| /* |
| * Copyright (C) 2012 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 IN..0TERRUPTION) 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 "config.h" |
| #include "RenderMultiColumnFlowThread.h" |
| |
| #include "HitTestResult.h" |
| #include "LayoutState.h" |
| #include "RenderIterator.h" |
| #include "RenderMultiColumnSet.h" |
| #include "RenderMultiColumnSpannerPlaceholder.h" |
| #include "RenderView.h" |
| #include "TransformState.h" |
| |
| namespace WebCore { |
| |
| bool RenderMultiColumnFlowThread::gShiftingSpanner = false; |
| |
| RenderMultiColumnFlowThread::RenderMultiColumnFlowThread(Document& document, Ref<RenderStyle>&& style) |
| : RenderFlowThread(document, WTF::move(style)) |
| , m_lastSetWorkedOn(nullptr) |
| , m_columnCount(1) |
| , m_columnWidth(0) |
| , m_columnHeightAvailable(0) |
| , m_inLayout(false) |
| , m_inBalancingPass(false) |
| , m_needsHeightsRecalculation(false) |
| , m_progressionIsInline(false) |
| , m_progressionIsReversed(false) |
| , m_beingEvacuated(false) |
| { |
| setFlowThreadState(InsideInFlowThread); |
| } |
| |
| RenderMultiColumnFlowThread::~RenderMultiColumnFlowThread() |
| { |
| } |
| |
| void RenderMultiColumnFlowThread::removeFlowChildInfo(RenderObject* child) |
| { |
| RenderFlowThread::removeFlowChildInfo(child); |
| flowThreadRelativeWillBeRemoved(child); |
| } |
| |
| const char* RenderMultiColumnFlowThread::renderName() const |
| { |
| return "RenderMultiColumnFlowThread"; |
| } |
| |
| RenderMultiColumnSet* RenderMultiColumnFlowThread::firstMultiColumnSet() const |
| { |
| for (RenderObject* sibling = nextSibling(); sibling; sibling = sibling->nextSibling()) { |
| if (is<RenderMultiColumnSet>(*sibling)) |
| return downcast<RenderMultiColumnSet>(sibling); |
| } |
| return nullptr; |
| } |
| |
| RenderMultiColumnSet* RenderMultiColumnFlowThread::lastMultiColumnSet() const |
| { |
| for (RenderObject* sibling = multiColumnBlockFlow()->lastChild(); sibling; sibling = sibling->previousSibling()) { |
| if (is<RenderMultiColumnSet>(*sibling)) |
| return downcast<RenderMultiColumnSet>(sibling); |
| } |
| return nullptr; |
| } |
| |
| RenderBox* RenderMultiColumnFlowThread::firstColumnSetOrSpanner() const |
| { |
| if (RenderObject* sibling = nextSibling()) { |
| ASSERT(is<RenderBox>(*sibling)); |
| ASSERT(is<RenderMultiColumnSet>(*sibling) || findColumnSpannerPlaceholder(downcast<RenderBox>(sibling))); |
| return downcast<RenderBox>(sibling); |
| } |
| return nullptr; |
| } |
| |
| RenderBox* RenderMultiColumnFlowThread::nextColumnSetOrSpannerSiblingOf(const RenderBox* child) |
| { |
| if (!child) |
| return nullptr; |
| if (RenderObject* sibling = child->nextSibling()) |
| return downcast<RenderBox>(sibling); |
| return nullptr; |
| } |
| |
| RenderBox* RenderMultiColumnFlowThread::previousColumnSetOrSpannerSiblingOf(const RenderBox* child) |
| { |
| if (!child) |
| return nullptr; |
| if (RenderObject* sibling = child->previousSibling()) { |
| if (is<RenderFlowThread>(*sibling)) |
| return nullptr; |
| return downcast<RenderBox>(sibling); |
| } |
| return nullptr; |
| } |
| |
| void RenderMultiColumnFlowThread::layout() |
| { |
| ASSERT(!m_inLayout); |
| m_inLayout = true; |
| m_lastSetWorkedOn = nullptr; |
| if (RenderBox* first = firstColumnSetOrSpanner()) { |
| if (is<RenderMultiColumnSet>(*first)) { |
| m_lastSetWorkedOn = downcast<RenderMultiColumnSet>(first); |
| m_lastSetWorkedOn->beginFlow(this); |
| } |
| } |
| RenderFlowThread::layout(); |
| if (RenderMultiColumnSet* lastSet = lastMultiColumnSet()) { |
| if (!nextColumnSetOrSpannerSiblingOf(lastSet)) |
| lastSet->endFlow(this, logicalHeight()); |
| lastSet->expandToEncompassFlowThreadContentsIfNeeded(); |
| } |
| m_inLayout = false; |
| m_lastSetWorkedOn = nullptr; |
| } |
| |
| RenderMultiColumnSet* RenderMultiColumnFlowThread::findSetRendering(RenderObject* renderer) const |
| { |
| for (RenderMultiColumnSet* multicolSet = firstMultiColumnSet(); multicolSet; multicolSet = multicolSet->nextSiblingMultiColumnSet()) { |
| if (multicolSet->containsRendererInFlowThread(renderer)) |
| return multicolSet; |
| } |
| return nullptr; |
| } |
| |
| void RenderMultiColumnFlowThread::populate() |
| { |
| RenderBlockFlow* multicolContainer = multiColumnBlockFlow(); |
| ASSERT(!nextSibling()); |
| // Reparent children preceding the flow thread into the flow thread. It's multicol content |
| // now. At this point there's obviously nothing after the flow thread, but renderers (column |
| // sets and spanners) will be inserted there as we insert elements into the flow thread. |
| LayoutStateDisabler layoutStateDisabler(&view()); |
| multicolContainer->moveChildrenTo(this, multicolContainer->firstChild(), this, true); |
| } |
| |
| void RenderMultiColumnFlowThread::evacuateAndDestroy() |
| { |
| RenderBlockFlow* multicolContainer = multiColumnBlockFlow(); |
| m_beingEvacuated = true; |
| |
| // Delete the line box tree. |
| deleteLines(); |
| |
| LayoutStateDisabler layoutStateDisabler(&view()); |
| |
| // First promote all children of the flow thread. Before we move them to the flow thread's |
| // container, we need to unregister the flow thread, so that they aren't just re-added again to |
| // the flow thread that we're trying to empty. |
| multicolContainer->setMultiColumnFlowThread(nullptr); |
| moveAllChildrenTo(multicolContainer, true); |
| |
| // Move spanners back to their original DOM position in the tree, and destroy the placeholders. |
| SpannerMap::iterator it; |
| while ((it = m_spannerMap.begin()) != m_spannerMap.end()) { |
| RenderBox* spanner = it->key; |
| RenderMultiColumnSpannerPlaceholder* placeholder = it->value; |
| RenderBlockFlow& originalContainer = downcast<RenderBlockFlow>(*placeholder->parent()); |
| multicolContainer->removeChild(*spanner); |
| originalContainer.addChild(spanner, placeholder); |
| placeholder->destroy(); |
| m_spannerMap.remove(it); |
| } |
| |
| // Remove all sets. |
| while (RenderMultiColumnSet* columnSet = firstMultiColumnSet()) |
| columnSet->destroy(); |
| |
| destroy(); |
| } |
| |
| void RenderMultiColumnFlowThread::addRegionToThread(RenderRegion* renderRegion) |
| { |
| auto* columnSet = downcast<RenderMultiColumnSet>(renderRegion); |
| if (RenderMultiColumnSet* nextSet = columnSet->nextSiblingMultiColumnSet()) { |
| RenderRegionList::iterator it = m_regionList.find(nextSet); |
| ASSERT(it != m_regionList.end()); |
| m_regionList.insertBefore(it, columnSet); |
| } else |
| m_regionList.add(columnSet); |
| renderRegion->setIsValid(true); |
| } |
| |
| void RenderMultiColumnFlowThread::willBeRemovedFromTree() |
| { |
| // Detach all column sets from the flow thread. Cannot destroy them at this point, since they |
| // are siblings of this object, and there may be pointers to this object's sibling somewhere |
| // further up on the call stack. |
| for (RenderMultiColumnSet* columnSet = firstMultiColumnSet(); columnSet; columnSet = columnSet->nextSiblingMultiColumnSet()) |
| columnSet->detachRegion(); |
| multiColumnBlockFlow()->setMultiColumnFlowThread(nullptr); |
| RenderFlowThread::willBeRemovedFromTree(); |
| } |
| |
| RenderObject* RenderMultiColumnFlowThread::resolveMovedChild(RenderObject* child) const |
| { |
| if (child->style().columnSpan() != ColumnSpanAll || !is<RenderBox>(*child)) { |
| // We only need to resolve for column spanners. |
| return child; |
| } |
| // The renderer for the actual DOM node that establishes a spanner is moved from its original |
| // location in the render tree to becoming a sibling of the column sets. In other words, it's |
| // moved out from the flow thread (and becomes a sibling of it). When we for instance want to |
| // create and insert a renderer for the sibling node immediately preceding the spanner, we need |
| // to map that spanner renderer to the spanner's placeholder, which is where the new inserted |
| // renderer belongs. |
| if (RenderMultiColumnSpannerPlaceholder* placeholder = findColumnSpannerPlaceholder(downcast<RenderBox>(child))) |
| return placeholder; |
| |
| // This is an invalid spanner, or its placeholder hasn't been created yet. This happens when |
| // moving an entire subtree into the flow thread, when we are processing the insertion of this |
| // spanner's preceding sibling, and we obviously haven't got as far as processing this spanner |
| // yet. |
| return child; |
| } |
| |
| static bool isValidColumnSpanner(RenderMultiColumnFlowThread* flowThread, RenderObject* descendant) |
| { |
| // We assume that we're inside the flow thread. This function is not to be called otherwise. |
| ASSERT(descendant->isDescendantOf(flowThread)); |
| |
| // First make sure that the renderer itself has the right properties for becoming a spanner. |
| RenderStyle& style = descendant->style(); |
| if (style.columnSpan() != ColumnSpanAll || !is<RenderBox>(*descendant) || descendant->isFloatingOrOutOfFlowPositioned()) |
| return false; |
| |
| RenderElement* container = descendant->parent(); |
| if (!is<RenderBlockFlow>(*container) || container->childrenInline()) { |
| // Needs to be block-level. |
| return false; |
| } |
| |
| // We need to have the flow thread as the containing block. A spanner cannot break out of the flow thread. |
| RenderFlowThread* enclosingFlowThread = descendant->flowThreadContainingBlock(); |
| if (enclosingFlowThread != flowThread) |
| return false; |
| |
| // This looks like a spanner, but if we're inside something unbreakable, it's not to be treated as one. |
| for (RenderBox* ancestor = downcast<RenderBox>(*descendant).containingBlock(); ancestor; ancestor = ancestor->containingBlock()) { |
| if (ancestor->isRenderFlowThread()) { |
| // Don't allow any intervening non-multicol fragmentation contexts. The spec doesn't say |
| // anything about disallowing this, but it's just going to be too complicated to |
| // implement (not to mention specify behavior). |
| return ancestor == flowThread; |
| } |
| ASSERT(ancestor->style().columnSpan() != ColumnSpanAll || !isValidColumnSpanner(flowThread, ancestor)); |
| if (ancestor->isUnsplittableForPagination()) |
| return false; |
| } |
| ASSERT_NOT_REACHED(); |
| return false; |
| } |
| |
| RenderObject* RenderMultiColumnFlowThread::processPossibleSpannerDescendant(RenderObject*& subtreeRoot, RenderObject* descendant) |
| { |
| RenderBlockFlow* multicolContainer = multiColumnBlockFlow(); |
| RenderObject* nextRendererInFlowThread = descendant->nextInPreOrderAfterChildren(this); |
| RenderObject* insertBeforeMulticolChild = nullptr; |
| RenderObject* nextDescendant = descendant; |
| |
| if (isValidColumnSpanner(this, descendant)) { |
| // This is a spanner (column-span:all). Such renderers are moved from where they would |
| // otherwise occur in the render tree to becoming a direct child of the multicol container, |
| // so that they live among the column sets. This simplifies the layout implementation, and |
| // basically just relies on regular block layout done by the RenderBlockFlow that |
| // establishes the multicol container. |
| RenderBlockFlow* container = downcast<RenderBlockFlow>(descendant->parent()); |
| RenderMultiColumnSet* setToSplit = nullptr; |
| if (nextRendererInFlowThread) { |
| setToSplit = findSetRendering(descendant); |
| if (setToSplit) { |
| setToSplit->setNeedsLayout(); |
| insertBeforeMulticolChild = setToSplit->nextSibling(); |
| } |
| } |
| // Moving a spanner's renderer so that it becomes a sibling of the column sets requires us |
| // to insert an anonymous placeholder in the tree where the spanner's renderer otherwise |
| // would have been. This is needed for a two reasons: We need a way of separating inline |
| // content before and after the spanner, so that it becomes separate line boxes. Secondly, |
| // this placeholder serves as a break point for column sets, so that, when encountered, we |
| // end flowing one column set and move to the next one. |
| RenderMultiColumnSpannerPlaceholder* placeholder = RenderMultiColumnSpannerPlaceholder::createAnonymous(this, downcast<RenderBox>(descendant), &container->style()); |
| container->addChild(placeholder, descendant->nextSibling()); |
| container->removeChild(*descendant); |
| |
| // This is a guard to stop an ancestor flow thread from processing the spanner. |
| gShiftingSpanner = true; |
| multicolContainer->RenderBlock::addChild(descendant, insertBeforeMulticolChild); |
| gShiftingSpanner = false; |
| |
| // The spanner has now been moved out from the flow thread, but we don't want to |
| // examine its children anyway. They are all part of the spanner and shouldn't trigger |
| // creation of column sets or anything like that. Continue at its original position in |
| // the tree, i.e. where the placeholder was just put. |
| if (subtreeRoot == descendant) |
| subtreeRoot = placeholder; |
| nextDescendant = placeholder; |
| } else { |
| // This is regular multicol content, i.e. not part of a spanner. |
| if (is<RenderMultiColumnSpannerPlaceholder>(nextRendererInFlowThread)) { |
| // Inserted right before a spanner. Is there a set for us there? |
| RenderMultiColumnSpannerPlaceholder& placeholder = downcast<RenderMultiColumnSpannerPlaceholder>(*nextRendererInFlowThread); |
| if (RenderObject* previous = placeholder.spanner()->previousSibling()) { |
| if (is<RenderMultiColumnSet>(*previous)) |
| return nextDescendant; // There's already a set there. Nothing to do. |
| } |
| insertBeforeMulticolChild = placeholder.spanner(); |
| } else if (RenderMultiColumnSet* lastSet = lastMultiColumnSet()) { |
| // This child is not an immediate predecessor of a spanner, which means that if this |
| // child precedes a spanner at all, there has to be a column set created for us there |
| // already. If it doesn't precede any spanner at all, on the other hand, we need a |
| // column set at the end of the multicol container. We don't really check here if the |
| // child inserted precedes any spanner or not (as that's an expensive operation). Just |
| // make sure we have a column set at the end. It's no big deal if it remains unused. |
| if (!lastSet->nextSibling()) |
| return nextDescendant; |
| } |
| } |
| // Need to create a new column set when there's no set already created. We also always insert |
| // another column set after a spanner. Even if it turns out that there are no renderers |
| // following the spanner, there may be bottom margins there, which take up space. |
| RenderMultiColumnSet* newSet = new RenderMultiColumnSet(*this, RenderStyle::createAnonymousStyleWithDisplay(&multicolContainer->style(), BLOCK)); |
| newSet->initializeStyle(); |
| multicolContainer->RenderBlock::addChild(newSet, insertBeforeMulticolChild); |
| invalidateRegions(); |
| |
| // We cannot handle immediate column set siblings at the moment (and there's no need for |
| // it, either). There has to be at least one spanner separating them. |
| ASSERT(!previousColumnSetOrSpannerSiblingOf(newSet) || !previousColumnSetOrSpannerSiblingOf(newSet)->isRenderMultiColumnSet()); |
| ASSERT(!nextColumnSetOrSpannerSiblingOf(newSet) || !nextColumnSetOrSpannerSiblingOf(newSet)->isRenderMultiColumnSet()); |
| |
| return nextDescendant; |
| } |
| |
| void RenderMultiColumnFlowThread::flowThreadDescendantInserted(RenderObject* descendant) |
| { |
| if (gShiftingSpanner || m_beingEvacuated || descendant->isInFlowRenderFlowThread()) |
| return; |
| RenderObject* subtreeRoot = descendant; |
| for (; descendant; descendant = (descendant ? descendant->nextInPreOrder(subtreeRoot) : nullptr)) { |
| if (is<RenderMultiColumnSpannerPlaceholder>(*descendant)) { |
| // A spanner's placeholder has been inserted. The actual spanner renderer is moved from |
| // where it would otherwise occur (if it weren't a spanner) to becoming a sibling of the |
| // column sets. |
| RenderMultiColumnSpannerPlaceholder& placeholder = downcast<RenderMultiColumnSpannerPlaceholder>(*descendant); |
| if (placeholder.flowThread() != this) { |
| // This isn't our spanner! It shifted here from an ancestor multicolumn block. It's going to end up |
| // becoming our spanner instead, but for it to do that we first have to nuke the original spanner, |
| // and get the spanner content back into this flow thread. |
| RenderBox* spanner = placeholder.spanner(); |
| |
| // Insert after the placeholder, but don't let a notification happen. |
| gShiftingSpanner = true; |
| RenderBlockFlow& ancestorBlock = downcast<RenderBlockFlow>(*spanner->parent()); |
| ancestorBlock.moveChildTo(placeholder.parentBox(), spanner, placeholder.nextSibling(), true); |
| gShiftingSpanner = false; |
| |
| // We have to nuke the placeholder, since the ancestor already lost the mapping to it when |
| // we shifted the placeholder down into this flow thread. |
| if (subtreeRoot == descendant) |
| subtreeRoot = spanner; |
| placeholder.parent()->removeChild(placeholder); |
| |
| // Now we process the spanner. |
| descendant = processPossibleSpannerDescendant(subtreeRoot, spanner); |
| continue; |
| } |
| |
| ASSERT(!m_spannerMap.get(placeholder.spanner())); |
| m_spannerMap.add(placeholder.spanner(), &placeholder); |
| ASSERT(!placeholder.firstChild()); // There should be no children here, but if there are, we ought to skip them. |
| continue; |
| } |
| |
| descendant = processPossibleSpannerDescendant(subtreeRoot, descendant); |
| } |
| } |
| |
| void RenderMultiColumnFlowThread::handleSpannerRemoval(RenderObject* spanner) |
| { |
| // The placeholder may already have been removed, but if it hasn't, do so now. |
| if (RenderMultiColumnSpannerPlaceholder* placeholder = m_spannerMap.get(downcast<RenderBox>(spanner))) { |
| placeholder->parent()->removeChild(*placeholder); |
| m_spannerMap.remove(downcast<RenderBox>(spanner)); |
| } |
| |
| if (RenderObject* next = spanner->nextSibling()) { |
| if (RenderObject* previous = spanner->previousSibling()) { |
| if (previous->isRenderMultiColumnSet() && next->isRenderMultiColumnSet()) { |
| // Merge two sets that no longer will be separated by a spanner. |
| next->destroy(); |
| previous->setNeedsLayout(); |
| } |
| } |
| } |
| } |
| |
| void RenderMultiColumnFlowThread::flowThreadRelativeWillBeRemoved(RenderObject* relative) |
| { |
| if (m_beingEvacuated) |
| return; |
| invalidateRegions(); |
| if (is<RenderMultiColumnSpannerPlaceholder>(*relative)) { |
| // Remove the map entry for this spanner, but leave the actual spanner renderer alone. Also |
| // keep the reference to the spanner, since the placeholder may be about to be re-inserted |
| // in the tree. |
| ASSERT(relative->isDescendantOf(this)); |
| m_spannerMap.remove(downcast<RenderMultiColumnSpannerPlaceholder>(*relative).spanner()); |
| return; |
| } |
| if (relative->style().columnSpan() == ColumnSpanAll) { |
| if (relative->parent() != parent()) |
| return; // not a valid spanner. |
| |
| handleSpannerRemoval(relative); |
| } |
| // Note that we might end up with empty column sets if all column content is removed. That's no |
| // big deal though (and locating them would be expensive), and they will be found and re-used if |
| // content is added again later. |
| } |
| |
| void RenderMultiColumnFlowThread::flowThreadDescendantBoxLaidOut(RenderBox* descendant) |
| { |
| if (!is<RenderMultiColumnSpannerPlaceholder>(*descendant)) |
| return; |
| auto& placeholder = downcast<RenderMultiColumnSpannerPlaceholder>(*descendant); |
| RenderBlock* container = placeholder.containingBlock(); |
| |
| for (RenderBox* prev = previousColumnSetOrSpannerSiblingOf(placeholder.spanner()); prev; prev = previousColumnSetOrSpannerSiblingOf(prev)) { |
| if (is<RenderMultiColumnSet>(*prev)) { |
| downcast<RenderMultiColumnSet>(*prev).endFlow(container, placeholder.logicalTop()); |
| break; |
| } |
| } |
| |
| for (RenderBox* next = nextColumnSetOrSpannerSiblingOf(placeholder.spanner()); next; next = nextColumnSetOrSpannerSiblingOf(next)) { |
| if (is<RenderMultiColumnSet>(*next)) { |
| m_lastSetWorkedOn = downcast<RenderMultiColumnSet>(next); |
| m_lastSetWorkedOn->beginFlow(container); |
| break; |
| } |
| } |
| } |
| |
| void RenderMultiColumnFlowThread::computeLogicalHeight(LayoutUnit logicalHeight, LayoutUnit logicalTop, LogicalExtentComputedValues& computedValues) const |
| { |
| // We simply remain at our intrinsic height. |
| computedValues.m_extent = logicalHeight; |
| computedValues.m_position = logicalTop; |
| } |
| |
| LayoutUnit RenderMultiColumnFlowThread::initialLogicalWidth() const |
| { |
| return columnWidth(); |
| } |
| |
| void RenderMultiColumnFlowThread::setPageBreak(const RenderBlock* block, LayoutUnit offset, LayoutUnit spaceShortage) |
| { |
| if (auto* multicolSet = downcast<RenderMultiColumnSet>(regionAtBlockOffset(block, offset))) |
| multicolSet->recordSpaceShortage(spaceShortage); |
| } |
| |
| void RenderMultiColumnFlowThread::updateMinimumPageHeight(const RenderBlock* block, LayoutUnit offset, LayoutUnit minHeight) |
| { |
| if (auto* multicolSet = downcast<RenderMultiColumnSet>(regionAtBlockOffset(block, offset))) |
| multicolSet->updateMinimumColumnHeight(minHeight); |
| } |
| |
| RenderRegion* RenderMultiColumnFlowThread::regionAtBlockOffset(const RenderBox* box, LayoutUnit offset, bool extendLastRegion) const |
| { |
| if (!m_inLayout) |
| return RenderFlowThread::regionAtBlockOffset(box, offset, extendLastRegion); |
| |
| // Layout in progress. We are calculating the set heights as we speak, so the region range |
| // information is not up-to-date. |
| |
| RenderMultiColumnSet* columnSet = m_lastSetWorkedOn ? m_lastSetWorkedOn : firstMultiColumnSet(); |
| if (!columnSet) { |
| // If there's no set, bail. This multicol is empty or only consists of spanners. There |
| // are no regions. |
| return nullptr; |
| } |
| // The last set worked on is a good guess. But if we're not within the bounds, search for the |
| // right one. |
| if (offset < columnSet->logicalTopInFlowThread()) { |
| do { |
| if (RenderMultiColumnSet* prev = columnSet->previousSiblingMultiColumnSet()) |
| columnSet = prev; |
| else |
| break; |
| } while (offset < columnSet->logicalTopInFlowThread()); |
| } else { |
| while (offset >= columnSet->logicalBottomInFlowThread()) { |
| RenderMultiColumnSet* next = columnSet->nextSiblingMultiColumnSet(); |
| if (!next || !next->hasBeenFlowed()) |
| break; |
| columnSet = next; |
| } |
| } |
| return columnSet; |
| } |
| |
| void RenderMultiColumnFlowThread::setRegionRangeForBox(const RenderBox* box, RenderRegion* startRegion, RenderRegion* endRegion) |
| { |
| // Some column sets may have zero height, which means that two or more sets may start at the |
| // exact same flow thread position, which means that some parts of the code may believe that a |
| // given box lives in sets that it doesn't really live in. Make some adjustments here and |
| // include such sets if they are adjacent to the start and/or end regions. |
| for (RenderMultiColumnSet* columnSet = downcast<RenderMultiColumnSet>(*startRegion).previousSiblingMultiColumnSet(); columnSet; columnSet = columnSet->previousSiblingMultiColumnSet()) { |
| if (columnSet->logicalHeightInFlowThread()) |
| break; |
| startRegion = columnSet; |
| } |
| for (RenderMultiColumnSet* columnSet = downcast<RenderMultiColumnSet>(*startRegion).nextSiblingMultiColumnSet(); columnSet; columnSet = columnSet->nextSiblingMultiColumnSet()) { |
| if (columnSet->logicalHeightInFlowThread()) |
| break; |
| endRegion = columnSet; |
| } |
| |
| RenderFlowThread::setRegionRangeForBox(box, startRegion, endRegion); |
| } |
| |
| bool RenderMultiColumnFlowThread::addForcedRegionBreak(const RenderBlock* block, LayoutUnit offset, RenderBox* /*breakChild*/, bool /*isBefore*/, LayoutUnit* offsetBreakAdjustment) |
| { |
| if (auto* multicolSet = downcast<RenderMultiColumnSet>(regionAtBlockOffset(block, offset))) { |
| multicolSet->addForcedBreak(offset); |
| if (offsetBreakAdjustment) |
| *offsetBreakAdjustment = pageLogicalHeightForOffset(offset) ? pageRemainingLogicalHeightForOffset(offset, IncludePageBoundary) : LayoutUnit::fromPixel(0); |
| return true; |
| } |
| return false; |
| } |
| |
| void RenderMultiColumnFlowThread::computeLineGridPaginationOrigin(LayoutState& layoutState) const |
| { |
| if (!progressionIsInline()) |
| return; |
| |
| // We need to cache a line grid pagination origin so that we understand how to reset the line grid |
| // at the top of each column. |
| // Get the current line grid and offset. |
| const auto lineGrid = layoutState.lineGrid(); |
| if (!lineGrid) |
| return; |
| |
| // Get the hypothetical line box used to establish the grid. |
| auto lineGridBox = lineGrid->lineGridBox(); |
| if (!lineGridBox) |
| return; |
| |
| bool isHorizontalWritingMode = lineGrid->isHorizontalWritingMode(); |
| |
| LayoutUnit lineGridBlockOffset = isHorizontalWritingMode ? layoutState.lineGridOffset().height() : layoutState.lineGridOffset().width(); |
| |
| // Now determine our position on the grid. Our baseline needs to be adjusted to the nearest baseline multiple |
| // as established by the line box. |
| // FIXME: Need to handle crazy line-box-contain values that cause the root line box to not be considered. I assume |
| // the grid should honor line-box-contain. |
| LayoutUnit gridLineHeight = lineGridBox->lineBottomWithLeading() - lineGridBox->lineTopWithLeading(); |
| if (!gridLineHeight) |
| return; |
| |
| LayoutUnit firstLineTopWithLeading = lineGridBlockOffset + lineGridBox->lineTopWithLeading(); |
| |
| if (layoutState.isPaginated() && layoutState.pageLogicalHeight()) { |
| LayoutUnit pageLogicalTop = isHorizontalWritingMode ? layoutState.pageOffset().height() : layoutState.pageOffset().width(); |
| if (pageLogicalTop > firstLineTopWithLeading) { |
| // Shift to the next highest line grid multiple past the page logical top. Cache the delta |
| // between this new value and the page logical top as the pagination origin. |
| LayoutUnit remainder = roundToInt(pageLogicalTop - firstLineTopWithLeading) % roundToInt(gridLineHeight); |
| LayoutUnit paginationDelta = gridLineHeight - remainder; |
| if (isHorizontalWritingMode) |
| layoutState.setLineGridPaginationOrigin(LayoutSize(layoutState.lineGridPaginationOrigin().width(), paginationDelta)); |
| else |
| layoutState.setLineGridPaginationOrigin(LayoutSize(paginationDelta, layoutState.lineGridPaginationOrigin().height())); |
| } |
| } |
| } |
| |
| LayoutSize RenderMultiColumnFlowThread::offsetFromContainer(RenderElement& enclosingContainer, const LayoutPoint& physicalPoint, bool* offsetDependsOnPoint) const |
| { |
| ASSERT(&enclosingContainer == container()); |
| |
| if (offsetDependsOnPoint) |
| *offsetDependsOnPoint = true; |
| |
| LayoutPoint translatedPhysicalPoint(physicalPoint); |
| if (RenderRegion* region = physicalTranslationFromFlowToRegion(translatedPhysicalPoint)) |
| translatedPhysicalPoint.moveBy(region->topLeftLocation()); |
| |
| LayoutSize offset(translatedPhysicalPoint.x(), translatedPhysicalPoint.y()); |
| if (is<RenderBox>(enclosingContainer)) |
| offset -= downcast<RenderBox>(enclosingContainer).scrolledContentOffset(); |
| return offset; |
| } |
| |
| void RenderMultiColumnFlowThread::mapAbsoluteToLocalPoint(MapCoordinatesFlags mode, TransformState& transformState) const |
| { |
| // First get the transform state's point into the block flow thread's physical coordinate space. |
| parent()->mapAbsoluteToLocalPoint(mode, transformState); |
| LayoutPoint transformPoint(transformState.mappedPoint()); |
| |
| // Now walk through each region. |
| const RenderMultiColumnSet* candidateColumnSet = nullptr; |
| LayoutPoint candidatePoint; |
| LayoutSize candidateContainerOffset; |
| |
| for (const auto& columnSet : childrenOfType<RenderMultiColumnSet>(*parent())) { |
| candidateContainerOffset = columnSet.offsetFromContainer(*parent(), LayoutPoint()); |
| |
| candidatePoint = transformPoint - candidateContainerOffset; |
| candidateColumnSet = &columnSet; |
| |
| // We really have no clue what to do with overflow. We'll just use the closest region to the point in that case. |
| LayoutUnit pointOffset = isHorizontalWritingMode() ? candidatePoint.y() : candidatePoint.x(); |
| LayoutUnit regionOffset = isHorizontalWritingMode() ? columnSet.topLeftLocation().y() : columnSet.topLeftLocation().x(); |
| if (pointOffset < regionOffset + columnSet.logicalHeight()) |
| break; |
| } |
| |
| // Once we have a good guess as to which region we hit tested through (and yes, this was just a heuristic, but it's |
| // the best we could do), then we can map from the region into the flow thread. |
| LayoutSize translationOffset = physicalTranslationFromRegionToFlow(candidateColumnSet, candidatePoint) + candidateContainerOffset; |
| bool preserve3D = mode & UseTransforms && (parent()->style().preserves3D() || style().preserves3D()); |
| if (mode & UseTransforms && shouldUseTransformFromContainer(parent())) { |
| TransformationMatrix t; |
| getTransformFromContainer(parent(), translationOffset, t); |
| transformState.applyTransform(t, preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform); |
| } else |
| transformState.move(translationOffset.width(), translationOffset.height(), preserve3D ? TransformState::AccumulateTransform : TransformState::FlattenTransform); |
| } |
| |
| LayoutSize RenderMultiColumnFlowThread::physicalTranslationFromRegionToFlow(const RenderMultiColumnSet* columnSet, const LayoutPoint& physicalPoint) const |
| { |
| LayoutPoint logicalPoint = columnSet->flipForWritingMode(physicalPoint); |
| LayoutPoint translatedPoint = columnSet->translateRegionPointToFlowThread(logicalPoint); |
| LayoutPoint physicalTranslatedPoint = columnSet->flipForWritingMode(translatedPoint); |
| return physicalPoint - physicalTranslatedPoint; |
| } |
| |
| RenderRegion* RenderMultiColumnFlowThread::mapFromFlowToRegion(TransformState& transformState) const |
| { |
| if (!hasValidRegionInfo()) |
| return nullptr; |
| |
| // Get back into our local flow thread space. |
| LayoutRect boxRect = transformState.mappedQuad().enclosingBoundingBox(); |
| flipForWritingMode(boxRect); |
| |
| // FIXME: We need to refactor RenderObject::absoluteQuads to be able to split the quads across regions, |
| // for now we just take the center of the mapped enclosing box and map it to a column. |
| LayoutPoint centerPoint = boxRect.center(); |
| LayoutUnit centerLogicalOffset = isHorizontalWritingMode() ? centerPoint.y() : centerPoint.x(); |
| RenderRegion* renderRegion = regionAtBlockOffset(this, centerLogicalOffset, true); |
| if (!renderRegion) |
| return nullptr; |
| transformState.move(physicalTranslationOffsetFromFlowToRegion(renderRegion, centerLogicalOffset)); |
| return renderRegion; |
| } |
| |
| LayoutSize RenderMultiColumnFlowThread::physicalTranslationOffsetFromFlowToRegion(const RenderRegion* renderRegion, const LayoutUnit logicalOffset) const |
| { |
| // Now that we know which multicolumn set we hit, we need to get the appropriate translation offset for the column. |
| const auto* columnSet = downcast<RenderMultiColumnSet>(renderRegion); |
| LayoutPoint translationOffset = columnSet->columnTranslationForOffset(logicalOffset); |
| |
| // Now we know how we want the rect to be translated into the region. At this point we're converting |
| // back to physical coordinates. |
| if (style().isFlippedBlocksWritingMode()) { |
| LayoutRect portionRect(columnSet->flowThreadPortionRect()); |
| LayoutRect columnRect = columnSet->columnRectAt(0); |
| LayoutUnit physicalDeltaFromPortionBottom = logicalHeight() - columnSet->logicalBottomInFlowThread(); |
| if (isHorizontalWritingMode()) |
| columnRect.setHeight(portionRect.height()); |
| else |
| columnRect.setWidth(portionRect.width()); |
| columnSet->flipForWritingMode(columnRect); |
| if (isHorizontalWritingMode()) |
| translationOffset.move(0, columnRect.y() - portionRect.y() - physicalDeltaFromPortionBottom); |
| else |
| translationOffset.move(columnRect.x() - portionRect.x() - physicalDeltaFromPortionBottom, 0); |
| } |
| |
| return LayoutSize(translationOffset.x(), translationOffset.y()); |
| } |
| |
| RenderRegion* RenderMultiColumnFlowThread::physicalTranslationFromFlowToRegion(LayoutPoint& physicalPoint) const |
| { |
| if (!hasValidRegionInfo()) |
| return nullptr; |
| |
| // Put the physical point into the flow thread's coordinate space. |
| LayoutPoint logicalPoint = flipForWritingMode(physicalPoint); |
| |
| // Now get the region that we are in. |
| LayoutUnit logicalOffset = isHorizontalWritingMode() ? logicalPoint.y() : logicalPoint.x(); |
| RenderRegion* renderRegion = regionAtBlockOffset(this, logicalOffset, true); |
| if (!renderRegion) |
| return nullptr; |
| |
| // Translate to the coordinate space of the region. |
| LayoutSize translationOffset = physicalTranslationOffsetFromFlowToRegion(renderRegion, logicalOffset); |
| |
| // Now shift the physical point into the region's coordinate space. |
| physicalPoint += translationOffset; |
| |
| return renderRegion; |
| } |
| |
| bool RenderMultiColumnFlowThread::isPageLogicalHeightKnown() const |
| { |
| if (RenderMultiColumnSet* columnSet = lastMultiColumnSet()) |
| return columnSet->computedColumnHeight(); |
| return false; |
| } |
| |
| bool RenderMultiColumnFlowThread::nodeAtPoint(const HitTestRequest& request, HitTestResult& result, const HitTestLocation& locationInContainer, const LayoutPoint& accumulatedOffset, HitTestAction hitTestAction) |
| { |
| // You cannot be inside an in-flow RenderFlowThread without a corresponding DOM node. It's better to |
| // just let the ancestor figure out where we are instead. |
| if (hitTestAction == HitTestBlockBackground) |
| return false; |
| bool inside = RenderFlowThread::nodeAtPoint(request, result, locationInContainer, accumulatedOffset, hitTestAction); |
| if (inside && !result.innerNode()) |
| return false; |
| return inside; |
| } |
| |
| bool RenderMultiColumnFlowThread::shouldCheckColumnBreaks() const |
| { |
| if (!parent()->isRenderView()) |
| return true; |
| return view().frameView().pagination().behavesLikeColumns; |
| } |
| |
| } |
