| /* |
| * 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 "core/layout/FlexibleBoxAlgorithm.h" |
| |
| #include "core/layout/LayoutBox.h" |
| |
| namespace blink { |
| |
| FlexItem::FlexItem(LayoutBox* box, |
| LayoutUnit flex_base_content_size, |
| LayoutUnit hypothetical_main_content_size, |
| LayoutUnit main_axis_border_and_padding, |
| LayoutUnit main_axis_margin) |
| : box(box), |
| flex_base_content_size(flex_base_content_size), |
| hypothetical_main_content_size(hypothetical_main_content_size), |
| main_axis_border_and_padding(main_axis_border_and_padding), |
| main_axis_margin(main_axis_margin), |
| frozen(false) { |
| DCHECK(!box->IsOutOfFlowPositioned()); |
| } |
| |
| void FlexLine::FreezeViolations(Vector<FlexItem*>& 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->Style()->FlexGrow(); |
| total_flex_shrink -= child->Style()->FlexShrink(); |
| total_weighted_flex_shrink -= |
| child->Style()->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; |
| |
| Vector<FlexItem*> 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->Style()->FlexGrow() |
| : child->Style()->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; |
| } |
| |
| FlexLayoutAlgorithm::FlexLayoutAlgorithm(const ComputedStyle* style, |
| LayoutUnit line_break_length, |
| const Vector<FlexItem>& all_items) |
| : style_(style), |
| line_break_length_(line_break_length), |
| all_items_(all_items), |
| next_item_index_(0) {} |
| |
| FlexLine* FlexLayoutAlgorithm::ComputeNextFlexLine() { |
| FlexLine new_line; |
| |
| bool line_has_in_flow_item = false; |
| |
| for (; next_item_index_ < all_items_.size(); ++next_item_index_) { |
| const FlexItem& flex_item = all_items_[next_item_index_]; |
| DCHECK(!flex_item.box->IsOutOfFlowPositioned()); |
| if (IsMultiline() && |
| new_line.sum_hypothetical_main_size + |
| flex_item.HypotheticalMainAxisMarginBoxSize() > |
| line_break_length_ && |
| line_has_in_flow_item) |
| break; |
| new_line.line_items.push_back(flex_item); |
| line_has_in_flow_item = true; |
| new_line.sum_flex_base_size += flex_item.FlexBaseMarginBoxSize(); |
| new_line.total_flex_grow += flex_item.box->Style()->FlexGrow(); |
| new_line.total_flex_shrink += flex_item.box->Style()->FlexShrink(); |
| new_line.total_weighted_flex_shrink += |
| flex_item.box->Style()->FlexShrink() * flex_item.flex_base_content_size; |
| new_line.sum_hypothetical_main_size += |
| flex_item.HypotheticalMainAxisMarginBoxSize(); |
| } |
| DCHECK(new_line.line_items.size() > 0 || |
| next_item_index_ == all_items_.size()); |
| if (new_line.line_items.size() > 0) { |
| flex_lines_.push_back(std::move(new_line)); |
| return &flex_lines_.back(); |
| } |
| return nullptr; |
| } |
| |
| } // namespace blink |
