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// Copyright 2017 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/ng/ng_page_layout_algorithm.h"
#include <algorithm>
#include "third_party/blink/renderer/core/layout/ng/ng_block_layout_algorithm.h"
#include "third_party/blink/renderer/core/layout/ng/ng_box_fragment.h"
#include "third_party/blink/renderer/core/layout/ng/ng_constraint_space_builder.h"
#include "third_party/blink/renderer/core/layout/ng/ng_length_utils.h"
#include "third_party/blink/renderer/core/layout/ng/ng_out_of_flow_layout_part.h"
#include "third_party/blink/renderer/core/layout/ng/ng_physical_box_fragment.h"
#include "third_party/blink/renderer/core/style/computed_style.h"
namespace blink {
NGPageLayoutAlgorithm::NGPageLayoutAlgorithm(
const NGLayoutAlgorithmParams& params)
: NGLayoutAlgorithm(params),
border_padding_(params.fragment_geometry.border +
params.fragment_geometry.padding),
border_scrollbar_padding_(border_padding_ +
params.fragment_geometry.scrollbar) {
container_builder_.SetIsNewFormattingContext(
params.space.IsNewFormattingContext());
container_builder_.SetInitialFragmentGeometry(params.fragment_geometry);
}
scoped_refptr<const NGLayoutResult> NGPageLayoutAlgorithm::Layout() {
LogicalSize border_box_size = container_builder_.InitialBorderBoxSize();
LogicalSize content_box_size =
ShrinkAvailableSize(border_box_size, border_scrollbar_padding_);
LogicalSize page_size = content_box_size;
NGConstraintSpace child_space = CreateConstraintSpaceForPages(page_size);
WritingMode writing_mode = ConstraintSpace().GetWritingMode();
scoped_refptr<const NGBlockBreakToken> break_token = BreakToken();
LayoutUnit intrinsic_block_size;
LogicalOffset page_offset(border_scrollbar_padding_.StartOffset());
// TODO(mstensho): Handle auto block size.
LogicalOffset page_progression(LayoutUnit(), page_size.block_size);
container_builder_.SetIsBlockFragmentationContextRoot();
do {
// Lay out one page. Each page will become a fragment.
NGFragmentGeometry fragment_geometry =
CalculateInitialFragmentGeometry(child_space, Node());
NGBlockLayoutAlgorithm child_algorithm(
{Node(), fragment_geometry, child_space, break_token.get()});
scoped_refptr<const NGLayoutResult> result = child_algorithm.Layout();
const auto& page = result->PhysicalFragment();
container_builder_.AddChild(page, page_offset);
LayoutUnit page_block_size = NGFragment(writing_mode, page).BlockSize();
intrinsic_block_size = std::max(intrinsic_block_size,
page_offset.block_offset + page_block_size);
page_offset += page_progression;
break_token = To<NGBlockBreakToken>(page.BreakToken());
} while (break_token);
container_builder_.SetIntrinsicBlockSize(intrinsic_block_size);
// Recompute the block-axis size now that we know our content size.
border_box_size.block_size = ComputeBlockSizeForFragment(
ConstraintSpace(), Style(), border_padding_, intrinsic_block_size,
border_box_size.inline_size);
container_builder_.SetBlockSize(border_box_size.block_size);
NGOutOfFlowLayoutPart(
Node(), ConstraintSpace(),
container_builder_.Borders() + container_builder_.Scrollbar(),
&container_builder_)
.Run();
// TODO(mstensho): Propagate baselines.
return container_builder_.ToBoxFragment();
}
MinMaxSizesResult NGPageLayoutAlgorithm::ComputeMinMaxSizes(
const MinMaxSizesInput& input) const {
NGFragmentGeometry fragment_geometry =
CalculateInitialMinMaxFragmentGeometry(ConstraintSpace(), Node());
NGBlockLayoutAlgorithm algorithm(
{Node(), fragment_geometry, ConstraintSpace()});
return algorithm.ComputeMinMaxSizes(input);
}
NGConstraintSpace NGPageLayoutAlgorithm::CreateConstraintSpaceForPages(
const LogicalSize& page_size) const {
NGConstraintSpaceBuilder space_builder(
ConstraintSpace(), Style().GetWritingMode(), /* is_new_fc */ true);
space_builder.SetAvailableSize(page_size);
space_builder.SetPercentageResolutionSize(page_size);
// TODO(mstensho): Handle auto block size.
space_builder.SetFragmentationType(kFragmentPage);
space_builder.SetFragmentainerBlockSize(page_size.block_size);
space_builder.SetIsAnonymous(true);
return space_builder.ToConstraintSpace();
}
} // namespace blink
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