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// Copyright 2016 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "core/layout/IntersectionGeometry.h"
#include "core/frame/FrameView.h"
#include "core/frame/LocalFrame.h"
#include "core/html/HTMLFrameOwnerElement.h"
#include "core/layout/LayoutBox.h"
#include "core/layout/LayoutView.h"
#include "core/layout/api/LayoutAPIShim.h"
#include "core/layout/api/LayoutViewItem.h"
#include "core/paint/PaintLayer.h"
namespace blink {
namespace {
bool isContainingBlockChainDescendant(LayoutObject* descendant,
LayoutObject* ancestor) {
LocalFrame* ancestorFrame = ancestor->document().frame();
LocalFrame* descendantFrame = descendant->document().frame();
if (ancestorFrame != descendantFrame)
return false;
while (descendant && descendant != ancestor)
descendant = descendant->containingBlock();
return descendant;
}
void mapRectUpToDocument(LayoutRect& rect,
const LayoutObject& descendant,
const Document& document) {
FloatQuad mappedQuad = descendant.localToAncestorQuad(
FloatQuad(FloatRect(rect)), document.layoutView(),
UseTransforms | ApplyContainerFlip);
rect = LayoutRect(mappedQuad.boundingBox());
}
void mapRectDownToDocument(LayoutRect& rect,
LayoutBoxModelObject* ancestor,
const Document& document) {
FloatQuad mappedQuad = document.layoutView()->ancestorToLocalQuad(
ancestor, FloatQuad(FloatRect(rect)),
UseTransforms | ApplyContainerFlip | TraverseDocumentBoundaries);
rect = LayoutRect(mappedQuad.boundingBox());
}
LayoutUnit computeMargin(const Length& length, LayoutUnit referenceLength) {
if (length.type() == Percent) {
return LayoutUnit(
static_cast<int>(referenceLength.toFloat() * length.percent() / 100.0));
}
DCHECK_EQ(length.type(), Fixed);
return LayoutUnit(length.intValue());
}
LayoutView* localRootView(Element& element) {
LocalFrame* frame = element.document().frame();
LocalFrame* frameRoot = frame ? frame->localFrameRoot() : nullptr;
return frameRoot ? frameRoot->contentLayoutObject() : nullptr;
}
} // namespace
IntersectionGeometry::IntersectionGeometry(Element* root,
Element& target,
const Vector<Length>& rootMargin,
bool shouldReportRootBounds)
: m_root(root ? root->layoutObject() : localRootView(target)),
m_target(target.layoutObject()),
m_rootMargin(rootMargin),
m_doesIntersect(0),
m_shouldReportRootBounds(shouldReportRootBounds),
m_rootIsImplicit(!root),
m_canComputeGeometry(initializeCanComputeGeometry(root, target)) {
if (m_canComputeGeometry)
initializeGeometry();
}
IntersectionGeometry::~IntersectionGeometry() {}
bool IntersectionGeometry::initializeCanComputeGeometry(Element* root,
Element& target) const {
DCHECK(m_rootMargin.isEmpty() || m_rootMargin.size() == 4);
if (root && !root->isConnected())
return false;
if (!m_root || !m_root->isBox())
return false;
if (!target.isConnected())
return false;
if (!m_target || (!m_target->isBoxModelObject() && !m_target->isText()))
return false;
if (root && !isContainingBlockChainDescendant(m_target, m_root))
return false;
return true;
}
void IntersectionGeometry::initializeGeometry() {
initializeTargetRect();
m_intersectionRect = m_targetRect;
initializeRootRect();
}
void IntersectionGeometry::initializeTargetRect() {
m_targetRect =
LayoutRect(toLayoutBoxModelObject(target())->borderBoundingBox());
}
void IntersectionGeometry::initializeRootRect() {
if (m_root->isLayoutView()) {
m_rootRect =
LayoutRect(toLayoutView(m_root)->frameView()->visibleContentRect());
m_root->mapToVisualRectInAncestorSpace(nullptr, m_rootRect);
} else if (m_root->isBox() && m_root->hasOverflowClip()) {
m_rootRect = LayoutRect(toLayoutBox(m_root)->contentBoxRect());
} else {
m_rootRect =
LayoutRect(toLayoutBoxModelObject(m_root)->borderBoundingBox());
}
applyRootMargin();
}
void IntersectionGeometry::applyRootMargin() {
if (m_rootMargin.isEmpty())
return;
// TODO(szager): Make sure the spec is clear that left/right margins are
// resolved against width and not height.
LayoutUnit topMargin = computeMargin(m_rootMargin[0], m_rootRect.height());
LayoutUnit rightMargin = computeMargin(m_rootMargin[1], m_rootRect.width());
LayoutUnit bottomMargin = computeMargin(m_rootMargin[2], m_rootRect.height());
LayoutUnit leftMargin = computeMargin(m_rootMargin[3], m_rootRect.width());
m_rootRect.setX(m_rootRect.x() - leftMargin);
m_rootRect.setWidth(m_rootRect.width() + leftMargin + rightMargin);
m_rootRect.setY(m_rootRect.y() - topMargin);
m_rootRect.setHeight(m_rootRect.height() + topMargin + bottomMargin);
}
void IntersectionGeometry::clipToRoot() {
// Map and clip rect into root element coordinates.
// TODO(szager): the writing mode flipping needs a test.
LayoutBox* ancestor = toLayoutBox(m_root);
m_doesIntersect = m_target->mapToVisualRectInAncestorSpace(
(rootIsImplicit() ? nullptr : ancestor), m_intersectionRect,
EdgeInclusive);
if (ancestor && ancestor->hasOverflowClip())
m_intersectionRect.move(-ancestor->scrolledContentOffset());
if (!m_doesIntersect)
return;
LayoutRect rootClipRect(m_rootRect);
if (ancestor)
ancestor->flipForWritingMode(rootClipRect);
m_doesIntersect &= m_intersectionRect.inclusiveIntersect(rootClipRect);
}
void IntersectionGeometry::mapTargetRectToTargetFrameCoordinates() {
Document& targetDocument = m_target->document();
LayoutSize scrollPosition =
LayoutSize(targetDocument.view()->getScrollOffset());
mapRectUpToDocument(m_targetRect, *m_target, targetDocument);
m_targetRect.move(-scrollPosition);
}
void IntersectionGeometry::mapRootRectToRootFrameCoordinates() {
m_root->frameView()->mapQuadToAncestorFrameIncludingScrollOffset(
m_rootRect, m_root,
rootIsImplicit() ? nullptr : m_root->document().layoutView(),
UseTransforms | ApplyContainerFlip);
}
void IntersectionGeometry::mapIntersectionRectToTargetFrameCoordinates() {
Document& targetDocument = m_target->document();
if (rootIsImplicit()) {
LocalFrame* targetFrame = targetDocument.frame();
Frame* rootFrame = targetFrame->tree().top();
LayoutSize scrollPosition =
LayoutSize(targetDocument.view()->getScrollOffset());
if (targetFrame != rootFrame)
mapRectDownToDocument(m_intersectionRect, nullptr, targetDocument);
m_intersectionRect.move(-scrollPosition);
} else {
LayoutSize scrollPosition =
LayoutSize(targetDocument.view()->getScrollOffset());
mapRectUpToDocument(m_intersectionRect, *m_root, m_root->document());
m_intersectionRect.move(-scrollPosition);
}
}
void IntersectionGeometry::computeGeometry() {
if (!canComputeGeometry())
return;
clipToRoot();
mapTargetRectToTargetFrameCoordinates();
if (m_doesIntersect)
mapIntersectionRectToTargetFrameCoordinates();
else
m_intersectionRect = LayoutRect();
// Small optimization: if we're not going to report root bounds, don't bother
// transforming them to the frame.
if (shouldReportRootBounds())
mapRootRectToRootFrameCoordinates();
}
} // namespace blink
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