bnc#886540: Default chart background for pptx docs should be transparent.

Charts in docx and xlsx OTOH use solid white as the default fill style.

Change-Id: Ic4351fe65cabc12d60214b67c7026a317841f2c7

include/oox/helper/graphichelper.hxx

@@ -24,6 +24,7 @@
 #include <map>
 #include <rtl/ustring.hxx>
 #include <com/sun/star/awt/DeviceInfo.hpp>
+#include <com/sun/star/drawing/FillStyle.hpp>
 #include <com/sun/star/uno/Reference.hxx>
 #include <oox/helper/binarystreambase.hxx>
 #include <oox/helper/storagebase.hxx>
@@ -75,6 +76,8 @@ public:
     /** Derived classes may implement to resolve a palette index to an RGB color. */
     virtual sal_Int32   getPaletteColor( sal_Int32 nPaletteIdx ) const;
 
+    virtual css::drawing::FillStyle getDefaultChartAreaFillStyle() const;
+
     // Device info and device dependent unit conversion -----------------------
 
     /** Returns information about the output device. */

oox/source/drawingml/chart/chartspaceconverter.cxx

@@ -25,8 +25,10 @@
 #include <com/sun/star/chart2/XTitled.hpp>
 #include <com/sun/star/chart2/data/XDataReceiver.hpp>
 #include <com/sun/star/drawing/XDrawPageSupplier.hpp>
+#include <com/sun/star/drawing/FillStyle.hpp>
 #include "oox/core/xmlfilterbase.hxx"
 #include "oox/drawingml/chart/chartconverter.hxx"
+#include <oox/helper/graphichelper.hxx>
 #include "drawingml/chart/chartdrawingfragment.hxx"
 #include "drawingml/chart/chartspacemodel.hxx"
 #include "drawingml/chart/plotareaconverter.hxx"
@@ -86,8 +88,12 @@ void ChartSpaceConverter::convertFromModel( const Reference< XShapes >& rxExtern
     {
     }
 
-    // formatting of the chart background
+    // formatting of the chart background.  The default fill style varies with applications.
     PropertySet aBackPropSet( getChartDocument()->getPageBackground() );
+    aBackPropSet.setProperty(
+        PROP_FillStyle,
+        uno::makeAny(getFilter().getGraphicHelper().getDefaultChartAreaFillStyle()));
+
     if( mrModel.mxShapeProp.is() )
     {
         getFormatter().convertFrameFormatting( aBackPropSet, mrModel.mxShapeProp, OBJECTTYPE_CHARTSPACE );

oox/source/helper/graphichelper.cxx

@@ -151,6 +151,11 @@ sal_Int32 GraphicHelper::getPaletteColor( sal_Int32 /*nPaletteIdx*/ ) const
     return API_RGB_TRANSPARENT;
 }
 
+drawing::FillStyle GraphicHelper::getDefaultChartAreaFillStyle() const
+{
+    return drawing::FillStyle_SOLID;
+}
+
 // Device info and device dependent unit conversion ---------------------------
 
 sal_Int32 GraphicHelper::convertScreenPixelXToHmm( double fPixelX ) const

oox/source/ppt/pptimport.cxx

@@ -189,6 +189,7 @@ class PptGraphicHelper : public GraphicHelper
 public:
     explicit            PptGraphicHelper( const PowerPointImport& rFilter );
     virtual sal_Int32   getSchemeColor( sal_Int32 nToken ) const SAL_OVERRIDE;
+    virtual drawing::FillStyle getDefaultChartAreaFillStyle() const;
 private:
     const PowerPointImport& mrFilter;
 };
@@ -204,6 +205,11 @@ sal_Int32 PptGraphicHelper::getSchemeColor( sal_Int32 nToken ) const
     return mrFilter.getSchemeColor( nToken );
 }
 
+drawing::FillStyle PptGraphicHelper::getDefaultChartAreaFillStyle() const
+{
+    return drawing::FillStyle_NONE;
+}
+
 } // namespace
 
 GraphicHelper* PowerPointImport::implCreateGraphicHelper() const