WaE and numerical inconsequence in gradient fallback render handling

(cherry picked from commit d8dfdae3)

Conflicts:
	drawinglayer/inc/drawinglayer/primitive2d/svggradientprimitive2d.hxx
	drawinglayer/source/primitive2d/svggradientprimitive2d.cxx

Change-Id: Ifcc795a3474efad1c1bca77088adfef36258ee95

drawinglayer/source/primitive2d/svggradientprimitive2d.cxx

@@ -299,7 +299,11 @@ namespace drawinglayer
         {
         }
 
-        bool SvgGradientHelper::equalTo(const SvgGradientHelper& rSvgGradientHelper) const
+        SvgGradientHelper::~SvgGradientHelper()
+        {
+        }
+
+        bool SvgGradientHelper::operator==(const SvgGradientHelper& rSvgGradientHelper) const
         {
             const SvgGradientHelper& rCompare = static_cast< const SvgGradientHelper& >(rSvgGradientHelper);
 
@@ -578,7 +582,7 @@ namespace drawinglayer
         {
             const SvgGradientHelper* pSvgGradientHelper = dynamic_cast< const SvgGradientHelper* >(&rPrimitive);
 
-            if(pSvgGradientHelper && SvgGradientHelper::equalTo(*pSvgGradientHelper))
+            if(pSvgGradientHelper && SvgGradientHelper::operator==(*pSvgGradientHelper))
             {
                 const SvgLinearGradientPrimitive2D& rCompare = static_cast< const SvgLinearGradientPrimitive2D& >(rPrimitive);
 
@@ -878,7 +882,7 @@ namespace drawinglayer
         {
             const SvgGradientHelper* pSvgGradientHelper = dynamic_cast< const SvgGradientHelper* >(&rPrimitive);
 
-            if(pSvgGradientHelper && SvgGradientHelper::equalTo(*pSvgGradientHelper))
+            if(pSvgGradientHelper && SvgGradientHelper::operator==(*pSvgGradientHelper))
             {
                 const SvgRadialGradientPrimitive2D& rCompare = static_cast< const SvgRadialGradientPrimitive2D& >(rPrimitive);
 

drawinglayer/source/processor2d/vclprocessor2d.cxx

@@ -1396,8 +1396,10 @@ namespace drawinglayer
             {
                 const basegfx::BColor aColorA(maBColorModifierStack.getModifiedColor(rCandidate.getColorA()));
                 const basegfx::BColor aColorB(maBColorModifierStack.getModifiedColor(rCandidate.getColorB()));
+
+                // calculate discrete unit in WorldCoordinates; use diagonal (1.0, 1.0) and divide by sqrt(2)
                 const basegfx::B2DVector aDiscreteVector(getViewInformation2D().getInverseObjectToViewTransformation() * basegfx::B2DVector(1.0, 1.0));
-                const double fDiscreteUnit(std::min(fabs(aDiscreteVector.getX()), fabs(aDiscreteVector.getY())));
+                const double fDiscreteUnit(aDiscreteVector.getLength() * (1.0 / 1.414213562373));
 
                 // use color distance and discrete lengths to calculate step count
                 const sal_uInt32 nSteps(calculateStepsForSvgGradient(aColorA, aColorB, fDelta, fDiscreteUnit));
@@ -1439,8 +1441,10 @@ namespace drawinglayer
             {
                 const basegfx::BColor aColorA(maBColorModifierStack.getModifiedColor(rCandidate.getColorA()));
                 const basegfx::BColor aColorB(maBColorModifierStack.getModifiedColor(rCandidate.getColorB()));
+
+                // calculate discrete unit in WorldCoordinates; use diagonal (1.0, 1.0) and divide by sqrt(2)
                 const basegfx::B2DVector aDiscreteVector(getViewInformation2D().getInverseObjectToViewTransformation() * basegfx::B2DVector(1.0, 1.0));
-                const double fDiscreteUnit(std::min(fabs(aDiscreteVector.getX()), fabs(aDiscreteVector.getY())));
+                const double fDiscreteUnit(aDiscreteVector.getLength() * (1.0 / 1.414213562373));
 
                 // use color distance and discrete lengths to calculate step count
                 const sal_uInt32 nSteps(calculateStepsForSvgGradient(aColorA, aColorB, fDeltaScale, fDiscreteUnit));

include/drawinglayer/primitive2d/svggradientprimitive2d.hxx

@@ -156,7 +156,7 @@ namespace drawinglayer
                 const basegfx::B2DPoint& rStart,
                 bool bUseUnitCoordinates,
                 SpreadMethod aSpreadMethod = Spread_pad);
-	    virtual ~SvgGradientHelper() {}
+            virtual ~SvgGradientHelper();
 
             /// data read access
             const basegfx::B2DHomMatrix& getGradientTransform() const { return maGradientTransform; }
@@ -167,7 +167,7 @@ namespace drawinglayer
             SpreadMethod getSpreadMethod() const { return maSpreadMethod; }
 
             /// compare operator
-	    bool equalTo(const SvgGradientHelper& rSvgGradientHelper) const;
+            bool operator==(const SvgGradientHelper& rSvgGradientHelper) const;
         };
     } // end of namespace primitive2d
 } // end of namespace drawinglayer