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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/resize_observer/resize_observation.h"
#include "third_party/blink/renderer/core/display_lock/display_lock_utilities.h"
#include "third_party/blink/renderer/core/frame/local_frame.h"
#include "third_party/blink/renderer/core/layout/adjust_for_absolute_zoom.h"
#include "third_party/blink/renderer/core/layout/layout_box.h"
#include "third_party/blink/renderer/core/page/page.h"
#include "third_party/blink/renderer/core/resize_observer/resize_observer.h"
#include "third_party/blink/renderer/core/resize_observer/resize_observer_box_options.h"
#include "third_party/blink/renderer/core/svg/svg_element.h"
#include "third_party/blink/renderer/core/svg/svg_graphics_element.h"
#include "third_party/blink/renderer/platform/geometry/layout_unit.h"
namespace blink {
ResizeObservation::ResizeObservation(Element* target,
ResizeObserver* observer,
ResizeObserverBoxOptions observed_box)
: target_(target),
observer_(observer),
observation_size_(0, 0),
observed_box_(observed_box) {
DCHECK(target_);
}
bool ResizeObservation::ObservationSizeOutOfSync() {
if (observation_size_ == ComputeTargetSize())
return false;
// Skip resize observations on locked elements.
if (UNLIKELY(target_ && DisplayLockUtilities::IsInLockedSubtreeCrossingFrames(
*target_))) {
return false;
}
return true;
}
void ResizeObservation::SetObservationSize(const LayoutSize& observation_size) {
observation_size_ = observation_size;
}
size_t ResizeObservation::TargetDepth() {
unsigned depth = 0;
for (Element* parent = target_; parent; parent = parent->parentElement())
++depth;
return depth;
}
LayoutSize ResizeObservation::ComputeTargetSize() const {
if (target_) {
if (LayoutObject* layout_object = target_->GetLayoutObject()) {
// https://drafts.csswg.org/resize-observer/#calculate-box-size states
// that the bounding box should be used for SVGGraphicsElements regardless
// of the observed box.
if (auto* svg_graphics_element =
DynamicTo<SVGGraphicsElement>(target_.Get())) {
return LayoutSize(svg_graphics_element->GetBBox().Size());
}
if (!layout_object->IsBox())
return LayoutSize();
if (LayoutBox* layout_box = ToLayoutBox(layout_object)) {
const ComputedStyle& style = layout_object->StyleRef();
switch (observed_box_) {
case ResizeObserverBoxOptions::BorderBox:
return LayoutSize(AdjustForAbsoluteZoom::AdjustLayoutUnit(
layout_box->LogicalWidth(), style),
AdjustForAbsoluteZoom::AdjustLayoutUnit(
layout_box->LogicalHeight(), style));
case ResizeObserverBoxOptions::ContentBox:
return LayoutSize(AdjustForAbsoluteZoom::AdjustLayoutUnit(
layout_box->ContentLogicalWidth(), style),
AdjustForAbsoluteZoom::AdjustLayoutUnit(
layout_box->ContentLogicalHeight(), style));
case ResizeObserverBoxOptions::DevicePixelContentBox: {
LayoutSize paint_offset =
layout_object->FirstFragment().PaintOffset().ToLayoutSize();
LayoutSize device_pixel_content_box_size(
SnapSizeToPixel(layout_box->ContentLogicalWidth(),
style.IsHorizontalWritingMode()
? paint_offset.Width()
: paint_offset.Height()),
SnapSizeToPixel(layout_box->ContentLogicalHeight(),
style.IsHorizontalWritingMode()
? paint_offset.Height()
: paint_offset.Width()));
// Get Device Scale Factor for cases where use-zoom-for-dsf is
// disabled. This is 1 if use-zoom-for-dsf is enabled.
float device_scale_factor = layout_object->GetFrame()
->GetPage()
->DeviceScaleFactorDeprecated();
device_pixel_content_box_size.Scale(device_scale_factor);
return device_pixel_content_box_size;
}
default:
NOTREACHED();
}
}
}
}
return LayoutSize();
}
void ResizeObservation::Trace(Visitor* visitor) const {
visitor->Trace(target_);
visitor->Trace(observer_);
}
} // namespace blink
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