third_party/WebKit/Source/core/layout/LayoutState.cpp

/*
 * Copyright (C) 2007 Apple Inc.  All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY APPLE INC. ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
 * PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL APPLE INC. OR
 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR
 * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY
 * OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

#include "core/layout/LayoutState.h"

#include "core/layout/LayoutFlowThread.h"
#include "core/layout/LayoutInline.h"
#include "core/layout/LayoutView.h"

namespace blink {

LayoutState::LayoutState(LayoutUnit pageLogicalHeight,
                         bool pageLogicalHeightChanged,
                         LayoutView& view)
    : m_isPaginated(pageLogicalHeight),
      m_pageLogicalHeightChanged(pageLogicalHeightChanged),
      m_containingBlockLogicalWidthChanged(false),
      m_flowThread(nullptr),
      m_next(nullptr),
      m_pageLogicalHeight(pageLogicalHeight),
      m_layoutObject(view) {
  ASSERT(!view.layoutState());
  view.pushLayoutState(*this);
}

LayoutState::LayoutState(LayoutBox& layoutObject,
                         const LayoutSize& offset,
                         LayoutUnit pageLogicalHeight,
                         bool pageLogicalHeightChanged,
                         bool containingBlockLogicalWidthChanged)
    : m_containingBlockLogicalWidthChanged(containingBlockLogicalWidthChanged),
      m_next(layoutObject.view()->layoutState()),
      m_layoutObject(layoutObject) {
  if (layoutObject.isLayoutFlowThread())
    m_flowThread = toLayoutFlowThread(&layoutObject);
  else if (!layoutObject.isOutOfFlowPositioned())
    m_flowThread = m_next->flowThread();
  else
    m_flowThread = nullptr;
  layoutObject.view()->pushLayoutState(*this);
  bool fixed = layoutObject.isOutOfFlowPositioned() &&
               layoutObject.style()->position() == FixedPosition;
  if (fixed) {
    // FIXME: This doesn't work correctly with transforms.
    FloatPoint fixedOffset =
        layoutObject.view()->localToAbsolute(FloatPoint(), IsFixed);
    m_layoutOffset = LayoutSize(fixedOffset.x(), fixedOffset.y()) + offset;
  } else {
    m_layoutOffset = m_next->m_layoutOffset + offset;
  }
  m_heightOffsetForTableHeaders = m_next->heightOffsetForTableHeaders();

  if (layoutObject.isOutOfFlowPositioned() && !fixed) {
    if (LayoutObject* container = layoutObject.container()) {
      if (container->style()->hasInFlowPosition() &&
          container->isLayoutInline())
        m_layoutOffset +=
            toLayoutInline(container)->offsetForInFlowPositionedInline(
                layoutObject);
    }
  }
  // If we establish a new page height, then cache the offset to the top of the
  // first page. We can compare this later on to figure out what part of the
  // page we're actually on.
  if (pageLogicalHeight || layoutObject.isLayoutFlowThread()) {
    m_pageLogicalHeight = pageLogicalHeight;
    bool isFlipped = layoutObject.style()->isFlippedBlocksWritingMode();
    m_pageOffset = LayoutSize(
        m_layoutOffset.width() +
            (!isFlipped
                 ? layoutObject.borderLeft() + layoutObject.paddingLeft()
                 : layoutObject.borderRight() + layoutObject.paddingRight()),
        m_layoutOffset.height() +
            (!isFlipped
                 ? layoutObject.borderTop() + layoutObject.paddingTop()
                 : layoutObject.borderBottom() + layoutObject.paddingBottom()));
    m_pageLogicalHeightChanged = pageLogicalHeightChanged;
    m_isPaginated = true;
  } else if (m_layoutObject.isSVG() && !m_layoutObject.isSVGRoot()) {
    // Pagination inside SVG is not allowed.
    m_flowThread = nullptr;
    m_pageLogicalHeightChanged = false;
    m_isPaginated = false;
  } else {
    // If we don't establish a new page height, then propagate the old page
    // height and offset down.
    m_pageLogicalHeight = m_next->m_pageLogicalHeight;
    m_pageLogicalHeightChanged = m_next->m_pageLogicalHeightChanged;
    m_pageOffset = m_next->m_pageOffset;

    // Disable pagination for objects we don't support. For now this includes
    // overflow:scroll/auto, inline blocks and writing mode roots.
    if (layoutObject.getPaginationBreakability() == LayoutBox::ForbidBreaks) {
      m_flowThread = nullptr;
      m_pageLogicalHeight = LayoutUnit();
      m_isPaginated = false;
    } else {
      m_isPaginated = m_pageLogicalHeight || m_flowThread;
    }
  }

  // FIXME: <http://bugs.webkit.org/show_bug.cgi?id=13443> Apply control clip if
  // present.
}

LayoutState::LayoutState(LayoutObject& root)
    : m_isPaginated(false),
      m_pageLogicalHeightChanged(false),
      m_containingBlockLogicalWidthChanged(false),
      m_flowThread(nullptr),
      m_next(root.view()->layoutState()),
      m_layoutObject(root) {
  ASSERT(!m_next);
  // We'll end up pushing in LayoutView itself, so don't bother adding it.
  if (root.isLayoutView())
    return;

  root.view()->pushLayoutState(*this);

  LayoutObject* container = root.container();
  FloatPoint absContentPoint =
      container->localToAbsolute(FloatPoint(), UseTransforms);
  m_layoutOffset = LayoutSize(absContentPoint.x(), absContentPoint.y());
}

LayoutState::~LayoutState() {
  if (m_layoutObject.view()->layoutState()) {
    ASSERT(m_layoutObject.view()->layoutState() == this);
    m_layoutObject.view()->popLayoutState();
  }
}

LayoutUnit LayoutState::pageLogicalOffset(
    const LayoutBox& child,
    const LayoutUnit& childLogicalOffset) const {
  if (child.isHorizontalWritingMode())
    return m_layoutOffset.height() + childLogicalOffset - m_pageOffset.height();
  return m_layoutOffset.width() + childLogicalOffset - m_pageOffset.width();
}

}  // namespace blink