bf25568703
Importantly, we now only consider overflow from descendants with explicltly visible overflow, and only from descendants that have the measured box as their containing block. Also, we now measure scrollable overflow for all boxes, not just scroll containers. This will allow us to fix a long-standing paint problem in the next commit.
443 lines
20 KiB
C++
443 lines
20 KiB
C++
/*
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* Copyright (c) 2022-2023, Andreas Kling <kling@serenityos.org>
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*
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* SPDX-License-Identifier: BSD-2-Clause
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*/
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#include <AK/Debug.h>
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#include <LibWeb/Layout/AvailableSpace.h>
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#include <LibWeb/Layout/BlockContainer.h>
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#include <LibWeb/Layout/LayoutState.h>
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#include <LibWeb/Layout/TextNode.h>
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#include <LibWeb/Layout/Viewport.h>
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namespace Web::Layout {
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LayoutState::LayoutState(LayoutState const* parent)
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: m_parent(parent)
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, m_root(find_root())
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{
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}
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LayoutState::~LayoutState()
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{
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}
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LayoutState::UsedValues& LayoutState::get_mutable(NodeWithStyleAndBoxModelMetrics const& box)
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{
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if (auto* used_values = used_values_per_layout_node.get(&box).value_or(nullptr))
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return *used_values;
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for (auto const* ancestor = m_parent; ancestor; ancestor = ancestor->m_parent) {
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if (auto* ancestor_used_values = ancestor->used_values_per_layout_node.get(&box).value_or(nullptr)) {
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auto cow_used_values = adopt_own(*new UsedValues(*ancestor_used_values));
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auto* cow_used_values_ptr = cow_used_values.ptr();
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used_values_per_layout_node.set(&box, move(cow_used_values));
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return *cow_used_values_ptr;
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}
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}
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auto const* containing_block_used_values = box.is_viewport() ? nullptr : &get(*box.containing_block());
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auto new_used_values = adopt_own(*new UsedValues);
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auto* new_used_values_ptr = new_used_values.ptr();
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new_used_values->set_node(const_cast<NodeWithStyleAndBoxModelMetrics&>(box), containing_block_used_values);
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used_values_per_layout_node.set(&box, move(new_used_values));
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return *new_used_values_ptr;
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}
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LayoutState::UsedValues const& LayoutState::get(NodeWithStyleAndBoxModelMetrics const& box) const
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{
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if (auto const* used_values = used_values_per_layout_node.get(&box).value_or(nullptr))
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return *used_values;
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for (auto const* ancestor = m_parent; ancestor; ancestor = ancestor->m_parent) {
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if (auto const* ancestor_used_values = ancestor->used_values_per_layout_node.get(&box).value_or(nullptr))
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return *ancestor_used_values;
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}
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auto const* containing_block_used_values = box.is_viewport() ? nullptr : &get(*box.containing_block());
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auto new_used_values = adopt_own(*new UsedValues);
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auto* new_used_values_ptr = new_used_values.ptr();
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new_used_values->set_node(const_cast<NodeWithStyleAndBoxModelMetrics&>(box), containing_block_used_values);
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const_cast<LayoutState*>(this)->used_values_per_layout_node.set(&box, move(new_used_values));
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return *new_used_values_ptr;
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}
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// https://www.w3.org/TR/css-overflow-3/#scrollable-overflow
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static CSSPixelRect measure_scrollable_overflow(Box const& box)
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{
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if (!box.paintable_box())
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return {};
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auto& paintable_box = const_cast<Painting::PaintableBox&>(*box.paintable_box());
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if (paintable_box.scrollable_overflow_rect().has_value())
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return paintable_box.scrollable_overflow_rect().value();
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// The scrollable overflow area is the union of:
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// - The scroll container’s own padding box.
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auto scrollable_overflow_rect = paintable_box.absolute_padding_box_rect();
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// - All line boxes directly contained by the scroll container.
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if (box.is_block_container() && box.children_are_inline()) {
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auto const& line_boxes = verify_cast<Painting::PaintableWithLines>(*box.paintable_box()).line_boxes();
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for (auto const& line_box : line_boxes) {
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scrollable_overflow_rect = scrollable_overflow_rect.united(line_box.absolute_rect());
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}
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}
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// - The border boxes of all boxes for which it is the containing block
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// and whose border boxes are positioned not wholly in the negative scrollable overflow region,
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// FIXME: accounting for transforms by projecting each box onto the plane of the element that establishes its 3D rendering context. [CSS3-TRANSFORMS]
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if (!box.children_are_inline()) {
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box.for_each_child_of_type<Box>([&box, &scrollable_overflow_rect](Box const& child) {
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if (!child.paintable_box())
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return IterationDecision::Continue;
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auto child_border_box = child.paintable_box()->absolute_border_box_rect();
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// NOTE: Here we check that the child is not wholly in the negative scrollable overflow region.
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if (child_border_box.bottom() > 0 && child_border_box.right() > 0)
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scrollable_overflow_rect = scrollable_overflow_rect.united(child_border_box);
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// - The scrollable overflow areas of all of the above boxes
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// (including zero-area boxes and accounting for transforms as described above),
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// provided they themselves have overflow: visible (i.e. do not themselves trap the overflow)
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// and that scrollable overflow is not already clipped (e.g. by the clip property or the contain property).
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if (is<Viewport>(box) || child.computed_values().overflow_x() == CSS::Overflow::Visible || child.computed_values().overflow_y() == CSS::Overflow::Visible) {
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auto child_scrollable_overflow = measure_scrollable_overflow(child);
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if (is<Viewport>(box) || child.computed_values().overflow_x() == CSS::Overflow::Visible)
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scrollable_overflow_rect.unite_horizontally(child_scrollable_overflow);
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if (is<Viewport>(box) || child.computed_values().overflow_y() == CSS::Overflow::Visible)
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scrollable_overflow_rect.unite_vertically(child_scrollable_overflow);
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}
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return IterationDecision::Continue;
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});
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}
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// FIXME: - The margin areas of grid item and flex item boxes for which the box establishes a containing block.
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// FIXME: - Additional padding added to the end-side of the scrollable overflow rectangle as necessary
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// to enable a scroll position that satisfies the requirements of place-content: end alignment.
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paintable_box.set_overflow_data(Painting::PaintableBox::OverflowData {
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.scrollable_overflow_rect = scrollable_overflow_rect,
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.has_scrollable_overflow = !paintable_box.absolute_padding_box_rect().contains(scrollable_overflow_rect),
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});
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return scrollable_overflow_rect;
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}
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void LayoutState::commit()
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{
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// Only the top-level LayoutState should ever be committed.
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VERIFY(!m_parent);
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HashTable<Layout::TextNode*> text_nodes;
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Vector<Painting::PaintableWithLines&> paintables_with_lines;
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for (auto& it : used_values_per_layout_node) {
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auto& used_values = *it.value;
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auto& node = const_cast<NodeWithStyleAndBoxModelMetrics&>(used_values.node());
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// Transfer box model metrics.
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node.box_model().inset = { used_values.inset_top, used_values.inset_right, used_values.inset_bottom, used_values.inset_left };
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node.box_model().padding = { used_values.padding_top, used_values.padding_right, used_values.padding_bottom, used_values.padding_left };
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node.box_model().border = { used_values.border_top, used_values.border_right, used_values.border_bottom, used_values.border_left };
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node.box_model().margin = { used_values.margin_top, used_values.margin_right, used_values.margin_bottom, used_values.margin_left };
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node.set_paintable(node.create_paintable());
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// For boxes, transfer all the state needed for painting.
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if (is<Layout::Box>(node)) {
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auto& box = static_cast<Layout::Box const&>(node);
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auto& paintable_box = const_cast<Painting::PaintableBox&>(*box.paintable_box());
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paintable_box.set_offset(used_values.offset);
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paintable_box.set_content_size(used_values.content_width(), used_values.content_height());
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paintable_box.set_containing_line_box_fragment(used_values.containing_line_box_fragment);
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if (used_values.override_borders_data().has_value()) {
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paintable_box.set_override_borders_data(used_values.override_borders_data().value());
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}
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if (used_values.table_cell_coordinates().has_value()) {
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paintable_box.set_table_cell_coordinates(used_values.table_cell_coordinates().value());
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}
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if (is<Layout::BlockContainer>(box)) {
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auto& paintable_with_lines = static_cast<Painting::PaintableWithLines&>(paintable_box);
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paintable_with_lines.set_line_boxes(move(used_values.line_boxes));
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paintables_with_lines.append(paintable_with_lines);
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}
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}
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}
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// Measure absolute rect of each line box. Also collect all text nodes.
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for (auto& paintable_with_lines : paintables_with_lines) {
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for (auto& line_box : paintable_with_lines.line_boxes()) {
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CSSPixelRect line_box_absolute_rect;
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for (auto const& fragment : line_box.fragments()) {
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line_box_absolute_rect = line_box_absolute_rect.united(fragment.absolute_rect());
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if (fragment.layout_node().is_text_node())
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text_nodes.set(static_cast<Layout::TextNode*>(const_cast<Layout::Node*>(&fragment.layout_node())));
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}
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const_cast<LineBox&>(line_box).set_absolute_rect(line_box_absolute_rect);
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}
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}
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// Measure overflow in scroll containers.
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for (auto& it : used_values_per_layout_node) {
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auto& used_values = *it.value;
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if (!used_values.node().is_box())
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continue;
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auto const& box = static_cast<Layout::Box const&>(used_values.node());
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measure_scrollable_overflow(box);
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}
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for (auto* text_node : text_nodes)
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text_node->set_paintable(text_node->create_paintable());
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}
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void LayoutState::UsedValues::set_node(NodeWithStyleAndBoxModelMetrics& node, UsedValues const* containing_block_used_values)
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{
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m_node = &node;
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// NOTE: In the code below, we decide if `node` has definite width and/or height.
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// This attempts to cover all the *general* cases where CSS considers sizes to be definite.
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// If `node` has definite values for min/max-width or min/max-height and a definite
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// preferred size in the same axis, we clamp the preferred size here as well.
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//
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// There are additional cases where CSS considers values to be definite. We model all of
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// those by having our engine consider sizes to be definite *once they are assigned to
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// the UsedValues by calling set_content_width() or set_content_height().
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auto const& computed_values = node.computed_values();
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auto adjust_for_box_sizing = [&](CSSPixels unadjusted_pixels, CSS::Size const& computed_size, bool width) -> CSSPixels {
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// box-sizing: content-box and/or automatic size don't require any adjustment.
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if (computed_values.box_sizing() == CSS::BoxSizing::ContentBox || computed_size.is_auto())
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return unadjusted_pixels;
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// box-sizing: border-box requires us to subtract the relevant border and padding from the size.
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CSSPixels border_and_padding;
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if (width) {
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border_and_padding = CSSPixels(computed_values.border_left().width)
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+ computed_values.padding().left().to_px(*m_node, containing_block_used_values->content_width())
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+ CSSPixels(computed_values.border_right().width)
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+ computed_values.padding().right().to_px(*m_node, containing_block_used_values->content_width());
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} else {
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border_and_padding = CSSPixels(computed_values.border_top().width)
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+ computed_values.padding().top().to_px(*m_node, containing_block_used_values->content_width())
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+ CSSPixels(computed_values.border_bottom().width)
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+ computed_values.padding().bottom().to_px(*m_node, containing_block_used_values->content_width());
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}
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return unadjusted_pixels - border_and_padding;
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};
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auto is_definite_size = [&](CSS::Size const& size, CSSPixels& resolved_definite_size, bool width) {
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// A size that can be determined without performing layout; that is,
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// a <length>,
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// a measure of text (without consideration of line-wrapping),
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// a size of the initial containing block,
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// or a <percentage> or other formula (such as the “stretch-fit” sizing of non-replaced blocks [CSS2]) that is resolved solely against definite sizes.
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auto containing_block_has_definite_size = containing_block_used_values ? (width ? containing_block_used_values->has_definite_width() : containing_block_used_values->has_definite_height()) : false;
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if (size.is_auto()) {
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// NOTE: The width of a non-flex-item block is considered definite if it's auto and the containing block has definite width.
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if (width
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&& !node.is_floating()
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&& !node.is_absolutely_positioned()
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&& node.display().is_block_outside()
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&& node.parent()
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&& !node.parent()->is_floating()
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&& (node.parent()->display().is_flow_root_inside()
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|| node.parent()->display().is_flow_inside())) {
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if (containing_block_has_definite_size) {
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CSSPixels available_width = containing_block_used_values->content_width();
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resolved_definite_size = available_width
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- margin_left
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- margin_right
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- padding_left
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- padding_right
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- border_left
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- border_right;
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return true;
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}
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return false;
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}
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return false;
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}
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if (size.is_calculated()) {
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if (size.calculated().contains_percentage()) {
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if (!containing_block_has_definite_size)
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return false;
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auto containing_block_size_as_length = width
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? CSS::Length::make_px(containing_block_used_values->content_width())
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: CSS::Length::make_px(containing_block_used_values->content_height());
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resolved_definite_size = adjust_for_box_sizing(size.calculated().resolve_length_percentage(node, containing_block_size_as_length).value_or(CSS::Length::make_auto()).to_px(node), size, width);
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return true;
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}
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resolved_definite_size = adjust_for_box_sizing(size.calculated().resolve_length(node)->to_px(node), size, width);
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return true;
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}
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if (size.is_length()) {
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VERIFY(!size.is_auto()); // This should have been covered by the Size::is_auto() branch above.
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resolved_definite_size = adjust_for_box_sizing(size.length().to_px(node), size, width);
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return true;
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}
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if (size.is_percentage()) {
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if (containing_block_has_definite_size) {
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auto containing_block_size = width ? containing_block_used_values->content_width() : containing_block_used_values->content_height();
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resolved_definite_size = adjust_for_box_sizing(containing_block_size * static_cast<double>(size.percentage().as_fraction()), size, width);
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return true;
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}
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return false;
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}
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// FIXME: Determine if calc() value is definite.
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return false;
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};
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CSSPixels min_width = 0;
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bool has_definite_min_width = is_definite_size(computed_values.min_width(), min_width, true);
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CSSPixels max_width = 0;
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bool has_definite_max_width = is_definite_size(computed_values.max_width(), max_width, true);
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CSSPixels min_height = 0;
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bool has_definite_min_height = is_definite_size(computed_values.min_height(), min_height, false);
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CSSPixels max_height = 0;
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bool has_definite_max_height = is_definite_size(computed_values.max_height(), max_height, false);
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m_has_definite_width = is_definite_size(computed_values.width(), m_content_width, true);
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m_has_definite_height = is_definite_size(computed_values.height(), m_content_height, false);
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if (m_has_definite_width) {
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if (has_definite_min_width)
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m_content_width = max(min_width, m_content_width);
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if (has_definite_max_width)
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m_content_width = min(max_width, m_content_width);
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}
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if (m_has_definite_height) {
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if (has_definite_min_height)
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m_content_height = max(min_height, m_content_height);
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if (has_definite_max_height)
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m_content_height = min(max_height, m_content_height);
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}
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}
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void LayoutState::UsedValues::set_content_width(CSSPixels width)
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{
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VERIFY(isfinite(width.to_double()));
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if (width < 0) {
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// Negative widths are not allowed in CSS. We have a bug somewhere! Clamp to 0 to avoid doing too much damage.
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dbgln_if(LIBWEB_CSS_DEBUG, "FIXME: Layout calculated a negative width for {}: {}", m_node->debug_description(), width);
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width = 0;
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}
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m_content_width = width;
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m_has_definite_width = true;
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}
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void LayoutState::UsedValues::set_content_height(CSSPixels height)
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{
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VERIFY(isfinite(height.to_double()));
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if (height < 0) {
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// Negative heights are not allowed in CSS. We have a bug somewhere! Clamp to 0 to avoid doing too much damage.
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dbgln_if(LIBWEB_CSS_DEBUG, "FIXME: Layout calculated a negative height for {}: {}", m_node->debug_description(), height);
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height = 0;
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}
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m_content_height = height;
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m_has_definite_height = true;
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}
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void LayoutState::UsedValues::set_temporary_content_width(CSSPixels width)
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{
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m_content_width = width;
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}
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void LayoutState::UsedValues::set_temporary_content_height(CSSPixels height)
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{
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m_content_height = height;
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}
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AvailableSize LayoutState::UsedValues::available_width_inside() const
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{
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if (width_constraint == SizeConstraint::MinContent)
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return AvailableSize::make_min_content();
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if (width_constraint == SizeConstraint::MaxContent)
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return AvailableSize::make_max_content();
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if (has_definite_width())
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return AvailableSize::make_definite(m_content_width);
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return AvailableSize::make_indefinite();
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}
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AvailableSize LayoutState::UsedValues::available_height_inside() const
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{
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if (height_constraint == SizeConstraint::MinContent)
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return AvailableSize::make_min_content();
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if (height_constraint == SizeConstraint::MaxContent)
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return AvailableSize::make_max_content();
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if (has_definite_height())
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return AvailableSize::make_definite(m_content_height);
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return AvailableSize::make_indefinite();
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}
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AvailableSpace LayoutState::UsedValues::available_inner_space_or_constraints_from(AvailableSpace const& outer_space) const
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{
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auto inner_width = available_width_inside();
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auto inner_height = available_height_inside();
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if (inner_width.is_indefinite() && outer_space.width.is_intrinsic_sizing_constraint())
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inner_width = outer_space.width;
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if (inner_height.is_indefinite() && outer_space.height.is_intrinsic_sizing_constraint())
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inner_height = outer_space.height;
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return AvailableSpace(inner_width, inner_height);
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}
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void LayoutState::UsedValues::set_content_offset(CSSPixelPoint new_offset)
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{
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set_content_x(new_offset.x());
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set_content_y(new_offset.y());
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}
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void LayoutState::UsedValues::set_content_x(CSSPixels x)
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{
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offset.set_x(x);
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}
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void LayoutState::UsedValues::set_content_y(CSSPixels y)
|
||
{
|
||
offset.set_y(y);
|
||
}
|
||
|
||
void LayoutState::UsedValues::set_indefinite_content_width()
|
||
{
|
||
m_has_definite_width = false;
|
||
}
|
||
|
||
void LayoutState::UsedValues::set_indefinite_content_height()
|
||
{
|
||
m_has_definite_height = false;
|
||
}
|
||
|
||
void LayoutState::UsedValues::set_min_content_width()
|
||
{
|
||
width_constraint = SizeConstraint::MinContent;
|
||
m_content_width = 0;
|
||
m_has_definite_height = false;
|
||
}
|
||
|
||
void LayoutState::UsedValues::set_max_content_width()
|
||
{
|
||
width_constraint = SizeConstraint::MaxContent;
|
||
m_content_width = INFINITY;
|
||
m_has_definite_width = false;
|
||
}
|
||
|
||
}
|