aShortIDs[i] = static_cast<sal_uInt16>(pGlyphIds[i]);
+        if (!aShortIDs[i])
+            if (nNotDef < 0)
+                nNotDef = i;
+    }
+
+    // nNotDef glyph must be in pos 0 => swap glyphids
+    if (nNotDef != 0)
+    {
+        if (nNotDef < 0)
+        {
+            if (nGlyphCount == 256)
+            {
+                SAL_WARN("vcl.fonts", "too many glyphs for subsetting");
+                return false;
+            }
+            nNotDef = nGlyphCount++;
+        }
+
+        aShortIDs[nNotDef] = aShortIDs[0];
+        aTempEncs[nNotDef] = aTempEncs[0];
+        aShortIDs[0] = 0;
+        aTempEncs[0] = 0;
+    }
+
+    std::unique_ptr<sal_uInt16[]> pMetrics
+        = GetTTSimpleGlyphMetrics(&rTTF, aShortIDs, nGlyphCount, bVertical);
+    if (!pMetrics)
+        return false;
+
+    sal_uInt16 nNotDefAdv = pMetrics[0];
+    pMetrics[0] = pMetrics[nNotDef];
+    pMetrics[nNotDef] = nNotDefAdv;
+    for (i = 0; i < nOrigGlyphCount; ++i)
+        pGlyphWidths[i] = pMetrics[i];
+    pMetrics.reset();
+
+    // write subset into destination file
+    return (CreateTTFromTTGlyphs(&rTTF, rSysPath.getStr(), aShortIDs, aTempEncs, nGlyphCount)
+            == vcl::SFErrCodes::Ok);
+}
+
+bool SalGraphics::CreateCFFfontSubset(const unsigned char* pFontBytes, int nByteLength,
+                                      const OString& rSysPath, const sal_GlyphId* pGlyphIds,
+                                      const sal_uInt8* pEncoding, sal_Int32* pGlyphWidths,
+                                      int nGlyphCount, FontSubsetInfo& rInfo)
+{
+    FILE* pOutFile = fopen(rSysPath.getStr(), "wb");
+    rInfo.LoadFont(FontType::CFF_FONT, pFontBytes, nByteLength);
+    bool bRet = rInfo.CreateFontSubset(FontType::TYPE1_PFB, pOutFile, nullptr, pGlyphIds, pEncoding,
+                                       nGlyphCount, pGlyphWidths);
+    fclose(pOutFile);
+    return bRet;
+}
+
+void SalGraphics::FillFontSubsetInfo(const vcl::TTGlobalFontInfo& rTTInfo, const OUString& pPSName,
+                                     FontSubsetInfo& rInfo)
+{
+    rInfo.m_aPSName = pPSName;
+    rInfo.m_nFontType = FontType::SFNT_TTF;
+    rInfo.m_aFontBBox
+        = tools::Rectangle(Point(rTTInfo.xMin, rTTInfo.yMin), Point(rTTInfo.xMax, rTTInfo.yMax));
+    rInfo.m_nCapHeight = rTTInfo.yMax; // Well ...
+    rInfo.m_nAscent = rTTInfo.winAscent;
+    rInfo.m_nDescent = rTTInfo.winDescent;
+
+    // mac fonts usually do not have an OS2-table
+    // => get valid ascent/descent values from other tables
+    if (!rInfo.m_nAscent)
+        rInfo.m_nAscent = +rTTInfo.typoAscender;
+    if (!rInfo.m_nAscent)
+        rInfo.m_nAscent = +rTTInfo.ascender;
+    if (!rInfo.m_nDescent)
+        rInfo.m_nDescent = +rTTInfo.typoDescender;
+    if (!rInfo.m_nDescent)
+        rInfo.m_nDescent = -rTTInfo.descender;
+}
+
 /* vim:set shiftwidth=4 softtabstop=4 expandtab: */
diff --git a/vcl/win/gdi/salfont.cxx b/vcl/win/gdi/salfont.cxx
index bc7f83b8b6f2..0d7930d20e71 100644
--- a/vcl/win/gdi/salfont.cxx
+++ b/vcl/win/gdi/salfont.cxx
@@ -1605,17 +1605,12 @@ bool WinSalGraphics::CreateFontSubset( const OUString& rToFile,
     // check if the font has a CFF-table
     const DWORD nCffTag = CalcTag( "CFF " );
     const RawFontData aRawCffData( getHDC(), nCffTag );
-    if( aRawCffData.get() )
+    if (aRawCffData.get())
     {
         pWinFontData->UpdateFromHDC( getHDC() );
-
-        // provide a font subset from the CFF-table
-        FILE* pOutFile = fopen( aToFile.getStr(), "wb" );
-        rInfo.LoadFont( FontType::CFF_FONT, aRawCffData.get(), aRawCffData.size() );
-        bool bRC = rInfo.CreateFontSubset( FontType::TYPE1_PFB, pOutFile, nullptr,
-                pGlyphIds, pEncoding, nGlyphCount, pGlyphWidths );
-        fclose( pOutFile );
-        return bRC;
+        return SalGraphics::CreateCFFfontSubset(aRawCffData.get(), aRawCffData.size(), aToFile,
+                                                pGlyphIds, pEncoding, pGlyphWidths, nGlyphCount,
+                                                rInfo);
     }
 
     // get raw font file data
@@ -1635,60 +1630,12 @@ bool WinSalGraphics::CreateFontSubset( const OUString& rToFile,
 
     TTGlobalFontInfo aTTInfo;
     ::GetTTGlobalFontInfo( aSftTTF.get(), &aTTInfo );
-    rInfo.m_nFontType   = FontType::SFNT_TTF;
-    rInfo.m_aPSName     = ImplSalGetUniString( aTTInfo.psname );
-    rInfo.m_nAscent     = aTTInfo.winAscent;
-    rInfo.m_nDescent    = aTTInfo.winDescent;
-    rInfo.m_aFontBBox   = tools::Rectangle( Point( aTTInfo.xMin, aTTInfo.yMin ),
-                                    Point( aTTInfo.xMax, aTTInfo.yMax ) );
-    rInfo.m_nCapHeight  = aTTInfo.yMax; // Well ...
-
-    // subset TTF-glyphs and get their properties
-    // take care that subset fonts require the NotDef glyph in pos 0
-    int nOrigCount = nGlyphCount;
-    sal_uInt16    aShortIDs[ 256 ];
-    sal_uInt8 aTempEncs[ 256 ];
-
-    int nNotDef=-1, i;
-    for( i = 0; i < nGlyphCount; ++i )
-    {
-        aTempEncs[i] = pEncoding[i];
-        aShortIDs[i] = static_cast<sal_uInt16>(pGlyphIds[i]);
-        if (!aShortIDs[i])
-            if( nNotDef < 0 )
-                nNotDef = i; // first NotDef glyph found
-    }
-
-    if( nNotDef != 0 )
-    {
-        // add fake NotDef glyph if needed
-        if( nNotDef < 0 )
-            nNotDef = nGlyphCount++;
-
-        // NotDef glyph must be in pos 0 => swap glyphids
-        aShortIDs[ nNotDef ] = aShortIDs[0];
-        aTempEncs[ nNotDef ] = aTempEncs[0];
-        aShortIDs[0] = 0;
-        aTempEncs[0] = 0;
-    }
-    SAL_WARN_IF( nGlyphCount >= 257, "vcl", "too many glyphs for subsetting" );
-
-    // fill pWidth array
-    std::unique_ptr<sal_uInt16[]> pMetrics =
-        ::GetTTSimpleGlyphMetrics( aSftTTF.get(), aShortIDs, nGlyphCount, aIFSD.mbVertical );
-    if( !pMetrics )
-        return false;
-    sal_uInt16 nNotDefAdv = pMetrics[0];
-    pMetrics[0]         = pMetrics[nNotDef];
-    pMetrics[nNotDef]   = nNotDefAdv;
-    for( i = 0; i < nOrigCount; ++i )
-        pGlyphWidths[i] = pMetrics[i];
-    pMetrics.reset();
+    OUString aPSName = ImplSalGetUniString(aTTInfo.psname);
+    FillFontSubsetInfo(aTTInfo, aPSName, rInfo);
 
     // write subset into destination file
-    nRC = ::CreateTTFromTTGlyphs( aSftTTF.get(), aToFile.getStr(), aShortIDs,
-            aTempEncs, nGlyphCount );
-    return (nRC == SFErrCodes::Ok);
+    return SalGraphics::CreateTTFfontSubset(*aSftTTF.get(), aToFile, aIFSD.mbVertical, pGlyphIds,
+                                            pEncoding, pGlyphWidths, nGlyphCount);
 }
 
 const void* WinSalGraphics::GetEmbedFontData(const PhysicalFontFace* pFont, long* pDataLen)