Made vtkScalarsToColor::MapValue() return const

Common/Core/vtkLookupTable.cxx

@@ -737,7 +737,7 @@ unsigned char* vtkLookupTable::GetNanColorAsUnsignedChars()
 
 //----------------------------------------------------------------------------
 // Given a scalar value v, return an RGBA color value from lookup table.
-unsigned char* vtkLookupTable::MapValue(double v)
+const unsigned char* vtkLookupTable::MapValue(double v)
 {
   vtkIdType index = this->GetIndex(v);
   if (index < 0)

Common/Core/vtkLookupTable.h

@@ -264,7 +264,7 @@ public:
   /**
    * Map one value through the lookup table, returning an RBGA[4] color.
    */
-  unsigned char* MapValue(double v) override;
+  const unsigned char* MapValue(double v) override;
 
   /**
    * Map one value through the lookup table and return the color as

Common/Core/vtkScalarsToColors.cxx

@@ -205,7 +205,7 @@ double vtkScalarsToColors::GetOpacity(double vtkNotUsed(v))
 }
 
 //----------------------------------------------------------------------------
-unsigned char *vtkScalarsToColors::MapValue(double v)
+const unsigned char *vtkScalarsToColors::MapValue(double v)
 {
   double rgb[3];
 

Common/Core/vtkScalarsToColors.h

@@ -90,7 +90,7 @@ public:
    * Map one value through the lookup table and return a color defined
    * as an RGBA unsigned char tuple (4 bytes).
    */
-  virtual unsigned char *MapValue(double v);
+  virtual const unsigned char *MapValue(double v);
 
   /**
    * Map one value through the lookup table and store the color as

IO/GeoJSON/vtkGeoJSONWriter.cxx

@@ -225,7 +225,7 @@ public:
          this->SetLookupTable(lut);
          lut->Delete();
        }
-       unsigned char *color = lut->MapValue(b);
+       const unsigned char *color = lut->MapValue(b);
        this->WriterHelper->append(",");
        this->WriterHelper->append((double)color[0]/255.0);
        this->WriterHelper->append(",");

Rendering/Core/vtkColorTransferFunction.cxx

@@ -654,7 +654,7 @@ void vtkColorTransferFunction::AddHSVSegment( double x1, double h1,
 
 //----------------------------------------------------------------------------
 // Returns the RGBA color evaluated at the specified location
-unsigned char *vtkColorTransferFunction::MapValue( double x )
+const unsigned char *vtkColorTransferFunction::MapValue( double x )
 {
   double rgb[3];
   this->GetColor( x, rgb );

Rendering/Core/vtkColorTransferFunction.h

@@ -129,7 +129,7 @@ public:
   /**
    * Map one value through the lookup table.
    */
-  unsigned char *MapValue(double v) override;
+  const unsigned char *MapValue(double v) override;
 
   //@{
   /**

Rendering/Core/vtkDiscretizableColorTransferFunction.cxx

@@ -305,7 +305,7 @@ void vtkDiscretizableColorTransferFunction::SetNanColor(double r, double g, doub
 }
 
 //-----------------------------------------------------------------------------
-unsigned char* vtkDiscretizableColorTransferFunction::MapValue(double v)
+const unsigned char* vtkDiscretizableColorTransferFunction::MapValue(double v)
 {
   this->Build();
   if (this->Discretize || this->IndexedLookup)

Rendering/Core/vtkDiscretizableColorTransferFunction.h

@@ -147,7 +147,7 @@ public:
    * Map one value through the lookup table and return a color defined
    * as a RGBA unsigned char tuple (4 bytes).
    */
-  unsigned char *MapValue(double v) override;
+  const unsigned char *MapValue(double v) override;
 
   /**
    * Map one value through the lookup table and return the color as