third_party/WebKit/Source/core/layout/ng/inline/ng_inline_layout_algorithm.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 NGInlineLayoutAlgorithm_h
#define NGInlineLayoutAlgorithm_h

#include "core/CoreExport.h"
#include "core/layout/ng/geometry/ng_logical_offset.h"
#include "core/layout/ng/inline/ng_inline_box_state.h"
#include "core/layout/ng/inline/ng_inline_break_token.h"
#include "core/layout/ng/inline/ng_inline_item_result.h"
#include "core/layout/ng/inline/ng_line_height_metrics.h"
#include "core/layout/ng/ng_constraint_space_builder.h"
#include "core/layout/ng/ng_fragment_builder.h"
#include "core/layout/ng/ng_layout_algorithm.h"
#include "core/layout/ng/ng_layout_opportunity_iterator.h"
#include "platform/fonts/FontBaseline.h"
#include "platform/heap/Handle.h"
#include "platform/wtf/Vector.h"

namespace blink {

class NGConstraintSpace;
class NGInlineBreakToken;
class NGInlineNode;
class NGInlineItem;
class NGLineBoxFragmentBuilder;
class NGTextFragmentBuilder;

// A class for inline layout (e.g. a <span> with no special style).
//
// This class determines the position of NGInlineItem and build line boxes.
//
// Uses NGLineBreaker to find NGInlineItems to form a line.
class CORE_EXPORT NGInlineLayoutAlgorithm final
    : public NGLayoutAlgorithm<NGInlineNode, NGInlineBreakToken> {
 public:
  NGInlineLayoutAlgorithm(NGInlineNode,
                          NGConstraintSpace*,
                          NGInlineBreakToken* = nullptr);

  // Create a line.
  // @return false if the line does not fit in the constraint space in block
  //         direction.
  bool CreateLine(NGLineInfo*, RefPtr<NGInlineBreakToken> = nullptr);

  RefPtr<NGLayoutResult> Layout() override;

 private:
  bool IsHorizontalWritingMode() const { return is_horizontal_writing_mode_; }

  void BidiReorder(NGInlineItemResults*);

  bool PlaceItems(NGLineInfo*, RefPtr<NGInlineBreakToken>);
  NGInlineBoxState* PlaceAtomicInline(const NGInlineItem&,
                                      NGInlineItemResult*,
                                      const NGLineInfo&,
                                      LayoutUnit position,
                                      NGLineBoxFragmentBuilder*,
                                      NGTextFragmentBuilder*);

  void ApplyTextAlign(ETextAlign,
                      LayoutUnit* line_left,
                      LayoutUnit inline_size,
                      LayoutUnit available_width);

  LayoutUnit ComputeContentSize(const NGLineInfo&, LayoutUnit line_bottom);

  void PropagateBaselinesFromChildren();
  bool AddBaseline(const NGBaselineRequest&, unsigned);

  NGInlineLayoutStateStack box_states_;
  LayoutUnit content_size_;
  LayoutUnit max_inline_size_;
  FontBaseline baseline_type_ = FontBaseline::kAlphabeticBaseline;

  NGLogicalOffset bfc_offset_;
  NGLogicalRect current_opportunity_;

  unsigned is_horizontal_writing_mode_ : 1;

  NGConstraintSpaceBuilder space_builder_;
  Vector<RefPtr<NGUnpositionedFloat>> unpositioned_floats_;
};

}  // namespace blink

#endif  // NGInlineLayoutAlgorithm_h