| /* |
| * Copyright (C) 2025 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. AND ITS CONTRIBUTORS ``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 ITS 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 "config.h" |
| #include "PositionedLayoutConstraints.h" |
| |
| #include "AnchorPositionEvaluator.h" |
| #include "ContainerNodeInlines.h" |
| #include "InlineIteratorBoxInlines.h" |
| #include "InlineIteratorInlineBox.h" |
| #include "RenderGrid.h" |
| #include "RenderInline.h" |
| #include "RenderLayer.h" |
| #include "RenderStyle.h" |
| #include "RenderTableRow.h" |
| #include "RenderView.h" |
| #include "StylePositionArea.h" |
| |
| namespace WebCore { |
| |
| using namespace CSS::Literals; |
| |
| PositionedLayoutConstraints::PositionedLayoutConstraints(const RenderBox& renderer, LogicalBoxAxis selfAxis) |
| : PositionedLayoutConstraints(renderer, renderer.style(), selfAxis) |
| { |
| } |
| |
| PositionedLayoutConstraints::PositionedLayoutConstraints(const RenderBox& renderer, const RenderStyle& style, LogicalBoxAxis selfAxis) |
| : m_renderer(renderer) |
| , m_container(downcast<RenderBoxModelObject>(*renderer.container())) // Using containingBlock() would be wrong for relpositioned inlines. |
| , m_containingWritingMode(m_container->writingMode()) |
| , m_writingMode(style.writingMode()) |
| , m_selfAxis(selfAxis) |
| , m_containingAxis(!isOrthogonal() ? selfAxis : oppositeAxis(selfAxis)) |
| , m_physicalAxis(selfAxis == LogicalBoxAxis::Inline ? m_writingMode.inlineAxis() : m_writingMode.blockAxis()) |
| , m_style(style) |
| , m_alignment(m_containingAxis == LogicalBoxAxis::Inline ? style.justifySelf().resolve() : style.alignSelf().resolve()) |
| , m_defaultAnchorBox(needsAnchor() ? Style::AnchorPositionEvaluator::defaultAnchorForBox(renderer) : nullptr) |
| , m_marginBefore { 0_css_px } |
| , m_marginAfter { 0_css_px } |
| , m_insetBefore { 0_css_px } |
| , m_insetAfter { 0_css_px } |
| { |
| ASSERT(m_container); |
| |
| // Compute basic containing block info. |
| m_originalContainingRange = renderer.containingBlockRangeForPositioned(*m_container, m_physicalAxis); |
| m_containingRange = m_originalContainingRange; |
| m_containingInlineSize = (LogicalBoxAxis::Inline == m_containingAxis) ? m_containingRange.size() |
| : renderer.containingBlockRangeForPositioned(*m_container, oppositeAxis(m_physicalAxis)).size(); |
| |
| // Adjust for scrollable area. |
| if (!m_style.positionArea().isNone() && PositionType::Fixed != m_style.position()) |
| expandToScrollableArea(m_containingRange); |
| |
| // Adjust for grid-area. |
| captureGridArea(); |
| |
| // Capture the anchor geometry and adjust for position-area. |
| captureAnchorGeometry(); |
| } |
| |
| void PositionedLayoutConstraints::computeInsets() |
| { |
| // Cache insets and margins, etc. |
| captureInsets(); |
| |
| if (m_useStaticPosition) |
| computeStaticPosition(); |
| |
| if (containingCoordsAreFlipped()) { |
| // Ideally this check is incorporated into captureInsets() but currently it needs to happen after computeStaticPosition() because containingCoordsAreFlipped() depends on m_useStaticPosition. |
| std::swap(m_marginBefore, m_marginAfter); |
| std::swap(m_insetBefore, m_insetAfter); |
| } |
| |
| // Compute the inset-modified containing block. |
| m_insetModifiedContainingRange = m_containingRange; |
| m_insetModifiedContainingRange.shiftMinEdgeBy(insetBeforeValue()); |
| m_insetModifiedContainingRange.shiftMaxEdgeBy(-insetAfterValue()); |
| } |
| |
| bool PositionedLayoutConstraints::needsAnchor() const |
| { |
| return !m_style.positionArea().isNone() || m_alignment.position() == ItemPosition::AnchorCenter; |
| } |
| |
| bool PositionedLayoutConstraints::containingCoordsAreFlipped() const |
| { |
| bool orthogonalOpposing = (m_containingAxis == LogicalBoxAxis::Inline && m_writingMode.isBlockFlipped()) || (m_containingAxis == LogicalBoxAxis::Block && m_containingWritingMode.isBlockFlipped()); |
| // FIXME: Static position has a confusing implementation. Leaving it alone for now. |
| return !m_useStaticPosition && ((isBlockOpposing() && m_containingAxis == LogicalBoxAxis::Block) || (isOrthogonal() && orthogonalOpposing)); |
| } |
| |
| void PositionedLayoutConstraints::captureInsets() |
| { |
| bool isHorizontal = BoxAxis::Horizontal == m_physicalAxis; |
| |
| if (isHorizontal) { |
| m_bordersPlusPadding = m_renderer->borderLeft() + m_renderer->paddingLeft() + m_renderer->paddingRight() + m_renderer->borderRight(); |
| m_useStaticPosition = m_style.left().isAuto() && m_style.right().isAuto() && !m_defaultAnchorBox; |
| } else { |
| m_bordersPlusPadding = m_renderer->borderTop() + m_renderer->paddingTop() + m_renderer->paddingBottom() + m_renderer->borderBottom(); |
| m_useStaticPosition = m_style.top().isAuto() && m_style.bottom().isAuto() && !m_defaultAnchorBox; |
| } |
| |
| if (LogicalBoxAxis::Inline == m_selfAxis) { |
| m_marginBefore = isHorizontal ? m_style.marginLeft() : m_style.marginTop(); |
| m_marginAfter = isHorizontal ? m_style.marginRight() : m_style.marginBottom(); |
| m_insetBefore = m_style.logicalLeft(); |
| m_insetAfter = m_style.logicalRight(); |
| } else { |
| m_marginBefore = m_style.marginBefore(); |
| m_marginAfter = m_style.marginAfter(); |
| m_insetBefore = m_style.logicalTop(); |
| m_insetAfter = m_style.logicalBottom(); |
| } |
| |
| if (m_defaultAnchorBox) { |
| // If the box uses anchor-center or position-area and does have a default anchor box, |
| // then it doesn't use static positioning. |
| m_useStaticPosition = false; |
| } |
| } |
| |
| // MARK: - Adjustments to the containing block. |
| |
| void PositionedLayoutConstraints::expandToScrollableArea(LayoutRange& containingRange, const std::optional<ScrollPosition> fromScrollPosition) const |
| { |
| // FIXME: Extend this logic to other scrollable containing blocks. |
| if (!is<RenderView>(m_container)) |
| return; |
| |
| auto initialContainingBlock = downcast<RenderBox>(m_container.get()); |
| for (CheckedPtr child = initialContainingBlock->firstChildBox(); child; child = child->nextSiblingBox()) { |
| if (child->isOutOfFlowPositioned()) |
| continue; |
| LayoutUnit outerSize = BoxAxis::Vertical == m_physicalAxis |
| ? child->height() + std::max(0_lu, child->marginTop() + child->marginBottom()) |
| : child->width() + std::max(0_lu, child->marginLeft() + child->marginRight()); |
| if (startIsBefore()) |
| containingRange.floorSizeFromMinEdge(outerSize); |
| else |
| containingRange.floorSizeFromMaxEdge(outerSize); |
| } |
| |
| if (fromScrollPosition) { |
| auto scrollOffset = BoxAxis::Horizontal == m_physicalAxis ? fromScrollPosition->x() : fromScrollPosition->y(); |
| containingRange.moveBy(-scrollOffset); |
| } |
| } |
| |
| void PositionedLayoutConstraints::captureGridArea() |
| { |
| const CheckedPtr gridContainer = dynamicDowncast<RenderGrid>(m_container.get()); |
| if (!gridContainer) |
| return; |
| |
| if (LogicalBoxAxis::Inline == m_containingAxis) { |
| m_containingRange = gridContainer->gridAreaRangeForOutOfFlow(m_renderer, Style::GridTrackSizingDirection::Columns); |
| m_containingInlineSize = m_containingRange.size(); |
| } else { |
| m_containingRange = gridContainer->gridAreaRangeForOutOfFlow(m_renderer, Style::GridTrackSizingDirection::Rows); |
| m_containingInlineSize = gridContainer->gridAreaRangeForOutOfFlow(m_renderer, Style::GridTrackSizingDirection::Columns).size(); |
| } |
| |
| if (!startIsBefore()) { |
| auto containerSize = BoxAxis::Horizontal == m_physicalAxis |
| ? gridContainer->width() : gridContainer->height(); |
| m_containingRange.moveTo(containerSize - m_containingRange.max()); |
| } |
| |
| // FIXME: Get PositionedLayoutConstraints to work in pre-corrected coordinates instead of assuming it's wrong and doing "fixup" afterwards, so we don't have to "unfixup" here. |
| if (LogicalBoxAxis::Inline == m_containingAxis) { |
| if (BoxAxis::Horizontal == m_physicalAxis) { |
| if (gridContainer->shouldPlaceVerticalScrollbarOnLeft()) |
| m_containingRange.moveBy(-gridContainer->verticalScrollbarWidth()); |
| } else { |
| if (!m_containingWritingMode.isInlineTopToBottom()) |
| m_containingRange.moveBy(-gridContainer->horizontalScrollbarHeight()); |
| } |
| } |
| } |
| |
| LayoutRange PositionedLayoutConstraints::extractRange(LayoutRect anchorRect) |
| { |
| LayoutRange anchorRange; |
| if (BoxAxis::Horizontal == m_physicalAxis) |
| anchorRange.set(anchorRect.x(), anchorRect.width()); |
| else |
| anchorRange.set(anchorRect.y(), anchorRect.height()); |
| |
| if (m_containingWritingMode.isBlockFlipped() && LogicalBoxAxis::Block == m_containingAxis) { |
| // Coordinate fixup for flipped blocks. |
| anchorRange.moveTo(m_containingRange.max() - anchorRange.max() + m_container->borderAfter()); |
| } |
| return anchorRange; |
| } |
| |
| void PositionedLayoutConstraints::captureAnchorGeometry() |
| { |
| if (!m_defaultAnchorBox) |
| return; |
| |
| // Store the anchor geometry. |
| LayoutRect anchorRect = Style::AnchorPositionEvaluator::computeAnchorRectRelativeToContainingBlock(*m_defaultAnchorBox, *m_container, m_renderer.get()); |
| m_anchorArea = extractRange(anchorRect); |
| |
| // Adjust containing block for position-area. |
| if (m_style.positionArea().isNone()) |
| return; |
| m_containingRange = adjustForPositionArea(m_containingRange, m_anchorArea, m_physicalAxis); |
| |
| // Margin basis is always against the inline axis. |
| if (LogicalBoxAxis::Inline == m_containingAxis) { |
| m_containingInlineSize = m_containingRange.size(); |
| return; |
| } |
| // Else we're representing the block axis, but need the inline dimensions. |
| auto inlineAxis = oppositeAxis(m_physicalAxis); |
| LayoutRange inlineContainingBlock(m_container->borderLogicalLeft(), m_containingInlineSize); |
| auto inlineAnchorArea = BoxAxis::Horizontal == inlineAxis |
| ? LayoutRange { anchorRect.x(), anchorRect.width() } |
| : LayoutRange { anchorRect.y(), anchorRect.height() }; |
| m_containingInlineSize = adjustForPositionArea(inlineContainingBlock, inlineAnchorArea, inlineAxis).size(); |
| } |
| |
| LayoutRange PositionedLayoutConstraints::adjustForPositionArea(const LayoutRange rangeToAdjust, const LayoutRange anchorArea, const BoxAxis containerAxis) |
| { |
| ASSERT(!m_style.positionArea().isNone()); |
| ASSERT(m_defaultAnchorBox); |
| ASSERT(needsAnchor()); |
| ASSERT(anchorArea.size() >= 0); |
| |
| auto adjustedRange = rangeToAdjust; |
| switch (m_style.positionArea().tryValue()->coordMatchedTrackForAxis(containerAxis, m_containingWritingMode, m_writingMode)) { |
| case Style::PositionAreaTrack::Start: |
| adjustedRange.shiftMaxEdgeTo(anchorArea.min()); |
| adjustedRange.floorSizeFromMaxEdge(); |
| return adjustedRange; |
| case Style::PositionAreaTrack::SpanStart: |
| adjustedRange.shiftMaxEdgeTo(anchorArea.max()); |
| adjustedRange.capMinEdgeTo(anchorArea.min()); |
| return adjustedRange; |
| case Style::PositionAreaTrack::End: |
| adjustedRange.shiftMinEdgeTo(anchorArea.max()); |
| adjustedRange.floorSizeFromMinEdge(); |
| return adjustedRange; |
| case Style::PositionAreaTrack::SpanEnd: |
| adjustedRange.shiftMinEdgeTo(anchorArea.min()); |
| adjustedRange.floorMaxEdgeTo(anchorArea.max()); |
| return adjustedRange; |
| case Style::PositionAreaTrack::Center: |
| adjustedRange = anchorArea; |
| return adjustedRange; |
| case Style::PositionAreaTrack::SpanAll: |
| adjustedRange.capMinEdgeTo(anchorArea.min()); |
| adjustedRange.floorMaxEdgeTo(anchorArea.max()); |
| return adjustedRange; |
| default: |
| ASSERT_NOT_REACHED(); |
| return adjustedRange; |
| }; |
| } |
| |
| // MARK: - Resolving margins and alignment (after sizing). |
| |
| std::optional<LayoutUnit> PositionedLayoutConstraints::remainingSpaceForStaticAlignment(LayoutUnit itemSize) const |
| { |
| if (!m_useStaticPosition || m_containingAxis == LogicalBoxAxis::Inline) |
| return { }; |
| |
| if (auto* parent = dynamicDowncast<RenderGrid>(m_renderer->parent())) { |
| auto& itemStyle = m_renderer->style(); |
| auto itemResolvedAlignSelf = itemStyle.alignSelf().resolve(&parent->style()); |
| |
| switch (itemResolvedAlignSelf.position()) { |
| case ItemPosition::Center: |
| case ItemPosition::FlexEnd: |
| case ItemPosition::SelfEnd: |
| case ItemPosition::End: { |
| if (m_container.get() == parent) |
| return { }; |
| |
| // FIXME: This is probably not the correct set of writing mode checks. |
| |
| auto& containingBlockStyle = m_container->style(); |
| if (!containingBlockStyle.writingMode().isHorizontal()) |
| return { }; |
| |
| if (!containingBlockStyle.writingMode().isBidiLTR()) |
| return { }; |
| |
| auto& parentStyle = parent->style(); |
| if (!parentStyle.writingMode().isHorizontal()) |
| return { }; |
| |
| if (!parentStyle.writingMode().isBidiLTR()) |
| return { }; |
| |
| if (!itemStyle.writingMode().isHorizontal()) |
| return { }; |
| |
| if (!itemStyle.writingMode().isBidiLTR()) |
| return { }; |
| |
| if (itemResolvedAlignSelf.positionType() != ItemPositionType::NonLegacy) |
| return { }; |
| |
| if (itemResolvedAlignSelf.overflow() != OverflowAlignment::Default) |
| return { }; |
| |
| auto remainingSpace = parent->contentBoxLogicalHeight() - itemSize; |
| #if ASSERT_ENABLED |
| m_isEligibleForStaticRangeAlignment = remainingSpace >= 0_lu; |
| #endif |
| if (remainingSpace >= 0_lu) |
| return remainingSpace; |
| return { }; |
| } |
| default: |
| return { }; |
| } |
| } |
| return { }; |
| } |
| |
| // See CSS2 § 10.3.7-8 and 10.6.4-5. |
| void PositionedLayoutConstraints::resolvePosition(RenderBox::LogicalExtentComputedValues& computedValues) const |
| { |
| // Static position should have resolved one of our insets by now. |
| ASSERT(!m_useStaticPosition || !(m_insetBefore.isAuto() && m_insetAfter.isAuto())); |
| |
| auto usedMarginBefore = marginBeforeValue(); |
| auto usedMarginAfter = marginAfterValue(); |
| auto alignmentShift = 0_lu; |
| |
| auto outerSize = usedMarginBefore + computedValues.extent + usedMarginAfter; |
| auto remainingSpace = insetModifiedContainingSize() - outerSize; |
| |
| bool honorAutoInsets = !m_defaultAnchorBox || m_alignment.isNormal(); |
| bool hasAutoBeforeInset = m_insetBefore.isAuto() && honorAutoInsets; |
| bool hasAutoAfterInset = m_insetAfter.isAuto() && honorAutoInsets; |
| bool hasAutoBeforeMargin = m_marginBefore.isAuto() && !m_defaultAnchorBox; |
| bool hasAutoAfterMargin = m_marginAfter.isAuto() && !m_defaultAnchorBox; |
| |
| if ((hasAutoBeforeMargin || hasAutoAfterMargin) && !hasAutoBeforeInset && !hasAutoAfterInset) { |
| // Distribute remainingSpace to auto margins. |
| if (hasAutoBeforeMargin && hasAutoAfterMargin) { |
| // Distribute usable space to both margins equally. |
| auto usableRemainingSpace = (LogicalBoxAxis::Inline == m_containingAxis) |
| ? std::max(0_lu, remainingSpace) : remainingSpace; |
| usedMarginBefore = usedMarginAfter = usableRemainingSpace / 2; |
| |
| // Distribute unused space to the end side. |
| auto unusedSpace = remainingSpace - (usedMarginBefore + usedMarginAfter); |
| if (startIsBefore()) |
| usedMarginAfter += unusedSpace; |
| else |
| usedMarginBefore += unusedSpace; |
| } else if (hasAutoBeforeMargin) |
| usedMarginBefore = remainingSpace; |
| else if (hasAutoAfterMargin) |
| usedMarginAfter = remainingSpace; |
| } else { |
| if (auto staticRemainingSpace = remainingSpaceForStaticAlignment(outerSize)) |
| alignmentShift = resolveAlignmentShift(*staticRemainingSpace, outerSize); |
| else if (hasAutoBeforeInset != hasAutoAfterInset) |
| alignmentShift = hasAutoAfterInset ? 0_lu : remainingSpace; |
| else // Align into remaining space. |
| alignmentShift = resolveAlignmentShift(remainingSpace, outerSize); |
| }; |
| |
| auto position = m_insetModifiedContainingRange.min() + usedMarginBefore + alignmentShift; |
| |
| computedValues.position = position; |
| if (LogicalBoxAxis::Inline == m_selfAxis) { |
| if (m_writingMode.isLogicalLeftInlineStart() == !containingCoordsAreFlipped()) { |
| computedValues.margins.start = usedMarginBefore; |
| computedValues.margins.end = usedMarginAfter; |
| } else { |
| computedValues.margins.start = usedMarginAfter; |
| computedValues.margins.end = usedMarginBefore; |
| } |
| } else if (containingCoordsAreFlipped()) { |
| computedValues.margins.before = usedMarginAfter; |
| computedValues.margins.after = usedMarginBefore; |
| } else { |
| computedValues.margins.before = usedMarginBefore; |
| computedValues.margins.after = usedMarginAfter; |
| } |
| } |
| |
| LayoutUnit PositionedLayoutConstraints::resolveAlignmentShift(LayoutUnit unusedSpace, LayoutUnit itemSize) const |
| { |
| bool startIsBefore = this->startIsBefore(); |
| bool isOverflowing = unusedSpace < 0_lu; |
| if (isOverflowing && OverflowAlignment::Safe == m_alignment.overflow()) |
| return startIsBefore ? 0_lu : unusedSpace; |
| |
| ItemPosition resolvedAlignment = resolveAlignmentValue(); |
| ASSERT(ItemPosition::Auto != resolvedAlignment); |
| |
| LayoutUnit shift; |
| if (ItemPosition::AnchorCenter == resolvedAlignment) { |
| auto anchorCenterPosition = m_anchorArea.min() + (m_anchorArea.size() - itemSize) / 2; |
| shift = anchorCenterPosition - m_insetModifiedContainingRange.min(); |
| if (m_alignment.overflow() == OverflowAlignment::Safe) { |
| if (startIsBefore) { |
| if (shift < 0) |
| shift = 0; |
| } else { |
| if (shift > unusedSpace) |
| shift = unusedSpace; |
| } |
| } |
| if (!isOverflowing && OverflowAlignment::Default == m_alignment.overflow()) { |
| // Avoid introducing overflow of the IMCB. |
| if (shift < 0) |
| shift = 0; |
| else if (shift > unusedSpace) |
| shift = unusedSpace; |
| } |
| } else { |
| auto alignmentSpace = StyleSelfAlignmentData::adjustmentFromStartEdge(unusedSpace, resolvedAlignment, m_containingAxis, m_containingWritingMode, m_writingMode); |
| shift = startIsBefore ? alignmentSpace : unusedSpace - alignmentSpace; |
| } |
| |
| if (isOverflowing && ItemPosition::Normal != resolvedAlignment |
| && OverflowAlignment::Default == m_alignment.overflow()) { |
| // Allow overflow, but try to stay within the containing block. |
| // See https://www.w3.org/TR/css-align-3/#auto-safety-position |
| |
| auto containingRange = m_originalContainingRange; |
| if (m_defaultAnchorBox && PositionType::Fixed == m_style.position()) { |
| // We didn't modify the m_containingRange to include scrollable area for positioning, |
| // but we should allow it for overflow management if we can scroll to reach that overflow. |
| if (auto renderView = dynamicDowncast<RenderView>(m_container.get())) { |
| auto& view = renderView->frameView(); |
| auto scrollPosition = view.constrainedScrollPosition(ScrollPosition(view.scrollPositionRespectingCustomFixedPosition())); |
| expandToScrollableArea(containingRange, scrollPosition); |
| } |
| } |
| |
| auto spaceAfter = std::max(0_lu, containingRange.max() - m_insetModifiedContainingRange.max()); |
| auto spaceBefore = std::max(0_lu, m_insetModifiedContainingRange.min() - containingRange.min()); |
| |
| auto [allowsInfiniteOverflowBefore, allowsInfiniteOverflowAfter] = containerAllowsInfiniteOverflow(); |
| |
| if (startIsBefore) { |
| // Avoid overflow on the end side |
| spaceAfter += (unusedSpace - shift); |
| if (spaceAfter < 0 && !allowsInfiniteOverflowAfter) |
| shift += spaceAfter; |
| // Disallow overflow on the start side. |
| spaceBefore += shift; |
| if (spaceBefore < 0 && !allowsInfiniteOverflowBefore) |
| shift -= spaceBefore; |
| } else { |
| // Avoid overflow on the end side |
| spaceBefore += shift; |
| if (spaceBefore < 0 && !allowsInfiniteOverflowBefore) |
| shift -= spaceBefore; |
| // Disallow overflow on the start side. |
| spaceAfter += (unusedSpace - shift); |
| if (spaceAfter < 0 && !allowsInfiniteOverflowAfter) |
| shift += spaceAfter; |
| } |
| |
| } |
| return shift; |
| } |
| |
| ItemPosition PositionedLayoutConstraints::resolveAlignmentValue() const |
| { |
| if (m_useStaticPosition) { |
| #if ASSERT_ENABLED |
| ASSERT(m_isEligibleForStaticRangeAlignment); |
| #endif |
| return m_style.alignSelf().resolve(m_renderer->parentStyle()).position(); |
| } |
| |
| auto alignmentPosition = [&] { |
| auto itemPosition = m_alignment.position(); |
| return (ItemPosition::Auto == itemPosition) ? ItemPosition::Normal : itemPosition; |
| }(); |
| |
| if (auto positionAreaValue = m_style.positionArea().tryValue(); positionAreaValue && ItemPosition::Normal == alignmentPosition) |
| alignmentPosition = positionAreaValue->defaultAlignmentForAxis(m_physicalAxis, m_containingWritingMode, m_writingMode); |
| |
| if (!m_defaultAnchorBox && alignmentPosition == ItemPosition::AnchorCenter) |
| return ItemPosition::Center; |
| return alignmentPosition; |
| } |
| |
| std::pair<bool, bool> PositionedLayoutConstraints::containerAllowsInfiniteOverflow() const |
| { |
| if (!(m_container->hasPotentiallyScrollableOverflow() || (is<RenderView>(m_container) && PositionType::Fixed != m_style.position()))) |
| return { false, false }; |
| auto* containerBox = dynamicDowncast<RenderBox>(m_container.get()); |
| ASSERT(containerBox); |
| if (!containerBox) |
| return { false, false }; |
| |
| auto overflowLimits = containerBox->allowedLayoutOverflow(); // Already in flipped coordinates. |
| return m_physicalAxis == BoxAxis::Vertical |
| ? std::pair<bool, bool> { !overflowLimits.top(), !overflowLimits.bottom() } |
| : std::pair<bool, bool> { !overflowLimits.left(), !overflowLimits.right() }; |
| } |
| |
| bool PositionedLayoutConstraints::alignmentAppliesStretch(ItemPosition normalAlignment) const |
| { |
| auto alignmentPosition = m_alignment.position(); |
| if (m_style.positionArea().isNone() && (ItemPosition::Auto == alignmentPosition || ItemPosition::Normal == alignmentPosition)) |
| alignmentPosition = normalAlignment; |
| return ItemPosition::Stretch == alignmentPosition; |
| } |
| |
| bool PositionedLayoutConstraints::insetFitsContent() const |
| { |
| return (m_insetBefore.isAuto() || m_insetAfter.isAuto()) |
| && !m_defaultAnchorBox; // position-area and align-center zero out auto insets. |
| } |
| |
| bool PositionedLayoutConstraints::needsGridAreaAdjustmentBeforeStaticPositioning() const |
| { |
| if (m_containingAxis == LogicalBoxAxis::Block) |
| return true; |
| |
| auto* parent = m_renderer->parent(); |
| // When the grid container is a parent we do not take the normal static positioning path. |
| if (!m_container->isRenderGrid() || parent == m_container) |
| return false; |
| |
| auto parentWritingMode = parent->writingMode(); |
| if (parentWritingMode.isLogicalLeftInlineStart() && !parentWritingMode.isOrthogonal(m_writingMode)) |
| return false; |
| |
| return true; |
| } |
| |
| // MARK: - Static Position Computation |
| |
| void PositionedLayoutConstraints::computeStaticPosition() |
| { |
| ASSERT(m_useStaticPosition); |
| |
| if (is<RenderGrid>(m_container)) { |
| // Grid Containers have special behavior, see https://www.w3.org/TR/css-grid/#abspos |
| if (m_container.get() == m_renderer->parent()) { |
| // Fake the static layout right here so it integrates with grid-area properly. |
| m_useStaticPosition = false; // Avoid the static position code path. |
| m_insetBefore = 0_css_px; |
| m_insetAfter = 0_css_px; |
| |
| if (m_alignment.isNormal()) { |
| // This very likely was 'auto' before resolution, so re-resolve it against the static position containing block. |
| if (LogicalBoxAxis::Inline == m_containingAxis) { |
| m_alignment = m_style.justifySelf().resolve(&m_container->style()); |
| } else |
| m_alignment = m_style.alignSelf().resolve(&m_container->style()); |
| } |
| if (m_alignment.isNormal()) |
| m_alignment.setPosition(ItemPosition::Start); |
| if (OverflowAlignment::Default == m_alignment.overflow()) |
| m_alignment.setOverflow(OverflowAlignment::Unsafe); |
| |
| // Unclear if this is spec-compliant, but it is the current interop behavior. |
| if (m_marginBefore.isAuto()) |
| m_marginBefore = 0_css_px; |
| if (m_marginAfter.isAuto()) |
| m_marginAfter = 0_css_px; |
| return; |
| } |
| // Rewind grid-area adjustments and fall through to the existing static position code. |
| if (needsGridAreaAdjustmentBeforeStaticPositioning()) |
| m_containingRange.moveTo(m_originalContainingRange.min()); |
| } |
| |
| auto staticDistance = m_selfAxis == LogicalBoxAxis::Inline ? computedInlineStaticDistance() : computedBlockStaticDistance(); |
| auto shouldUseInsetBefore = [&] { |
| if (m_selfAxis == LogicalBoxAxis::Block) |
| return true; |
| auto parentWritingMode = m_renderer->parent()->writingMode(); |
| auto shouldUseInsetBefore = parentWritingMode.isOrthogonal(selfWritingMode()) || !parentWritingMode.isInlineFlipped(); // This is what trunk has. |
| if (!shouldUseInsetBefore) { |
| // FIXME: Figure out why. |
| shouldUseInsetBefore = m_containingWritingMode.isOrthogonal(parentWritingMode) && m_containingWritingMode.isBlockFlipped(); |
| } |
| return shouldUseInsetBefore; |
| }; |
| // Since the static position is computed during in flow layout, the computed |
| // position should already have zoom computed in. We need to divide out the zoom |
| // so that we get the same position when evaluating the inset. |
| if (shouldUseInsetBefore()) |
| m_insetBefore = Style::InsetEdge::Fixed { staticDistance / m_style.usedZoomForLength().value }; |
| else |
| m_insetAfter = Style::InsetEdge::Fixed { (containingSize() - staticDistance) / m_style.usedZoomForLength().value }; |
| } |
| |
| static LayoutPoint positionInContainer(const RenderBox& container, const RenderBox& child, LayoutPoint positionInChild) |
| { |
| auto containerWritingMode = container.writingMode(); |
| auto childWritingMode = child.writingMode(); |
| auto childInFlowOffset = child.writingMode().isHorizontal() ? child.offsetForInFlowPosition() : child.offsetForInFlowPosition().transposedSize(); |
| auto childLogicalLeft = childInFlowOffset.width() + child.logicalLeft(); |
| auto childLogicalTop = childInFlowOffset.height() + child.logicalTop(); |
| |
| if (containerWritingMode.isOrthogonal(childWritingMode)) { |
| auto topLeft = LayoutPoint { childLogicalLeft + positionInChild.x(), childLogicalTop + positionInChild.y() }; |
| if (childWritingMode.isBlockFlipped()) |
| topLeft.setY(childLogicalTop + child.logicalHeight() - positionInChild.y()); |
| if (containerWritingMode.isBlockFlipped()) |
| topLeft.setX(childLogicalLeft + child.logicalWidth() - positionInChild.x()); |
| return topLeft.transposedPoint(); |
| } |
| |
| if (containerWritingMode.isBlockOpposing(childWritingMode)) |
| return { childLogicalLeft + positionInChild.x(), childLogicalTop + child.logicalHeight() - positionInChild.y() }; |
| |
| return { childLogicalLeft + positionInChild.x(), childLogicalTop + positionInChild.y() }; |
| } |
| |
| static LayoutPoint staticDistance(const RenderBoxModelObject& container, const RenderBox& outOfFlowBox) |
| { |
| // Static position is relative to the candidate box's parent (it is computed during normal in-flow layout as if the candidate box was in-flow) |
| // 1. traverse the ancestor chain and convert static position relative to each container all the way up to the containing block |
| // 2. adjust the final static position with the containing block's border |
| // 3. pick x or y depending on what direction we are actually interested in (note that it's always the block directon from the |
| // candidate box's point of view but it could very well be the inline distance from the containing block's point of view.) |
| |
| auto initialStaticPosition = [&] { |
| // Static position is already in the coordinate system of the container (minus the flip in inline direction). |
| auto staticPosition = LayoutPoint { outOfFlowBox.layer()->staticInlinePosition(), outOfFlowBox.layer()->staticBlockPosition() }; |
| // We are relative to a RenderBox ancestor unless the containing block itself is an inline box. |
| auto* staticPositionContainingBlock = outOfFlowBox.parent(); |
| for (; staticPositionContainingBlock && !is<RenderBox>(staticPositionContainingBlock) && staticPositionContainingBlock != &container; staticPositionContainingBlock = staticPositionContainingBlock->container()) { } |
| if (CheckedPtr renderBox = dynamicDowncast<RenderBox>(staticPositionContainingBlock); renderBox && renderBox->writingMode().isInlineFlipped()) |
| staticPosition.setX(renderBox->logicalWidth() - staticPosition.x()); |
| return staticPosition; |
| }; |
| |
| auto staticPosition = LayoutPoint { }; |
| auto* child = &outOfFlowBox; |
| auto hasSeenNonInlineBoxContainer = false; |
| for (auto* ancestorContainer = child->parent(); ancestorContainer && ancestorContainer != &container; ancestorContainer = ancestorContainer->container()) { |
| CheckedPtr containerBox = dynamicDowncast<RenderBox>(*ancestorContainer); |
| if (!containerBox || is<RenderTableRow>(*containerBox)) |
| continue; |
| |
| staticPosition = child == &outOfFlowBox ? initialStaticPosition() : positionInContainer(*containerBox, *child, staticPosition); |
| child = containerBox.get(); |
| hasSeenNonInlineBoxContainer = true; |
| } |
| |
| if (!hasSeenNonInlineBoxContainer && is<RenderInline>(container)) { |
| // This is a simple case of when the containing block is formed by a positioned inline box with no block boxes in-between (e.g <span style="position: relative">) |
| return initialStaticPosition(); |
| } |
| |
| auto* containingBlock = dynamicDowncast<RenderBox>(container); |
| // m_insetBefore is expected to be relative to the padding box (while staticPosition is relative to the border box). |
| auto containingBlockBorderSize = LayoutSize { }; |
| if (containingBlock) |
| containingBlockBorderSize = containingBlock->writingMode().isInlineFlipped() ? LayoutSize(containingBlock->borderEnd(), containingBlock->borderBefore()) : LayoutSize(containingBlock->borderStart(), containingBlock->borderBefore()); |
| else { |
| containingBlock = child->containingBlock(); |
| ASSERT(containingBlock); |
| // Note that we don't take the border here as we passed the real containing block. |
| } |
| |
| staticPosition = child == &outOfFlowBox ? initialStaticPosition() : positionInContainer(*containingBlock, *child, staticPosition); |
| staticPosition -= containingBlockBorderSize; |
| return staticPosition; |
| } |
| |
| LayoutUnit PositionedLayoutConstraints::computedInlineStaticDistance() const |
| { |
| // Note that at this point staticPosition is relative to the containing block (x is inline direction, y is block direction) which may not match with the box's slef writing mode. |
| auto staticPosition = staticDistance(*m_container, m_renderer.get()); |
| auto staticDistance = !isOrthogonal() ? staticPosition.x() : staticPosition.y(); |
| if (CheckedPtr gridContainer = dynamicDowncast<RenderGrid>(m_container.get())) { |
| // Special grid handling: move static distance back to relative to border box and adjust with our offset. |
| auto containingBlockBorderSize = !isOrthogonal() ? (gridContainer->writingMode().isInlineFlipped() ? gridContainer->borderEnd() : gridContainer->borderStart()) : gridContainer->borderBefore(); |
| staticDistance += containingBlockBorderSize; |
| staticDistance -= m_containingRange.min(); |
| } |
| return staticDistance; |
| } |
| |
| LayoutUnit PositionedLayoutConstraints::computedBlockStaticDistance() const |
| { |
| // Note that at this point staticPosition is relative to the containing block (x is inline direction, y is block direction) which may not match with the box's slef writing mode. |
| auto staticPosition = staticDistance(*m_container, m_renderer.get()); |
| return !isOrthogonal() ? staticPosition.y() : staticPosition.x(); |
| } |
| |
| static bool shouldInlineStaticDistanceAdjustedWithBoxHeight(WritingMode containinigBlockWritingMode, WritingMode parentWritingMode, WritingMode outOfFlowBoxWritingMode) |
| { |
| if (!containinigBlockWritingMode.isOrthogonal(parentWritingMode)) |
| return false; |
| |
| if (parentWritingMode.isOrthogonal(outOfFlowBoxWritingMode)) |
| return parentWritingMode.isBlockFlipped(); |
| |
| return containinigBlockWritingMode.isBlockFlipped() && !parentWritingMode.isInlineFlipped(); |
| } |
| |
| void PositionedLayoutConstraints::fixupLogicalLeftPosition(RenderBox::LogicalExtentComputedValues& computedValues) const |
| { |
| if (m_useStaticPosition) { |
| if (m_container.get() != m_renderer->parent() && shouldInlineStaticDistanceAdjustedWithBoxHeight(m_containingWritingMode, m_renderer->parent()->writingMode(), selfWritingMode())) |
| computedValues.position -= computedValues.extent; |
| return; |
| } |
| |
| if (m_writingMode.isHorizontal()) { |
| CheckedPtr containingBox = dynamicDowncast<RenderBox>(container()); |
| if (containingBox && containingBox->shouldPlaceVerticalScrollbarOnLeft()) |
| computedValues.position += containingBox->verticalScrollbarWidth(); |
| } |
| |
| // FIXME: This hack is needed to calculate the logical left position for a 'rtl' relatively |
| // positioned, inline because right now, it is using the logical left position |
| // of the first line box when really it should use the last line box. When |
| // this is fixed elsewhere, this adjustment should be removed. |
| |
| CheckedPtr renderInline = dynamicDowncast<RenderInline>(container()); |
| if (!renderInline || m_containingWritingMode.isLogicalLeftInlineStart()) |
| return; |
| |
| auto firstInlineBox = InlineIterator::lineLeftmostInlineBoxFor(*renderInline); |
| if (!firstInlineBox) |
| return; |
| |
| auto lastInlineBox = [&] { |
| auto inlineBox = firstInlineBox; |
| for (; inlineBox->nextInlineBoxLineRightward(); inlineBox.traverseInlineBoxLineRightward()) { } |
| return inlineBox; |
| }(); |
| if (firstInlineBox == lastInlineBox) |
| return; |
| |
| auto lastInlineBoxPaddingBoxVisualRight = lastInlineBox->logicalLeftIgnoringInlineDirection() + renderInline->borderLogicalLeft(); |
| // FIXME: This does not work with decoration break clone. |
| auto firstInlineBoxPaddingBoxVisualRight = firstInlineBox->logicalLeftIgnoringInlineDirection(); |
| auto adjustment = lastInlineBoxPaddingBoxVisualRight - firstInlineBoxPaddingBoxVisualRight; |
| computedValues.position += adjustment - m_containingRange.min(); |
| } |
| |
| // FIXME: Let's move this over to RenderBoxModelObject and collapse some of the logic here. |
| static bool shouldBlockStaticDistanceAdjustedWithBoxHeight(const RenderBoxModelObject& containingBlock, const RenderElement& parent, WritingMode outOfFlowBoxWritingMode) |
| { |
| // This is where we check if the final static position needs to be adjusted with the height of the out-of-flow box. |
| // In ::computeBlockStaticDistance we convert the static position relative to the containing block but in some cases |
| // this final static position still points to the wrong side of the box (i.e. at computeBlockStaticDistance we don't know yet the height |
| // which may contribute to the logical top position. see details below.) |
| |
| auto parentWritingMode = parent.writingMode(); |
| auto containinigBlockWritingMode = containingBlock.writingMode(); |
| |
| if (containinigBlockWritingMode.blockDirection() == parentWritingMode.blockDirection() && parentWritingMode.blockDirection() == outOfFlowBoxWritingMode.blockDirection()) |
| return false; |
| |
| auto isParentInlineFlipped = parentWritingMode.isInlineFlipped(); |
| if (containinigBlockWritingMode.isOrthogonal(outOfFlowBoxWritingMode)) { |
| if (&containingBlock == &parent) { |
| // <div id=containinigBlock class=rtl> |
| // <div id=outOfFlowBox class=ltr> |
| return isParentInlineFlipped; |
| } |
| |
| if (!containinigBlockWritingMode.isOrthogonal(parentWritingMode)) |
| return isParentInlineFlipped; |
| |
| return parentWritingMode.isBlockFlipped(); |
| } |
| |
| ASSERT(containinigBlockWritingMode.blockDirection() == outOfFlowBoxWritingMode.blockDirection() || containinigBlockWritingMode.isBlockOpposing(outOfFlowBoxWritingMode)); |
| if (!parentWritingMode.isOrthogonal(containinigBlockWritingMode)) { |
| // inline direction does not matter as all participants are on the same axis. |
| if (containinigBlockWritingMode.blockDirection() == outOfFlowBoxWritingMode.blockDirection()) { |
| // <div id=containinigBlock class=vrl> |
| // <div id=parent class=vlr> |
| // <div id=outOfFlowBox class=vrl> |
| return true; |
| } |
| |
| // <div id=containinigBlock class=vlr> |
| // <div id=parent class=vrl> |
| // <div id=outOfFlowBox class=vrl> |
| return parentWritingMode.isBlockOpposing(containinigBlockWritingMode); |
| } |
| |
| // Orhogonal parent. |
| // <div id=containinigBlock class=vrl> |
| // <div id=parent class=htb> |
| // <div id=outOfFlowBox class=vlr> |
| return containinigBlockWritingMode.isBlockFlipped() != isParentInlineFlipped; |
| } |
| |
| void PositionedLayoutConstraints::adjustLogicalTopWithLogicalHeightIfNeeded(RenderBox::LogicalExtentComputedValues& computedValues) const |
| { |
| if (!m_useStaticPosition || m_selfAxis != LogicalBoxAxis::Block) |
| return; |
| if (shouldBlockStaticDistanceAdjustedWithBoxHeight(*m_container, *m_renderer->parent(), m_writingMode)) |
| computedValues.position -= computedValues.extent; |
| } |
| |
| } |
