tdf#104921: Cleanup Kashida insertion logic

Communicate Kashida insertion positions in an explicit way.

Rest of LibreOffice communicate adjustments to character widths (e.g.
for justification or spacing) using so-called DX array. DX array is an
array of absolute character positions (e.g. DX[n] is the position after
character n from the start of the lines, and its widths is DX[n] -
DX[n-1]).

This DX array is modified also when Kashidas are inserted after a given
character for Arabic justification, by expanding its width. VCL would
use this to know where to insert the Kashidas and how many ones.

But because DX array is used for both widths adjustments and kashida
insertion, this turns out to be a source of bugs since VCL has tosecond
guess the DX array to find which is pure width adjustment and which also
involves Kashida insertion, and the heuristics it uses are fragile.

This change adds a second array of booleans that records where Kashida
is inserted and communicates it all the way from where Kashida insertion
is decoded in Writer and down to VCL layout.

This change passes the Kashida array only when it seems necessary (e.g.
during drawing but not when measuring text since the DX array is enough
in this case). Hopefully no places where Kashida insertion needs to be
passed down were missed.

A couple of glyph and layout flags that were used for old heuristics and
no longer needed and are removed.

This also fixes:
tdf#87731
tdf#106309
tdf#108604
tdf#112849
tdf#114257
tdf#127176
tdf#145647
tdf#146199

Change-Id: I4ed0850ef2fdc3e9143341afac649e7e7d463c39
Reviewed-on: https://gerrit.libreoffice.org/c/core/+/138068
Tested-by: Jenkins
Reviewed-by: Caolán McNamara <caolanm@redhat.com>

7 files changed, 52 insertions, 18 deletions

diff --git a/editeng/inc/editdoc.hxx b/editeng/inc/editdoc.hxx
index 6ce00d05c40b..25a3dca4b1fc 100644
--- a/editeng/inc/editdoc.hxx
+++ b/editeng/inc/editdoc.hxx
@@ -463,6 +463,7 @@ public:
 
 private:
     CharPosArrayType aPositions;
+    std::vector<sal_Bool> aKashidaPositions;
     sal_Int32          nTxtWidth;
     sal_Int32          nStartPosX;
     sal_Int32          nStart;     // could be replaced by nStartPortion
@@ -531,6 +532,9 @@ public:
     CharPosArrayType& GetCharPosArray() { return aPositions;}
     const CharPosArrayType& GetCharPosArray() const { return aPositions;}
 
+    std::vector<sal_Bool>& GetKashidaArray() { return aKashidaPositions; }
+    const std::vector<sal_Bool>& GetKashidaArray() const { return aKashidaPositions; }
+
     EditLine*       Clone() const;
 
     EditLine&   operator = ( const EditLine& rLine );
diff --git a/editeng/source/editeng/editeng.cxx b/editeng/source/editeng/editeng.cxx
index db4ae5db4491..88bc04a9efed 100644
--- a/editeng/source/editeng/editeng.cxx
+++ b/editeng/source/editeng/editeng.cxx
@@ -2465,7 +2465,8 @@ css::uno::Reference< css::datatransfer::XTransferable >
 // ======================    Virtual Methods    ========================
 
 void EditEngine::DrawingText( const Point&, const OUString&, sal_Int32, sal_Int32,
-                              o3tl::span<const sal_Int32>, const SvxFont&, sal_Int32 /*nPara*/, sal_uInt8 /*nRightToLeft*/,
+                              o3tl::span<const sal_Int32>, o3tl::span<const sal_Bool>,
+                              const SvxFont&, sal_Int32 /*nPara*/, sal_uInt8 /*nRightToLeft*/,
                               const EEngineData::WrongSpellVector*, const SvxFieldData*, bool, bool,
                               const css::lang::Locale*, const Color&, const Color&)
 
diff --git a/editeng/source/editeng/impedit3.cxx b/editeng/source/editeng/impedit3.cxx
index 143a763208e1..9d71560c108b 100644
--- a/editeng/source/editeng/impedit3.cxx
+++ b/editeng/source/editeng/impedit3.cxx
@@ -2147,6 +2147,10 @@ void ImpEditEngine::ImpAdjustBlocks( ParaPortion* pParaPortion, EditLine* pLine,
         nLastScript = nScript;
     }
 
+    // Save the number of blanks, we will use it below when marking Kashida
+    // positions.
+    auto nBlankSize = aPositions.size();
+
     // Kashidas ?
     ImpFindKashidas( pNode, nFirstChar, nLastChar, aPositions );
 
@@ -2186,6 +2190,19 @@ void ImpEditEngine::ImpAdjustBlocks( ParaPortion* pParaPortion, EditLine* pLine,
     DBG_ASSERT( nSomeExtraSpace < static_cast<tools::Long>(nGaps), "AdjustBlocks: ExtraSpace too large" );
     DBG_ASSERT( nSomeExtraSpace >= 0, "AdjustBlocks: ExtraSpace < 0 " );
 
+    // Mark Kashida positions, so that VCL knows where to insert Kashida and
+    // where to only expand the width.
+    if (aPositions.size() > nBlankSize)
+    {
+        pLine->GetKashidaArray().resize(pLine->GetCharPosArray().size(), false);
+        for (auto i = nBlankSize; i < aPositions.size(); i++)
+        {
+            auto nChar = aPositions[i];
+            if ( nChar < nLastChar )
+                pLine->GetKashidaArray()[nChar-nFirstChar] = 1 /*sal_True*/;
+        }
+    }
+
     // Correct the positions in the Array and the portion widths:
     // Last character won't be considered...
     for (auto const& nChar : aPositions)
@@ -2202,7 +2219,6 @@ void ImpEditEngine::ImpAdjustBlocks( ParaPortion* pParaPortion, EditLine* pLine,
                 rLastPortion.GetSize().AdjustWidth( 1 );
 
             // Correct positions in array
-            // Even for kashidas just change positions, VCL will then draw the kashida automatically
             sal_Int32 nPortionEnd = nPortionStart + rLastPortion.GetLen();
             for ( sal_Int32 _n = nChar; _n < nPortionEnd; _n++ )
             {
@@ -3293,6 +3309,7 @@ void ImpEditEngine::Paint( OutputDevice& rOutDev, tools::Rectangle aClipRect, Po
                                 sal_Int32 nTextStart = 0;
                                 sal_Int32 nTextLen = 0;
                                 o3tl::span<const sal_Int32> pDXArray;
+                                o3tl::span<const sal_Bool> pKashidaArray;
                                 std::vector<sal_Int32> aTmpDXArray;
 
                                 if ( rTextPortion.GetKind() == PortionKind::TEXT )
@@ -3303,6 +3320,12 @@ void ImpEditEngine::Paint( OutputDevice& rOutDev, tools::Rectangle aClipRect, Po
                                     pDXArray = o3tl::span(pLine->GetCharPosArray().data() + (nIndex - pLine->GetStart()),
                                                     pLine->GetCharPosArray().size() - (nIndex - pLine->GetStart()));
 
+                                    if (!pLine->GetKashidaArray().empty())
+                                    {
+                                        pKashidaArray = o3tl::span(pLine->GetKashidaArray().data() + (nIndex - pLine->GetStart()),
+                                                    pLine->GetKashidaArray().size() - (nIndex - pLine->GetStart()));
+                                    }
+
                                     // Paint control characters (#i55716#)
                                     /* XXX: Given that there's special handling
                                      * only for some specific characters
@@ -3552,7 +3575,7 @@ void ImpEditEngine::Paint( OutputDevice& rOutDev, tools::Rectangle aClipRect, Po
                                         ImplCalcDigitLang(aTmpFont.GetLanguage()));
 
                                     // StripPortions() data callback
-                                    GetEditEnginePtr()->DrawingText( aOutPos, aText, nTextStart, nTextLen, pDXArray,
+                                    GetEditEnginePtr()->DrawingText( aOutPos, aText, nTextStart, nTextLen, pDXArray, pKashidaArray,
                                         aTmpFont, n, rTextPortion.GetRightToLeftLevel(),
                                         !aWrongSpellVector.empty() ? &aWrongSpellVector : nullptr,
                                         pFieldData,
@@ -3656,7 +3679,7 @@ void ImpEditEngine::Paint( OutputDevice& rOutDev, tools::Rectangle aClipRect, Po
                                             --nTextLen;
 
                                         // output directly
-                                        aTmpFont.QuickDrawText( &rOutDev, aRealOutPos, aText, nTextStart, nTextLen, pDXArray );
+                                        aTmpFont.QuickDrawText( &rOutDev, aRealOutPos, aText, nTextStart, nTextLen, pDXArray, pKashidaArray );
 
                                         if ( bDrawFrame )
                                         {
@@ -3792,7 +3815,7 @@ void ImpEditEngine::Paint( OutputDevice& rOutDev, tools::Rectangle aClipRect, Po
                                     const Color aTextLineColor(rOutDev.GetTextLineColor());
 
                                     GetEditEnginePtr()->DrawingText(
-                                        aTmpPos, OUString(), 0, 0, {},
+                                        aTmpPos, OUString(), 0, 0, {}, {},
                                         aTmpFont, n, 0,
                                         nullptr,
                                         nullptr,
@@ -3841,7 +3864,7 @@ void ImpEditEngine::Paint( OutputDevice& rOutDev, tools::Rectangle aClipRect, Po
                 const Color aTextLineColor(rOutDev.GetTextLineColor());
 
                 GetEditEnginePtr()->DrawingText(
-                    aTmpPos, OUString(), 0, 0, {},
+                    aTmpPos, OUString(), 0, 0, {}, {},
                     aTmpFont, n, 0,
                     nullptr,
                     nullptr,
diff --git a/editeng/source/items/svxfont.cxx b/editeng/source/items/svxfont.cxx
index ca8c5f3fddc6..ac360873824a 100644
--- a/editeng/source/items/svxfont.cxx
+++ b/editeng/source/items/svxfont.cxx
@@ -545,21 +545,24 @@ Size SvxFont::GetTextSize(const OutputDevice& rOut, const OUString &rTxt,
 
 static void DrawTextArray( OutputDevice* pOut, const Point& rStartPt, const OUString& rStr,
                            o3tl::span<const sal_Int32> pDXAry,
+                           o3tl::span<const sal_Bool> pKashidaAry,
                            sal_Int32 nIndex, sal_Int32 nLen )
 {
     const SalLayoutGlyphs* layoutGlyphs = SalLayoutGlyphsCache::self()->GetLayoutGlyphs(pOut, rStr, nIndex, nLen);
-    pOut->DrawTextArray(rStartPt, rStr, pDXAry, nIndex, nLen, SalLayoutFlags::NONE, layoutGlyphs);
+    pOut->DrawTextArray(rStartPt, rStr, pDXAry, pKashidaAry, nIndex, nLen, SalLayoutFlags::NONE, layoutGlyphs);
 }
 
 void SvxFont::QuickDrawText( OutputDevice *pOut,
     const Point &rPos, const OUString &rTxt,
-    const sal_Int32 nIdx, const sal_Int32 nLen, o3tl::span<const sal_Int32> pDXArray ) const
+    const sal_Int32 nIdx, const sal_Int32 nLen,
+    o3tl::span<const sal_Int32> pDXArray,
+    o3tl::span<const sal_Bool> pKashidaArray) const
 {
 
     // Font has to be selected in OutputDevice...
     if ( !IsCaseMap() && !IsCapital() && !IsKern() && !IsEsc() )
     {
-        DrawTextArray( pOut, rPos, rTxt, pDXArray, nIdx, nLen );
+        DrawTextArray( pOut, rPos, rTxt, pDXArray, pKashidaArray, nIdx, nLen );
         return;
     }
 
@@ -596,9 +599,9 @@ void SvxFont::QuickDrawText( OutputDevice *pOut,
         else
         {
             if ( !IsCaseMap() )
-                DrawTextArray( pOut, aPos, rTxt, pDXArray, nIdx, nLen );
+                DrawTextArray( pOut, aPos, rTxt, pDXArray, pKashidaArray, nIdx, nLen );
             else
-                DrawTextArray( pOut, aPos, CalcCaseMap( rTxt ), pDXArray, nIdx, nLen );
+                DrawTextArray( pOut, aPos, CalcCaseMap( rTxt ), pDXArray, pKashidaArray, nIdx, nLen );
         }
     }
 }
diff --git a/editeng/source/outliner/outleeng.cxx b/editeng/source/outliner/outleeng.cxx
index e4fc414ad8e3..275636b6581e 100644
--- a/editeng/source/outliner/outleeng.cxx
+++ b/editeng/source/outliner/outleeng.cxx
@@ -141,7 +141,8 @@ OUString OutlinerEditEng::GetUndoComment( sal_uInt16 nUndoId ) const
 }
 
 void OutlinerEditEng::DrawingText( const Point& rStartPos, const OUString& rText, sal_Int32 nTextStart, sal_Int32 nTextLen,
-                                   o3tl::span<const sal_Int32> pDXArray, const SvxFont& rFont, sal_Int32 nPara, sal_uInt8 nRightToLeft,
+                                   o3tl::span<const sal_Int32> pDXArray, o3tl::span<const sal_Bool> pKashidaArray,
+                                   const SvxFont& rFont, sal_Int32 nPara, sal_uInt8 nRightToLeft,
                                    const EEngineData::WrongSpellVector* pWrongSpellVector,
                                    const SvxFieldData* pFieldData,
                                    bool bEndOfLine,
@@ -150,7 +151,7 @@ void OutlinerEditEng::DrawingText( const Point& rStartPos, const OUString& rText
                                    const Color& rOverlineColor,
                                    const Color& rTextLineColor)
 {
-    pOwner->DrawingText(rStartPos,rText,nTextStart,nTextLen,pDXArray,rFont,nPara,nRightToLeft,
+    pOwner->DrawingText(rStartPos,rText,nTextStart,nTextLen,pDXArray,pKashidaArray,rFont,nPara,nRightToLeft,
         pWrongSpellVector, pFieldData, bEndOfLine, bEndOfParagraph, false/*bEndOfBullet*/, pLocale, rOverlineColor, rTextLineColor);
 }
 
diff --git a/editeng/source/outliner/outleeng.hxx b/editeng/source/outliner/outleeng.hxx
index 963e74582ec0..d19b54eba06a 100644
--- a/editeng/source/outliner/outleeng.hxx
+++ b/editeng/source/outliner/outleeng.hxx
@@ -44,7 +44,8 @@ public:
     virtual void        ParagraphConnected( sal_Int32 nLeftParagraph, sal_Int32 nRightParagraph ) override;
 
     virtual void DrawingText( const Point& rStartPos, const OUString& rText, sal_Int32 nTextStart,
-                              sal_Int32 nTextLen, o3tl::span<const sal_Int32> pDXArray, const SvxFont& rFont,
+                              sal_Int32 nTextLen, o3tl::span<const sal_Int32> pDXArray,
+                              o3tl::span<const sal_Bool> pKashidaArray, const SvxFont& rFont,
                               sal_Int32 nPara, sal_uInt8 nRightToLeft,
                               const EEngineData::WrongSpellVector* pWrongSpellVector,
                               const SvxFieldData* pFieldData,
diff --git a/editeng/source/outliner/outliner.cxx b/editeng/source/outliner/outliner.cxx
index 4d67810c7a77..d7ea27662e77 100644
--- a/editeng/source/outliner/outliner.cxx
+++ b/editeng/source/outliner/outliner.cxx
@@ -974,7 +974,7 @@ void Outliner::PaintBullet(sal_Int32 nPara, const Point& rStartPos, const Point&
                     aTextPos.AdjustY( -(aMetric.GetDescent()) );
                 }
 
-                DrawingText(aTextPos, pPara->GetText(), 0, pPara->GetText().getLength(), aBuf,
+                DrawingText(aTextPos, pPara->GetText(), 0, pPara->GetText().getLength(), aBuf, {},
                     aSvxFont, nPara, bRightToLeftPara ? 1 : 0, nullptr, nullptr, false, false, true, nullptr, Color(), Color());
             }
             else
@@ -1650,7 +1650,8 @@ void Outliner::StripPortions()
 }
 
 void Outliner::DrawingText( const Point& rStartPos, const OUString& rText, sal_Int32 nTextStart,
-                            sal_Int32 nTextLen, o3tl::span<const sal_Int32> pDXArray,const SvxFont& rFont,
+                            sal_Int32 nTextLen, o3tl::span<const sal_Int32> pDXArray,
+                            o3tl::span<const sal_Bool> pKashidaArray, const SvxFont& rFont,
                             sal_Int32 nPara, sal_uInt8 nRightToLeft,
                             const EEngineData::WrongSpellVector* pWrongSpellVector,
                             const SvxFieldData* pFieldData,
@@ -1663,7 +1664,7 @@ void Outliner::DrawingText( const Point& rStartPos, const OUString& rText, sal_I
 {
     if(aDrawPortionHdl.IsSet())
     {
-        DrawPortionInfo aInfo( rStartPos, rText, nTextStart, nTextLen, rFont, nPara, pDXArray, pWrongSpellVector,
+        DrawPortionInfo aInfo( rStartPos, rText, nTextStart, nTextLen, rFont, nPara, pDXArray, pKashidaArray, pWrongSpellVector,
             pFieldData, pLocale, rOverlineColor, rTextLineColor, nRightToLeft, false, 0, bEndOfLine, bEndOfParagraph, bEndOfBullet);
 
         aDrawPortionHdl.Call( &aInfo );
@@ -1676,7 +1677,7 @@ void Outliner::DrawingTab( const Point& rStartPos, tools::Long nWidth, const OUS
 {
     if(aDrawPortionHdl.IsSet())
     {
-        DrawPortionInfo aInfo( rStartPos, rChar, 0, rChar.getLength(), rFont, nPara, {}, nullptr,
+        DrawPortionInfo aInfo( rStartPos, rChar, 0, rChar.getLength(), rFont, nPara, {}, {}, nullptr,
             nullptr, nullptr, rOverlineColor, rTextLineColor, nRightToLeft, true, nWidth, bEndOfLine, bEndOfParagraph, false);
 
         aDrawPortionHdl.Call( &aInfo );