third_party/WebKit/Source/core/layout/ng/ng_length_utils.cc

// 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 "core/layout/ng/ng_length_utils.h"

#include "core/layout/ng/ng_constraint_space.h"
#include "core/style/ComputedStyle.h"
#include "platform/LayoutUnit.h"
#include "platform/Length.h"

namespace blink {
// TODO(layout-ng):
// - Handle border-box correctly
// - positioned and/or replaced calculations
// - Handle margins for fill-available and width: auto

LayoutUnit resolveInlineLength(const NGConstraintSpace& constraintSpace,
                               const Length& length,
                               LengthResolveType type) {
  // TODO(layout-ng): Handle min/max/fit-content
  DCHECK(!length.isMaxSizeNone());

  if (type == LengthResolveType::MinSize && length.isAuto())
    return LayoutUnit();

  return valueForLength(length, constraintSpace.ContainerSize().inlineSize);
}

LayoutUnit resolveBlockLength(const NGConstraintSpace& constraintSpace,
                              const Length& length,
                              LayoutUnit contentSize,
                              LengthResolveType type) {
  DCHECK(!length.isMaxSizeNone());

  if (type == LengthResolveType::MinSize && length.isAuto())
    return LayoutUnit();

  if (length.isAuto())
    return contentSize;

  if (length.isMinContent() || length.isMaxContent() || length.isFitContent())
    return contentSize;

  return valueForLength(length, constraintSpace.ContainerSize().blockSize);
}

LayoutUnit computeInlineSizeForFragment(
    const NGConstraintSpace& constraintSpace,
    const ComputedStyle& style) {
  if (constraintSpace.fixedInlineSize())
    return constraintSpace.ContainerSize().inlineSize;

  LayoutUnit extent = resolveInlineLength(constraintSpace, style.logicalWidth(),
                                          LengthResolveType::ContentSize);

  Length maxLength = style.logicalMaxWidth();
  if (!maxLength.isMaxSizeNone()) {
    LayoutUnit max = resolveInlineLength(constraintSpace, maxLength,
                                         LengthResolveType::MaxSize);
    extent = std::min(extent, max);
  }

  LayoutUnit min = resolveInlineLength(constraintSpace, style.logicalMinWidth(),
                                       LengthResolveType::MinSize);
  extent = std::max(extent, min);

  if (style.boxSizing() == BoxSizingContentBox) {
    // TODO(layout-ng): Compute border/padding size and add it
  }

  return extent;
}

LayoutUnit computeBlockSizeForFragment(const NGConstraintSpace& constraintSpace,
                                       const ComputedStyle& style,
                                       LayoutUnit contentSize) {
  if (constraintSpace.fixedBlockSize())
    return constraintSpace.ContainerSize().blockSize;

  LayoutUnit extent =
      resolveBlockLength(constraintSpace, style.logicalHeight(), contentSize,
                         LengthResolveType::ContentSize);
  Length maxLength = style.logicalMaxHeight();

  if (!maxLength.isMaxSizeNone()) {
    LayoutUnit max = resolveBlockLength(constraintSpace, maxLength, contentSize,
                                        LengthResolveType::MaxSize);
    extent = std::min(extent, max);
  }

  LayoutUnit min = resolveBlockLength(constraintSpace, style.logicalMinHeight(),
                                      contentSize, LengthResolveType::MinSize);
  extent = std::max(extent, min);

  if (style.boxSizing() == BoxSizingContentBox) {
    // TODO(layout-ng): Compute border/padding size and add it
  }

  return extent;
}

}  // namespace blink