*** DO NOT LAND *** Attempt to understand Regions complexity

Source/core/rendering/HitTestLocation.cpp

 /*
  * Copyright (C) 2006, 2008, 2011 Apple Inc. All rights reserved.
  * Copyright (C) 2012 Nokia Corporation and/or its subsidiary(-ies)
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
  * License as published by the Free Software Foundation; either
  * version 2 of the License, or (at your option) any later version.
  *
  * This library is distributed in the hope that it will be useful,
@@ skipping 13 matching lines @@
 
 #include "HTMLNames.h"
 #include "SVGNames.h"
 #include "XLinkNames.h"
 
 namespace WebCore {
 
 using namespace HTMLNames;
 
 HitTestLocation::HitTestLocation()
-    : m_region(0)
-    , m_isRectBased(false)
+    : m_isRectBased(false)
     , m_isRectilinear(true)
 {
 }
 
 HitTestLocation::HitTestLocation(const LayoutPoint& point)
     : m_point(point)
     , m_boundingBox(rectForPoint(point, 0, 0, 0, 0))
     , m_transformedPoint(point)
     , m_transformedRect(m_boundingBox)
-    , m_region(0)
     , m_isRectBased(false)
     , m_isRectilinear(true)
 {
 }
 
 HitTestLocation::HitTestLocation(const FloatPoint& point)
     : m_point(flooredLayoutPoint(point))
     , m_boundingBox(rectForPoint(m_point, 0, 0, 0, 0))
     , m_transformedPoint(point)
     , m_transformedRect(m_boundingBox)
-    , m_region(0)
     , m_isRectBased(false)
     , m_isRectilinear(true)
 {
 }
 
 HitTestLocation::HitTestLocation(const FloatPoint& point, const FloatQuad& quad)
     : m_transformedPoint(point)
     , m_transformedRect(quad)
-    , m_region(0)
     , m_isRectBased(true)
 {
     m_point = flooredLayoutPoint(point);
     m_boundingBox = enclosingIntRect(quad.boundingBox());
     m_isRectilinear = quad.isRectilinear();
 }
 
 HitTestLocation::HitTestLocation(const LayoutPoint& centerPoint, unsigned topPadding, unsigned rightPadding, unsigned bottomPadding, unsigned leftPadding)
     : m_point(centerPoint)
     , m_boundingBox(rectForPoint(centerPoint, topPadding, rightPadding, bottomPadding, leftPadding))
     , m_transformedPoint(centerPoint)
-    , m_region(0)
     , m_isRectBased(topPadding || rightPadding || bottomPadding || leftPadding)
     , m_isRectilinear(true)
 {
     m_transformedRect = FloatQuad(m_boundingBox);
 }
 
-HitTestLocation::HitTestLocation(const HitTestLocation& other, const LayoutSize& offset, RenderRegion* region)
+HitTestLocation::HitTestLocation(const HitTestLocation& other, const LayoutSize& offset)
     : m_point(other.m_point)
     , m_boundingBox(other.m_boundingBox)
     , m_transformedPoint(other.m_transformedPoint)
     , m_transformedRect(other.m_transformedRect)
-    , m_region(region ? region : other.m_region)
     , m_isRectBased(other.m_isRectBased)
     , m_isRectilinear(other.m_isRectilinear)
 {
     move(offset);
 }
 
 HitTestLocation::HitTestLocation(const HitTestLocation& other)
     : m_point(other.m_point)
     , m_boundingBox(other.m_boundingBox)
     , m_transformedPoint(other.m_transformedPoint)
     , m_transformedRect(other.m_transformedRect)
-    , m_region(other.m_region)
     , m_isRectBased(other.m_isRectBased)
     , m_isRectilinear(other.m_isRectilinear)
 {
 }
 
 HitTestLocation::~HitTestLocation()
 {
 }
 
 HitTestLocation& HitTestLocation::operator=(const HitTestLocation& other)
 {
     m_point = other.m_point;
     m_boundingBox = other.m_boundingBox;
     m_transformedPoint = other.m_transformedPoint;
     m_transformedRect = other.m_transformedRect;
-    m_region = other.m_region;
     m_isRectBased = other.m_isRectBased;
     m_isRectilinear = other.m_isRectilinear;
 
     return *this;
 }
 
 void HitTestLocation::move(const LayoutSize& offset)
 {
     m_point.move(offset);
     m_transformedPoint.move(offset);
@@ skipping 45 matching lines @@
 
     IntSize actualPadding(leftPadding + rightPadding, topPadding + bottomPadding);
     // As IntRect is left inclusive and right exclusive (seeing IntRect::contains(x, y)), adding "1".
     // FIXME: Remove this once non-rect based hit-detection stops using IntRect:intersects.
     actualPadding += IntSize(1, 1);
 
     return IntRect(actualPoint, actualPadding);
 }
 
 } // namespace WebCore