third_party/blink/renderer/core/layout/ng/ng_block_node.h

// 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.

#ifndef NGBlockNode_h
#define NGBlockNode_h

#include "third_party/blink/renderer/core/core_export.h"
#include "third_party/blink/renderer/core/layout/ng/geometry/ng_physical_offset.h"
#include "third_party/blink/renderer/core/layout/ng/ng_layout_input_node.h"
#include "third_party/blink/renderer/platform/fonts/font_baseline.h"

namespace blink {

class LayoutBox;
class NGBreakToken;
class NGConstraintSpace;
class NGFragmentBuilder;
class NGLayoutResult;
class NGPhysicalBoxFragment;
class NGPhysicalFragment;
struct MinMaxSize;
struct NGBaselineRequest;
struct NGBoxStrut;
struct NGLogicalOffset;

// Represents a node to be laid out.
class CORE_EXPORT NGBlockNode final : public NGLayoutInputNode {
  friend NGLayoutInputNode;
 public:
  explicit NGBlockNode(LayoutBox*);

  scoped_refptr<NGLayoutResult> Layout(
      const NGConstraintSpace& constraint_space,
      NGBreakToken* break_token = nullptr);
  NGLayoutInputNode NextSibling() const;

  // Computes the value of min-content and max-content for this box.
  // If the underlying layout algorithm's ComputeMinMaxSize returns
  // no value, this function will synthesize these sizes using Layout with
  // special constraint spaces -- infinite available size for max content, zero
  // available size for min content, and percentage resolution size zero for
  // both.
  // An optional constraint space may be supplied, which will be used to resolve
  // percentage padding on this node, to set up the right min/max size
  // contribution. This is typically desirable for the subtree root of the
  // min/max calculation (e.g. the node that will undergo shrink-to-fit). It is
  // also used to provide provide a sensible available inline size when
  // calculating min/max for orthogonal flows. This constraint space will not be
  // passed on to children. If no constraint space is specified, a zero-sized
  // one will be used.
  MinMaxSize ComputeMinMaxSize(WritingMode container_writing_mode,
                               const MinMaxSizeInput&,
                               const NGConstraintSpace* = nullptr);

  NGBoxStrut GetScrollbarSizes() const;

  NGLayoutInputNode FirstChild() const;

  bool IsInlineLevel() const;
  bool IsAtomicInlineLevel() const;

  // Layout an atomic inline; e.g., inline block.
  scoped_refptr<NGLayoutResult> LayoutAtomicInline(const NGConstraintSpace&,
                                                   FontBaseline,
                                                   bool use_first_line_style);

  // Runs layout on the underlying LayoutObject and creates a fragment for the
  // resulting geometry.
  scoped_refptr<NGLayoutResult> RunOldLayout(const NGConstraintSpace&);

  // Called if this is an out-of-flow block which needs to be
  // positioned with legacy layout.
  void UseOldOutOfFlowPositioning();

  // Save static position for legacy AbsPos layout.
  void SaveStaticOffsetForLegacy(const NGLogicalOffset&,
                                 const LayoutObject* offset_container);

  // Write back resolved margins to legacy.
  void StoreMargins(const NGConstraintSpace&, const NGBoxStrut& margins);

  static bool CanUseNewLayout(const LayoutBox&);
  bool CanUseNewLayout() const;

  String ToString() const;

 private:
  // After we run the layout algorithm, this function copies back the geometry
  // data to the layout box.
  void CopyFragmentDataToLayoutBox(const NGConstraintSpace&,
                                   const NGLayoutResult&);
  void PlaceChildrenInLayoutBox(const NGConstraintSpace&,
                                const NGPhysicalBoxFragment&,
                                const NGPhysicalOffset& offset_from_start);
  void PlaceChildrenInFlowThread(const NGConstraintSpace&,
                                 const NGPhysicalBoxFragment&);
  void CopyChildFragmentPosition(
      const NGPhysicalFragment& fragment,
      const NGPhysicalOffset& additional_offset = NGPhysicalOffset());

  void CopyBaselinesFromOldLayout(const NGConstraintSpace&, NGFragmentBuilder*);
  LayoutUnit AtomicInlineBaselineFromOldLayout(const NGBaselineRequest&,
                                               const NGConstraintSpace&);

  void UpdateShapeOutsideInfoIfNeeded(
      LayoutUnit percentage_resolution_inline_size);
};

DEFINE_TYPE_CASTS(NGBlockNode,
                  NGLayoutInputNode,
                  node,
                  node->IsBlock(),
                  node.IsBlock());

}  // namespace blink

#endif  // NGBlockNode