/*
* Copyright (c) 2020-2022, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#include <AK/TemporaryChange.h>
#include <LibWeb/CSS/Length.h>
#include <LibWeb/DOM/Node.h>
#include <LibWeb/Dump.h>
#include <LibWeb/HTML/BrowsingContext.h>
#include <LibWeb/Layout/BlockContainer.h>
#include <LibWeb/Layout/BlockFormattingContext.h>
#include <LibWeb/Layout/Box.h>
#include <LibWeb/Layout/InlineFormattingContext.h>
#include <LibWeb/Layout/LineBuilder.h>
#include <LibWeb/Layout/ListItemBox.h>
#include <LibWeb/Layout/ListItemMarkerBox.h>
#include <LibWeb/Layout/ReplacedBox.h>
#include <LibWeb/Layout/SVGSVGBox.h>
#include <LibWeb/Layout/TableWrapper.h>
#include <LibWeb/Layout/Viewport.h>
namespace Web::Layout {
BlockFormattingContext::BlockFormattingContext(LayoutState& state, LayoutMode layout_mode, BlockContainer const& root, FormattingContext* parent)
: FormattingContext(Type::Block, layout_mode, state, root, parent)
{
}
BlockFormattingContext::~BlockFormattingContext()
{
if (!m_was_notified_after_parent_dimensioned_my_root_box) {
// HACK: The parent formatting context never notified us after assigning dimensions to our root box.
// Pretend that it did anyway, to make sure absolutely positioned children get laid out.
// FIXME: Get rid of this hack once parent contexts behave properly.
parent_context_did_dimension_child_root_box();
}
}
CSSPixels BlockFormattingContext::automatic_content_width() const
{
if (root().children_are_inline())
return m_state.get(root()).content_width();
return greatest_child_width(root());
}
CSSPixels BlockFormattingContext::automatic_content_height() const
{
return compute_auto_height_for_block_formatting_context_root(root());
}
static bool margins_collapse_through(Box const& box, LayoutState& state)
{
// FIXME: A box's own margins collapse if the 'min-height' property is zero, and it has neither top or bottom borders
// nor top or bottom padding, and it has a 'height' of either 0 or 'auto', and it does not contain a line box, and
// all of its in-flow children's margins (if any) collapse.
// https://www.w3.org/TR/CSS22/box.html#collapsing-margins
// FIXME: For the purpose of margin collapsing (CSS 2 §8.3.1 Collapsing margins), if the block axis is the
// ratio-dependent axis, it is not considered to have a computed block-size of auto.
// https://www.w3.org/TR/css-sizing-4/#aspect-ratio-margin-collapse
if (box.computed_values().clear() != CSS::Clear::None)
return false;
return state.get(box).border_box_height() == 0;
}
void BlockFormattingContext::run(AvailableSpace const& available_space)
{
if (is<Viewport>(root())) {
layout_viewport(available_space);
return;
}
if (root().children_are_inline())
layout_inline_children(root(), available_space);
else
layout_block_level_children(root(), available_space);
// Assign collapsed margin left after children layout of formatting context to the last child box
if (m_margin_state.current_collapsed_margin() != 0) {
for (auto* child_box = root().last_child_of_type<Box>(); child_box; child_box = child_box->previous_sibling_of_type<Box>()) {
if (child_box->is_absolutely_positioned() || child_box->is_floating())
continue;
if (margins_collapse_through(*child_box, m_state))
continue;
m_state.get_mutable(*child_box).margin_bottom = m_margin_state.current_collapsed_margin();
break;
}
}
}
void BlockFormattingContext::parent_context_did_dimension_child_root_box()
{
m_was_notified_after_parent_dimensioned_my_root_box = true;
// Left-side floats: offset_from_edge is from left edge (0) to left content edge of floating_box.
for (auto& floating_box : m_left_floats.all_boxes) {
auto& box_state = m_state.get_mutable(floating_box->box);
box_state.set_content_x(floating_box->offset_from_edge);
}
// Right-side floats: offset_from_edge is from right edge (float_containing_block_width) to the left content edge of floating_box.
for (auto& floating_box : m_right_floats.all_boxes) {
auto float_containing_block_width = containing_block_width_for(floating_box->box);
auto& box_state = m_state.get_mutable(floating_box->box);
box_state.set_content_x(float_containing_block_width - floating_box->offset_from_edge);
}
if (m_layout_mode == LayoutMode::Normal) {
// We can also layout absolutely positioned boxes within this BFC.
for (auto& box : m_absolutely_positioned_boxes) {
auto& cb_state = m_state.get(*box->containing_block());
auto available_width = AvailableSize::make_definite(cb_state.content_width() + cb_state.padding_left + cb_state.padding_right);
auto available_height = AvailableSize::make_definite(cb_state.content_height() + cb_state.padding_top + cb_state.padding_bottom);
layout_absolutely_positioned_element(box, AvailableSpace(available_width, available_height));
}
}
}
bool BlockFormattingContext::box_should_avoid_floats_because_it_establishes_fc(Box const& box)
{
if (auto formatting_context_type = formatting_context_type_created_by_box(box); formatting_context_type.has_value()) {
if (formatting_context_type.value() == Type::Block)
return true;
if (formatting_context_type.value() == Type::Flex)
return true;
if (formatting_context_type.value() == Type::Grid)
return true;
}
return false;
}
void BlockFormattingContext::compute_width(Box const& box, AvailableSpace const& available_space)
{
if (box.is_absolutely_positioned()) {
compute_width_for_absolutely_positioned_element(box, available_space);
return;
}
auto remaining_available_space = available_space;
if (available_space.width.is_definite() && box_should_avoid_floats_because_it_establishes_fc(box)) {
// NOTE: Although CSS 2.2 specification says that only block formatting contexts should avoid floats,
// we also do this for flex and grid formatting contexts, because that how other engines behave.
// 9.5 Floats
// The border box of a table, a block-level replaced element, or an element in the normal flow that establishes a
// new block formatting context (such as an element with 'overflow' other than 'visible') must not overlap the margin
// box of any floats in the same block formatting context as the element itself. If necessary, implementations should
// clear the said element by placing it below any preceding floats, but may place it adjacent to such floats if there is
// sufficient space. They may even make the border box of said element narrower than defined by section 10.3.3.
// CSS2 does not define when a UA may put said element next to the float or by how much said element may
// become narrower.
auto intrusion = intrusion_by_floats_into_box(box, 0);
auto remaining_width = available_space.width.to_px_or_zero() - intrusion.left - intrusion.right;
remaining_available_space.width = AvailableSize::make_definite(remaining_width);
}
if (box_is_sized_as_replaced_element(box)) {
// FIXME: This should not be done *by* ReplacedBox
if (is<ReplacedBox>(box)) {
auto& replaced = verify_cast<ReplacedBox>(box);
// FIXME: This const_cast is gross.
const_cast<ReplacedBox&>(replaced).prepare_for_replaced_layout();
}
compute_width_for_block_level_replaced_element_in_normal_flow(box, remaining_available_space);
if (box.is_floating()) {
// 10.3.6 Floating, replaced elements:
// https://www.w3.org/TR/CSS22/visudet.html#float-replaced-width
return;
}
}
if (box.is_floating()) {
// 10.3.5 Floating, non-replaced elements:
// https://www.w3.org/TR/CSS22/visudet.html#float-width
compute_width_for_floating_box(box, available_space);
return;
}
auto const& computed_values = box.computed_values();
auto width_of_containing_block = remaining_available_space.width.to_px_or_zero();
auto zero_value = CSS::Length::make_px(0);
auto margin_left = CSS::Length::make_auto();
auto margin_right = CSS::Length::make_auto();
auto const padding_left = computed_values.padding().left().resolved(box, width_of_containing_block).to_px(box);
auto const padding_right = computed_values.padding().right().resolved(box, width_of_containing_block).to_px(box);
auto& box_state = m_state.get_mutable(box);
box_state.border_left = computed_values.border_left().width;
box_state.border_right = computed_values.border_right().width;
box_state.padding_left = padding_left;
box_state.padding_right = padding_right;
// NOTE: If we are calculating the min-content or max-content width of this box,
// and the width should be treated as auto, then we can simply return here,
// as the preferred width and min/max constraints are irrelevant for intrinsic sizing.
if (box_state.width_constraint != SizeConstraint::None)
return;
auto try_compute_width = [&](CSS::Length const& a_width) {
CSS::Length width = a_width;
margin_left = computed_values.margin().left().resolved(box, width_of_containing_block);
margin_right = computed_values.margin().right().resolved(box, width_of_containing_block);
CSSPixels total_px = computed_values.border_left().width + computed_values.border_right().width;
for (auto& value : { margin_left, CSS::Length::make_px(padding_left), width, CSS::Length::make_px(padding_right), margin_right }) {
total_px += value.to_px(box);
}
if (!box.is_inline()) {
// 10.3.3 Block-level, non-replaced elements in normal flow
// If 'width' is not 'auto' and 'border-left-width' + 'padding-left' + 'width' + 'padding-right' + 'border-right-width' (plus any of 'margin-left' or 'margin-right' that are not 'auto') is larger than the width of the containing block, then any 'auto' values for 'margin-left' or 'margin-right' are, for the following rules, treated as zero.
if (!width.is_auto() && total_px > width_of_containing_block) {
if (margin_left.is_auto())
margin_left = zero_value;
if (margin_right.is_auto())
margin_right = zero_value;
}
// 10.3.3 cont'd.
auto underflow_px = width_of_containing_block - total_px;
if (available_space.width.is_intrinsic_sizing_constraint())
underflow_px = 0;
if (width.is_auto()) {
if (margin_left.is_auto())
margin_left = zero_value;
if (margin_right.is_auto())
margin_right = zero_value;
if (available_space.width.is_definite()) {
if (underflow_px >= 0) {
width = CSS::Length::make_px(underflow_px);
} else {
width = zero_value;
margin_right = CSS::Length::make_px(margin_right.to_px(box) + underflow_px);
}
}
} else {
if (!margin_left.is_auto() && !margin_right.is_auto()) {
margin_right = CSS::Length::make_px(margin_right.to_px(box) + underflow_px);
} else if (!margin_left.is_auto() && margin_right.is_auto()) {
margin_right = CSS::Length::make_px(underflow_px);
} else if (margin_left.is_auto() && !margin_right.is_auto()) {
margin_left = CSS::Length::make_px(underflow_px);
} else { // margin_left.is_auto() && margin_right.is_auto()
auto half_of_the_underflow = CSS::Length::make_px(underflow_px / 2);
margin_left = half_of_the_underflow;
margin_right = half_of_the_underflow;
}
}
}
return width;
};
auto input_width = [&] {
if (box_is_sized_as_replaced_element(box)) {
// NOTE: Replaced elements had their width calculated independently above.
// We use that width as the input here to ensure that margins get resolved.
return CSS::Length::make_px(box_state.content_width());
}
if (is<TableWrapper>(box))
return CSS::Length::make_px(compute_table_box_width_inside_table_wrapper(box, remaining_available_space));
if (should_treat_width_as_auto(box, remaining_available_space))
return CSS::Length::make_auto();
return CSS::Length::make_px(calculate_inner_width(box, remaining_available_space.width, computed_values.width()));
}();
// 1. The tentative used width is calculated (without 'min-width' and 'max-width')
auto used_width = try_compute_width(input_width);
// 2. The tentative used width is greater than 'max-width', the rules above are applied again,
// but this time using the computed value of 'max-width' as the computed value for 'width'.
if (!should_treat_max_width_as_none(box, available_space.width)) {
auto max_width = calculate_inner_width(box, remaining_available_space.width, computed_values.max_width());
auto used_width_px = used_width.is_auto() ? CSSPixels { 0 } : used_width.to_px(box);
if (used_width_px > max_width) {
used_width = try_compute_width(CSS::Length::make_px(max_width));
}
}
// 3. If the resulting width is smaller than 'min-width', the rules above are applied again,
// but this time using the value of 'min-width' as the computed value for 'width'.
if (!computed_values.min_width().is_auto()) {
auto min_width = calculate_inner_width(box, remaining_available_space.width, computed_values.min_width());
auto used_width_px = used_width.is_auto() ? remaining_available_space.width : AvailableSize::make_definite(used_width.to_px(box));
if (used_width_px < min_width) {
used_width = try_compute_width(CSS::Length::make_px(min_width));
}
}
if (!box_is_sized_as_replaced_element(box) && !used_width.is_auto())
box_state.set_content_width(used_width.to_px(box));
box_state.margin_left = margin_left.to_px(box);
box_state.margin_right = margin_right.to_px(box);
}
void BlockFormattingContext::compute_width_for_floating_box(Box const& box, AvailableSpace const& available_space)
{
// 10.3.5 Floating, non-replaced elements
auto& computed_values = box.computed_values();
auto zero_value = CSS::Length::make_px(0);
auto width_of_containing_block = available_space.width.to_px_or_zero();
auto margin_left = computed_values.margin().left().resolved(box, width_of_containing_block);
auto margin_right = computed_values.margin().right().resolved(box, width_of_containing_block);
auto const padding_left = computed_values.padding().left().resolved(box, width_of_containing_block).to_px(box);
auto const padding_right = computed_values.padding().right().resolved(box, width_of_containing_block).to_px(box);
// If 'margin-left', or 'margin-right' are computed as 'auto', their used value is '0'.
if (margin_left.is_auto())
margin_left = zero_value;
if (margin_right.is_auto())
margin_right = zero_value;
auto compute_width = [&](auto width) {
// If 'width' is computed as 'auto', the used value is the "shrink-to-fit" width.
if (width.is_auto()) {
auto result = calculate_shrink_to_fit_widths(box);
if (available_space.width.is_definite()) {
// Find the available width: in this case, this is the width of the containing
// block minus the used values of 'margin-left', 'border-left-width', 'padding-left',
// 'padding-right', 'border-right-width', 'margin-right', and the widths of any relevant scroll bars.
auto available_width = available_space.width.to_px_or_zero()
- margin_left.to_px(box) - computed_values.border_left().width - padding_left
- padding_right - computed_values.border_right().width - margin_right.to_px(box);
// Then the shrink-to-fit width is: min(max(preferred minimum width, available width), preferred width).
width = CSS::Length::make_px(min(max(result.preferred_minimum_width, available_width), result.preferred_width));
} else if (available_space.width.is_indefinite() || available_space.width.is_max_content()) {
// Fold the formula for shrink-to-fit width for indefinite and max-content available width.
width = CSS::Length::make_px(result.preferred_width);
} else {
// Fold the formula for shrink-to-fit width for min-content available width.
width = CSS::Length::make_px(min(result.preferred_minimum_width, result.preferred_width));
}
}
return width;
};
auto input_width = [&] {
if (should_treat_width_as_auto(box, available_space))
return CSS::Length::make_auto();
return CSS::Length::make_px(calculate_inner_width(box, available_space.width, computed_values.width()));
}();
// 1. The tentative used width is calculated (without 'min-width' and 'max-width')
auto width = compute_width(input_width);
// 2. The tentative used width is greater than 'max-width', the rules above are applied again,
// but this time using the computed value of 'max-width' as the computed value for 'width'.
if (!should_treat_max_width_as_none(box, available_space.width)) {
auto max_width = calculate_inner_width(box, available_space.width, computed_values.max_width());
if (width.to_px(box) > max_width)
width = compute_width(CSS::Length::make_px(max_width));
}
// 3. If the resulting width is smaller than 'min-width', the rules above are applied again,
// but this time using the value of 'min-width' as the computed value for 'width'.
if (!computed_values.min_width().is_auto()) {
auto min_width = calculate_inner_width(box, available_space.width, computed_values.min_width());
if (width.to_px(box) < min_width)
width = compute_width(CSS::Length::make_px(min_width));
}
auto& box_state = m_state.get_mutable(box);
box_state.set_content_width(width.to_px(box));
box_state.margin_left = margin_left.to_px(box);
box_state.margin_right = margin_right.to_px(box);
box_state.border_left = computed_values.border_left().width;
box_state.border_right = computed_values.border_right().width;
box_state.padding_left = padding_left;
box_state.padding_right = padding_right;
}
void BlockFormattingContext::compute_width_for_block_level_replaced_element_in_normal_flow(Box const& box, AvailableSpace const& available_space)
{
// 10.3.6 Floating, replaced elements
auto& computed_values = box.computed_values();
auto zero_value = CSS::Length::make_px(0);
auto width_of_containing_block = available_space.width.to_px_or_zero();
// 10.3.4 Block-level, replaced elements in normal flow
// The used value of 'width' is determined as for inline replaced elements. Then the rules for
// non-replaced block-level elements are applied to determine the margins.
auto margin_left = computed_values.margin().left().resolved(box, width_of_containing_block);
auto margin_right = computed_values.margin().right().resolved(box, width_of_containing_block);
auto const padding_left = computed_values.padding().left().resolved(box, width_of_containing_block).to_px(box);
auto const padding_right = computed_values.padding().right().resolved(box, width_of_containing_block).to_px(box);
// If 'margin-left', or 'margin-right' are computed as 'auto', their used value is '0'.
if (margin_left.is_auto())
margin_left = zero_value;
if (margin_right.is_auto())
margin_right = zero_value;
auto& box_state = m_state.get_mutable(box);
box_state.set_content_width(compute_width_for_replaced_element(box, available_space));
box_state.margin_left = margin_left.to_px(box);
box_state.margin_right = margin_right.to_px(box);
box_state.border_left = computed_values.border_left().width;
box_state.border_right = computed_values.border_right().width;
box_state.padding_left = padding_left;
box_state.padding_right = padding_right;
}
void BlockFormattingContext::compute_height(Box const& box, AvailableSpace const& available_space)
{
auto const& computed_values = box.computed_values();
auto& box_used_values = m_state.get_mutable(box);
// Then work out what the height is, based on box type and CSS properties.
CSSPixels height = 0;
if (box_is_sized_as_replaced_element(box)) {
height = compute_height_for_replaced_element(box, available_space);
} else {
if (should_treat_height_as_auto(box, available_space)) {
height = compute_auto_height_for_block_level_element(box, m_state.get(box).available_inner_space_or_constraints_from(available_space));
} else {
height = calculate_inner_height(box, available_space.height, computed_values.height());
}
}
if (!should_treat_max_height_as_none(box, available_space.height)) {
if (!computed_values.max_height().is_auto()) {
auto max_height = calculate_inner_height(box, available_space.height, computed_values.max_height());
height = min(height, max_height);
}
}
if (!computed_values.min_height().is_auto()) {
height = max(height, calculate_inner_height(box, available_space.height, computed_values.min_height()));
}
if (box.document().in_quirks_mode()
&& box.dom_node()
&& box.dom_node()->is_html_html_element()
&& box.computed_values().height().is_auto()) {
// 3.6. The html element fills the viewport quirk
// https://quirks.spec.whatwg.org/#the-html-element-fills-the-viewport-quirk
// FIXME: Handle vertical writing mode.
auto& box_state = m_state.get_mutable(box);
// 1. Let margins be sum of the used values of the margin-left and margin-right properties of element
// if element has a vertical writing mode, otherwise let margins be the sum of the used values of
// the margin-top and margin-bottom properties of element.
auto margins = box_state.margin_top + box_state.margin_bottom;
// 2. Let size be the size of the initial containing block in the block flow direction minus margins.
auto size = m_state.get(*box.containing_block()).content_height() - margins;
// 3. Return the bigger value of size and the normal border box size the element would have
// according to the CSS specification.
height = max(size, height);
// NOTE: The height of the root element when affected by this quirk is considered to be definite.
box_used_values.set_has_definite_height(true);
}
box_used_values.set_content_height(height);
}
void BlockFormattingContext::layout_inline_children(BlockContainer const& block_container, AvailableSpace const& available_space)
{
VERIFY(block_container.children_are_inline());
auto& block_container_state = m_state.get_mutable(block_container);
InlineFormattingContext context(m_state, m_layout_mode, block_container, block_container_state, *this);
context.run(available_space);
if (!block_container_state.has_definite_width()) {
// NOTE: min-width or max-width for boxes with inline children can only be applied after inside layout
// is done and width of box content is known
auto used_width_px = context.automatic_content_width();
// https://www.w3.org/TR/css-sizing-3/#sizing-values
// Percentages are resolved against the width/height, as appropriate, of the box’s containing block.
auto containing_block_width = m_state.get(*block_container.containing_block()).content_width();
auto available_width = AvailableSize::make_definite(containing_block_width);
if (!should_treat_max_width_as_none(block_container, available_space.width)) {
auto max_width_px = calculate_inner_width(block_container, available_width, block_container.computed_values().max_width());
if (used_width_px > max_width_px)
used_width_px = max_width_px;
}
auto should_treat_min_width_as_auto = [&] {
auto const& available_width = available_space.width;
auto const& min_width = block_container.computed_values().min_width();
if (min_width.is_auto())
return true;
if (min_width.is_fit_content() && available_width.is_intrinsic_sizing_constraint())
return true;
if (min_width.is_max_content() && available_width.is_max_content())
return true;
if (min_width.is_min_content() && available_width.is_min_content())
return true;
return false;
}();
if (!should_treat_min_width_as_auto) {
auto min_width_px = calculate_inner_width(block_container, available_width, block_container.computed_values().min_width());
if (used_width_px < min_width_px)
used_width_px = min_width_px;
}
block_container_state.set_content_width(used_width_px);
block_container_state.set_content_height(context.automatic_content_height());
}
}
CSSPixels BlockFormattingContext::compute_auto_height_for_block_level_element(Box const& box, AvailableSpace const& available_space)
{
if (creates_block_formatting_context(box)) {
return compute_auto_height_for_block_formatting_context_root(box);
}
auto const& box_state = m_state.get(box);
auto display = box.display();
if (display.is_flex_inside()) {
// https://drafts.csswg.org/css-flexbox-1/#algo-main-container
// NOTE: The automatic block size of a block-level flex container is its max-content size.
return calculate_max_content_height(box, available_space.width.to_px_or_zero());
}
if (display.is_grid_inside()) {
// https://www.w3.org/TR/css-grid-2/#intrinsic-sizes
// In both inline and block formatting contexts, the grid container’s auto block size is its
// max-content size.
return calculate_max_content_height(box, available_space.width.to_px_or_zero());
}
if (display.is_table_inside()) {
return calculate_max_content_height(box, available_space.width.to_px_or_zero());
}
// https://www.w3.org/TR/CSS22/visudet.html#normal-block
// 10.6.3 Block-level non-replaced elements in normal flow when 'overflow' computes to 'visible'
// The element's height is the distance from its top content edge to the first applicable of the following:
// 1. the bottom edge of the last line box, if the box establishes a inline formatting context with one or more lines
if (box.children_are_inline() && !box_state.line_boxes.is_empty())
return box_state.line_boxes.last().bottom();
// 2. the bottom edge of the bottom (possibly collapsed) margin of its last in-flow child, if the child's bottom margin does not collapse with the element's bottom margin
// 3. the bottom border edge of the last in-flow child whose top margin doesn't collapse with the element's bottom margin
if (!box.children_are_inline()) {
for (auto* child_box = box.last_child_of_type<Box>(); child_box; child_box = child_box->previous_sibling_of_type<Box>()) {
if (child_box->is_absolutely_positioned() || child_box->is_floating())
continue;
// FIXME: This is hack. If the last child is a list-item marker box, we ignore it for purposes of height calculation.
// Perhaps markers should not be considered in-flow(?) Perhaps they should always be the first child of the list-item
// box instead of the last child.
if (child_box->is_list_item_marker_box())
continue;
auto const& child_box_state = m_state.get(*child_box);
if (margins_collapse_through(*child_box, m_state))
continue;
auto margin_bottom = m_margin_state.current_collapsed_margin();
if (box_state.padding_bottom == 0 && box_state.border_bottom == 0) {
m_margin_state.box_last_in_flow_child_margin_bottom_collapsed = true;
margin_bottom = 0;
}
return max(CSSPixels(0), child_box_state.offset.y() + child_box_state.content_height() + child_box_state.border_box_bottom() + margin_bottom);
}
}
// 4. zero, otherwise
return 0;
}
void BlockFormattingContext::layout_block_level_box(Box const& box, BlockContainer const& block_container, CSSPixels& bottom_of_lowest_margin_box, AvailableSpace const& available_space)
{
auto& box_state = m_state.get_mutable(box);
if (box.is_absolutely_positioned()) {
box_state.vertical_offset_of_parent_block_container = m_y_offset_of_current_block_container.value();
m_absolutely_positioned_boxes.append(box);
return;
}
// NOTE: ListItemMarkerBoxes are placed by their corresponding ListItemBox.
if (is<ListItemMarkerBox>(box))
return;
resolve_vertical_box_model_metrics(box);
if (box.is_floating()) {
auto const y = m_y_offset_of_current_block_container.value();
auto margin_top = !m_margin_state.has_block_container_waiting_for_final_y_position() ? m_margin_state.current_collapsed_margin() : 0;
layout_floating_box(box, block_container, available_space, margin_top + y);
bottom_of_lowest_margin_box = max(bottom_of_lowest_margin_box, box_state.offset.y() + box_state.content_height() + box_state.margin_box_bottom());
return;
}
m_margin_state.add_margin(box_state.margin_top);
auto introduce_clearance = clear_floating_boxes(box, {});
if (introduce_clearance == DidIntroduceClearance::Yes)
m_margin_state.reset();
auto const y = m_y_offset_of_current_block_container.value();
auto box_is_html_element_in_quirks_mode = box.document().in_quirks_mode()
&& box.dom_node()
&& box.dom_node()->is_html_html_element()
&& box.computed_values().height().is_auto();
// NOTE: In quirks mode, the html element's height matches the viewport so it can be treated as definite
if (box_state.has_definite_height() || box_is_html_element_in_quirks_mode) {
compute_height(box, available_space);
}
auto independent_formatting_context = create_independent_formatting_context_if_needed(m_state, m_layout_mode, box);
// NOTE: It is possible to encounter SVGMaskBox nodes while doing layout of formatting context established by <foreignObject> with a mask.
// We should skip and let SVGFormattingContext take care of them.
if (box.is_svg_mask_box())
return;
if (!independent_formatting_context && !is<BlockContainer>(box)) {
dbgln("FIXME: Block-level box is not BlockContainer but does not create formatting context: {}", box.debug_description());
return;
}
m_margin_state.update_block_waiting_for_final_y_position();
CSSPixels margin_top = m_margin_state.current_collapsed_margin();
if (m_margin_state.has_block_container_waiting_for_final_y_position()) {
// If first child margin top will collapse with margin-top of containing block then margin-top of child is 0
margin_top = 0;
}
if (independent_formatting_context) {
// Margins of elements that establish new formatting contexts do not collapse with their in-flow children
m_margin_state.reset();
}
place_block_level_element_in_normal_flow_vertically(box, y + margin_top);
compute_width(box, available_space);
place_block_level_element_in_normal_flow_horizontally(box, available_space);
// NOTE: Flex containers with `auto` height are treated as `max-content`, so we can compute their height early.
if (box.is_replaced_box() || box.display().is_flex_inside())
compute_height(box, available_space);
// Before we insert the children of a list item we need to know the location of the marker.
// If we do not do this then left-floating elements inside the list item will push the marker to the right,
// in some cases even causing it to overlap with the non-floating content of the list.
CSSPixels left_space_before_children_formatted;
if (is<ListItemBox>(box)) {
auto const& li_box = static_cast<ListItemBox const&>(box);
// We need to ensure that our height and width are final before we calculate our left offset.
// Otherwise, the y at which we calculate the intrusion by floats might be incorrect.
ensure_sizes_correct_for_left_offset_calculation(li_box);
auto const& list_item_state = m_state.get(li_box);
auto const& marker_state = m_state.get(*li_box.marker());
auto offset_y = max(CSSPixels(0), (li_box.marker()->computed_values().line_height() - marker_state.content_height()) / 2);
auto space_used_before_children_formatted = intrusion_by_floats_into_box(list_item_state, offset_y);
left_space_before_children_formatted = space_used_before_children_formatted.left;
}
if (independent_formatting_context) {
// This box establishes a new formatting context. Pass control to it.
independent_formatting_context->run(box_state.available_inner_space_or_constraints_from(available_space));
} else {
// This box participates in the current block container's flow.
if (box.children_are_inline()) {
layout_inline_children(verify_cast<BlockContainer>(box), box_state.available_inner_space_or_constraints_from(available_space));
} else {
if (box_state.border_top > 0 || box_state.padding_top > 0) {
// margin-top of block container can't collapse with it's children if it has non zero border or padding
m_margin_state.reset();
} else if (!m_margin_state.has_block_container_waiting_for_final_y_position()) {
// margin-top of block container can be updated during children layout hence it's final y position yet to be determined
m_margin_state.register_block_container_y_position_update_callback([&, introduce_clearance](CSSPixels margin_top) {
if (introduce_clearance == DidIntroduceClearance::No) {
place_block_level_element_in_normal_flow_vertically(box, margin_top + y);
}
});
}
layout_block_level_children(verify_cast<BlockContainer>(box), box_state.available_inner_space_or_constraints_from(available_space));
}
}
// Tables already set their height during the independent formatting context run. When multi-line text cells are involved, using different
// available space here than during the independent formatting context run can result in different line breaks and thus a different height.
if (!box.display().is_table_inside()) {
compute_height(box, available_space);
}
if (independent_formatting_context || !margins_collapse_through(box, m_state)) {
if (!m_margin_state.box_last_in_flow_child_margin_bottom_collapsed) {
m_margin_state.reset();
}
m_y_offset_of_current_block_container = box_state.offset.y() + box_state.content_height() + box_state.border_box_bottom();
}
m_margin_state.box_last_in_flow_child_margin_bottom_collapsed = false;
m_margin_state.add_margin(box_state.margin_bottom);
m_margin_state.update_block_waiting_for_final_y_position();
compute_inset(box);
// Now that our children are formatted we place the ListItemBox with the left space we remembered.
if (is<ListItemBox>(box)) {
layout_list_item_marker(static_cast<ListItemBox const&>(box), left_space_before_children_formatted);
}
bottom_of_lowest_margin_box = max(bottom_of_lowest_margin_box, box_state.offset.y() + box_state.content_height() + box_state.margin_box_bottom());
if (independent_formatting_context)
independent_formatting_context->parent_context_did_dimension_child_root_box();
}
void BlockFormattingContext::layout_block_level_children(BlockContainer const& block_container, AvailableSpace const& available_space)
{
VERIFY(!block_container.children_are_inline());
CSSPixels bottom_of_lowest_margin_box = 0;
TemporaryChange<Optional<CSSPixels>> change { m_y_offset_of_current_block_container, CSSPixels(0) };
block_container.for_each_child_of_type<Box>([&](Box& box) {
layout_block_level_box(box, block_container, bottom_of_lowest_margin_box, available_space);
return IterationDecision::Continue;
});
m_margin_state.block_container_y_position_update_callback = {};
if (m_layout_mode == LayoutMode::IntrinsicSizing) {
auto& block_container_state = m_state.get_mutable(block_container);
if (!block_container_state.has_definite_width()) {
auto width = greatest_child_width(block_container);
auto const& computed_values = block_container.computed_values();
// NOTE: Min and max constraints are not applied to a box that is being sized as intrinsic because
// according to css-sizing-3 spec:
// The min-content size of a box in each axis is the size it would have if it was a float given an
// auto size in that axis (and no minimum or maximum size in that axis) and if its containing block
// was zero-sized in that axis.
if (block_container_state.width_constraint == SizeConstraint::None) {
if (!should_treat_max_width_as_none(block_container, available_space.width)) {
auto max_width = calculate_inner_width(block_container, available_space.width,
computed_values.max_width());
width = min(width, max_width);
}
if (!computed_values.min_width().is_auto()) {
auto min_width = calculate_inner_width(block_container, available_space.width,
computed_values.min_width());
width = max(width, min_width);
}
}
block_container_state.set_content_width(width);
block_container_state.set_content_height(bottom_of_lowest_margin_box);
}
}
}
void BlockFormattingContext::resolve_vertical_box_model_metrics(Box const& box)
{
auto& box_state = m_state.get_mutable(box);
auto const& computed_values = box.computed_values();
auto width_of_containing_block = containing_block_width_for(box);
box_state.margin_top = computed_values.margin().top().to_px(box, width_of_containing_block);
box_state.margin_bottom = computed_values.margin().bottom().to_px(box, width_of_containing_block);
box_state.border_top = computed_values.border_top().width;
box_state.border_bottom = computed_values.border_bottom().width;
box_state.padding_top = computed_values.padding().top().to_px(box, width_of_containing_block);
box_state.padding_bottom = computed_values.padding().bottom().to_px(box, width_of_containing_block);
}
CSSPixels BlockFormattingContext::BlockMarginState::current_collapsed_margin() const
{
CSSPixels smallest_margin = 0;
CSSPixels largest_margin = 0;
size_t negative_margin_count = 0;
for (auto margin : current_collapsible_margins) {
if (margin < 0)
++negative_margin_count;
largest_margin = max(largest_margin, margin);
smallest_margin = min(smallest_margin, margin);
}
CSSPixels collapsed_margin = 0;
if (negative_margin_count == current_collapsible_margins.size()) {
// When all margins are negative, the size of the collapsed margin is the smallest (most negative) margin.
collapsed_margin = smallest_margin;
} else if (negative_margin_count > 0) {
// When negative margins are involved, the size of the collapsed margin is the sum of the largest positive margin and the smallest (most negative) negative margin.
collapsed_margin = largest_margin + smallest_margin;
} else {
// Otherwise, collapse all the adjacent margins by using only the largest one.
collapsed_margin = largest_margin;
}
return collapsed_margin;
}
BlockFormattingContext::DidIntroduceClearance BlockFormattingContext::clear_floating_boxes(Node const& child_box, Optional<InlineFormattingContext&> inline_formatting_context)
{
auto const& computed_values = child_box.computed_values();
auto result = DidIntroduceClearance::No;
auto clear_floating_boxes = [&](FloatSideData& float_side) {
if (!float_side.current_boxes.is_empty()) {
// NOTE: Floating boxes are globally relevant within this BFC, *but* their offset coordinates
// are relative to their containing block.
// This means that we have to first convert to a root-space Y coordinate before clearing,
// and then convert back to a local Y coordinate when assigning the cleared offset to
// the `child_box` layout state.
// First, find the lowest margin box edge on this float side and calculate the Y offset just below it.
CSSPixels clearance_y_in_root = 0;
for (auto const& floating_box : float_side.current_boxes) {
auto floating_box_rect_in_root = margin_box_rect_in_ancestor_coordinate_space(floating_box.used_values, root());
clearance_y_in_root = max(clearance_y_in_root, floating_box_rect_in_root.bottom());
}
// Then, convert the clearance Y to a coordinate relative to the containing block of `child_box`.
CSSPixels clearance_y_in_containing_block = clearance_y_in_root;
for (auto* containing_block = child_box.containing_block(); containing_block && containing_block != &root(); containing_block = containing_block->containing_block())
clearance_y_in_containing_block -= m_state.get(*containing_block).offset.y();
if (inline_formatting_context.has_value()) {
if (clearance_y_in_containing_block > inline_formatting_context->vertical_float_clearance()) {
result = DidIntroduceClearance::Yes;
inline_formatting_context->set_vertical_float_clearance(clearance_y_in_containing_block);
}
} else if (clearance_y_in_containing_block > m_y_offset_of_current_block_container.value()) {
result = DidIntroduceClearance::Yes;
m_y_offset_of_current_block_container = clearance_y_in_containing_block;
}
float_side.clear();
}
};
if (computed_values.clear() == CSS::Clear::Left || computed_values.clear() == CSS::Clear::Both)
clear_floating_boxes(m_left_floats);
if (computed_values.clear() == CSS::Clear::Right || computed_values.clear() == CSS::Clear::Both)
clear_floating_boxes(m_right_floats);
return result;
}
void BlockFormattingContext::place_block_level_element_in_normal_flow_vertically(Box const& child_box, CSSPixels y)
{
auto& box_state = m_state.get_mutable(child_box);
y += box_state.border_box_top();
box_state.set_content_offset(CSSPixelPoint { box_state.offset.x(), y });
}
// Returns whether the given box has the given ancestor on the path to root, ignoring the anonymous blocks.
static bool box_has_ancestor_in_non_anonymous_containing_block_chain(Box const* box, Box const& ancestor, Box const& root)
{
Box const* current_ancestor = box ? box->non_anonymous_containing_block() : &root;
while (current_ancestor != &root) {
if (current_ancestor == &ancestor)
return true;
current_ancestor = current_ancestor->non_anonymous_containing_block();
}
return false;
}
void BlockFormattingContext::place_block_level_element_in_normal_flow_horizontally(Box const& child_box, AvailableSpace const& available_space)
{
auto& box_state = m_state.get_mutable(child_box);
CSSPixels x = 0;
CSSPixels available_width_within_containing_block = available_space.width.to_px_or_zero();
if ((!m_left_floats.current_boxes.is_empty() || !m_right_floats.current_boxes.is_empty())
&& creates_block_formatting_context(child_box)) {
auto box_in_root_rect = content_box_rect_in_ancestor_coordinate_space(box_state, root());
auto space_and_containing_margin = space_used_and_containing_margin_for_floats(box_in_root_rect.y());
available_width_within_containing_block -= space_and_containing_margin.left_used_space + space_and_containing_margin.right_used_space;
auto const& containing_box_state = m_state.get(*child_box.containing_block());
if (box_has_ancestor_in_non_anonymous_containing_block_chain(space_and_containing_margin.matching_left_float_box, *child_box.non_anonymous_containing_block(), root()))
x = space_and_containing_margin.left_used_space;
else
// If the floating box doesn't share a containing block with the child box, the child box margin should overlap with the width of the floating box.
x = max(space_and_containing_margin.left_used_space - containing_box_state.margin_left, 0);
}
if (child_box.containing_block()->computed_values().text_align() == CSS::TextAlign::LibwebCenter) {
x += (available_width_within_containing_block / 2) - box_state.content_width() / 2;
} else if (child_box.containing_block()->computed_values().text_align() == CSS::TextAlign::LibwebRight) {
// Subtracting the left margin here because left and right margins need to be swapped when aligning to the right
x += available_width_within_containing_block - box_state.content_width() - box_state.margin_box_left();
} else {
x += box_state.margin_box_left();
}
box_state.set_content_offset({ x, box_state.offset.y() });
}
void BlockFormattingContext::layout_viewport(AvailableSpace const& available_space)
{
// NOTE: If we are laying out a standalone SVG document, we give it some special treatment:
// The root <svg> container gets the same size as the viewport,
// and we call directly into the SVG layout code from here.
if (root().first_child() && root().first_child()->is_svg_svg_box()) {
auto const& svg_root = verify_cast<SVGSVGBox>(*root().first_child());
auto content_height = m_state.get(*svg_root.containing_block()).content_height();
m_state.get_mutable(svg_root).set_content_height(content_height);
auto svg_formatting_context = create_independent_formatting_context_if_needed(m_state, m_layout_mode, svg_root);
svg_formatting_context->run(available_space);
} else {
if (root().children_are_inline())
layout_inline_children(root(), available_space);
else
layout_block_level_children(root(), available_space);
}
}
void BlockFormattingContext::layout_floating_box(Box const& box, BlockContainer const&, AvailableSpace const& available_space, CSSPixels y, LineBuilder* line_builder)
{
VERIFY(box.is_floating());
auto& box_state = m_state.get_mutable(box);
auto const& computed_values = box.computed_values();
resolve_vertical_box_model_metrics(box);
compute_width(box, available_space);
// NOTE: Flex containers with `auto` height are treated as `max-content`, so we can compute their height early.
if (box.is_replaced_box() || box.display().is_flex_inside())
compute_height(box, available_space);
auto independent_formatting_context = layout_inside(box, m_layout_mode, box_state.available_inner_space_or_constraints_from(available_space));
compute_height(box, available_space);
// First we place the box normally (to get the right y coordinate.)
// If we have a LineBuilder, we're in the middle of inline layout, otherwise this is block layout.
if (line_builder) {
auto y = max(line_builder->y_for_float_to_be_inserted_here(box), line_builder->inline_formatting_context().vertical_float_clearance());
box_state.set_content_y(y + box_state.margin_box_top());
} else {
place_block_level_element_in_normal_flow_vertically(box, y + box_state.margin_top);
place_block_level_element_in_normal_flow_horizontally(box, available_space);
}
// Then we float it to the left or right.
auto float_box = [&](FloatSide side, FloatSideData& side_data, FloatSideData& other_side_data) {
CSSPixels offset_from_edge = 0;
auto float_to_edge = [&] {
if (side == FloatSide::Left)
offset_from_edge = box_state.margin_box_left();
else
offset_from_edge = box_state.content_width() + box_state.margin_box_right();
};
auto box_in_root_rect = content_box_rect_in_ancestor_coordinate_space(box_state, root());
CSSPixels y_in_root = box_in_root_rect.y();
CSSPixels y = box_state.offset.y();
if (side_data.current_boxes.is_empty()) {
// This is the first floating box on this side. Go all the way to the edge.
float_to_edge();
side_data.y_offset = 0;
} else {
// NOTE: If we're in inline layout, the LineBuilder has already provided the right Y offset.
// In block layout, we adjust by the side's current Y offset here.
if (!line_builder)
y_in_root += side_data.y_offset;
bool did_touch_preceding_float = false;
bool did_place_next_to_preceding_float = false;
// Walk all currently tracked floats on the side we're floating towards.
// We're looking for the innermost preceding float that intersects vertically with `box`.
for (auto& preceding_float : side_data.current_boxes.in_reverse()) {
auto const preceding_float_rect = margin_box_rect_in_ancestor_coordinate_space(preceding_float.used_values, root());
if (!preceding_float_rect.contains_vertically(y_in_root))
continue;
// We found a preceding float that intersects vertically with the current float.
// Now we need to find out if there's enough inline-axis space to stack them next to each other.
CSSPixels tentative_offset_from_edge = 0;
bool fits_next_to_preceding_float = false;
if (side == FloatSide::Left) {
tentative_offset_from_edge = max(preceding_float.offset_from_edge + preceding_float.used_values.content_width() + preceding_float.used_values.margin_box_right(), 0) + box_state.margin_box_left();
if (available_space.width.is_definite()) {
fits_next_to_preceding_float = (tentative_offset_from_edge + box_state.content_width() + box_state.margin_box_right()) <= available_space.width.to_px_or_zero();
} else if (available_space.width.is_max_content() || available_space.width.is_indefinite()) {
fits_next_to_preceding_float = true;
}
} else {
tentative_offset_from_edge = preceding_float.offset_from_edge + preceding_float.used_values.margin_box_left() + box_state.margin_box_right() + box_state.content_width();
fits_next_to_preceding_float = tentative_offset_from_edge >= 0;
}
did_touch_preceding_float = true;
if (!fits_next_to_preceding_float)
break;
offset_from_edge = tentative_offset_from_edge;
did_place_next_to_preceding_float = true;
break;
}
auto has_clearance = false;
if (side == FloatSide::Left) {
has_clearance = computed_values.clear() == CSS::Clear::Left || computed_values.clear() == CSS::Clear::Both;
} else if (side == FloatSide::Right) {
has_clearance = computed_values.clear() == CSS::Clear::Right || computed_values.clear() == CSS::Clear::Both;
}
if (!did_touch_preceding_float || !did_place_next_to_preceding_float || has_clearance) {
// One of three things happened:
// - This box does not touch another floating box.
// - We ran out of horizontal space on this "float line", and need to break.
// - This box has clearance.
// Either way, we float this box all the way to the edge.
float_to_edge();
CSSPixels lowest_margin_edge = 0;
for (auto const& current : side_data.current_boxes) {
lowest_margin_edge = max(lowest_margin_edge, current.used_values.margin_box_height());
}
side_data.y_offset += lowest_margin_edge;
// Also, forget all previous boxes floated to this side while since they're no longer relevant.
side_data.clear();
}
}
// NOTE: If we're in inline layout, the LineBuilder has already provided the right Y offset.
// In block layout, we adjust by the side's current Y offset here.
// FIXME: It's annoying that we have different behavior for inline vs block here.
// Find a way to unify the behavior so we don't need to branch here.
if (!line_builder)
y += side_data.y_offset;
auto top_margin_edge = y - box_state.margin_box_top();
side_data.all_boxes.append(adopt_own(*new FloatingBox {
.box = box,
.used_values = box_state,
.offset_from_edge = offset_from_edge,
.top_margin_edge = top_margin_edge,
.bottom_margin_edge = y + box_state.content_height() + box_state.margin_box_bottom(),
}));
side_data.current_boxes.append(*side_data.all_boxes.last());
if (side == FloatSide::Left) {
side_data.current_width = offset_from_edge + box_state.content_width() + box_state.margin_box_right();
} else {
side_data.current_width = offset_from_edge + box_state.margin_box_left();
}
side_data.max_width = max(side_data.current_width, side_data.max_width);
// NOTE: We don't set the X position here, that happens later, once we know the root block width.
// See parent_context_did_dimension_child_root_box() for that logic.
box_state.set_content_y(y);
// If the new box was inserted below the bottom of the opposite side,
// we reset the other side back to its edge.
if (top_margin_edge > other_side_data.y_offset)
other_side_data.clear();
};
// Next, float to the left and/or right
if (box.computed_values().float_() == CSS::Float::Left) {
float_box(FloatSide::Left, m_left_floats, m_right_floats);
} else if (box.computed_values().float_() == CSS::Float::Right) {
float_box(FloatSide::Right, m_right_floats, m_left_floats);
}
m_state.get_mutable(root()).add_floating_descendant(box);
if (line_builder)
line_builder->recalculate_available_space();
compute_inset(box);
if (independent_formatting_context)
independent_formatting_context->parent_context_did_dimension_child_root_box();
}
void BlockFormattingContext::ensure_sizes_correct_for_left_offset_calculation(ListItemBox const& list_item_box)
{
if (!list_item_box.marker())
return;
auto& marker = *list_item_box.marker();
auto& marker_state = m_state.get_mutable(marker);
CSSPixels image_width = 0;
CSSPixels image_height = 0;
if (auto const* list_style_image = marker.list_style_image()) {
image_width = list_style_image->natural_width().value_or(0);
image_height = list_style_image->natural_height().value_or(0);
}
auto default_marker_width = max(4, marker.first_available_font().pixel_size_rounded_up() - 4);
auto marker_text = marker.text().value_or("");
if (marker_text.is_empty()) {
marker_state.set_content_width(image_width + default_marker_width);
} else {
auto text_width = marker.first_available_font().width(marker_text);
marker_state.set_content_width(image_width + CSSPixels::nearest_value_for(text_width));
}
marker_state.set_content_height(max(image_height, marker.first_available_font().pixel_size_rounded_up() + 1));
}
void BlockFormattingContext::layout_list_item_marker(ListItemBox const& list_item_box, CSSPixels const& left_space_before_list_item_elements_formatted)
{
if (!list_item_box.marker())
return;
auto& marker = *list_item_box.marker();
auto& marker_state = m_state.get_mutable(marker);
auto& list_item_state = m_state.get_mutable(list_item_box);
auto default_marker_width = max(4, marker.first_available_font().pixel_size_rounded_up() - 4);
auto final_marker_width = marker_state.content_width() + default_marker_width;
if (marker.list_style_position() == CSS::ListStylePosition::Inside) {
list_item_state.set_content_offset({ final_marker_width, list_item_state.offset.y() });
list_item_state.set_content_width(list_item_state.content_width() - final_marker_width);
}
auto offset_y = max(CSSPixels(0), (marker.computed_values().line_height() - marker_state.content_height()) / 2);
marker_state.set_content_offset({ left_space_before_list_item_elements_formatted - final_marker_width, offset_y });
if (marker_state.content_height() > list_item_state.content_height())
list_item_state.set_content_height(marker_state.content_height());
}
BlockFormattingContext::SpaceUsedAndContainingMarginForFloats BlockFormattingContext::space_used_and_containing_margin_for_floats(CSSPixels y) const
{
SpaceUsedAndContainingMarginForFloats space_and_containing_margin;
for (auto const& floating_box_ptr : m_left_floats.all_boxes.in_reverse()) {
auto const& floating_box = *floating_box_ptr;
// NOTE: The floating box is *not* in the final horizontal position yet, but the size and vertical position is valid.
auto rect = margin_box_rect_in_ancestor_coordinate_space(floating_box.used_values, root());
if (rect.contains_vertically(y)) {
CSSPixels offset_from_containing_block_chain_margins_between_here_and_root = 0;
for (auto const* containing_block = floating_box.used_values.containing_block_used_values(); containing_block && &containing_block->node() != &root(); containing_block = containing_block->containing_block_used_values()) {
offset_from_containing_block_chain_margins_between_here_and_root += containing_block->margin_box_left();
}
space_and_containing_margin.left_used_space = floating_box.offset_from_edge
+ floating_box.used_values.content_width()
+ floating_box.used_values.margin_box_right();
space_and_containing_margin.left_total_containing_margin = offset_from_containing_block_chain_margins_between_here_and_root;
space_and_containing_margin.matching_left_float_box = floating_box.box;
break;
}
}
for (auto const& floating_box_ptr : m_right_floats.all_boxes.in_reverse()) {
auto const& floating_box = *floating_box_ptr;
// NOTE: The floating box is *not* in the final horizontal position yet, but the size and vertical position is valid.
auto rect = margin_box_rect_in_ancestor_coordinate_space(floating_box.used_values, root());
if (rect.contains_vertically(y)) {
CSSPixels offset_from_containing_block_chain_margins_between_here_and_root = 0;
for (auto const* containing_block = floating_box.used_values.containing_block_used_values(); containing_block && &containing_block->node() != &root(); containing_block = containing_block->containing_block_used_values()) {
offset_from_containing_block_chain_margins_between_here_and_root += containing_block->margin_box_right();
}
space_and_containing_margin.right_used_space = floating_box.offset_from_edge
+ floating_box.used_values.margin_box_left();
space_and_containing_margin.right_total_containing_margin = offset_from_containing_block_chain_margins_between_here_and_root;
break;
}
}
return space_and_containing_margin;
}
FormattingContext::SpaceUsedByFloats BlockFormattingContext::intrusion_by_floats_into_box(Box const& box, CSSPixels y_in_box) const
{
return intrusion_by_floats_into_box(m_state.get(box), y_in_box);
}
FormattingContext::SpaceUsedByFloats BlockFormattingContext::intrusion_by_floats_into_box(LayoutState::UsedValues const& box_used_values, CSSPixels y_in_box) const
{
// NOTE: Floats are relative to the BFC root box, not necessarily the containing block of this IFC.
auto box_in_root_rect = content_box_rect_in_ancestor_coordinate_space(box_used_values, root());
CSSPixels y_in_root = box_in_root_rect.y() + y_in_box;
auto space_and_containing_margin = space_used_and_containing_margin_for_floats(y_in_root);
auto left_side_floats_limit_to_right = space_and_containing_margin.left_total_containing_margin + space_and_containing_margin.left_used_space;
auto right_side_floats_limit_to_right = space_and_containing_margin.right_used_space + space_and_containing_margin.right_total_containing_margin;
auto left_intrusion = max(CSSPixels(0), left_side_floats_limit_to_right - max(CSSPixels(0), box_in_root_rect.x()));
CSSPixels offset_from_containing_block_chain_margins_between_here_and_root = 0;
for (auto const* containing_block = &box_used_values; containing_block && &containing_block->node() != &root(); containing_block = containing_block->containing_block_used_values()) {
offset_from_containing_block_chain_margins_between_here_and_root = max(offset_from_containing_block_chain_margins_between_here_and_root, containing_block->margin_box_right());
}
auto right_intrusion = max(CSSPixels(0), right_side_floats_limit_to_right - offset_from_containing_block_chain_margins_between_here_and_root);
return { left_intrusion, right_intrusion };
}
CSSPixels BlockFormattingContext::greatest_child_width(Box const& box) const
{
// Similar to FormattingContext::greatest_child_width()
// but this one takes floats into account!
CSSPixels max_width = m_left_floats.max_width + m_right_floats.max_width;
if (box.children_are_inline()) {
for (auto const& line_box : m_state.get(verify_cast<BlockContainer>(box)).line_boxes) {
CSSPixels width_here = line_box.width();
CSSPixels extra_width_from_left_floats = 0;
for (auto& left_float : m_left_floats.all_boxes) {
// NOTE: Floats directly affect the automatic size of their containing block, but only indirectly anything above in the tree.
if (left_float->box->containing_block() != &box)
continue;
if (line_box.baseline() >= left_float->top_margin_edge || line_box.baseline() <= left_float->bottom_margin_edge) {
extra_width_from_left_floats = max(extra_width_from_left_floats, left_float->offset_from_edge + left_float->used_values.content_width() + left_float->used_values.margin_box_right());
}
}
CSSPixels extra_width_from_right_floats = 0;
for (auto& right_float : m_right_floats.all_boxes) {
// NOTE: Floats directly affect the automatic size of their containing block, but only indirectly anything above in the tree.
if (right_float->box->containing_block() != &box)
continue;
if (line_box.baseline() >= right_float->top_margin_edge || line_box.baseline() <= right_float->bottom_margin_edge) {
extra_width_from_right_floats = max(extra_width_from_right_floats, right_float->offset_from_edge + right_float->used_values.margin_box_left());
}
}
width_here += extra_width_from_left_floats + extra_width_from_right_floats;
max_width = max(max_width, width_here);
}
} else {
box.for_each_child_of_type<Box>([&](Box const& child) {
if (!child.is_absolutely_positioned())
max_width = max(max_width, m_state.get(child).margin_box_width());
return IterationDecision::Continue;
});
}
return max_width;
}
}