Scaling and offset fix for FELighting (software and skia paths)

Source/platform/graphics/filters/SpotLightSource.cpp

 /*
  * Copyright (C) 2008 Alex Mathews <possessedpenguinbob@gmail.com>
  * Copyright (C) 2004, 2005, 2006, 2007 Nikolas Zimmermann <zimmermann@kde.org>
  * Copyright (C) 2004, 2005 Rob Buis <buis@kde.org>
  * Copyright (C) 2005 Eric Seidel <eric@webkit.org>
  * Copyright (C) 2010 Zoltan Herczeg <zherczeg@webkit.org>
  * Copyright (C) 2011 University of Szeged
  * Copyright (C) 2011 Renata Hodovan <reni@webkit.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ skipping 22 matching lines @@
 #include "platform/graphics/filters/SpotLightSource.h"
 
 #include "platform/text/TextStream.h"
 
 namespace WebCore {
 
 // spot-light edge darkening depends on an absolute treshold
 // according to the SVG 1.1 SE light regression tests
 static const float antiAliasTreshold = 0.016f;
 
-void SpotLightSource::initPaintingData(PaintingData& paintingData)
+void SpotLightSource::initPaintingData(PaintingData& paintingData) const
 {
     paintingData.privateColorVector = paintingData.colorVector;
     paintingData.directionVector.setX(m_direction.x() - m_position.x());
     paintingData.directionVector.setY(m_direction.y() - m_position.y());
     paintingData.directionVector.setZ(m_direction.z() - m_position.z());
     paintingData.directionVector.normalize();
 
     if (!m_limitingConeAngle) {
         paintingData.coneCutOffLimit = 0.0f;
         paintingData.coneFullLight = -antiAliasTreshold;
     } else {
         float limitingConeAngle = m_limitingConeAngle;
         if (limitingConeAngle < 0.0f)
             limitingConeAngle = -limitingConeAngle;
         if (limitingConeAngle > 90.0f)
             limitingConeAngle = 90.0f;
         paintingData.coneCutOffLimit = cosf(deg2rad(180.0f - limitingConeAngle));
         paintingData.coneFullLight = paintingData.coneCutOffLimit - antiAliasTreshold;
     }
 
     // Optimization for common specularExponent values
     if (!m_specularExponent)
         paintingData.specularExponent = 0;
     else if (m_specularExponent == 1.0f)
         paintingData.specularExponent = 1;
     else // It is neither 0.0f nor 1.0f
         paintingData.specularExponent = 2;
 }
 
-void SpotLightSource::updatePaintingData(PaintingData& paintingData, int x, int y, float z)
+void SpotLightSource::updatePaintingData(PaintingData& paintingData, int x, int y, float z) const
 {
     paintingData.lightVector.setX(m_position.x() - x);
     paintingData.lightVector.setY(m_position.y() - y);
     paintingData.lightVector.setZ(m_position.z() - z);
     paintingData.lightVectorLength = paintingData.lightVector.length();
 
     float cosineOfAngle = (paintingData.lightVector * paintingData.directionVector) / paintingData.lightVectorLength;
     if (cosineOfAngle > paintingData.coneCutOffLimit) {
         // No light is produced, scanlines are not updated
         paintingData.colorVector.setX(0.0f);
@@ skipping 101 matching lines @@
 {
     ts << "[type=SPOT-LIGHT] ";
     ts << "[position=\"" << position() << "\"]";
     ts << "[direction=\"" << direction() << "\"]";
     ts << "[specularExponent=\"" << specularExponent() << "\"]";
     ts << "[limitingConeAngle=\"" << limitingConeAngle() << "\"]";
     return ts;
 }
 
 }; // namespace WebCore