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// 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/FragmentainerIterator.h"
#include "core/layout/LayoutMultiColumnSet.h"
namespace blink {
FragmentainerIterator::FragmentainerIterator(
const LayoutFlowThread& flowThread,
const LayoutRect& physicalBoundingBoxInFlowThread,
const LayoutRect& clipRectInMulticolContainer)
: m_flowThread(flowThread),
m_clipRectInMulticolContainer(clipRectInMulticolContainer),
m_currentFragmentainerGroupIndex(0) {
// Put the bounds into flow thread-local coordinates by flipping it first.
// This is how rectangles typically are represented in layout, i.e. with the
// block direction coordinate flipped, if writing mode is vertical-rl.
LayoutRect boundsInFlowThread = physicalBoundingBoxInFlowThread;
m_flowThread.flipForWritingMode(boundsInFlowThread);
if (m_flowThread.isHorizontalWritingMode()) {
m_logicalTopInFlowThread = boundsInFlowThread.y();
m_logicalBottomInFlowThread = boundsInFlowThread.maxY();
} else {
m_logicalTopInFlowThread = boundsInFlowThread.x();
m_logicalBottomInFlowThread = boundsInFlowThread.maxX();
}
// Jump to the first interesting column set.
m_currentColumnSet = flowThread.columnSetAtBlockOffset(
m_logicalTopInFlowThread, LayoutBox::AssociateWithLatterPage);
if (!m_currentColumnSet) {
setAtEnd();
return;
}
// Then find the first interesting fragmentainer group.
m_currentFragmentainerGroupIndex =
m_currentColumnSet->fragmentainerGroupIndexAtFlowThreadOffset(
m_logicalTopInFlowThread, LayoutBox::AssociateWithLatterPage);
// Now find the first and last fragmentainer we're interested in. We'll also
// clip against the clip rect here. In case the clip rect doesn't intersect
// with any of the fragmentainers, we have to move on to the next
// fragmentainer group, and see if we find something there.
if (!setFragmentainersOfInterest()) {
moveToNextFragmentainerGroup();
if (atEnd())
return;
}
}
void FragmentainerIterator::advance() {
DCHECK(!atEnd());
if (m_currentFragmentainerIndex < m_endFragmentainerIndex) {
m_currentFragmentainerIndex++;
} else {
// That was the last fragmentainer to visit in this fragmentainer group.
// Advance to the next group.
moveToNextFragmentainerGroup();
if (atEnd())
return;
}
}
LayoutSize FragmentainerIterator::paginationOffset() const {
DCHECK(!atEnd());
const MultiColumnFragmentainerGroup& group = currentGroup();
LayoutUnit fragmentainerLogicalTopInFlowThread =
group.logicalTopInFlowThread() +
m_currentFragmentainerIndex * group.logicalHeight();
return group.flowThreadTranslationAtOffset(
fragmentainerLogicalTopInFlowThread, LayoutBox::AssociateWithLatterPage,
CoordinateSpaceConversion::Visual);
}
LayoutRect FragmentainerIterator::fragmentainerInFlowThread() const {
DCHECK(!atEnd());
LayoutRect fragmentainerInFlowThread =
currentGroup().flowThreadPortionRectAt(m_currentFragmentainerIndex);
m_flowThread.flipForWritingMode(fragmentainerInFlowThread);
return fragmentainerInFlowThread;
}
LayoutRect FragmentainerIterator::clipRectInFlowThread() const {
DCHECK(!atEnd());
LayoutRect clipRect = currentGroup().flowThreadPortionOverflowRectAt(
m_currentFragmentainerIndex);
m_flowThread.flipForWritingMode(clipRect);
return clipRect;
}
const MultiColumnFragmentainerGroup& FragmentainerIterator::currentGroup()
const {
DCHECK(!atEnd());
return m_currentColumnSet
->fragmentainerGroups()[m_currentFragmentainerGroupIndex];
}
void FragmentainerIterator::moveToNextFragmentainerGroup() {
do {
m_currentFragmentainerGroupIndex++;
if (m_currentFragmentainerGroupIndex >=
m_currentColumnSet->fragmentainerGroups().size()) {
// That was the last fragmentainer group in this set. Advance to the next.
m_currentColumnSet = m_currentColumnSet->nextSiblingMultiColumnSet();
m_currentFragmentainerGroupIndex = 0;
if (!m_currentColumnSet ||
m_currentColumnSet->logicalTopInFlowThread() >=
m_logicalBottomInFlowThread) {
setAtEnd();
return; // No more sets or next set out of range. We're done.
}
}
if (currentGroup().logicalTopInFlowThread() >=
m_logicalBottomInFlowThread) {
// This fragmentainer group doesn't intersect with the range we're
// interested in. We're done.
setAtEnd();
return;
}
} while (!setFragmentainersOfInterest());
}
bool FragmentainerIterator::setFragmentainersOfInterest() {
const MultiColumnFragmentainerGroup& group = currentGroup();
// Figure out the start and end fragmentainers for the block range we're
// interested in. We might not have to walk the entire fragmentainer group.
group.columnIntervalForBlockRangeInFlowThread(
m_logicalTopInFlowThread, m_logicalBottomInFlowThread,
m_currentFragmentainerIndex, m_endFragmentainerIndex);
if (hasClipRect()) {
// Now intersect with the fragmentainers that actually intersect with the
// visual clip rect, to narrow it down even further. The clip rect needs to
// be relative to the current fragmentainer group.
LayoutRect clipRect = m_clipRectInMulticolContainer;
LayoutSize offset = group.flowThreadTranslationAtOffset(
group.logicalTopInFlowThread(), LayoutBox::AssociateWithFormerPage,
CoordinateSpaceConversion::Visual);
clipRect.move(-offset);
unsigned firstFragmentainerInClipRect, lastFragmentainerInClipRect;
group.columnIntervalForVisualRect(clipRect, firstFragmentainerInClipRect,
lastFragmentainerInClipRect);
// If the two fragmentainer intervals are disjoint, there's nothing of
// interest in this fragmentainer group.
if (firstFragmentainerInClipRect > m_endFragmentainerIndex ||
lastFragmentainerInClipRect < m_currentFragmentainerIndex)
return false;
if (m_currentFragmentainerIndex < firstFragmentainerInClipRect)
m_currentFragmentainerIndex = firstFragmentainerInClipRect;
if (m_endFragmentainerIndex > lastFragmentainerInClipRect)
m_endFragmentainerIndex = lastFragmentainerInClipRect;
}
DCHECK(m_endFragmentainerIndex >= m_currentFragmentainerIndex);
return true;
}
} // namespace blink
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