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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 "third_party/blink/renderer/core/layout/intersection_geometry.h"
#include "third_party/blink/renderer/core/frame/local_frame.h"
#include "third_party/blink/renderer/core/frame/local_frame_view.h"
#include "third_party/blink/renderer/core/frame/settings.h"
#include "third_party/blink/renderer/core/html/html_frame_owner_element.h"
#include "third_party/blink/renderer/core/layout/layout_box.h"
#include "third_party/blink/renderer/core/layout/layout_view.h"
#include "third_party/blink/renderer/core/page/page.h"
#include "third_party/blink/renderer/core/paint/paint_layer.h"
namespace blink {
namespace {
bool IsContainingBlockChainDescendant(LayoutObject* descendant,
LayoutObject* ancestor) {
LocalFrame* ancestor_frame = ancestor->GetDocument().GetFrame();
LocalFrame* descendant_frame = descendant->GetDocument().GetFrame();
if (ancestor_frame != descendant_frame)
return false;
while (descendant && descendant != ancestor)
descendant = descendant->ContainingBlock();
return descendant;
}
void MapRectUpToDocument(LayoutRect& rect,
const LayoutObject& descendant,
const Document& document) {
FloatQuad mapped_quad = descendant.LocalToAncestorQuad(
FloatQuad(FloatRect(rect)), document.GetLayoutView(),
kUseTransforms | kApplyContainerFlip);
rect = LayoutRect(mapped_quad.BoundingBox());
}
void MapRectDownToDocument(LayoutRect& rect,
LayoutBoxModelObject* ancestor,
const Document& document) {
FloatQuad mapped_quad = document.GetLayoutView()->AncestorToLocalQuad(
ancestor, FloatQuad(FloatRect(rect)),
kUseTransforms | kApplyContainerFlip | kTraverseDocumentBoundaries);
rect = LayoutRect(mapped_quad.BoundingBox());
}
LayoutUnit ComputeMargin(const Length& length, LayoutUnit reference_length) {
if (length.GetType() == kPercent) {
return LayoutUnit(static_cast<int>(reference_length.ToFloat() *
length.Percent() / 100.0));
}
DCHECK_EQ(length.GetType(), kFixed);
return LayoutUnit(length.IntValue());
}
LayoutView* LocalRootView(Element& element) {
LocalFrame* frame = element.GetDocument().GetFrame();
LocalFrame* frame_root = frame ? &frame->LocalFrameRoot() : nullptr;
return frame_root ? frame_root->ContentLayoutObject() : nullptr;
}
} // namespace
IntersectionGeometry::IntersectionGeometry(Element* root,
Element& target,
const Vector<Length>& root_margin,
bool should_report_root_bounds)
: root_(root ? root->GetLayoutObject() : LocalRootView(target)),
target_(target.GetLayoutObject()),
root_margin_(root_margin),
does_intersect_(0),
should_report_root_bounds_(should_report_root_bounds),
root_is_implicit_(!root),
can_compute_geometry_(InitializeCanComputeGeometry(root, target)) {
if (can_compute_geometry_)
InitializeGeometry();
}
IntersectionGeometry::~IntersectionGeometry() = default;
bool IntersectionGeometry::InitializeCanComputeGeometry(Element* root,
Element& target) const {
DCHECK(root_margin_.IsEmpty() || root_margin_.size() == 4);
if (root && !root->isConnected())
return false;
if (!root_ || !root_->IsBox())
return false;
if (!target.isConnected())
return false;
if (!target_ || (!target_->IsBoxModelObject() && !target_->IsText()))
return false;
if (root && !IsContainingBlockChainDescendant(target_, root_))
return false;
return true;
}
void IntersectionGeometry::InitializeGeometry() {
InitializeTargetRect();
intersection_rect_ = target_rect_;
InitializeRootRect();
}
void IntersectionGeometry::InitializeTargetRect() {
if (target_->IsBoxModelObject()) {
target_rect_ =
LayoutRect(ToLayoutBoxModelObject(target_)->BorderBoundingBox());
} else {
target_rect_ = ToLayoutText(target_)->LinesBoundingBox();
}
}
void IntersectionGeometry::InitializeRootRect() {
if (root_->IsLayoutView() && root_->GetDocument().IsInMainFrame()) {
// The main frame is a bit special as the scrolling viewport can differ in
// size from the LayoutView itself. There's two situations this occurs in:
// 1) The ForceZeroLayoutHeight quirk setting is used in Android WebView for
// compatibility and sets the initial-containing-block's (a.k.a.
// LayoutView) height to 0. Thus, we can't use its size for intersection
// testing. Use the FrameView geometry instead.
// 2) An element wider than the ICB can cause us to resize the FrameView so
// we can zoom out to fit the entire element width.
root_rect_ = ToLayoutView(root_)->OverflowClipRect(LayoutPoint());
} else if (root_->IsBox() && root_->HasOverflowClip()) {
root_rect_ = LayoutRect(ToLayoutBox(root_)->ContentBoxRect());
} else {
root_rect_ = LayoutRect(ToLayoutBoxModelObject(root_)->BorderBoundingBox());
}
ApplyRootMargin();
}
void IntersectionGeometry::ApplyRootMargin() {
if (root_margin_.IsEmpty())
return;
// TODO(szager): Make sure the spec is clear that left/right margins are
// resolved against width and not height.
LayoutUnit top_margin = ComputeMargin(root_margin_[0], root_rect_.Height());
LayoutUnit right_margin = ComputeMargin(root_margin_[1], root_rect_.Width());
LayoutUnit bottom_margin =
ComputeMargin(root_margin_[2], root_rect_.Height());
LayoutUnit left_margin = ComputeMargin(root_margin_[3], root_rect_.Width());
root_rect_.SetX(root_rect_.X() - left_margin);
root_rect_.SetWidth(root_rect_.Width() + left_margin + right_margin);
root_rect_.SetY(root_rect_.Y() - top_margin);
root_rect_.SetHeight(root_rect_.Height() + top_margin + bottom_margin);
}
void IntersectionGeometry::ClipToRoot() {
// Map and clip rect into root element coordinates.
// TODO(szager): the writing mode flipping needs a test.
LayoutBox* local_ancestor = nullptr;
if (!RootIsImplicit() || root_->GetDocument().IsInMainFrame())
local_ancestor = ToLayoutBox(root_);
// If we're throttled, then we can't guarantee that geometry mapper is up to
// date, so we fall back to the slow path. If we're unthrottled, then ensure
// that prepaint has run and the frame view doesn't need a paint property
// update.
#if DCHECK_IS_ON()
{
auto* frame_view = target_->GetFrameView();
auto* layout_view = frame_view->GetLayoutView();
DCHECK(frame_view->ShouldThrottleRendering() || !layout_view ||
!(layout_view->NeedsPaintPropertyUpdate() ||
layout_view->DescendantNeedsPaintPropertyUpdate()));
}
#endif
VisualRectFlags use_geometry_mapper =
target_->GetFrameView()->ShouldThrottleRendering()
? kDefaultVisualRectFlags
: kUseGeometryMapper;
VisualRectFlags flags =
static_cast<VisualRectFlags>(use_geometry_mapper | kEdgeInclusive);
does_intersect_ = target_->MapToVisualRectInAncestorSpace(
local_ancestor, intersection_rect_, flags);
if (!does_intersect_ || !local_ancestor)
return;
if (local_ancestor->HasOverflowClip())
intersection_rect_.Move(-local_ancestor->ScrolledContentOffset());
LayoutRect root_clip_rect(root_rect_);
local_ancestor->FlipForWritingMode(root_clip_rect);
does_intersect_ &= intersection_rect_.InclusiveIntersect(root_clip_rect);
}
void IntersectionGeometry::MapTargetRectToTargetFrameCoordinates() {
Document& target_document = target_->GetDocument();
MapRectUpToDocument(target_rect_, *target_, target_document);
}
void IntersectionGeometry::MapRootRectToRootFrameCoordinates() {
root_rect_ = LayoutRect(
root_
->LocalToAncestorQuad(
FloatQuad(FloatRect(root_rect_)),
RootIsImplicit() ? nullptr : root_->GetDocument().GetLayoutView(),
kUseTransforms | kApplyContainerFlip)
.BoundingBox());
}
void IntersectionGeometry::MapIntersectionRectToTargetFrameCoordinates() {
Document& target_document = target_->GetDocument();
if (RootIsImplicit()) {
LocalFrame* target_frame = target_document.GetFrame();
Frame& root_frame = target_frame->Tree().Top();
if (target_frame != &root_frame)
MapRectDownToDocument(intersection_rect_, nullptr, target_document);
} else {
MapRectUpToDocument(intersection_rect_, *root_, root_->GetDocument());
}
}
void IntersectionGeometry::ComputeGeometry() {
if (!CanComputeGeometry())
return;
DCHECK(root_);
DCHECK(target_);
ClipToRoot();
MapTargetRectToTargetFrameCoordinates();
if (does_intersect_)
MapIntersectionRectToTargetFrameCoordinates();
else
intersection_rect_ = 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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