refactor handling of double border widths:

Word uses a completely different definition of "width" of a double border
than OOo and ODF: for Word the width is apparently the largest of the 3
component widths, while OOo and ODF define the width as the total with of
all 3 components.  The new border implementation in LO 3.4 was apparently
inspired by Word's double border definition, which resulted in
various import filter regressions, see the previous fixes:

36e43b52992735c622833e923faa63774b9e2f76
e2ffb71305c5f085eec6d396651c76d6daee3406
70a6a4d425558340bb49507975343a3e0a1bdde8

These fixes set the ScaleMetrics, which actually seems sub-optimal as
there is a ScaleItemSet function somewhere that apparently re-scales
all items in an itemset, which could undo the fixes.

Also, one of the fixes actually managed to break RTF/DOCX import
of double borders, as that ended up in the same code via the API.

This commit now reverses the change, so that the width of a border is
now always the total with of all components, which is (imho) much more
intutitive, and also leads to a consistent UI where selecting say 3pt
width has predictable results, no matter what the border style.

The border widths are now converted in the Word format import/export
filters (writerfilter and sw/source/filter/ww8), and various tests
were adapted to the new handling.

Change-Id: I50456c49b1a298569607e6c88f19f18441348ac3

1 files changed, 25 insertions, 6 deletions

diff --git a/svtools/source/control/ctrlbox.cxx b/svtools/source/control/ctrlbox.cxx
index be53f12867c4..7dff33ddd20b 100644
--- a/svtools/source/control/ctrlbox.cxx
+++ b/svtools/source/control/ctrlbox.cxx
@@ -322,7 +322,12 @@ long BorderWidthImpl::GetLine1( long nWidth ) const
 {
     long result = static_cast<long>(m_nRate1);
     if ( ( m_nFlags & CHANGE_LINE1 ) > 0 )
-        result = static_cast<long>(m_nRate1 * nWidth);
+    {
+        long const nConstant2 = (m_nFlags & CHANGE_LINE2) ? 0 : m_nRate2;
+        long const nConstantD = (m_nFlags & CHANGE_DIST ) ? 0 : m_nRateGap;
+        result = std::max<long>(0,
+            static_cast<long>(m_nRate1 * nWidth) - (nConstant2 + nConstantD));
+    }
     return result;
 }
 
@@ -330,7 +335,12 @@ long BorderWidthImpl::GetLine2( long nWidth ) const
 {
     long result = static_cast<long>(m_nRate2);
     if ( ( m_nFlags & CHANGE_LINE2 ) > 0 )
-        result = static_cast<long>(m_nRate2 * nWidth);
+    {
+        long const nConstant1 = (m_nFlags & CHANGE_LINE1) ? 0 : m_nRate1;
+        long const nConstantD = (m_nFlags & CHANGE_DIST ) ? 0 : m_nRateGap;
+        result = std::max<long>(0,
+            static_cast<long>(m_nRate2 * nWidth) - (nConstant1 + nConstantD));
+    }
     return result;
 }
 
@@ -338,7 +348,12 @@ long BorderWidthImpl::GetGap( long nWidth ) const
 {
     long result = static_cast<long>(m_nRateGap);
     if ( ( m_nFlags & CHANGE_DIST ) > 0 )
-        result = static_cast<long>(m_nRateGap * nWidth);
+    {
+        long const nConstant1 = (m_nFlags & CHANGE_LINE1) ? 0 : m_nRate1;
+        long const nConstant2 = (m_nFlags & CHANGE_LINE2) ? 0 : m_nRate2;
+        result = std::max<long>(0,
+            static_cast<long>(m_nRateGap * nWidth) - (nConstant1 + nConstant2));
+    }
 
     // Avoid having too small distances (less than 0.1pt)
     if ( result < MINGAPWIDTH && m_nRate1 > 0 && m_nRate2 > 0 )
@@ -387,6 +402,11 @@ long BorderWidthImpl::GuessWidth( long nLine1, long nLine2, long nGap )
     else if ( !bGapChange && nWidthGap < 0 )
         bInvalid = true;
 
+    // non-constant line width factors must sum to 1
+    assert((((bLine1Change) ? m_nRate1 : 0) +
+            ((bLine2Change) ? m_nRate2 : 0) +
+            ((bGapChange) ? m_nRateGap : 0)) - 1.0 < 0.00001 );
+
     double nWidth = 0.0;
     if ( (!bInvalid) && (!aToCompare.empty()) )
     {
@@ -397,11 +417,10 @@ long BorderWidthImpl::GuessWidth( long nLine1, long nLine2, long nGap )
             bInvalid = ( nWidth != *pIt );
             ++pIt;
         }
-        if ( bInvalid )
-            nWidth = 0.0;
+        nWidth = (bInvalid) ?  0.0 : nLine1 + nLine2 + nGap;
     }
 
-    return long( nWidth );
+    return nWidth;
 }
 
 /** Utility class storing the border line width, style and colors. The widths