better algorithm for OOXML column width import, tdf#91267

This patch contains a magic factor of 1.047 that is necessary as the set
value and retrieved value are not the same. When we ahve too much time
(propably never) we should explore why the value that we set for the
column width is not equal to the one that we see on the screen.

Change-Id: I317127ea5b8af2d5e8386758e66907a44fe58579

1 files changed, 22 insertions, 1 deletions

diff --git a/sc/source/filter/oox/worksheethelper.cxx b/sc/source/filter/oox/worksheethelper.cxx
index aaa45a9b79ba..3dfbf8a3b663 100644
--- a/sc/source/filter/oox/worksheethelper.cxx
+++ b/sc/source/filter/oox/worksheethelper.cxx
@@ -78,6 +78,7 @@
 #include <svl/stritem.hxx>
 #include <editeng/editobj.hxx>
 #include <editeng/flditem.hxx>
+#include <vcl/virdev.hxx>
 
 namespace oox {
 namespace xls {
@@ -1166,11 +1167,31 @@ void WorksheetGlobals::convertColumns()
     convertOutlines( aColLevels, nMaxCol + 1, 0, false, false );
 }
 
+namespace {
+
+sal_Int32 getColumnWidth(UnitConverter& rConverter, double nWidth)
+{
+    double nCoeff = rConverter.getCoefficient(UNIT_DIGIT);
+    VirtualDevice aDev;
+
+    long nPixel = aDev.LogicToPixel(Point(nCoeff, 0), MapMode(MAP_100TH_MM)).getX();
+
+
+    // the 1.047 has been experimentally chosen based on measurements witha  screen ruler
+    // TODO: fix the display of cells so that it no longer requires this hack
+    // algorithm from OOXML spec part1: 18.3.1.13
+    sal_Int32 nColWidthPixel= std::floor(((256*nWidth + std::floor(128.0/nPixel))/256.0)*nPixel) * 1.047;
+
+    return aDev.PixelToLogic(Point(nColWidthPixel, 0), MapMode(MAP_100TH_MM)).getX();
+}
+
+}
+
 void WorksheetGlobals::convertColumns( OutlineLevelVec& orColLevels,
         const ValueRange& rColRange, const ColumnModel& rModel )
 {
     // column width: convert 'number of characters' to column width in 1/100 mm
-    sal_Int32 nWidth = getUnitConverter().scaleToMm100( rModel.mfWidth, UNIT_DIGIT );
+    sal_Int32 nWidth = getColumnWidth(getUnitConverter(), rModel.mfWidth);
     // macro sheets have double width
     if( meSheetType == SHEETTYPE_MACROSHEET )
         nWidth *= 2;