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

Change-Id: Icff215064e6c442fd36eac8e01b01fb6acb27594
Reviewed-on: https://gerrit.libreoffice.org/19517
Tested-by: Jenkins <ci@libreoffice.org>
Reviewed-by: Norbert Thiebaud <nthiebaud@gmail.com>

8 files changed, 55 insertions, 13 deletions

diff --git a/include/vcl/metric.hxx b/include/vcl/metric.hxx
index ba2393d4123e..ddf27eb85455 100644
--- a/include/vcl/metric.hxx
+++ b/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;
diff --git a/sw/source/core/inc/scriptinfo.hxx b/sw/source/core/inc/scriptinfo.hxx
index ee476ac983e4..2201343dc183 100644
--- a/sw/source/core/inc/scriptinfo.hxx
+++ b/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
diff --git a/sw/source/core/text/porlay.cxx b/sw/source/core/text/porlay.cxx
index d7c217dc31d3..c5952abf2b65 100644
--- a/sw/source/core/text/porlay.cxx
+++ b/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;
diff --git a/sw/source/core/txtnode/fntcache.cxx b/sw/source/core/txtnode/fntcache.cxx
index 2f09296b023b..ea290e4e7f06 100644
--- a/sw/source/core/txtnode/fntcache.cxx
+++ b/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( m_nActual ) ) )
+                            rInf.GetKanaComp(), (sal_uInt16)GetHeight( m_nActual ),
+                            lcl_IsFullstopCentered( rInf.GetOut() ) ) )
         {
             long nKernAdd = nKern;
             sal_Int32 nTmpBreak = nTextBreak2;
diff --git a/vcl/inc/impfont.hxx b/vcl/inc/impfont.hxx
index 25aa15afb75e..fd9fb347516c 100644
--- a/vcl/inc/impfont.hxx
+++ b/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                IsScalable() const      { return ((mnMiscFlags & SCALABLE_FLAG) != 0); }
 
diff --git a/vcl/inc/outfont.hxx b/vcl/inc/outfont.hxx
index c4c30fbc81bd..0becf0ad55e5 100644
--- a/vcl/inc/outfont.hxx
+++ b/vcl/inc/outfont.hxx
@@ -183,6 +183,7 @@ 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
diff --git a/vcl/source/gdi/metric.cxx b/vcl/source/gdi/metric.cxx
index 5ed467ef912e..05630c63f895 100644
--- a/vcl/source/gdi/metric.cxx
+++ b/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 );
diff --git a/vcl/source/outdev/font.cxx b/vcl/source/outdev/font.cxx
index fd7b818ac871..6d641648eb03 100644
--- a/vcl/source/outdev/font.cxx
+++ b/vcl/source/outdev/font.cxx
@@ -216,6 +216,8 @@ 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 );
@@ -1744,6 +1746,7 @@ ImplFontMetricData::ImplFontMetricData( const FontSelectPattern& rFontSelData )
     , mnMinKashida( 0 )
     , meFamilyType(FAMILY_DONTKNOW)
     , mbScalableFont(false)
+    , mbFullstopCentered(false)
     , mnUnderlineSize( 0 )
     , mnUnderlineOffset( 0 )
     , mnBUnderlineSize( 0 )
@@ -1788,6 +1791,7 @@ ImplFontMetricData::ImplFontMetricData( const FontSelectPattern& rFontSelData )
     }
 }
 
+
 void ImplFontMetricData::ImplInitTextLineSize( const OutputDevice* pDev )
 {
     long nDescent = mnDescent;
@@ -1870,6 +1874,21 @@ 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()