[harfbuzz] Fix text width calculation, 3rd try

It turns out storing the width in the layout is not so good idea,
because in some mysterious cases when font fallback is involved we call
GetTextWidth() without calling LayoutText() first, and we return the
width of the previous text run.

It seems all I needed is to pass down the X offset with the glyph item,
and take it into account when calculating the width.

Change-Id: Idbdb6bba00573fb6ca773701757d667e21ac0912

4 files changed, 13 insertions, 20 deletions

diff --git a/vcl/generic/glyphs/gcach_layout.cxx b/vcl/generic/glyphs/gcach_layout.cxx
index cb6c1953a74a..935a0e5180d7 100644
--- a/vcl/generic/glyphs/gcach_layout.cxx
+++ b/vcl/generic/glyphs/gcach_layout.cxx
@@ -72,17 +72,6 @@ bool ServerFontLayout::LayoutText( ImplLayoutArgs& rArgs )
 }
 
 // -----------------------------------------------------------------------
-long ServerFontLayout::GetTextWidth() const
-{
-    long nWidth;
-    if (bUseHarfBuzz)
-        nWidth = GetWidth();
-    else
-        nWidth = GenericSalLayout::GetTextWidth();
-
-    return nWidth;
-}
-
 void ServerFontLayout::AdjustLayout( ImplLayoutArgs& rArgs )
 {
     GenericSalLayout::AdjustLayout( rArgs );
@@ -524,7 +513,7 @@ bool HbLayoutEngine::layout(ServerFontLayout& rLayout, ImplLayoutArgs& rArgs)
             int32_t nYAdvance = pHbPositions[i].y_advance >> 6;
 
             Point aNewPos = Point(aCurrPos.X() + nXOffset, -(aCurrPos.Y() + nYOffset));
-            const GlyphItem aGI(nCharPos, nGlyphIndex, aNewPos, nGlyphFlags, nXAdvance);
+            const GlyphItem aGI(nCharPos, nGlyphIndex, aNewPos, nGlyphFlags, nXAdvance, nXOffset);
             rLayout.AppendGlyph(aGI);
 
             aCurrPos.X() += nXAdvance;
@@ -533,7 +522,6 @@ bool HbLayoutEngine::layout(ServerFontLayout& rLayout, ImplLayoutArgs& rArgs)
 
         hb_buffer_destroy(pHbBuffer);
     }
-    rLayout.SetWidth(aCurrPos.X());
 
     hb_font_destroy(pHbFont);
 
diff --git a/vcl/inc/generic/glyphcache.hxx b/vcl/inc/generic/glyphcache.hxx
index 5345360d8c52..e03e03485ee4 100644
--- a/vcl/inc/generic/glyphcache.hxx
+++ b/vcl/inc/generic/glyphcache.hxx
@@ -317,7 +317,6 @@ private:
     SAL_DLLPRIVATE  ServerFontLayout& operator=( const ServerFontLayout& );
 
     bool            bUseHarfBuzz;
-    long            mnTextWidth;
 
 public:
                     ServerFontLayout( ServerFont& );
@@ -325,12 +324,7 @@ public:
     virtual void    AdjustLayout( ImplLayoutArgs& );
     virtual void    ApplyDXArray( ImplLayoutArgs& );
     virtual void    DrawText( SalGraphics& ) const;
-    virtual long    GetTextWidth() const;
     ServerFont&     GetServerFont() const   { return mrServerFont; }
-
-    // used by layout engine
-    void            SetWidth( long nWidth ) { mnTextWidth = nWidth; }
-    long            GetWidth() const { return mnTextWidth; }
 };
 
 // =======================================================================
diff --git a/vcl/inc/sallayout.hxx b/vcl/inc/sallayout.hxx
index 5d99acb768df..6b25f5bae386 100644
--- a/vcl/inc/sallayout.hxx
+++ b/vcl/inc/sallayout.hxx
@@ -310,6 +310,7 @@ struct GlyphItem
     int     mnCharPos;      // index in string
     int     mnOrigWidth;    // original glyph width
     int     mnNewWidth;     // width after adjustments
+    int     mnXOffset;
     sal_GlyphId mnGlyphIndex;
     Point   maLinearPos;    // absolute position of non rotated string
 
@@ -320,9 +321,19 @@ public:
                 long nFlags, int nOrigWidth )
             :   mnFlags(nFlags), mnCharPos(nCharPos),
                 mnOrigWidth(nOrigWidth), mnNewWidth(nOrigWidth),
+                mnXOffset(0),
                 mnGlyphIndex(nGlyphIndex), maLinearPos(rLinearPos)
             {}
 
+            GlyphItem( int nCharPos, sal_GlyphId nGlyphIndex, const Point& rLinearPos,
+                long nFlags, int nOrigWidth, int nXOffset )
+            :   mnFlags(nFlags), mnCharPos(nCharPos),
+                mnOrigWidth(nOrigWidth), mnNewWidth(nOrigWidth),
+                mnXOffset(nXOffset),
+                mnGlyphIndex(nGlyphIndex), maLinearPos(rLinearPos)
+            {}
+
+
     enum{ FALLBACK_MASK=0xFF, IS_IN_CLUSTER=0x100, IS_RTL_GLYPH=0x200, IS_DIACRITIC=0x400 };
 
     bool    IsClusterStart() const  { return ((mnFlags & IS_IN_CLUSTER) == 0); }
diff --git a/vcl/source/gdi/sallayout.cxx b/vcl/source/gdi/sallayout.cxx
index e90f7820f7e4..6955679350ad 100644
--- a/vcl/source/gdi/sallayout.cxx
+++ b/vcl/source/gdi/sallayout.cxx
@@ -996,7 +996,7 @@ long GenericSalLayout::GetTextWidth() const
         long nXPos = pG->maLinearPos.X();
         if( nMinPos > nXPos )
             nMinPos = nXPos;
-        nXPos += pG->mnNewWidth;
+        nXPos += pG->mnNewWidth - pG->mnXOffset;
         if( nMaxPos < nXPos )
             nMaxPos = nXPos;
     }