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// Copyright 2015 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/MultiColumnFragmentainerGroup.h"
#include "core/layout/ColumnBalancer.h"
#include "core/layout/FragmentationContext.h"
#include "core/layout/LayoutMultiColumnSet.h"
namespace blink {
MultiColumnFragmentainerGroup::MultiColumnFragmentainerGroup(
const LayoutMultiColumnSet& columnSet)
: m_columnSet(columnSet) {}
bool MultiColumnFragmentainerGroup::isFirstGroup() const {
return &m_columnSet.firstFragmentainerGroup() == this;
}
bool MultiColumnFragmentainerGroup::isLastGroup() const {
return &m_columnSet.lastFragmentainerGroup() == this;
}
LayoutSize MultiColumnFragmentainerGroup::offsetFromColumnSet() const {
LayoutSize offset(LayoutUnit(), logicalTop());
if (!m_columnSet.flowThread()->isHorizontalWritingMode())
return offset.transposedSize();
return offset;
}
LayoutUnit
MultiColumnFragmentainerGroup::blockOffsetInEnclosingFragmentationContext()
const {
return logicalTop() + m_columnSet.logicalTopFromMulticolContentEdge() +
m_columnSet.multiColumnFlowThread()
->blockOffsetInEnclosingFragmentationContext();
}
void MultiColumnFragmentainerGroup::resetColumnHeight() {
m_maxColumnHeight = calculateMaxColumnHeight();
LayoutMultiColumnFlowThread* flowThread = m_columnSet.multiColumnFlowThread();
if (m_columnSet.heightIsAuto()) {
FragmentationContext* enclosingFragmentationContext =
flowThread->enclosingFragmentationContext();
if (enclosingFragmentationContext &&
enclosingFragmentationContext->isFragmentainerLogicalHeightKnown()) {
// Set an initial height, based on the fragmentainer height in the outer
// fragmentation context, in order to tell how much content this
// MultiColumnFragmentainerGroup can hold, and when we need to append a
// new one.
m_columnHeight = m_maxColumnHeight;
return;
}
}
// If the multicol container has a definite height, use it as the column
// height. This even applies when we are to balance the columns. We'll still
// use the definite height as an initial height, and lay out once at that
// column height. If it turns out that the content needs less than this
// height, we have to balance and shrink the height and lay out the columns
// over again.
if (LayoutUnit logicalHeight = flowThread->columnHeightAvailable()) {
setAndConstrainColumnHeight(heightAdjustedForRowOffset(logicalHeight));
} else {
m_columnHeight = LayoutUnit();
}
}
bool MultiColumnFragmentainerGroup::recalculateColumnHeight(
LayoutMultiColumnSet& columnSet) {
LayoutUnit oldColumnHeight = m_columnHeight;
m_maxColumnHeight = calculateMaxColumnHeight();
// Only the last row may have auto height, and thus be balanced. There are no
// good reasons to balance the preceding rows, and that could potentially lead
// to an insane number of layout passes as well.
if (isLastGroup() && columnSet.heightIsAuto()) {
LayoutUnit newColumnHeight;
if (!columnSet.isInitialHeightCalculated()) {
// Initial balancing: Start with the lowest imaginable column height. Also
// calculate the height of the tallest piece of unbreakable content.
// Columns should never get any shorter than that (unless constrained by
// max-height). Propagate this to our containing column set, in case there
// is an outer multicol container that also needs to balance. After having
// calculated the initial column height, the multicol container needs
// another layout pass with the column height that we just calculated.
InitialColumnHeightFinder initialHeightFinder(
columnSet, logicalTopInFlowThread(), logicalBottomInFlowThread());
columnSet.propagateTallestUnbreakableLogicalHeight(
initialHeightFinder.tallestUnbreakableLogicalHeight());
newColumnHeight = initialHeightFinder.initialMinimalBalancedHeight();
} else {
// Rebalancing: After having laid out again, we'll need to rebalance if
// the height wasn't enough and we're allowed to stretch it, and then
// re-lay out. There are further details on the column balancing
// machinery in ColumnBalancer and its derivates.
newColumnHeight = rebalanceColumnHeightIfNeeded();
}
setAndConstrainColumnHeight(newColumnHeight);
} else {
// The position of the column set may have changed, in which case height
// available for columns may have changed as well.
setAndConstrainColumnHeight(m_columnHeight);
}
if (m_columnHeight == oldColumnHeight)
return false; // No change. We're done.
return true; // Need another pass.
}
LayoutSize MultiColumnFragmentainerGroup::flowThreadTranslationAtOffset(
LayoutUnit offsetInFlowThread,
LayoutBox::PageBoundaryRule rule,
CoordinateSpaceConversion mode) const {
LayoutMultiColumnFlowThread* flowThread = m_columnSet.multiColumnFlowThread();
// A column out of range doesn't have a flow thread portion, so we need to
// clamp to make sure that we stay within the actual columns. This means that
// content in the overflow area will be mapped to the last actual column,
// instead of being mapped to an imaginary column further ahead.
unsigned columnIndex = offsetInFlowThread >= logicalBottomInFlowThread()
? actualColumnCount() - 1
: columnIndexAtOffset(offsetInFlowThread, rule);
LayoutRect portionRect(flowThreadPortionRectAt(columnIndex));
flowThread->flipForWritingMode(portionRect);
portionRect.moveBy(flowThread->physicalLocation());
LayoutRect columnRect(columnRectAt(columnIndex));
columnRect.move(offsetFromColumnSet());
m_columnSet.flipForWritingMode(columnRect);
columnRect.moveBy(m_columnSet.physicalLocation());
LayoutSize translationRelativeToFlowThread =
columnRect.location() - portionRect.location();
if (mode == CoordinateSpaceConversion::Containing)
return translationRelativeToFlowThread;
LayoutSize enclosingTranslation;
if (LayoutMultiColumnFlowThread* enclosingFlowThread =
flowThread->enclosingFlowThread()) {
const MultiColumnFragmentainerGroup& firstRow =
flowThread->firstMultiColumnSet()->firstFragmentainerGroup();
// Translation that would map points in the coordinate space of the
// outermost flow thread to visual points in the first column in the first
// fragmentainer group (row) in our multicol container.
LayoutSize enclosingTranslationOrigin =
enclosingFlowThread->flowThreadTranslationAtOffset(
firstRow.blockOffsetInEnclosingFragmentationContext(),
LayoutBox::AssociateWithLatterPage, mode);
// Translation that would map points in the coordinate space of the
// outermost flow thread to visual points in the first column in this
// fragmentainer group.
enclosingTranslation = enclosingFlowThread->flowThreadTranslationAtOffset(
blockOffsetInEnclosingFragmentationContext(),
LayoutBox::AssociateWithLatterPage, mode);
// What we ultimately return from this method is a translation that maps
// points in the coordinate space of our flow thread to a visual point in a
// certain column in this fragmentainer group. We had to go all the way up
// to the outermost flow thread, since this fragmentainer group may be in a
// different outer column than the first outer column that this multicol
// container lives in. It's the visual distance between the first
// fragmentainer group and this fragmentainer group that we need to add to
// the translation.
enclosingTranslation -= enclosingTranslationOrigin;
}
return enclosingTranslation + translationRelativeToFlowThread;
}
LayoutUnit MultiColumnFragmentainerGroup::columnLogicalTopForOffset(
LayoutUnit offsetInFlowThread) const {
unsigned columnIndex = columnIndexAtOffset(
offsetInFlowThread, LayoutBox::AssociateWithLatterPage);
return logicalTopInFlowThreadAt(columnIndex);
}
LayoutPoint MultiColumnFragmentainerGroup::visualPointToFlowThreadPoint(
const LayoutPoint& visualPoint,
SnapToColumnPolicy snap) const {
unsigned columnIndex = columnIndexAtVisualPoint(visualPoint);
LayoutRect columnRect = columnRectAt(columnIndex);
LayoutPoint localPoint(visualPoint);
localPoint.moveBy(-columnRect.location());
if (!m_columnSet.isHorizontalWritingMode()) {
if (snap == SnapToColumn) {
LayoutUnit columnStart = m_columnSet.style()->isLeftToRightDirection()
? LayoutUnit()
: columnRect.height();
if (localPoint.x() < 0)
localPoint = LayoutPoint(LayoutUnit(), columnStart);
else if (localPoint.x() > logicalHeight())
localPoint = LayoutPoint(logicalHeight(), columnStart);
}
return LayoutPoint(localPoint.x() + logicalTopInFlowThreadAt(columnIndex),
localPoint.y());
}
if (snap == SnapToColumn) {
LayoutUnit columnStart = m_columnSet.style()->isLeftToRightDirection()
? LayoutUnit()
: columnRect.width();
if (localPoint.y() < 0)
localPoint = LayoutPoint(columnStart, LayoutUnit());
else if (localPoint.y() > logicalHeight())
localPoint = LayoutPoint(columnStart, logicalHeight());
}
return LayoutPoint(localPoint.x(),
localPoint.y() + logicalTopInFlowThreadAt(columnIndex));
}
LayoutRect MultiColumnFragmentainerGroup::fragmentsBoundingBox(
const LayoutRect& boundingBoxInFlowThread) const {
// Find the start and end column intersected by the bounding box.
LayoutRect flippedBoundingBoxInFlowThread(boundingBoxInFlowThread);
LayoutFlowThread* flowThread = m_columnSet.flowThread();
flowThread->flipForWritingMode(flippedBoundingBoxInFlowThread);
bool isHorizontalWritingMode = m_columnSet.isHorizontalWritingMode();
LayoutUnit boundingBoxLogicalTop = isHorizontalWritingMode
? flippedBoundingBoxInFlowThread.y()
: flippedBoundingBoxInFlowThread.x();
LayoutUnit boundingBoxLogicalBottom =
isHorizontalWritingMode ? flippedBoundingBoxInFlowThread.maxY()
: flippedBoundingBoxInFlowThread.maxX();
if (boundingBoxLogicalBottom <= logicalTopInFlowThread() ||
boundingBoxLogicalTop >= logicalBottomInFlowThread()) {
// The bounding box doesn't intersect this fragmentainer group.
return LayoutRect();
}
unsigned startColumn;
unsigned endColumn;
columnIntervalForBlockRangeInFlowThread(
boundingBoxLogicalTop, boundingBoxLogicalBottom, startColumn, endColumn);
LayoutRect startColumnFlowThreadOverflowPortion =
flowThreadPortionOverflowRectAt(startColumn);
flowThread->flipForWritingMode(startColumnFlowThreadOverflowPortion);
LayoutRect startColumnRect(boundingBoxInFlowThread);
startColumnRect.intersect(startColumnFlowThreadOverflowPortion);
startColumnRect.move(flowThreadTranslationAtOffset(
logicalTopInFlowThreadAt(startColumn), LayoutBox::AssociateWithLatterPage,
CoordinateSpaceConversion::Containing));
if (startColumn == endColumn)
return startColumnRect; // It all takes place in one column. We're done.
LayoutRect endColumnFlowThreadOverflowPortion =
flowThreadPortionOverflowRectAt(endColumn);
flowThread->flipForWritingMode(endColumnFlowThreadOverflowPortion);
LayoutRect endColumnRect(boundingBoxInFlowThread);
endColumnRect.intersect(endColumnFlowThreadOverflowPortion);
endColumnRect.move(flowThreadTranslationAtOffset(
logicalTopInFlowThreadAt(endColumn), LayoutBox::AssociateWithLatterPage,
CoordinateSpaceConversion::Containing));
return unionRect(startColumnRect, endColumnRect);
}
LayoutRect MultiColumnFragmentainerGroup::calculateOverflow() const {
// Note that we just return the bounding rectangle of the column boxes here.
// We currently don't examine overflow caused by the actual content that ends
// up in each column.
LayoutRect overflowRect;
if (unsigned columnCount = actualColumnCount()) {
overflowRect = columnRectAt(0);
if (columnCount > 1)
overflowRect.uniteEvenIfEmpty(columnRectAt(columnCount - 1));
}
return overflowRect;
}
unsigned MultiColumnFragmentainerGroup::actualColumnCount() const {
// We must always return a value of 1 or greater. Column count = 0 is a
// meaningless situation, and will confuse and cause problems in other parts
// of the code.
if (!m_columnHeight)
return 1;
// Our flow thread portion determines our column count. We have as many
// columns as needed to fit all the content.
LayoutUnit flowThreadPortionHeight = logicalHeightInFlowThread();
if (!flowThreadPortionHeight)
return 1;
unsigned count = (flowThreadPortionHeight / m_columnHeight).floor();
// flowThreadPortionHeight may be saturated, so detect the remainder manually.
if (count * m_columnHeight < flowThreadPortionHeight)
count++;
ASSERT(count >= 1);
return count;
}
LayoutUnit MultiColumnFragmentainerGroup::heightAdjustedForRowOffset(
LayoutUnit height) const {
// Let's avoid zero height, as that would cause an infinite amount of columns
// to be created.
return std::max(
height - logicalTop() - m_columnSet.logicalTopFromMulticolContentEdge(),
LayoutUnit(1));
}
LayoutUnit MultiColumnFragmentainerGroup::calculateMaxColumnHeight() const {
LayoutMultiColumnFlowThread* flowThread = m_columnSet.multiColumnFlowThread();
LayoutUnit maxColumnHeight = flowThread->maxColumnLogicalHeight();
LayoutUnit maxHeight = heightAdjustedForRowOffset(maxColumnHeight);
if (FragmentationContext* enclosingFragmentationContext =
flowThread->enclosingFragmentationContext()) {
if (enclosingFragmentationContext->isFragmentainerLogicalHeightKnown()) {
// We're nested inside another fragmentation context whose fragmentainer
// heights are known. This constrains the max height.
LayoutUnit remainingOuterLogicalHeight =
enclosingFragmentationContext->remainingLogicalHeightAt(
blockOffsetInEnclosingFragmentationContext());
ASSERT(remainingOuterLogicalHeight > 0);
if (maxHeight > remainingOuterLogicalHeight)
maxHeight = remainingOuterLogicalHeight;
}
}
return maxHeight;
}
void MultiColumnFragmentainerGroup::setAndConstrainColumnHeight(
LayoutUnit newHeight) {
m_columnHeight = newHeight;
if (m_columnHeight > m_maxColumnHeight)
m_columnHeight = m_maxColumnHeight;
}
LayoutUnit MultiColumnFragmentainerGroup::rebalanceColumnHeightIfNeeded()
const {
if (actualColumnCount() <= m_columnSet.usedColumnCount()) {
// With the current column height, the content fits without creating
// overflowing columns. We're done.
return m_columnHeight;
}
if (m_columnHeight >= m_maxColumnHeight) {
// We cannot stretch any further. We'll just have to live with the
// overflowing columns. This typically happens if the max column height is
// less than the height of the tallest piece of unbreakable content (e.g.
// lines).
return m_columnHeight;
}
MinimumSpaceShortageFinder shortageFinder(
columnSet(), logicalTopInFlowThread(), logicalBottomInFlowThread());
if (shortageFinder.forcedBreaksCount() + 1 >= m_columnSet.usedColumnCount()) {
// Too many forced breaks to allow any implicit breaks. Initial balancing
// should already have set a good height. There's nothing more we should do.
return m_columnHeight;
}
// If the initial guessed column height wasn't enough, stretch it now. Stretch
// by the lowest amount of space.
LayoutUnit minSpaceShortage = shortageFinder.minimumSpaceShortage();
ASSERT(minSpaceShortage > 0); // We should never _shrink_ the height!
ASSERT(minSpaceShortage !=
LayoutUnit::max()); // If this happens, we probably have a bug.
if (minSpaceShortage == LayoutUnit::max())
return m_columnHeight; // So bail out rather than looping infinitely.
return m_columnHeight + minSpaceShortage;
}
LayoutRect MultiColumnFragmentainerGroup::columnRectAt(
unsigned columnIndex) const {
LayoutUnit columnLogicalWidth = m_columnSet.pageLogicalWidth();
LayoutUnit columnLogicalHeight = m_columnHeight;
LayoutUnit columnLogicalTop;
LayoutUnit columnLogicalLeft;
LayoutUnit columnGap = m_columnSet.columnGap();
LayoutUnit portionOutsideFlowThread =
logicalTopInFlowThread() + (columnIndex + 1) * columnLogicalHeight -
logicalBottomInFlowThread();
if (portionOutsideFlowThread > 0) {
// The last column may not be using all available space.
ASSERT(columnIndex + 1 == actualColumnCount());
columnLogicalHeight -= portionOutsideFlowThread;
ASSERT(columnLogicalHeight >= 0);
}
if (m_columnSet.multiColumnFlowThread()->progressionIsInline()) {
if (m_columnSet.style()->isLeftToRightDirection())
columnLogicalLeft += columnIndex * (columnLogicalWidth + columnGap);
else
columnLogicalLeft += m_columnSet.contentLogicalWidth() -
columnLogicalWidth -
columnIndex * (columnLogicalWidth + columnGap);
} else {
columnLogicalTop += columnIndex * (m_columnHeight + columnGap);
}
LayoutRect columnRect(columnLogicalLeft, columnLogicalTop, columnLogicalWidth,
columnLogicalHeight);
if (!m_columnSet.isHorizontalWritingMode())
return columnRect.transposedRect();
return columnRect;
}
LayoutRect MultiColumnFragmentainerGroup::flowThreadPortionRectAt(
unsigned columnIndex) const {
LayoutUnit logicalTop = logicalTopInFlowThreadAt(columnIndex);
LayoutUnit logicalBottom = logicalTop + m_columnHeight;
if (logicalBottom > logicalBottomInFlowThread()) {
// The last column may not be using all available space.
ASSERT(columnIndex + 1 == actualColumnCount());
logicalBottom = logicalBottomInFlowThread();
ASSERT(logicalBottom >= logicalTop);
}
LayoutUnit portionLogicalHeight = logicalBottom - logicalTop;
if (m_columnSet.isHorizontalWritingMode())
return LayoutRect(LayoutUnit(), logicalTop, m_columnSet.pageLogicalWidth(),
portionLogicalHeight);
return LayoutRect(logicalTop, LayoutUnit(), portionLogicalHeight,
m_columnSet.pageLogicalWidth());
}
LayoutRect MultiColumnFragmentainerGroup::flowThreadPortionOverflowRectAt(
unsigned columnIndex) const {
// This function determines the portion of the flow thread that paints for the
// column. Along the inline axis, columns are unclipped at outside edges
// (i.e., the first and last column in the set), and they clip to half the
// column gap along interior edges.
//
// In the block direction, we will not clip overflow out of the top of the
// first column, or out of the bottom of the last column. This applies only to
// the true first column and last column across all column sets.
//
// FIXME: Eventually we will know overflow on a per-column basis, but we can't
// do this until we have a painting mode that understands not to paint
// contents from a previous column in the overflow area of a following column.
bool isFirstColumnInRow = !columnIndex;
bool isLastColumnInRow = columnIndex == actualColumnCount() - 1;
bool isLTR = m_columnSet.style()->isLeftToRightDirection();
bool isLeftmostColumn = isLTR ? isFirstColumnInRow : isLastColumnInRow;
bool isRightmostColumn = isLTR ? isLastColumnInRow : isFirstColumnInRow;
LayoutRect portionRect = flowThreadPortionRectAt(columnIndex);
bool isFirstColumnInMulticolContainer =
isFirstColumnInRow && this == &m_columnSet.firstFragmentainerGroup() &&
!m_columnSet.previousSiblingMultiColumnSet();
bool isLastColumnInMulticolContainer =
isLastColumnInRow && this == &m_columnSet.lastFragmentainerGroup() &&
!m_columnSet.nextSiblingMultiColumnSet();
// Calculate the overflow rectangle, based on the flow thread's, clipped at
// column logical top/bottom unless it's the first/last column.
LayoutRect overflowRect = m_columnSet.overflowRectForFlowThreadPortion(
portionRect, isFirstColumnInMulticolContainer,
isLastColumnInMulticolContainer);
// Avoid overflowing into neighboring columns, by clipping in the middle of
// adjacent column gaps. Also make sure that we avoid rounding errors.
LayoutUnit columnGap = m_columnSet.columnGap();
if (m_columnSet.isHorizontalWritingMode()) {
if (!isLeftmostColumn)
overflowRect.shiftXEdgeTo(portionRect.x() - columnGap / 2);
if (!isRightmostColumn)
overflowRect.shiftMaxXEdgeTo(portionRect.maxX() + columnGap -
columnGap / 2);
} else {
if (!isLeftmostColumn)
overflowRect.shiftYEdgeTo(portionRect.y() - columnGap / 2);
if (!isRightmostColumn)
overflowRect.shiftMaxYEdgeTo(portionRect.maxY() + columnGap -
columnGap / 2);
}
return overflowRect;
}
unsigned MultiColumnFragmentainerGroup::columnIndexAtOffset(
LayoutUnit offsetInFlowThread,
LayoutBox::PageBoundaryRule pageBoundaryRule) const {
// Handle the offset being out of range.
if (offsetInFlowThread < m_logicalTopInFlowThread)
return 0;
if (!m_columnHeight)
return 0;
unsigned columnIndex =
((offsetInFlowThread - m_logicalTopInFlowThread) / m_columnHeight)
.floor();
if (pageBoundaryRule == LayoutBox::AssociateWithFormerPage &&
columnIndex > 0 &&
logicalTopInFlowThreadAt(columnIndex) == offsetInFlowThread) {
// We are exactly at a column boundary, and we've been told to associate
// offsets at column boundaries with the former column, not the latter.
columnIndex--;
}
return columnIndex;
}
unsigned MultiColumnFragmentainerGroup::columnIndexAtVisualPoint(
const LayoutPoint& visualPoint) const {
bool isColumnProgressionInline =
m_columnSet.multiColumnFlowThread()->progressionIsInline();
bool isHorizontalWritingMode = m_columnSet.isHorizontalWritingMode();
LayoutUnit columnLengthInColumnProgressionDirection =
isColumnProgressionInline ? m_columnSet.pageLogicalWidth()
: logicalHeight();
LayoutUnit offsetInColumnProgressionDirection =
isHorizontalWritingMode == isColumnProgressionInline ? visualPoint.x()
: visualPoint.y();
if (!m_columnSet.style()->isLeftToRightDirection() &&
isColumnProgressionInline)
offsetInColumnProgressionDirection =
m_columnSet.logicalWidth() - offsetInColumnProgressionDirection;
LayoutUnit columnGap = m_columnSet.columnGap();
if (columnLengthInColumnProgressionDirection + columnGap <= 0)
return 0;
// Column boundaries are in the middle of the column gap.
int index = ((offsetInColumnProgressionDirection + columnGap / 2) /
(columnLengthInColumnProgressionDirection + columnGap))
.toInt();
if (index < 0)
return 0;
return std::min(unsigned(index), actualColumnCount() - 1);
}
void MultiColumnFragmentainerGroup::columnIntervalForBlockRangeInFlowThread(
LayoutUnit logicalTopInFlowThread,
LayoutUnit logicalBottomInFlowThread,
unsigned& firstColumn,
unsigned& lastColumn) const {
logicalTopInFlowThread =
std::max(logicalTopInFlowThread, this->logicalTopInFlowThread());
logicalBottomInFlowThread =
std::min(logicalBottomInFlowThread, this->logicalBottomInFlowThread());
ASSERT(logicalTopInFlowThread <= logicalBottomInFlowThread);
firstColumn = columnIndexAtOffset(logicalTopInFlowThread,
LayoutBox::AssociateWithLatterPage);
if (logicalBottomInFlowThread == logicalTopInFlowThread) {
// Zero-height block range. There'll be one column in the interval. Set it
// right away. This is important if we're at a column boundary, since
// calling columnIndexAtOffset() with the end-exclusive bottom offset would
// actually give us the *previous* column.
lastColumn = firstColumn;
} else {
lastColumn = columnIndexAtOffset(logicalBottomInFlowThread,
LayoutBox::AssociateWithFormerPage);
}
}
void MultiColumnFragmentainerGroup::columnIntervalForVisualRect(
const LayoutRect& rect,
unsigned& firstColumn,
unsigned& lastColumn) const {
bool isColumnProgressionInline =
m_columnSet.multiColumnFlowThread()->progressionIsInline();
bool isFlippedColumnProgression =
!m_columnSet.style()->isLeftToRightDirection() &&
isColumnProgressionInline;
if (m_columnSet.isHorizontalWritingMode() == isColumnProgressionInline) {
if (isFlippedColumnProgression) {
firstColumn = columnIndexAtVisualPoint(rect.maxXMinYCorner());
lastColumn = columnIndexAtVisualPoint(rect.minXMinYCorner());
} else {
firstColumn = columnIndexAtVisualPoint(rect.minXMinYCorner());
lastColumn = columnIndexAtVisualPoint(rect.maxXMinYCorner());
}
} else {
if (isFlippedColumnProgression) {
firstColumn = columnIndexAtVisualPoint(rect.minXMaxYCorner());
lastColumn = columnIndexAtVisualPoint(rect.minXMinYCorner());
} else {
firstColumn = columnIndexAtVisualPoint(rect.minXMinYCorner());
lastColumn = columnIndexAtVisualPoint(rect.minXMaxYCorner());
}
}
ASSERT(firstColumn <= lastColumn);
}
MultiColumnFragmentainerGroupList::MultiColumnFragmentainerGroupList(
LayoutMultiColumnSet& columnSet)
: m_columnSet(columnSet) {
append(MultiColumnFragmentainerGroup(m_columnSet));
}
// An explicit empty destructor of MultiColumnFragmentainerGroupList should be
// in MultiColumnFragmentainerGroup.cpp, because if an implicit destructor is
// used, msvc 2015 tries to generate its destructor (because the class is
// dll-exported class) and causes a compile error because of lack of
// MultiColumnFragmentainerGroup::operator=. Since
// MultiColumnFragmentainerGroup is non-copyable, we cannot define the
// operator=.
MultiColumnFragmentainerGroupList::~MultiColumnFragmentainerGroupList() {}
MultiColumnFragmentainerGroup&
MultiColumnFragmentainerGroupList::addExtraGroup() {
append(MultiColumnFragmentainerGroup(m_columnSet));
return last();
}
void MultiColumnFragmentainerGroupList::deleteExtraGroups() {
shrink(1);
}
} // namespace blink
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