| /* |
| * Copyright (C) 2011 Google 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: |
| * |
| * * Redistributions of source code must retain the above copyright |
| * notice, this list of conditions and the following disclaimer. |
| * * 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. |
| * * Neither the name of Google Inc. nor the names of its |
| * contributors may be used to endorse or promote products derived from |
| * this software without specific prior written permission. |
| * |
| * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND 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 THE COPYRIGHT |
| * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
| * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
| * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
| * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
| * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
| * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
| * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
| */ |
| |
| #include "third_party/blink/renderer/core/layout/flexible_box_algorithm.h" |
| |
| #include "third_party/blink/renderer/core/layout/layout_box.h" |
| #include "third_party/blink/renderer/core/layout/layout_flexible_box.h" |
| #include "third_party/blink/renderer/core/layout/min_max_size.h" |
| |
| namespace blink { |
| |
| FlexItem::FlexItem(LayoutBox* box, |
| LayoutUnit flex_base_content_size, |
| MinMaxSize min_max_sizes, |
| LayoutUnit main_axis_border_and_padding, |
| LayoutUnit main_axis_margin) |
| : algorithm(nullptr), |
| line_number(0), |
| box(box), |
| flex_base_content_size(flex_base_content_size), |
| min_max_sizes(min_max_sizes), |
| hypothetical_main_content_size( |
| min_max_sizes.ClampSizeToMinAndMax(flex_base_content_size)), |
| main_axis_border_and_padding(main_axis_border_and_padding), |
| main_axis_margin(main_axis_margin), |
| frozen(false), |
| ng_input_node(/* LayoutBox* */ nullptr) { |
| DCHECK(!box->IsOutOfFlowPositioned()); |
| DCHECK_GE(min_max_sizes.max_size, LayoutUnit()) |
| << "Use LayoutUnit::Max() for no max size"; |
| } |
| |
| bool FlexItem::MainAxisIsInlineAxis() const { |
| return algorithm->IsHorizontalFlow() == box->IsHorizontalWritingMode(); |
| } |
| |
| LayoutUnit FlexItem::FlowAwareMarginStart() const { |
| if (algorithm->IsHorizontalFlow()) { |
| return algorithm->IsLeftToRightFlow() ? box->MarginLeft() |
| : box->MarginRight(); |
| } |
| return algorithm->IsLeftToRightFlow() ? box->MarginTop() |
| : box->MarginBottom(); |
| } |
| |
| LayoutUnit FlexItem::FlowAwareMarginEnd() const { |
| if (algorithm->IsHorizontalFlow()) { |
| return algorithm->IsLeftToRightFlow() ? box->MarginRight() |
| : box->MarginLeft(); |
| } |
| return algorithm->IsLeftToRightFlow() ? box->MarginBottom() |
| : box->MarginTop(); |
| } |
| |
| LayoutUnit FlexItem::FlowAwareMarginBefore() const { |
| switch (algorithm->GetTransformedWritingMode()) { |
| case TransformedWritingMode::kTopToBottomWritingMode: |
| return box->MarginTop(); |
| case TransformedWritingMode::kBottomToTopWritingMode: |
| return box->MarginBottom(); |
| case TransformedWritingMode::kLeftToRightWritingMode: |
| return box->MarginLeft(); |
| case TransformedWritingMode::kRightToLeftWritingMode: |
| return box->MarginRight(); |
| } |
| NOTREACHED(); |
| return box->MarginTop(); |
| } |
| |
| LayoutUnit FlexItem::CrossAxisMarginExtent() const { |
| return algorithm->IsHorizontalFlow() ? box->MarginHeight() |
| : box->MarginWidth(); |
| } |
| |
| LayoutUnit FlexItem::MarginBoxAscent() const { |
| LayoutUnit ascent(box->FirstLineBoxBaseline()); |
| if (ascent == -1) |
| ascent = cross_axis_size; |
| return ascent + FlowAwareMarginBefore(); |
| } |
| |
| LayoutUnit FlexItem::AvailableAlignmentSpace() const { |
| LayoutUnit cross_extent = CrossAxisMarginExtent() + cross_axis_size; |
| return Line()->cross_axis_extent - cross_extent; |
| } |
| |
| bool FlexItem::HasAutoMarginsInCrossAxis() const { |
| if (algorithm->IsHorizontalFlow()) { |
| return box->StyleRef().MarginTop().IsAuto() || |
| box->StyleRef().MarginBottom().IsAuto(); |
| } |
| return box->StyleRef().MarginLeft().IsAuto() || |
| box->StyleRef().MarginRight().IsAuto(); |
| } |
| |
| ItemPosition FlexItem::Alignment() const { |
| return FlexLayoutAlgorithm::AlignmentForChild(*algorithm->Style(), |
| box->StyleRef()); |
| } |
| |
| void FlexItem::UpdateAutoMarginsInMainAxis(LayoutUnit auto_margin_offset) { |
| DCHECK_GE(auto_margin_offset, LayoutUnit()); |
| |
| if (algorithm->IsHorizontalFlow()) { |
| if (box->StyleRef().MarginLeft().IsAuto()) |
| box->SetMarginLeft(auto_margin_offset); |
| if (box->StyleRef().MarginRight().IsAuto()) |
| box->SetMarginRight(auto_margin_offset); |
| } else { |
| if (box->StyleRef().MarginTop().IsAuto()) |
| box->SetMarginTop(auto_margin_offset); |
| if (box->StyleRef().MarginBottom().IsAuto()) |
| box->SetMarginBottom(auto_margin_offset); |
| } |
| } |
| |
| void FlexItem::ComputeStretchedSize() { |
| // TODO(dgrogan): Pass resolved cross-axis MinMaxSize to FlexItem |
| // constructor. Then use cross_axis_min_max.ClampSizeToMinAndMax instead of |
| // relying on legacy in this method. |
| DCHECK_EQ(Alignment(), ItemPosition::kStretch); |
| if (MainAxisIsInlineAxis() && box->StyleRef().LogicalHeight().IsAuto()) { |
| LayoutUnit stretched_logical_height = |
| std::max(box->BorderAndPaddingLogicalHeight(), |
| Line()->cross_axis_extent - CrossAxisMarginExtent()); |
| cross_axis_size = box->ConstrainLogicalHeightByMinMax( |
| stretched_logical_height, box->IntrinsicContentLogicalHeight()); |
| } else if (!MainAxisIsInlineAxis() && |
| box->StyleRef().LogicalWidth().IsAuto()) { |
| // This doesn't work in NG because CrossAxisContentExtent() isn't yet |
| // implemented there. |
| if (box->Parent()->IsLayoutNGFlexibleBox()) |
| return; |
| LayoutUnit child_width = |
| (Line()->cross_axis_extent - CrossAxisMarginExtent()) |
| .ClampNegativeToZero(); |
| LayoutFlexibleBox* flexbox = ToLayoutFlexibleBox(box->Parent()); |
| cross_axis_size = box->ConstrainLogicalWidthByMinMax( |
| child_width, flexbox->CrossAxisContentExtent(), flexbox); |
| } |
| } |
| |
| void FlexLine::FreezeViolations(ViolationsVector& violations) { |
| for (size_t i = 0; i < violations.size(); ++i) { |
| DCHECK(!violations[i]->frozen) << i; |
| LayoutBox* child = violations[i]->box; |
| LayoutUnit child_size = violations[i]->flexed_content_size; |
| remaining_free_space -= child_size - violations[i]->flex_base_content_size; |
| total_flex_grow -= child->StyleRef().FlexGrow(); |
| total_flex_shrink -= child->StyleRef().FlexShrink(); |
| total_weighted_flex_shrink -= |
| child->StyleRef().FlexShrink() * violations[i]->flex_base_content_size; |
| // totalWeightedFlexShrink can be negative when we exceed the precision of |
| // a double when we initially calcuate totalWeightedFlexShrink. We then |
| // subtract each child's weighted flex shrink with full precision, now |
| // leading to a negative result. See |
| // css3/flexbox/large-flex-shrink-assert.html |
| total_weighted_flex_shrink = std::max(total_weighted_flex_shrink, 0.0); |
| violations[i]->frozen = true; |
| } |
| } |
| |
| void FlexLine::FreezeInflexibleItems() { |
| // Per https://drafts.csswg.org/css-flexbox/#resolve-flexible-lengths step 2, |
| // we freeze all items with a flex factor of 0 as well as those with a min/max |
| // size violation. |
| FlexSign flex_sign = Sign(); |
| remaining_free_space = container_main_inner_size - sum_flex_base_size; |
| |
| ViolationsVector new_inflexible_items; |
| for (size_t i = 0; i < line_items.size(); ++i) { |
| FlexItem& flex_item = line_items[i]; |
| LayoutBox* child = flex_item.box; |
| DCHECK(!flex_item.box->IsOutOfFlowPositioned()); |
| DCHECK(!flex_item.frozen) << i; |
| float flex_factor = (flex_sign == kPositiveFlexibility) |
| ? child->StyleRef().FlexGrow() |
| : child->StyleRef().FlexShrink(); |
| if (flex_factor == 0 || |
| (flex_sign == kPositiveFlexibility && |
| flex_item.flex_base_content_size > |
| flex_item.hypothetical_main_content_size) || |
| (flex_sign == kNegativeFlexibility && |
| flex_item.flex_base_content_size < |
| flex_item.hypothetical_main_content_size)) { |
| flex_item.flexed_content_size = flex_item.hypothetical_main_content_size; |
| new_inflexible_items.push_back(&flex_item); |
| } |
| } |
| FreezeViolations(new_inflexible_items); |
| initial_free_space = remaining_free_space; |
| } |
| |
| bool FlexLine::ResolveFlexibleLengths() { |
| LayoutUnit total_violation; |
| LayoutUnit used_free_space; |
| ViolationsVector min_violations; |
| ViolationsVector max_violations; |
| |
| FlexSign flex_sign = Sign(); |
| double sum_flex_factors = |
| (flex_sign == kPositiveFlexibility) ? total_flex_grow : total_flex_shrink; |
| if (sum_flex_factors > 0 && sum_flex_factors < 1) { |
| LayoutUnit fractional(initial_free_space * sum_flex_factors); |
| if (fractional.Abs() < remaining_free_space.Abs()) |
| remaining_free_space = fractional; |
| } |
| |
| for (size_t i = 0; i < line_items.size(); ++i) { |
| FlexItem& flex_item = line_items[i]; |
| LayoutBox* child = flex_item.box; |
| |
| // This check also covers out-of-flow children. |
| if (flex_item.frozen) |
| continue; |
| |
| LayoutUnit child_size = flex_item.flex_base_content_size; |
| double extra_space = 0; |
| if (remaining_free_space > 0 && total_flex_grow > 0 && |
| flex_sign == kPositiveFlexibility && std::isfinite(total_flex_grow)) { |
| extra_space = |
| remaining_free_space * child->StyleRef().FlexGrow() / total_flex_grow; |
| } else if (remaining_free_space < 0 && total_weighted_flex_shrink > 0 && |
| flex_sign == kNegativeFlexibility && |
| std::isfinite(total_weighted_flex_shrink) && |
| child->StyleRef().FlexShrink()) { |
| extra_space = remaining_free_space * child->StyleRef().FlexShrink() * |
| flex_item.flex_base_content_size / |
| total_weighted_flex_shrink; |
| } |
| if (std::isfinite(extra_space)) |
| child_size += LayoutUnit::FromFloatRound(extra_space); |
| |
| LayoutUnit adjusted_child_size = flex_item.ClampSizeToMinAndMax(child_size); |
| DCHECK_GE(adjusted_child_size, 0); |
| flex_item.flexed_content_size = adjusted_child_size; |
| used_free_space += adjusted_child_size - flex_item.flex_base_content_size; |
| |
| LayoutUnit violation = adjusted_child_size - child_size; |
| if (violation > 0) |
| min_violations.push_back(&flex_item); |
| else if (violation < 0) |
| max_violations.push_back(&flex_item); |
| total_violation += violation; |
| } |
| |
| if (total_violation) { |
| FreezeViolations(total_violation < 0 ? max_violations : min_violations); |
| } else { |
| remaining_free_space -= used_free_space; |
| } |
| |
| return !total_violation; |
| } |
| |
| LayoutUnit FlexLine::ApplyMainAxisAutoMarginAdjustment() { |
| if (remaining_free_space <= LayoutUnit()) |
| return LayoutUnit(); |
| |
| int number_of_auto_margins = 0; |
| bool is_horizontal = algorithm->IsHorizontalFlow(); |
| for (size_t i = 0; i < line_items.size(); ++i) { |
| LayoutBox* child = line_items[i].box; |
| DCHECK(!child->IsOutOfFlowPositioned()); |
| if (is_horizontal) { |
| if (child->StyleRef().MarginLeft().IsAuto()) |
| ++number_of_auto_margins; |
| if (child->StyleRef().MarginRight().IsAuto()) |
| ++number_of_auto_margins; |
| } else { |
| if (child->StyleRef().MarginTop().IsAuto()) |
| ++number_of_auto_margins; |
| if (child->StyleRef().MarginBottom().IsAuto()) |
| ++number_of_auto_margins; |
| } |
| } |
| if (!number_of_auto_margins) |
| return LayoutUnit(); |
| |
| LayoutUnit size_of_auto_margin = |
| remaining_free_space / number_of_auto_margins; |
| remaining_free_space = LayoutUnit(); |
| return size_of_auto_margin; |
| } |
| |
| void FlexLine::ComputeLineItemsPosition(LayoutUnit main_axis_offset, |
| LayoutUnit& cross_axis_offset) { |
| // Recalculate the remaining free space. The adjustment for flex factors |
| // between 0..1 means we can't just use remainingFreeSpace here. |
| remaining_free_space = container_main_inner_size; |
| for (size_t i = 0; i < line_items.size(); ++i) { |
| FlexItem& flex_item = line_items[i]; |
| DCHECK(!flex_item.box->IsOutOfFlowPositioned()); |
| remaining_free_space -= flex_item.FlexedMarginBoxSize(); |
| } |
| |
| const StyleContentAlignmentData justify_content = |
| FlexLayoutAlgorithm::ResolvedJustifyContent(*algorithm->Style()); |
| |
| LayoutUnit auto_margin_offset = ApplyMainAxisAutoMarginAdjustment(); |
| const LayoutUnit available_free_space = remaining_free_space; |
| main_axis_offset += FlexLayoutAlgorithm::InitialContentPositionOffset( |
| available_free_space, justify_content, line_items.size()); |
| LayoutUnit max_descent; // Used when align-items: baseline. |
| LayoutUnit max_child_cross_axis_extent; |
| bool should_flip_main_axis = !algorithm->StyleRef().IsColumnFlexDirection() && |
| !algorithm->IsLeftToRightFlow(); |
| for (size_t i = 0; i < line_items.size(); ++i) { |
| FlexItem& flex_item = line_items[i]; |
| |
| DCHECK(!flex_item.box->IsOutOfFlowPositioned()); |
| |
| flex_item.UpdateAutoMarginsInMainAxis(auto_margin_offset); |
| |
| LayoutUnit child_cross_axis_margin_box_extent; |
| if (flex_item.Alignment() == ItemPosition::kBaseline && |
| !flex_item.HasAutoMarginsInCrossAxis()) { |
| LayoutUnit ascent = flex_item.MarginBoxAscent(); |
| LayoutUnit descent = |
| (flex_item.CrossAxisMarginExtent() + flex_item.cross_axis_size) - |
| ascent; |
| |
| max_ascent = std::max(max_ascent, ascent); |
| max_descent = std::max(max_descent, descent); |
| |
| child_cross_axis_margin_box_extent = max_ascent + max_descent; |
| } else { |
| child_cross_axis_margin_box_extent = flex_item.cross_axis_intrinsic_size + |
| flex_item.CrossAxisMarginExtent(); |
| } |
| max_child_cross_axis_extent = std::max(max_child_cross_axis_extent, |
| child_cross_axis_margin_box_extent); |
| |
| main_axis_offset += flex_item.FlowAwareMarginStart(); |
| |
| LayoutUnit child_main_extent = flex_item.FlexedBorderBoxSize(); |
| // In an RTL column situation, this will apply the margin-right/margin-end |
| // on the left. This will be fixed later in |
| // LayoutFlexibleBox::FlipForRightToLeftColumn. |
| flex_item.desired_location = LayoutPoint( |
| should_flip_main_axis |
| ? container_logical_width - main_axis_offset - child_main_extent |
| : main_axis_offset, |
| cross_axis_offset + flex_item.FlowAwareMarginBefore()); |
| main_axis_offset += child_main_extent + flex_item.FlowAwareMarginEnd(); |
| |
| if (i != line_items.size() - 1) { |
| // The last item does not get extra space added. |
| main_axis_offset += |
| FlexLayoutAlgorithm::ContentDistributionSpaceBetweenChildren( |
| available_free_space, justify_content, line_items.size()); |
| } |
| } |
| |
| main_axis_extent = main_axis_offset; |
| |
| this->cross_axis_offset = cross_axis_offset; |
| cross_axis_extent = max_child_cross_axis_extent; |
| |
| cross_axis_offset += max_child_cross_axis_extent; |
| } |
| |
| FlexLayoutAlgorithm::FlexLayoutAlgorithm(const ComputedStyle* style, |
| LayoutUnit line_break_length) |
| : style_(style), |
| line_break_length_(line_break_length), |
| next_item_index_(0) {} |
| |
| FlexLine* FlexLayoutAlgorithm::ComputeNextFlexLine( |
| LayoutUnit container_logical_width) { |
| LayoutUnit sum_flex_base_size; |
| double total_flex_grow = 0; |
| double total_flex_shrink = 0; |
| double total_weighted_flex_shrink = 0; |
| LayoutUnit sum_hypothetical_main_size; |
| |
| bool line_has_in_flow_item = false; |
| |
| wtf_size_t start_index = next_item_index_; |
| |
| for (; next_item_index_ < all_items_.size(); ++next_item_index_) { |
| FlexItem& flex_item = all_items_[next_item_index_]; |
| DCHECK(!flex_item.box->IsOutOfFlowPositioned()); |
| if (IsMultiline() && |
| sum_hypothetical_main_size + |
| flex_item.HypotheticalMainAxisMarginBoxSize() > |
| line_break_length_ && |
| line_has_in_flow_item) { |
| break; |
| } |
| line_has_in_flow_item = true; |
| sum_flex_base_size += flex_item.FlexBaseMarginBoxSize(); |
| total_flex_grow += flex_item.box->StyleRef().FlexGrow(); |
| total_flex_shrink += flex_item.box->StyleRef().FlexShrink(); |
| total_weighted_flex_shrink += flex_item.box->StyleRef().FlexShrink() * |
| flex_item.flex_base_content_size; |
| sum_hypothetical_main_size += flex_item.HypotheticalMainAxisMarginBoxSize(); |
| flex_item.line_number = flex_lines_.size(); |
| } |
| |
| DCHECK(next_item_index_ > start_index || |
| next_item_index_ == all_items_.size()); |
| if (next_item_index_ > start_index) { |
| return &flex_lines_.emplace_back( |
| this, FlexItemVectorView(&all_items_, start_index, next_item_index_), |
| container_logical_width, sum_flex_base_size, total_flex_grow, |
| total_flex_shrink, total_weighted_flex_shrink, |
| sum_hypothetical_main_size); |
| } |
| return nullptr; |
| } |
| |
| bool FlexLayoutAlgorithm::IsHorizontalFlow() const { |
| return IsHorizontalFlow(*style_); |
| } |
| |
| bool FlexLayoutAlgorithm::IsColumnFlow() const { |
| return StyleRef().IsColumnFlexDirection(); |
| } |
| |
| bool FlexLayoutAlgorithm::IsHorizontalFlow(const ComputedStyle& style) { |
| if (style.IsHorizontalWritingMode()) |
| return !style.IsColumnFlexDirection(); |
| return style.IsColumnFlexDirection(); |
| } |
| |
| bool FlexLayoutAlgorithm::IsLeftToRightFlow() const { |
| if (style_->IsColumnFlexDirection()) { |
| return blink::IsHorizontalWritingMode(style_->GetWritingMode()) || |
| IsFlippedLinesWritingMode(style_->GetWritingMode()); |
| } |
| return style_->IsLeftToRightDirection() ^ |
| (style_->FlexDirection() == EFlexDirection::kRowReverse); |
| } |
| |
| const StyleContentAlignmentData& |
| FlexLayoutAlgorithm::ContentAlignmentNormalBehavior() { |
| // The justify-content property applies along the main axis, but since |
| // flexing in the main axis is controlled by flex, stretch behaves as |
| // flex-start (ignoring the specified fallback alignment, if any). |
| // https://drafts.csswg.org/css-align/#distribution-flex |
| static const StyleContentAlignmentData kNormalBehavior = { |
| ContentPosition::kNormal, ContentDistributionType::kStretch}; |
| return kNormalBehavior; |
| } |
| |
| bool FlexLayoutAlgorithm::ShouldApplyMinSizeAutoForChild( |
| const LayoutBox& child) const { |
| // css-flexbox section 4.5 |
| Length min = IsHorizontalFlow() ? child.StyleRef().MinWidth() |
| : child.StyleRef().MinHeight(); |
| return min.IsAuto() && !child.ShouldApplySizeContainment() && |
| MainAxisOverflowForChild(child) == EOverflow::kVisible; |
| } |
| |
| TransformedWritingMode FlexLayoutAlgorithm::GetTransformedWritingMode() const { |
| return GetTransformedWritingMode(*style_); |
| } |
| |
| TransformedWritingMode FlexLayoutAlgorithm::GetTransformedWritingMode( |
| const ComputedStyle& style) { |
| WritingMode mode = style.GetWritingMode(); |
| if (!style.IsColumnFlexDirection()) { |
| static_assert( |
| static_cast<TransformedWritingMode>(WritingMode::kHorizontalTb) == |
| TransformedWritingMode::kTopToBottomWritingMode && |
| static_cast<TransformedWritingMode>(WritingMode::kVerticalLr) == |
| TransformedWritingMode::kLeftToRightWritingMode && |
| static_cast<TransformedWritingMode>(WritingMode::kVerticalRl) == |
| TransformedWritingMode::kRightToLeftWritingMode, |
| "WritingMode and TransformedWritingMode must match values."); |
| return static_cast<TransformedWritingMode>(mode); |
| } |
| |
| switch (mode) { |
| case WritingMode::kHorizontalTb: |
| return style.IsLeftToRightDirection() |
| ? TransformedWritingMode::kLeftToRightWritingMode |
| : TransformedWritingMode::kRightToLeftWritingMode; |
| case WritingMode::kVerticalLr: |
| case WritingMode::kVerticalRl: |
| return style.IsLeftToRightDirection() |
| ? TransformedWritingMode::kTopToBottomWritingMode |
| : TransformedWritingMode::kBottomToTopWritingMode; |
| // TODO(layout-dev): Sideways-lr and sideways-rl are not yet supported. |
| default: |
| break; |
| } |
| NOTREACHED(); |
| return TransformedWritingMode::kTopToBottomWritingMode; |
| } |
| |
| StyleContentAlignmentData FlexLayoutAlgorithm::ResolvedJustifyContent( |
| const ComputedStyle& style) { |
| ContentPosition position = |
| style.ResolvedJustifyContentPosition(ContentAlignmentNormalBehavior()); |
| ContentDistributionType distribution = |
| style.ResolvedJustifyContentDistribution( |
| ContentAlignmentNormalBehavior()); |
| OverflowAlignment overflow = style.JustifyContentOverflowAlignment(); |
| // For flex, justify-content: stretch behaves as flex-start: |
| // https://drafts.csswg.org/css-align/#distribution-flex |
| if (distribution == ContentDistributionType::kStretch) { |
| position = ContentPosition::kFlexStart; |
| distribution = ContentDistributionType::kDefault; |
| } |
| return StyleContentAlignmentData(position, distribution, overflow); |
| } |
| |
| StyleContentAlignmentData FlexLayoutAlgorithm::ResolvedAlignContent( |
| const ComputedStyle& style) { |
| ContentPosition position = |
| style.ResolvedAlignContentPosition(ContentAlignmentNormalBehavior()); |
| ContentDistributionType distribution = |
| style.ResolvedAlignContentDistribution(ContentAlignmentNormalBehavior()); |
| OverflowAlignment overflow = style.AlignContentOverflowAlignment(); |
| return StyleContentAlignmentData(position, distribution, overflow); |
| } |
| |
| ItemPosition FlexLayoutAlgorithm::AlignmentForChild( |
| const ComputedStyle& flexbox_style, |
| const ComputedStyle& child_style) { |
| ItemPosition align = |
| child_style.ResolvedAlignSelf(ItemPosition::kStretch, &flexbox_style) |
| .GetPosition(); |
| DCHECK_NE(align, ItemPosition::kAuto); |
| DCHECK_NE(align, ItemPosition::kNormal); |
| |
| if (align == ItemPosition::kBaseline && |
| IsHorizontalFlow(flexbox_style) != child_style.IsHorizontalWritingMode()) |
| align = ItemPosition::kFlexStart; |
| |
| if (flexbox_style.FlexWrap() == EFlexWrap::kWrapReverse) { |
| if (align == ItemPosition::kFlexStart) |
| align = ItemPosition::kFlexEnd; |
| else if (align == ItemPosition::kFlexEnd) |
| align = ItemPosition::kFlexStart; |
| } |
| |
| return align; |
| } |
| |
| LayoutUnit FlexLayoutAlgorithm::InitialContentPositionOffset( |
| LayoutUnit available_free_space, |
| const StyleContentAlignmentData& data, |
| unsigned number_of_items) { |
| if (data.GetPosition() == ContentPosition::kFlexEnd) |
| return available_free_space; |
| if (data.GetPosition() == ContentPosition::kCenter) |
| return available_free_space / 2; |
| if (data.Distribution() == ContentDistributionType::kSpaceAround) { |
| if (available_free_space > 0 && number_of_items) |
| return available_free_space / (2 * number_of_items); |
| |
| return available_free_space / 2; |
| } |
| if (data.Distribution() == ContentDistributionType::kSpaceEvenly) { |
| if (available_free_space > 0 && number_of_items) |
| return available_free_space / (number_of_items + 1); |
| // Fallback to 'center' |
| return available_free_space / 2; |
| } |
| return LayoutUnit(); |
| } |
| |
| LayoutUnit FlexLayoutAlgorithm::ContentDistributionSpaceBetweenChildren( |
| LayoutUnit available_free_space, |
| const StyleContentAlignmentData& data, |
| unsigned number_of_items) { |
| if (available_free_space > 0 && number_of_items > 1) { |
| if (data.Distribution() == ContentDistributionType::kSpaceBetween) |
| return available_free_space / (number_of_items - 1); |
| if (data.Distribution() == ContentDistributionType::kSpaceAround || |
| data.Distribution() == ContentDistributionType::kStretch) |
| return available_free_space / number_of_items; |
| if (data.Distribution() == ContentDistributionType::kSpaceEvenly) |
| return available_free_space / (number_of_items + 1); |
| } |
| return LayoutUnit(); |
| } |
| |
| EOverflow FlexLayoutAlgorithm::MainAxisOverflowForChild( |
| const LayoutBox& child) const { |
| if (IsHorizontalFlow()) |
| return child.StyleRef().OverflowX(); |
| return child.StyleRef().OverflowY(); |
| } |
| |
| } // namespace blink |
