tdf#87309: SVG - use black as default currentColor if no color was specified

improves import of attachment https://bugs.documentfoundation.org/attachment.cgi?id=110836 from issue 62284

Change-Id: Icb056774746ce270138a54e9dfe9ca6987a64769
Reviewed-on: https://gerrit.libreoffice.org/14242Reviewed-by: Katarina Behrens <bubli@bubli.org>
Tested-by: Katarina Behrens <bubli@bubli.org>

svgio/inc/svgio/svgreader/svgstyleattributes.hxx

@@ -406,6 +406,9 @@ namespace svgio
             const basegfx::BColor* getColor() const;
             void setColor(const SvgPaint& rColor) { maColor = rColor; }
 
+            /// Resolve current color (defaults to black if no color is specified)
+            const basegfx::BColor* getCurrentColor() const;
+
             /// Opacity content
             SvgNumber getOpacity() const { return maOpacity; }
             void setOpacity(const SvgNumber& rOpacity = SvgNumber()) { maOpacity = rOpacity; }

svgio/source/svgreader/svgstyleattributes.cxx

@@ -1888,19 +1888,28 @@ namespace svgio
             return false;
         }
 
+        const basegfx::BColor* SvgStyleAttributes::getCurrentColor() const
+        {
+            static basegfx::BColor aBlack(0.0, 0.0, 0.0);
+            const basegfx::BColor *aColor = getColor();
+            if( aColor )
+                return aColor;
+            else
+                return &aBlack;
+        }
+
         const basegfx::BColor* SvgStyleAttributes::getFill() const
         {
             if(mbIsClipPathContent)
             {
                 static basegfx::BColor aBlack(0.0, 0.0, 0.0);
-
                 return &aBlack;
             }
             else if(maFill.isSet())
             {
                 if(maFill.isCurrent())
                 {
-                    return getColor();
+                    return getCurrentColor();
                 }
                 else if(maFill.isOn())
                 {
@@ -1930,7 +1939,7 @@ namespace svgio
             {
                 if(maStroke.isCurrent())
                 {
-                    return getColor();
+                    return getCurrentColor();
                 }
                 else if(maStroke.isOn())
                 {
@@ -1954,7 +1963,7 @@ namespace svgio
         {
             if(maStopColor.isCurrent())
             {
-                return *getColor();
+                return *getCurrentColor();
             }
             else
             {