tdf#81144 Chinese full-width punctuation does not align properly

Ideographic fullstop and comma in most Chinese fonts are centered,
while those in Japanese fonts align closer to the left. Original
compression algorithm trimed right side of the punctuation, making
fullwidth fullstop or comma in Chinese font visually unbalanced.
In worst case, it crowds together with the followed compressed
punctuation.

This patch fix the situation in the folowing way
1) make compression less stronger.
2) Trim space according to glyph bearing to font height ratio.
3) fix a memory access violation issue

Reviewed-on: https://gerrit.libreoffice.org/19517Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Norbert Thiebaud <nthiebaud@gmail.com>

Conflicts:
	sw/source/core/txtnode/fntcache.cxx

Change-Id: Icff215064e6c442fd36eac8e01b01fb6acb27594
Reviewed-on: https://gerrit.libreoffice.org/19764Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
(cherry picked from commit f5ed3a29)

include/vcl/metric.hxx

@@ -72,6 +72,7 @@ public:
     long                GetExtLeading() const;
     long                GetLineHeight() const;
     long                GetSlant() const;
+    bool                IsFullstopCentered() const;
 
     FontMetric&         operator=( const FontMetric& rMetric );
     bool                operator==( const FontMetric& rMetric ) const;

sw/source/core/inc/scriptinfo.hxx

@@ -37,7 +37,7 @@ typedef std::list< sal_Int32 > PositionList;
 class SwScriptInfo
 {
 public:
-    enum CompType { KANA, SPECIAL_LEFT, SPECIAL_RIGHT, NONE };
+    enum CompType { KANA, SPECIAL_LEFT, SPECIAL_RIGHT, NONE, SPECIAL_MIDDLE};
 
 private:
     //! Records a single change in script type.
@@ -255,6 +255,7 @@ public:
     // modifies the kerning array according to a given compress value
     long Compress( long* pKernArray, sal_Int32 nIdx, sal_Int32 nLen,
                    const sal_uInt16 nCompress, const sal_uInt16 nFontHeight,
+                   const bool bCentered,
                    Point* pPoint = NULL ) const;
 
 /** Performs a kashida justification on the kerning array

sw/source/core/text/porlay.cxx

@@ -874,12 +874,15 @@ void SwScriptInfo::InitScriptInfo( const SwTextNode& rNode, bool bRTL )
                     eState = SPECIAL_LEFT;
                     break;
                 // Right punctuation found
-                case 0x3001: case 0x3002: case 0x3009: case 0x300B:
+                case 0x3009: case 0x300B:
                 case 0x300D: case 0x300F: case 0x3011: case 0x3015:
                 case 0x3017: case 0x3019: case 0x301B: case 0x301E:
                 case 0x301F:
                     eState = SPECIAL_RIGHT;
                     break;
+                case 0x3001: case 0x3002:   // Fullstop or comma
+                    eState = SPECIAL_MIDDLE ;
+                    break;
                 default:
                     eState = ( 0x3040 <= cChar && 0x3100 > cChar ) ? KANA : NONE;
                 }
@@ -1509,6 +1512,7 @@ size_t SwScriptInfo::HasKana( sal_Int32 nStart, const sal_Int32 nLen ) const
 
 long SwScriptInfo::Compress( long* pKernArray, sal_Int32 nIdx, sal_Int32 nLen,
                              const sal_uInt16 nCompress, const sal_uInt16 nFontHeight,
+                             bool bCenter,
                              Point* pPoint ) const
 {
     SAL_WARN_IF( !nCompress, "sw.core", "Compression without compression?!" );
@@ -1571,7 +1575,7 @@ long SwScriptInfo::Compress( long* pKernArray, sal_Int32 nIdx, sal_Int32 nLen,
                 long nMove = 0;
                 if( SwScriptInfo::KANA != nType )
                 {
-                    nLast /= 20000;
+                    nLast /= 24000;
                     if( pPoint && SwScriptInfo::SPECIAL_LEFT == nType )
                     {
                         if( nI )
@@ -1582,12 +1586,14 @@ long SwScriptInfo::Compress( long* pKernArray, sal_Int32 nIdx, sal_Int32 nLen,
                             nLast = 0;
                         }
                     }
+                    else if( bCenter && SwScriptInfo::SPECIAL_MIDDLE == nType )
+                        nMove = nLast / 2;
                 }
                 else
                     nLast /= 100000;
                 nSub -= nLast;
                 nLast = pKernArray[ nI ];
-                if( nMove )
+                if( nI && nMove )
                     pKernArray[ nI - 1 ] += nMove;
                 pKernArray[ nI++ ] -= nSub;
                 ++nIdx;

sw/source/core/txtnode/fntcache.cxx

@@ -629,6 +629,12 @@ static bool lcl_IsMonoSpaceFont( const vcl::RenderContext& rOut )
     return nWidth1 == nWidth2;
 }
 
+static bool lcl_IsFullstopCentered( const vcl::RenderContext& rOut )
+{
+    const FontMetric aMetric( rOut.GetFontMetric() );
+    return aMetric.IsFullstopCentered() ;
+}
+
 /* This helper structure (SwForbidden) contains the already marked parts of the string
     to avoid double lines (e.g grammar + spell check error) */
 
@@ -1053,7 +1059,7 @@ void SwFntObj::DrawText( SwDrawTextInfo &rInf )
                         lcl_IsMonoSpaceFont( *(rInf.GetpOut()) ) )
                     {
                         pSI->Compress( pKernArray, rInf.GetIdx(), rInf.GetLen(),
-                            rInf.GetKanaComp(), (sal_uInt16)aFont.GetSize().Height(), &aTextOriginPos );
+                            rInf.GetKanaComp(), (sal_uInt16)aFont.GetSize().Height(), lcl_IsFullstopCentered( rInf.GetOut() ) , &aTextOriginPos );
                         bSpecialJust = true;
                     }
                     ///Asian Justification
@@ -1224,7 +1230,7 @@ void SwFntObj::DrawText( SwDrawTextInfo &rInf )
                 {
                     pSI->Compress( pKernArray, rInf.GetIdx(), rInf.GetLen(),
                                    rInf.GetKanaComp(),
-                                   (sal_uInt16)aFont.GetSize().Height(), &aTextOriginPos );
+                                   (sal_uInt16)aFont.GetSize().Height(), lcl_IsFullstopCentered( rInf.GetOut() ), &aTextOriginPos );
                     bSpecialJust = true;
                 }
 
@@ -1434,10 +1440,10 @@ void SwFntObj::DrawText( SwDrawTextInfo &rInf )
                 Point aTmpPos( aTextOriginPos );
                 pSI->Compress( pScrArray, rInf.GetIdx(), rInf.GetLen(),
                                rInf.GetKanaComp(),
-                               (sal_uInt16)aFont.GetSize().Height(), &aTmpPos );
+                               (sal_uInt16)aFont.GetSize().Height(), lcl_IsFullstopCentered( rInf.GetOut() ), &aTmpPos );
                 pSI->Compress( pKernArray, rInf.GetIdx(), rInf.GetLen(),
                                rInf.GetKanaComp(),
-                               (sal_uInt16)aFont.GetSize().Height(), &aTextOriginPos );
+                               (sal_uInt16)aFont.GetSize().Height(), lcl_IsFullstopCentered( rInf.GetOut() ), &aTextOriginPos );
             }
 
             // Asian Justification
@@ -1904,7 +1910,7 @@ Size SwFntObj::GetTextSize( SwDrawTextInfo& rInf )
         if( bCompress )
             rInf.SetKanaDiff( rInf.GetScriptInfo()->Compress( pKernArray,
                 rInf.GetIdx(), nLn, rInf.GetKanaComp(),
-                (sal_uInt16)aFont.GetSize().Height() ) );
+                (sal_uInt16)aFont.GetSize().Height() ,lcl_IsFullstopCentered( rInf.GetOut() ) ) );
         else
             rInf.SetKanaDiff( 0 );
 
@@ -1967,7 +1973,7 @@ Size SwFntObj::GetTextSize( SwDrawTextInfo& rInf )
                                         rInf.GetIdx(), nLn );
             rInf.SetKanaDiff( rInf.GetScriptInfo()->Compress( pKernArray,
                 rInf.GetIdx(), nLn, rInf.GetKanaComp(),
-                (sal_uInt16) aFont.GetSize().Height() ) );
+                (sal_uInt16) aFont.GetSize().Height() ,lcl_IsFullstopCentered( rInf.GetOut() ) ) );
             aTextSize.Width() = pKernArray[ nLn - 1 ];
             delete[] pKernArray;
         }
@@ -2027,7 +2033,8 @@ sal_Int32 SwFntObj::GetCrsrOfst( SwDrawTextInfo &rInf )
         {
             pSI->Compress( pKernArray, rInf.GetIdx(), rInf.GetLen(),
                            rInf.GetKanaComp(),
-                           (sal_uInt16) aFont.GetSize().Height() );
+                           (sal_uInt16) aFont.GetSize().Height(),
+                           lcl_IsFullstopCentered( rInf.GetOut() ) );
         }
 
         // Asian Justification
@@ -2466,7 +2473,8 @@ sal_Int32 SwFont::GetTextBreak( SwDrawTextInfo& rInf, long nTextWidth )
         rInf.GetOut().GetTextArray( rInf.GetText(), pKernArray,
                                     rInf.GetIdx(), nLn );
         if( rInf.GetScriptInfo()->Compress( pKernArray, rInf.GetIdx(), nLn,
-                            rInf.GetKanaComp(), (sal_uInt16)GetHeight( nActual ) ) )
+                            rInf.GetKanaComp(), (sal_uInt16)GetHeight( nActual ) ,
+                            lcl_IsFullstopCentered( rInf.GetOut() ) ) )
         {
             long nKernAdd = nKern;
             sal_Int32 nTmpBreak = nTextBreak2;

vcl/inc/impfont.hxx

@@ -103,7 +103,7 @@ private:
     sal_uInt16          mnMiscFlags;   // Misc Flags
     sal_uInt32          mnRefCount;    // Reference Counter
 
-    enum { DEVICE_FLAG=1, SCALABLE_FLAG=2, LATIN_FLAG=4, CJK_FLAG=8, CTL_FLAG=16 };
+    enum { DEVICE_FLAG=1, SCALABLE_FLAG=2, LATIN_FLAG=4, CJK_FLAG=8, CTL_FLAG=16, FULLSTOP_CENTERED_FLAG=32 };
 
 public:
                         ImplFontMetric();
@@ -116,6 +116,7 @@ public:
     long                GetExtLeading() const   { return mnExtLeading; }
     long                GetLineHeight() const   { return mnLineHeight; }
     long                GetSlant() const        { return mnSlant; }
+    bool                IsFullstopCentered() const { return  ((mnMiscFlags & FULLSTOP_CENTERED_FLAG ) != 0); }
 
     bool                IsDeviceFont() const    { return ((mnMiscFlags & DEVICE_FLAG) != 0); }
     bool                IsScalable() const      { return ((mnMiscFlags & SCALABLE_FLAG) != 0); }

vcl/inc/outfont.hxx

@@ -187,6 +187,7 @@ public: // TODO: hide members behind accessor methods
     bool                mbDevice;                   // Flag for Device Fonts
     bool                mbScalableFont;
     bool                mbKernableFont;
+    bool                mbFullstopCentered;
 
     // font metrics that are usually derived from the measurements
     long                mnUnderlineSize;            // Lineheight of Underline

vcl/source/gdi/metric.cxx

@@ -151,6 +151,11 @@ long FontMetric::GetSlant() const
     return mpImplMetric->GetSlant();
 }
 
+bool FontMetric::IsFullstopCentered() const
+{
+    return mpImplMetric->IsFullstopCentered();
+}
+
 FontMetric& FontMetric::operator =( const FontMetric& rMetric )
 {
     vcl::FontInfo::operator=( rMetric );

vcl/source/outdev/font.cxx

@@ -215,6 +215,8 @@ FontMetric OutputDevice::GetFontMetric() const
             aMetric.mpImplMetric->mnMiscFlags |= ImplFontMetric::DEVICE_FLAG;
     if( pMetric->mbScalableFont )
             aMetric.mpImplMetric->mnMiscFlags |= ImplFontMetric::SCALABLE_FLAG;
+    if ( pMetric->mbFullstopCentered)
+            aMetric.mpImplMetric->mnMiscFlags |= ImplFontMetric::FULLSTOP_CENTERED_FLAG;
     aMetric.mpImplMetric->mnAscent      = ImplDevicePixelToLogicHeight( pMetric->mnAscent+mnEmphasisAscent );
     aMetric.mpImplMetric->mnDescent     = ImplDevicePixelToLogicHeight( pMetric->mnDescent+mnEmphasisDescent );
     aMetric.mpImplMetric->mnIntLeading  = ImplDevicePixelToLogicHeight( pMetric->mnIntLeading+mnEmphasisAscent );
@@ -1731,6 +1733,7 @@ ImplFontMetricData::ImplFontMetricData( const FontSelectPattern& rFontSelData )
     , mnMinKashida( 0 )
     , meFamilyType(FAMILY_DONTKNOW)
     , mbScalableFont(false)
+    , mbFullstopCentered(false)
     , mnUnderlineSize( 0 )
     , mnUnderlineOffset( 0 )
     , mnBUnderlineSize( 0 )
@@ -1775,6 +1778,7 @@ ImplFontMetricData::ImplFontMetricData( const FontSelectPattern& rFontSelData )
     }
 }
 
+
 void ImplFontMetricData::ImplInitTextLineSize( const OutputDevice* pDev )
 {
     long nDescent = mnDescent;
@@ -1857,6 +1861,21 @@ void ImplFontMetricData::ImplInitTextLineSize( const OutputDevice* pDev )
     mnDStrikeoutSize       = n2LineHeight;
     mnDStrikeoutOffset1    = nStrikeoutOffset - n2LineDY2 - n2LineHeight;
     mnDStrikeoutOffset2    = mnDStrikeoutOffset1 + n2LineDY + n2LineHeight;
+
+    const vcl::Font& rFont ( pDev->GetFont() );
+    bool bCentered = true;
+    if (MsLangId::isCJK(rFont.GetLanguage()))
+    {
+        const OUString sFullstop( sal_Unicode( 0x3001 ) ); // Fullwidth fullstop
+        Rectangle aRect;
+        pDev->GetTextBoundRect( aRect, sFullstop );
+        const sal_uInt16 nH = rFont.GetSize().Height();
+        const sal_uInt16 nB = aRect.Left();
+        // Use 18.75% as a threshold to define a centered fullwidth fullstop.
+        // In general, nB/nH < 5% for most Japanese fonts.
+        bCentered = (nB > (((nH >> 1)+nH)>>3)) ? true : false;
+    }
+    mbFullstopCentered = bCentered ;
 }
 
 void ImplFontMetricData::ImplInitAboveTextLineSize()