third_party/WebKit/Source/core/layout/ng/inline/ng_baseline.h

// 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.

#ifndef NGBaseline_h
#define NGBaseline_h

#include "platform/LayoutUnit.h"
#include "platform/fonts/FontBaseline.h"

namespace blink {

class LayoutBox;
class NGLayoutInputNode;

enum class NGBaselineAlgorithmType {
  // Compute baselines for atomic inlines.
  kAtomicInline,
  // Compute baselines for atomic inlines using the first line style.
  kAtomicInlineForFirstLine,
  // Compute baseline of first line box.
  kFirstLine
};

// Baselines are products of layout.
// To compute baseline, add requests to NGConstraintSpace and run Layout().
struct NGBaselineRequest {
  NGBaselineAlgorithmType algorithm_type;
  FontBaseline baseline_type;
};

bool operator==(const NGBaselineRequest&, const NGBaselineRequest&);
bool operator!=(const NGBaselineRequest&, const NGBaselineRequest&);

// Represents a computed baseline position.
struct NGBaseline {
  NGBaselineRequest request;
  LayoutUnit offset;

  // @return if the node needs to propagate baseline requests/results.
  static bool ShouldPropagateBaselines(const NGLayoutInputNode);
  static bool ShouldPropagateBaselines(LayoutBox*);
};

}  // namespace blink

#endif  // NGBaseline_h