tdf#42915, NaN in a date axis can destroy the whole chart

The NaN value forces the scaling of the axis to be based on years
and introduces gaps in the rendering.

Reviewed-on: https://gerrit.libreoffice.org/64267
Tested-by: Jenkins
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>

related tdf#42915, pass NaN through date transformation

Many places in chart2 use NaN to mean no available value. Not propagating
NaN through the helper disables all this functionality.

Reviewed-on: https://gerrit.libreoffice.org/64266
Tested-by: Jenkins
Reviewed-by: Markus Mohrhard <markus.mohrhard@googlemail.com>
Reviewed-on: https://gerrit.libreoffice.org/64304
(cherry picked from commit 55c53825)
Reviewed-on: https://gerrit.libreoffice.org/64310Reviewed-by: Caolán McNamara <caolanm@redhat.com>
Tested-by: Caolán McNamara <caolanm@redhat.com>
(cherry picked from commit 0a906dc7)

Change-Id: I78219be289d76edb53b5672209e1c031ab62def9
37f966007b5b7cc16778c5c6903710fbd144631b

chart2/source/view/axes/DateHelper.cxx

@@ -69,6 +69,9 @@ bool DateHelper::IsLessThanOneYearAway( const Date& rD1, const Date& rD2 )
 
 double DateHelper::RasterizeDateValue( double fValue, const Date& rNullDate, long TimeResolution )
 {
+    if (rtl::math::isNan(fValue))
+        return fValue;
+
     Date aDate(rNullDate); aDate.AddDays(::rtl::math::approxFloor(fValue));
     switch(TimeResolution)
     {

chart2/source/view/charttypes/AreaChart.cxx

@@ -757,7 +757,12 @@ void AreaChart::createShapes()
                     //collect data point information (logic coordinates, style ):
                     double fLogicX = (*aSeriesIter)->getXValue(nIndex);
                     if (bDateCategory)
+                    {
+                        if (rtl::math::isNan(fLogicX))
+                            continue;
+
                         fLogicX = DateHelper::RasterizeDateValue( fLogicX, m_aNullDate, m_nTimeResolution );
+                    }
                     double fLogicY = (*aSeriesIter)->getYValue(nIndex);
 
                     if( m_nDimension==3 && m_bArea && rSeriesList.size()!=1 )

chart2/source/view/charttypes/VSeriesPlotter.cxx

@@ -1462,10 +1462,17 @@ long VSeriesPlotter::calculateTimeResolutionOnXAxis()
             aNullDate = m_apNumberFormatterWrapper->getNullDate();
         if( aIt!=aEnd )
         {
+            while (rtl::math::isNan(*aIt) && aIt != aEnd)
+            {
+                ++aIt;
+            }
             Date aPrevious(aNullDate); aPrevious.AddDays(rtl::math::approxFloor(*aIt));
             ++aIt;
             for(;aIt!=aEnd;++aIt)
             {
+                if (rtl::math::isNan(*aIt))
+                    continue;
+
                 Date aCurrent(aNullDate); aCurrent.AddDays(rtl::math::approxFloor(*aIt));
                 if( nRet == css::chart::TimeUnit::YEAR )
                 {