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

Source/core/rendering/RenderBoxModelObject.cpp

 /*
  * Copyright (C) 1999 Lars Knoll (knoll@kde.org)
  *           (C) 1999 Antti Koivisto (koivisto@kde.org)
  *           (C) 2005 Allan Sandfeld Jensen (kde@carewolf.com)
  *           (C) 2005, 2006 Samuel Weinig (sam.weinig@gmail.com)
  * Copyright (C) 2005, 2006, 2007, 2008, 2009 Apple Inc. All rights reserved.
  * Copyright (C) 2010 Google Inc. All rights reserved.
  *
  * This library is free software; you can redistribute it and/or
  * modify it under the terms of the GNU Library General Public
@@ skipping 19 matching lines @@
 #include "core/frame/Settings.h"
 #include "core/html/HTMLFrameOwnerElement.h"
 #include "core/page/scrolling/ScrollingConstraints.h"
 #include "core/rendering/CompositedLayerMapping.h"
 #include "core/rendering/ImageQualityController.h"
 #include "core/rendering/RenderBlock.h"
 #include "core/rendering/RenderGeometryMap.h"
 #include "core/rendering/RenderInline.h"
 #include "core/rendering/RenderLayer.h"
 #include "core/rendering/RenderLayerCompositor.h"
-#include "core/rendering/RenderNamedFlowThread.h"
-#include "core/rendering/RenderRegion.h"
 #include "core/rendering/RenderView.h"
 #include "core/rendering/style/ShadowList.h"
 #include "platform/geometry/TransformState.h"
 #include "platform/graphics/DrawLooper.h"
 #include "platform/graphics/GraphicsContextStateSaver.h"
 #include "platform/graphics/Path.h"
 #include "wtf/CurrentTime.h"
 
 using namespace std;
 
@@ skipping 229 matching lines @@
     // If the offsetParent of the element is null, or is the HTML body element,
     // return the distance between the canvas origin and the left border edge
     // of the element and stop this algorithm.
     Element* element = offsetParent();
     if (!element)
         return referencePoint;
 
     if (const RenderBoxModelObject* offsetParent = element->renderBoxModelObject()) {
         if (offsetParent->isBox() && !offsetParent->isBody())
             referencePoint.move(-toRenderBox(offsetParent)->borderLeft(), -toRenderBox(offsetParent)->borderTop());
-        if (!isOutOfFlowPositioned() || flowThreadContainingBlock()) {
+        if (!isOutOfFlowPositioned()) {
             if (isRelPositioned())
                 referencePoint.move(relativePositionOffset());
             else if (isStickyPositioned())
                 referencePoint.move(stickyPositionOffset());
 
-            // CSS regions specification says that region flows should return the body element as their offsetParent.
-            // Since we will bypass the body’s renderer anyway, just end the loop if we encounter a region flow (named flow thread).
-            // See http://dev.w3.org/csswg/css-regions/#cssomview-offset-attributes
             RenderObject* current;
-            for (current = parent(); current != offsetParent && !current->isRenderNamedFlowThread() && current->parent(); current = current->parent()) {
+            for (current = parent(); current != offsetParent && current->parent(); current = current->parent()) {
                 // FIXME: What are we supposed to do inside SVG content?
                 if (!isOutOfFlowPositioned()) {
                     if (current->isBox() && !current->isTableRow())
                         referencePoint.moveBy(toRenderBox(current)->topLeftLocation());
                     referencePoint.move(current->parent()->offsetForColumns(referencePoint));
                 }
             }
 
-            // Compute the offset position for elements inside named flow threads for which the offsetParent was the body.
-            // See https://code.google.com/p/chromium/issues/detail?id=242168
-            if (current->isRenderNamedFlowThread())
-                referencePoint = toRenderNamedFlowThread(current)->adjustedPositionRelativeToOffsetParent(*this, referencePoint);
-            else if (offsetParent->isBox() && offsetParent->isBody() && !offsetParent->isPositioned())
+            if (offsetParent->isBox() && offsetParent->isBody() && !offsetParent->isPositioned())
                 referencePoint.moveBy(toRenderBox(offsetParent)->topLeftLocation());
         }
     }
 
     return referencePoint;
 }
 
 void RenderBoxModelObject::computeStickyPositionConstraints(StickyPositionViewportConstraints& constraints, const FloatRect& constrainingRect) const
 {
     RenderBlock* containingBlock = this->containingBlock();
@@ skipping 53 matching lines @@
 }
 
 LayoutSize RenderBoxModelObject::stickyPositionOffset() const
 {
     FloatRect constrainingRect;
 
     ASSERT(hasLayer());
     RenderLayer* enclosingClippingLayer = layer()->enclosingOverflowClipLayer(ExcludeSelf);
     if (enclosingClippingLayer) {
         RenderBox* enclosingClippingBox = toRenderBox(enclosingClippingLayer->renderer());
-        LayoutRect clipRect = enclosingClippingBox->overflowClipRect(LayoutPoint(), 0); // FIXME: make this work in regions.
+        LayoutRect clipRect = enclosingClippingBox->overflowClipRect(LayoutPoint());
         constrainingRect = enclosingClippingBox->localToContainerQuad(FloatRect(clipRect), view()).boundingBox();
     } else {
         LayoutRect viewportRect = view()->frameView()->viewportConstrainedVisibleContentRect();
         constrainingRect = viewportRect;
     }
 
     StickyPositionViewportConstraints constraints;
     computeStickyPositionConstraints(constraints, constrainingRect);
 
     // The sticky offset is physical, so we can just return the delta computed in absolute coords (though it may be wrong with transforms).
@@ skipping 220 matching lines @@
     int bLeft = includeLeftEdge ? borderLeft() : 0;
     int bRight = includeRightEdge ? borderRight() : 0;
     LayoutUnit pLeft = includeLeftEdge ? paddingLeft() : LayoutUnit();
     LayoutUnit pRight = includeRightEdge ? paddingRight() : LayoutUnit();
 
     GraphicsContextStateSaver clipWithScrollingStateSaver(*context, clippedWithLocalScrolling);
     LayoutRect scrolledPaintRect = rect;
     if (clippedWithLocalScrolling) {
         // Clip to the overflow area.
         RenderBox* thisBox = toRenderBox(this);
-        context->clip(thisBox->overflowClipRect(rect.location(), paintInfo.renderRegion));
+        context->clip(thisBox->overflowClipRect(rect.location()));
 
         // Adjust the paint rect to reflect a scrolled content box with borders at the ends.
         IntSize offset = thisBox->scrolledContentOffset();
         scrolledPaintRect.move(-offset);
         scrolledPaintRect.setWidth(bLeft + thisBox->scrollWidth() + bRight);
         scrolledPaintRect.setHeight(borderTop() + thisBox->scrollHeight() + borderBottom());
     }
 
     GraphicsContextStateSaver backgroundClipStateSaver(*context, false);
     IntRect maskRect;
@@ skipping 119 matching lines @@
     if (bgLayer->clip() == TextFillBox) {
         // Create the text mask layer.
         context->setCompositeOperation(CompositeDestinationIn);
         context->beginTransparencyLayer(1);
 
         // FIXME: Workaround for https://code.google.com/p/skia/issues/detail?id=1291.
         context->clearRect(maskRect);
 
         // Now draw the text into the mask. We do this by painting using a special paint phase that signals to
         // InlineTextBoxes that they should just add their contents to the clip.
-        PaintInfo info(context, maskRect, PaintPhaseTextClip, PaintBehaviorForceBlackText, 0, paintInfo.renderRegion);
+        PaintInfo info(context, maskRect, PaintPhaseTextClip, PaintBehaviorForceBlackText, 0);
         context->setCompositeOperation(CompositeSourceOver);
         if (box) {
             RootInlineBox* root = box->root();
             box->paint(info, LayoutPoint(scrolledPaintRect.x() - box->x(), scrolledPaintRect.y() - box->y()), root->lineTop(), root->lineBottom());
         } else {
             LayoutSize localOffset = isBox() ? toRenderBox(this)->locationOffset() : LayoutSize();
             paint(info, scrolledPaintRect.location() - localOffset);
         }
 
         context->endLayer();
@@ skipping 1950 matching lines @@
 
 void RenderBoxModelObject::mapAbsoluteToLocalPoint(MapCoordinatesFlags mode, TransformState& transformState) const
 {
     // We don't expect to be called during layout.
     ASSERT(!view() || !view()->layoutStateEnabled());
 
     RenderObject* o = container();
     if (!o)
         return;
 
-    // The point inside a box that's inside a region has its coordinates relative to the region,
-    // not the FlowThread that is its container in the RenderObject tree.
-    if (o->isRenderFlowThread() && isRenderBlock()) {
-        // FIXME: switch to Box instead of Block when we'll have range information for boxes as well, not just for blocks.
-        RenderRegion* startRegion;
-        RenderRegion* ignoredEndRegion;
-        toRenderFlowThread(o)->getRegionRangeForBox(toRenderBlock(this), startRegion, ignoredEndRegion);
-        // If there is no region to use the FlowThread, then there's no region range for the content in that FlowThread.
-        // An API like elementFromPoint might crash without this check.
-        if (startRegion)
-            o = startRegion;
-    }
-
     o->mapAbsoluteToLocalPoint(mode, transformState);
 
     LayoutSize containerOffset = offsetFromContainer(o, LayoutPoint());
 
     if (!style()->hasOutOfFlowPosition() && o->hasColumns()) {
         RenderBlock* block = toRenderBlock(o);
         LayoutPoint point(roundedLayoutPoint(transformState.mappedPoint()));
         point -= containerOffset;
         block->adjustForColumnRect(containerOffset, point);
     }
@@ skipping 75 matching lines @@
     ASSERT(!beforeChild || toBoxModelObject == beforeChild->parent());
     for (RenderObject* child = startChild; child && child != endChild; ) {
         // Save our next sibling as moveChildTo will clear it.
         RenderObject* nextSibling = child->nextSibling();
         moveChildTo(toBoxModelObject, child, beforeChild, fullRemoveInsert);
         child = nextSibling;
     }
 }
 
 } // namespace WebCore