938 lines
38 KiB
C++
938 lines
38 KiB
C++
/*
|
||
* Copyright (c) 2021, Andreas Kling <kling@serenityos.org>
|
||
* Copyright (c) 2021, Tobias Christiansen <tobyase@serenityos.org>
|
||
*
|
||
* SPDX-License-Identifier: BSD-2-Clause
|
||
*/
|
||
|
||
#include "InlineFormattingContext.h"
|
||
#include <AK/Function.h>
|
||
#include <AK/StdLibExtras.h>
|
||
#include <LibWeb/Layout/BlockContainer.h>
|
||
#include <LibWeb/Layout/BlockFormattingContext.h>
|
||
#include <LibWeb/Layout/Box.h>
|
||
#include <LibWeb/Layout/FlexFormattingContext.h>
|
||
#include <LibWeb/Layout/InitialContainingBlock.h>
|
||
#include <LibWeb/Layout/TextNode.h>
|
||
|
||
namespace Web::Layout {
|
||
|
||
static float get_pixel_size(Box const& box, CSS::Length const& length)
|
||
{
|
||
return length.resolved(CSS::Length::make_px(0), box, box.containing_block()->width()).to_px(box);
|
||
}
|
||
|
||
FlexFormattingContext::FlexFormattingContext(Box& flex_container, FormattingContext* parent)
|
||
: FormattingContext(flex_container, parent)
|
||
, m_flex_direction(flex_container.computed_values().flex_direction())
|
||
{
|
||
}
|
||
|
||
FlexFormattingContext::~FlexFormattingContext()
|
||
{
|
||
}
|
||
|
||
struct DirectionAgnosticMargins {
|
||
float main_before { 0 };
|
||
float main_after { 0 };
|
||
float cross_before { 0 };
|
||
float cross_after { 0 };
|
||
};
|
||
|
||
struct FlexItem {
|
||
Box& box;
|
||
float flex_base_size { 0 };
|
||
float hypothetical_main_size { 0 };
|
||
float hypothetical_cross_size { 0 };
|
||
float hypothetical_cross_size_with_margins() { return hypothetical_cross_size + margins.cross_before + margins.cross_after; }
|
||
float target_main_size { 0 };
|
||
bool frozen { false };
|
||
Optional<float> flex_factor {};
|
||
float scaled_flex_shrink_factor { 0 };
|
||
float max_content_flex_fraction { 0 };
|
||
float main_size { 0 };
|
||
float cross_size { 0 };
|
||
float main_offset { 0 };
|
||
float cross_offset { 0 };
|
||
DirectionAgnosticMargins margins {};
|
||
bool is_min_violation { false };
|
||
bool is_max_violation { false };
|
||
};
|
||
|
||
struct FlexLine {
|
||
Vector<FlexItem*> items;
|
||
float cross_size { 0 };
|
||
};
|
||
|
||
void FlexFormattingContext::run(Box& flex_container, LayoutMode)
|
||
{
|
||
// This implements https://www.w3.org/TR/css-flexbox-1/#layout-algorithm
|
||
|
||
// FIXME: Implement reverse and ordering.
|
||
|
||
bool is_row = is_row_layout();
|
||
|
||
auto calculate_hypothetical_cross_size = [&is_row, this](Box& box) {
|
||
bool cross_constrained = false;
|
||
if (is_row) {
|
||
if (!box.computed_values().height().is_undefined_or_auto() || !box.computed_values().min_height().is_undefined_or_auto()) {
|
||
cross_constrained = true;
|
||
}
|
||
} else {
|
||
if (!box.computed_values().width().is_undefined_or_auto() || !box.computed_values().min_width().is_undefined_or_auto()) {
|
||
cross_constrained = true;
|
||
}
|
||
}
|
||
|
||
if (!cross_constrained && box.children_are_inline()) {
|
||
auto& block_container = verify_cast<BlockContainer>(box);
|
||
BlockFormattingContext bfc(block_container, this);
|
||
bfc.run(box, LayoutMode::Default);
|
||
InlineFormattingContext ifc(block_container, &bfc);
|
||
ifc.run(box, LayoutMode::OnlyRequiredLineBreaks);
|
||
|
||
if (is_row)
|
||
return box.height();
|
||
return box.width();
|
||
}
|
||
if (is_row) {
|
||
return BlockFormattingContext::compute_theoretical_height(box);
|
||
} else {
|
||
BlockFormattingContext context(verify_cast<BlockContainer>(box), this);
|
||
context.compute_width(box);
|
||
return box.width();
|
||
}
|
||
};
|
||
|
||
Vector<FlexItem> flex_items;
|
||
|
||
// 1. Generate anonymous flex items
|
||
generate_anonymous_flex_items(flex_container, flex_items);
|
||
|
||
// 2. Determine the available main and cross space for the flex items
|
||
float main_max_size = NumericLimits<float>::max();
|
||
float main_min_size = 0;
|
||
float cross_max_size = NumericLimits<float>::max();
|
||
float cross_min_size = 0;
|
||
bool main_is_constrained = false;
|
||
bool cross_is_constrained = false;
|
||
bool main_size_is_infinite = false;
|
||
auto available_space = determine_available_main_and_cross_space(flex_container, main_size_is_infinite, main_is_constrained, cross_is_constrained, main_min_size, main_max_size, cross_min_size, cross_max_size);
|
||
auto main_available_size = available_space.main;
|
||
[[maybe_unused]] auto cross_available_size = available_space.cross;
|
||
|
||
// 3. Determine the flex base size and hypothetical main size of each item
|
||
for (auto& flex_item : flex_items) {
|
||
determine_flex_base_size_and_hypothetical_main_size(flex_container, flex_item);
|
||
}
|
||
|
||
// 4. Determine the main size of the flex container
|
||
determine_main_size_of_flex_container(flex_container, flex_items, main_is_constrained, main_size_is_infinite, main_available_size, main_min_size, main_max_size);
|
||
|
||
// 5. Collect flex items into flex lines:
|
||
// After this step no additional items are to be added to flex_lines or any of its items!
|
||
auto flex_lines = collect_flex_items_into_flex_lines(flex_container, flex_items, main_available_size);
|
||
|
||
// 6. Resolve the flexible lengths
|
||
resolve_flexible_lengths(flex_lines, main_available_size);
|
||
|
||
// Cross Size Determination
|
||
// 7. Determine the hypothetical cross size of each item
|
||
for (auto& flex_item : flex_items) {
|
||
flex_item.hypothetical_cross_size = calculate_hypothetical_cross_size(flex_item.box);
|
||
}
|
||
|
||
// 8. Calculate the cross size of each flex line.
|
||
if (flex_lines.size() == 1 && has_definite_cross_size(flex_container)) {
|
||
flex_lines[0].cross_size = specified_cross_size(flex_container);
|
||
} else {
|
||
for (auto& flex_line : flex_lines) {
|
||
// FIXME: Implement 8.1
|
||
|
||
// FIXME: This isn't spec but makes sense here
|
||
if (has_definite_cross_size(flex_container) && flex_container.computed_values().align_items() == CSS::AlignItems::Stretch) {
|
||
flex_line.cross_size = specified_cross_size(flex_container) / flex_lines.size();
|
||
continue;
|
||
}
|
||
|
||
// 8.2
|
||
float largest_hypothetical_cross_size = 0;
|
||
for (auto& flex_item : flex_line.items) {
|
||
if (largest_hypothetical_cross_size < flex_item->hypothetical_cross_size_with_margins())
|
||
largest_hypothetical_cross_size = flex_item->hypothetical_cross_size_with_margins();
|
||
}
|
||
|
||
// 8.3
|
||
flex_line.cross_size = max(0.0f, largest_hypothetical_cross_size);
|
||
}
|
||
|
||
if (flex_lines.size() == 1) {
|
||
clamp(flex_lines[0].cross_size, cross_min_size, cross_max_size);
|
||
}
|
||
}
|
||
|
||
// 9. Handle 'align-content: stretch'.
|
||
// FIXME: This
|
||
|
||
// 10. Collapse visibility:collapse items.
|
||
// FIXME: This
|
||
|
||
// 11. Determine the used cross size of each flex item.
|
||
// FIXME: Get the alignment via "align-self" of the item (which accesses "align-items" of the parent if unset)
|
||
for (auto& flex_line : flex_lines) {
|
||
for (auto& flex_item : flex_line.items) {
|
||
if (is_cross_auto(flex_item->box) && flex_container.computed_values().align_items() == CSS::AlignItems::Stretch) {
|
||
flex_item->cross_size = flex_line.cross_size;
|
||
} else {
|
||
flex_item->cross_size = flex_item->hypothetical_cross_size;
|
||
}
|
||
}
|
||
}
|
||
|
||
// 12. Distribute any remaining free space.
|
||
for (auto& flex_line : flex_lines) {
|
||
// 12.1.
|
||
float used_main_space = 0;
|
||
size_t auto_margins = 0;
|
||
for (auto& flex_item : flex_line.items) {
|
||
used_main_space += flex_item->main_size;
|
||
if (is_main_axis_margin_first_auto(flex_item->box))
|
||
++auto_margins;
|
||
if (is_main_axis_margin_second_auto(flex_item->box))
|
||
++auto_margins;
|
||
}
|
||
float remaining_free_space = main_available_size - used_main_space;
|
||
if (remaining_free_space > 0) {
|
||
float size_per_auto_margin = remaining_free_space / (float)auto_margins;
|
||
for (auto& flex_item : flex_line.items) {
|
||
if (is_main_axis_margin_first_auto(flex_item->box))
|
||
set_main_axis_first_margin(flex_item->box, size_per_auto_margin);
|
||
if (is_main_axis_margin_second_auto(flex_item->box))
|
||
set_main_axis_second_margin(flex_item->box, size_per_auto_margin);
|
||
}
|
||
} else {
|
||
for (auto& flex_item : flex_line.items) {
|
||
if (is_main_axis_margin_first_auto(flex_item->box))
|
||
set_main_axis_first_margin(flex_item->box, 0);
|
||
if (is_main_axis_margin_second_auto(flex_item->box))
|
||
set_main_axis_second_margin(flex_item->box, 0);
|
||
}
|
||
}
|
||
|
||
// 12.2.
|
||
float space_between_items = 0;
|
||
float space_before_first_item = 0;
|
||
auto number_of_items = flex_line.items.size();
|
||
|
||
switch (flex_container.computed_values().justify_content()) {
|
||
case CSS::JustifyContent::FlexStart:
|
||
break;
|
||
case CSS::JustifyContent::FlexEnd:
|
||
space_before_first_item = main_available_size - used_main_space;
|
||
break;
|
||
case CSS::JustifyContent::Center:
|
||
space_before_first_item = (main_available_size - used_main_space) / 2.0f;
|
||
break;
|
||
case CSS::JustifyContent::SpaceBetween:
|
||
space_between_items = remaining_free_space / (number_of_items - 1);
|
||
break;
|
||
case CSS::JustifyContent::SpaceAround:
|
||
space_between_items = remaining_free_space / number_of_items;
|
||
space_before_first_item = space_between_items / 2.0f;
|
||
break;
|
||
}
|
||
|
||
// FIXME: Support reverse
|
||
float main_offset = space_before_first_item;
|
||
for (auto& flex_item : flex_line.items) {
|
||
flex_item->main_offset = main_offset;
|
||
main_offset += flex_item->main_size + space_between_items;
|
||
}
|
||
}
|
||
|
||
// 13. Resolve cross-axis auto margins.
|
||
// FIXME: This
|
||
|
||
// 14. Align all flex items along the cross-axis
|
||
// FIXME: Get the alignment via "align-self" of the item (which accesses "align-items" of the parent if unset)
|
||
// FIXME: Take better care of margins
|
||
float line_cross_offset = 0;
|
||
for (auto& flex_line : flex_lines) {
|
||
for (auto* flex_item : flex_line.items) {
|
||
switch (flex_container.computed_values().align_items()) {
|
||
case CSS::AlignItems::Baseline:
|
||
// FIXME: Implement this
|
||
// Fallthrough
|
||
case CSS::AlignItems::FlexStart:
|
||
case CSS::AlignItems::Stretch:
|
||
flex_item->cross_offset = line_cross_offset + flex_item->margins.cross_before;
|
||
break;
|
||
case CSS::AlignItems::FlexEnd:
|
||
flex_item->cross_offset = line_cross_offset + flex_line.cross_size - flex_item->cross_size;
|
||
break;
|
||
case CSS::AlignItems::Center:
|
||
flex_item->cross_offset = line_cross_offset + (flex_line.cross_size / 2.0f) - (flex_item->cross_size / 2.0f);
|
||
break;
|
||
default:
|
||
break;
|
||
}
|
||
}
|
||
|
||
line_cross_offset += flex_line.cross_size;
|
||
}
|
||
|
||
// 15. Determine the flex container’s used cross size:
|
||
if (has_definite_cross_size(flex_container)) {
|
||
float clamped_cross_size = clamp(specified_cross_size(flex_container), cross_min_size, cross_max_size);
|
||
set_cross_size(flex_container, clamped_cross_size);
|
||
} else {
|
||
float sum_of_flex_lines_cross_sizes = 0;
|
||
for (auto& flex_line : flex_lines) {
|
||
sum_of_flex_lines_cross_sizes += flex_line.cross_size;
|
||
}
|
||
float clamped_cross_size = clamp(sum_of_flex_lines_cross_sizes, cross_min_size, cross_max_size);
|
||
set_cross_size(flex_container, clamped_cross_size);
|
||
}
|
||
|
||
// 16. Align all flex lines
|
||
// FIXME: Support align-content
|
||
// FIXME: Support reverse
|
||
for (auto& flex_line : flex_lines) {
|
||
for (auto* flex_item : flex_line.items) {
|
||
set_main_size(flex_item->box, flex_item->main_size);
|
||
set_cross_size(flex_item->box, flex_item->cross_size);
|
||
set_offset(flex_item->box, flex_item->main_offset, flex_item->cross_offset);
|
||
}
|
||
}
|
||
}
|
||
|
||
static void populate_specified_margins(FlexItem& item, CSS::FlexDirection flex_direction)
|
||
{
|
||
auto width_of_containing_block = item.box.width_of_logical_containing_block();
|
||
// FIXME: This should also take reverse-ness into account
|
||
if (flex_direction == CSS::FlexDirection::Row || flex_direction == CSS::FlexDirection::RowReverse) {
|
||
item.margins.main_before = item.box.computed_values().margin().left.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
|
||
item.margins.main_after = item.box.computed_values().margin().right.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
|
||
item.margins.cross_before = item.box.computed_values().margin().top.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
|
||
item.margins.cross_after = item.box.computed_values().margin().bottom.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
|
||
} else {
|
||
item.margins.main_before = item.box.computed_values().margin().top.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
|
||
item.margins.main_after = item.box.computed_values().margin().bottom.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
|
||
item.margins.cross_before = item.box.computed_values().margin().left.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
|
||
item.margins.cross_after = item.box.computed_values().margin().right.resolved_or_zero(item.box, width_of_containing_block).to_px(item.box);
|
||
}
|
||
};
|
||
|
||
// https://www.w3.org/TR/css-flexbox-1/#flex-items
|
||
void FlexFormattingContext::generate_anonymous_flex_items(Box& flex_container, Vector<FlexItem>& flex_items)
|
||
{
|
||
// More like, sift through the already generated items.
|
||
// After this step no items are to be added or removed from flex_items!
|
||
// It holds every item we need to consider and there should be nothing in the following
|
||
// calculations that could change that.
|
||
// This is particularly important since we take references to the items stored in flex_items
|
||
// later, whose addresses won't be stable if we added or removed any items.
|
||
if (!flex_container.has_definite_width()) {
|
||
flex_container.set_width(flex_container.containing_block()->width());
|
||
} else {
|
||
flex_container.set_width(flex_container.computed_values().width().resolved_or_zero(flex_container, flex_container.containing_block()->width()).to_px(flex_container));
|
||
}
|
||
|
||
if (!flex_container.has_definite_height()) {
|
||
flex_container.set_height(flex_container.containing_block()->height());
|
||
} else {
|
||
flex_container.set_height(flex_container.computed_values().height().resolved_or_zero(flex_container, flex_container.containing_block()->height()).to_px(flex_container));
|
||
}
|
||
|
||
flex_container.for_each_child_of_type<Box>([&](Box& child_box) {
|
||
layout_inside(child_box, LayoutMode::Default);
|
||
// Skip anonymous text runs that are only whitespace.
|
||
if (child_box.is_anonymous() && !child_box.first_child_of_type<BlockContainer>()) {
|
||
bool contains_only_white_space = true;
|
||
child_box.for_each_in_inclusive_subtree_of_type<TextNode>([&contains_only_white_space](auto& text_node) {
|
||
if (!text_node.text_for_rendering().is_whitespace()) {
|
||
contains_only_white_space = false;
|
||
return IterationDecision::Break;
|
||
}
|
||
return IterationDecision::Continue;
|
||
});
|
||
if (contains_only_white_space)
|
||
return IterationDecision::Continue;
|
||
}
|
||
|
||
// Skip any "out-of-flow" children
|
||
if (child_box.is_out_of_flow(*this))
|
||
return IterationDecision::Continue;
|
||
|
||
child_box.set_flex_item(true);
|
||
FlexItem flex_item = { child_box };
|
||
populate_specified_margins(flex_item, m_flex_direction);
|
||
flex_items.append(move(flex_item));
|
||
return IterationDecision::Continue;
|
||
});
|
||
}
|
||
|
||
bool FlexFormattingContext::has_definite_main_size(Box const& box) const
|
||
{
|
||
return is_row_layout() ? box.has_definite_width() : box.has_definite_height();
|
||
}
|
||
|
||
float FlexFormattingContext::specified_main_size(Box const& box) const
|
||
{
|
||
return is_row_layout() ? box.width() : box.height();
|
||
}
|
||
|
||
float FlexFormattingContext::specified_cross_size(Box const& box) const
|
||
{
|
||
return is_row_layout() ? box.height() : box.width();
|
||
}
|
||
|
||
bool FlexFormattingContext::has_main_min_size(Box const& box) const
|
||
{
|
||
auto value = is_row_layout() ? box.computed_values().min_width() : box.computed_values().min_height();
|
||
return !value.is_undefined_or_auto();
|
||
}
|
||
|
||
bool FlexFormattingContext::has_cross_min_size(Box const& box) const
|
||
{
|
||
auto value = is_row_layout() ? box.computed_values().min_height() : box.computed_values().min_width();
|
||
return !value.is_undefined_or_auto();
|
||
}
|
||
|
||
bool FlexFormattingContext::has_definite_cross_size(Box const& box) const
|
||
{
|
||
return (is_row_layout() ? box.has_definite_height() : box.has_definite_width()) && cross_size_is_absolute_or_resolved_nicely(box);
|
||
}
|
||
|
||
bool FlexFormattingContext::cross_size_is_absolute_or_resolved_nicely(NodeWithStyle const& box) const
|
||
{
|
||
auto length = is_row_layout() ? box.computed_values().height() : box.computed_values().width();
|
||
|
||
if (length.is_absolute() || length.is_relative())
|
||
return true;
|
||
if (length.is_undefined_or_auto())
|
||
return false;
|
||
|
||
if (!box.parent())
|
||
return false;
|
||
if (length.is_percentage() && cross_size_is_absolute_or_resolved_nicely(*box.parent()))
|
||
return true;
|
||
return false;
|
||
}
|
||
|
||
float FlexFormattingContext::specified_main_size_of_child_box(Box const& flex_container, Box const& child_box) const
|
||
{
|
||
auto main_size_of_parent = specified_main_size(flex_container);
|
||
auto value = is_row_layout() ? child_box.computed_values().width() : child_box.computed_values().height();
|
||
return value.resolved_or_zero(child_box, main_size_of_parent).to_px(child_box);
|
||
}
|
||
|
||
float FlexFormattingContext::specified_main_min_size(Box const& box) const
|
||
{
|
||
return is_row_layout()
|
||
? get_pixel_size(box, box.computed_values().min_width())
|
||
: get_pixel_size(box, box.computed_values().min_height());
|
||
}
|
||
|
||
float FlexFormattingContext::specified_cross_min_size(Box const& box) const
|
||
{
|
||
return is_row_layout()
|
||
? get_pixel_size(box, box.computed_values().min_height())
|
||
: get_pixel_size(box, box.computed_values().min_width());
|
||
}
|
||
|
||
bool FlexFormattingContext::has_main_max_size(Box const& box) const
|
||
{
|
||
return is_row_layout()
|
||
? !box.computed_values().max_width().is_undefined_or_auto()
|
||
: !box.computed_values().max_height().is_undefined_or_auto();
|
||
}
|
||
|
||
bool FlexFormattingContext::has_cross_max_size(Box const& box) const
|
||
{
|
||
return is_row_layout()
|
||
? !box.computed_values().max_height().is_undefined_or_auto()
|
||
: !box.computed_values().max_width().is_undefined_or_auto();
|
||
}
|
||
|
||
float FlexFormattingContext::specified_main_max_size(Box const& box) const
|
||
{
|
||
return is_row_layout()
|
||
? get_pixel_size(box, box.computed_values().max_width())
|
||
: get_pixel_size(box, box.computed_values().max_height());
|
||
}
|
||
|
||
float FlexFormattingContext::specified_cross_max_size(Box const& box) const
|
||
{
|
||
return is_row_layout()
|
||
? get_pixel_size(box, box.computed_values().max_height())
|
||
: get_pixel_size(box, box.computed_values().max_width());
|
||
}
|
||
|
||
float FlexFormattingContext::calculated_main_size(Box const& box) const
|
||
{
|
||
return is_row_layout() ? box.width() : box.height();
|
||
}
|
||
|
||
bool FlexFormattingContext::is_cross_auto(Box const& box) const
|
||
{
|
||
return is_row_layout() ? box.computed_values().height().is_auto() : box.computed_values().width().is_auto();
|
||
}
|
||
|
||
bool FlexFormattingContext::is_main_axis_margin_first_auto(Box const& box) const
|
||
{
|
||
return is_row_layout() ? box.computed_values().margin().left.is_auto() : box.computed_values().margin().top.is_auto();
|
||
}
|
||
|
||
bool FlexFormattingContext::is_main_axis_margin_second_auto(Box const& box) const
|
||
{
|
||
return is_row_layout() ? box.computed_values().margin().right.is_auto() : box.computed_values().margin().bottom.is_auto();
|
||
}
|
||
|
||
void FlexFormattingContext::set_main_size(Box& box, float size)
|
||
{
|
||
if (is_row_layout())
|
||
box.set_width(size);
|
||
else
|
||
box.set_height(size);
|
||
}
|
||
|
||
void FlexFormattingContext::set_cross_size(Box& box, float size)
|
||
{
|
||
if (is_row_layout())
|
||
box.set_height(size);
|
||
else
|
||
box.set_width(size);
|
||
}
|
||
|
||
void FlexFormattingContext::set_offset(Box& box, float main_offset, float cross_offset)
|
||
{
|
||
if (is_row_layout())
|
||
box.set_offset(main_offset, cross_offset);
|
||
else
|
||
box.set_offset(cross_offset, main_offset);
|
||
}
|
||
|
||
void FlexFormattingContext::set_main_axis_first_margin(Box& box, float margin)
|
||
{
|
||
if (is_row_layout())
|
||
box.box_model().margin.left = margin;
|
||
else
|
||
box.box_model().margin.top = margin;
|
||
}
|
||
|
||
void FlexFormattingContext::set_main_axis_second_margin(Box& box, float margin)
|
||
{
|
||
if (is_row_layout())
|
||
box.box_model().margin.right = margin;
|
||
else
|
||
box.box_model().margin.bottom = margin;
|
||
}
|
||
|
||
float FlexFormattingContext::sum_of_margin_padding_border_in_main_axis(Box const& box) const
|
||
{
|
||
auto& margin = box.box_model().margin;
|
||
auto& padding = box.box_model().padding;
|
||
auto& border = box.box_model().border;
|
||
|
||
if (is_row_layout()) {
|
||
return margin.left + margin.right
|
||
+ padding.left + padding.right
|
||
+ border.left + border.right;
|
||
} else {
|
||
return margin.top + margin.bottom
|
||
+ padding.top + padding.bottom
|
||
+ border.top + border.bottom;
|
||
}
|
||
}
|
||
|
||
// https://www.w3.org/TR/css-flexbox-1/#algo-available
|
||
FlexFormattingContext::AvailableSpace FlexFormattingContext::determine_available_main_and_cross_space(const Box& flex_container, bool& main_size_is_infinite, bool& main_is_constrained, bool& cross_is_constrained, float& main_min_size, float& main_max_size, float& cross_min_size, float& cross_max_size) const
|
||
{
|
||
auto containing_block_effective_main_size = [&](Box const& box) {
|
||
if (is_row_layout()) {
|
||
if (box.containing_block()->has_definite_width())
|
||
return box.containing_block()->width();
|
||
main_size_is_infinite = true;
|
||
return NumericLimits<float>::max();
|
||
} else {
|
||
if (box.containing_block()->has_definite_height())
|
||
return box.containing_block()->height();
|
||
main_size_is_infinite = true;
|
||
return NumericLimits<float>::max();
|
||
}
|
||
};
|
||
|
||
float main_available_space = 0;
|
||
float cross_available_space = 0;
|
||
|
||
if (has_definite_main_size(flex_container)) {
|
||
main_is_constrained = true;
|
||
main_available_space = specified_main_size(flex_container);
|
||
} else {
|
||
if (has_main_max_size(flex_container)) {
|
||
main_max_size = specified_main_max_size(flex_container);
|
||
main_available_space = main_max_size;
|
||
main_is_constrained = true;
|
||
}
|
||
if (has_main_min_size(flex_container)) {
|
||
main_min_size = specified_main_min_size(flex_container);
|
||
main_is_constrained = true;
|
||
}
|
||
|
||
if (!main_is_constrained) {
|
||
auto available_main_size = containing_block_effective_main_size(flex_container);
|
||
main_available_space = available_main_size - sum_of_margin_padding_border_in_main_axis(flex_container);
|
||
if (flex_container.computed_values().flex_wrap() == CSS::FlexWrap::Wrap || flex_container.computed_values().flex_wrap() == CSS::FlexWrap::WrapReverse) {
|
||
main_available_space = specified_main_size(*flex_container.containing_block());
|
||
main_is_constrained = true;
|
||
}
|
||
}
|
||
}
|
||
|
||
if (has_definite_cross_size(flex_container)) {
|
||
cross_available_space = specified_cross_size(flex_container);
|
||
} else {
|
||
if (has_cross_max_size(flex_container)) {
|
||
cross_max_size = specified_cross_max_size(flex_container);
|
||
cross_is_constrained = true;
|
||
}
|
||
if (has_cross_min_size(flex_container)) {
|
||
cross_min_size = specified_cross_min_size(flex_container);
|
||
cross_is_constrained = true;
|
||
}
|
||
|
||
// FIXME: Is this right? Probably not.
|
||
if (!cross_is_constrained)
|
||
cross_available_space = cross_max_size;
|
||
}
|
||
|
||
return AvailableSpace { .main = main_available_space, .cross = cross_available_space };
|
||
}
|
||
|
||
float FlexFormattingContext::layout_for_maximum_main_size(Box& box)
|
||
{
|
||
bool main_constrained = false;
|
||
if (is_row_layout()) {
|
||
if (!box.computed_values().width().is_undefined_or_auto() || !box.computed_values().min_width().is_undefined_or_auto()) {
|
||
main_constrained = true;
|
||
}
|
||
} else {
|
||
if (!box.computed_values().height().is_undefined_or_auto() || !box.computed_values().min_height().is_undefined_or_auto()) {
|
||
main_constrained = true;
|
||
}
|
||
}
|
||
|
||
if (!main_constrained && box.children_are_inline()) {
|
||
auto& block_container = verify_cast<BlockContainer>(box);
|
||
BlockFormattingContext bfc(block_container, this);
|
||
bfc.run(box, LayoutMode::Default);
|
||
InlineFormattingContext ifc(block_container, &bfc);
|
||
|
||
if (is_row_layout()) {
|
||
ifc.run(box, LayoutMode::OnlyRequiredLineBreaks);
|
||
return box.width();
|
||
} else {
|
||
ifc.run(box, LayoutMode::AllPossibleLineBreaks);
|
||
return box.height();
|
||
}
|
||
}
|
||
if (is_row_layout()) {
|
||
layout_inside(box, LayoutMode::OnlyRequiredLineBreaks);
|
||
return box.width();
|
||
} else {
|
||
return BlockFormattingContext::compute_theoretical_height(box);
|
||
}
|
||
}
|
||
|
||
// https://www.w3.org/TR/css-flexbox-1/#algo-main-item
|
||
void FlexFormattingContext::determine_flex_base_size_and_hypothetical_main_size(Box const& flex_container, FlexItem& flex_item)
|
||
{
|
||
auto& child_box = flex_item.box;
|
||
auto const& flex_basis = child_box.computed_values().flex_basis();
|
||
if (flex_basis.type == CSS::FlexBasis::Length) {
|
||
// A
|
||
auto specified_base_size = get_pixel_size(child_box, flex_basis.length);
|
||
if (specified_base_size == 0)
|
||
flex_item.flex_base_size = calculated_main_size(flex_item.box);
|
||
else
|
||
flex_item.flex_base_size = specified_base_size;
|
||
} else if (flex_basis.type == CSS::FlexBasis::Content
|
||
&& has_definite_cross_size(child_box)
|
||
// FIXME: && has intrinsic aspect ratio.
|
||
&& false) {
|
||
// B
|
||
TODO();
|
||
// flex_base_size is calculated from definite cross size and intrinsic aspect ratio
|
||
} else if (flex_basis.type == CSS::FlexBasis::Content
|
||
// FIXME: && sized under min-content or max-content contstraints
|
||
&& false) {
|
||
// C
|
||
TODO();
|
||
// Size child_box under the constraints, flex_base_size is then the resulting main_size.
|
||
} else if (flex_basis.type == CSS::FlexBasis::Content
|
||
// FIXME: && main_size is infinite && inline axis is parallel to the main axis
|
||
&& false && false) {
|
||
// D
|
||
TODO();
|
||
// Use rules for a flex_container in orthogonal flow
|
||
} else {
|
||
// E
|
||
// FIXME: This is probably too naive.
|
||
// FIXME: Care about FlexBasis::Auto
|
||
if (has_definite_main_size(child_box)) {
|
||
flex_item.flex_base_size = specified_main_size_of_child_box(flex_container, child_box);
|
||
} else {
|
||
flex_item.flex_base_size = layout_for_maximum_main_size(child_box);
|
||
}
|
||
}
|
||
auto clamp_min = has_main_min_size(child_box)
|
||
? specified_main_min_size(child_box)
|
||
: 0;
|
||
auto clamp_max = has_main_max_size(child_box)
|
||
? specified_main_max_size(child_box)
|
||
: NumericLimits<float>::max();
|
||
|
||
flex_item.hypothetical_main_size = clamp(flex_item.flex_base_size, clamp_min, clamp_max);
|
||
}
|
||
|
||
// https://www.w3.org/TR/css-flexbox-1/#algo-main-container
|
||
void FlexFormattingContext::determine_main_size_of_flex_container(Box& flex_container, Vector<FlexItem>& flex_items, bool const main_is_constrained, bool const main_size_is_infinite, float& main_available_size, float const main_min_size, float const main_max_size)
|
||
{
|
||
if ((!main_is_constrained && main_size_is_infinite) || main_available_size == 0) {
|
||
// Uses https://www.w3.org/TR/css-flexbox-1/#intrinsic-main-sizes
|
||
// 9.9.1
|
||
// 1.
|
||
float largest_max_content_flex_fraction = 0;
|
||
for (auto& flex_item : flex_items) {
|
||
// FIXME: This needs some serious work.
|
||
float max_content_contribution = calculated_main_size(flex_item.box);
|
||
float max_content_flex_fraction = max_content_contribution - flex_item.flex_base_size;
|
||
if (max_content_flex_fraction > 0) {
|
||
max_content_flex_fraction /= max(flex_item.box.computed_values().flex_grow_factor().value_or(1), 1.0f);
|
||
} else {
|
||
max_content_flex_fraction /= max(flex_item.box.computed_values().flex_shrink_factor().value_or(1), 1.0f) * flex_item.flex_base_size;
|
||
}
|
||
flex_item.max_content_flex_fraction = max_content_flex_fraction;
|
||
|
||
if (max_content_flex_fraction > largest_max_content_flex_fraction)
|
||
largest_max_content_flex_fraction = max_content_flex_fraction;
|
||
}
|
||
|
||
// 2. Omitted
|
||
// 3.
|
||
float result = 0;
|
||
for (auto& flex_item : flex_items) {
|
||
auto product = 0;
|
||
if (flex_item.max_content_flex_fraction > 0) {
|
||
product = largest_max_content_flex_fraction * flex_item.box.computed_values().flex_grow_factor().value_or(1);
|
||
} else {
|
||
product = largest_max_content_flex_fraction * max(flex_item.box.computed_values().flex_shrink_factor().value_or(1), 1.0f) * flex_item.flex_base_size;
|
||
}
|
||
result += flex_item.flex_base_size + product;
|
||
}
|
||
main_available_size = clamp(result, main_min_size, main_max_size);
|
||
}
|
||
set_main_size(flex_container, main_available_size);
|
||
}
|
||
|
||
// https://www.w3.org/TR/css-flexbox-1/#algo-line-break
|
||
Vector<FlexLine> FlexFormattingContext::collect_flex_items_into_flex_lines(Box const& flex_container, Vector<FlexItem>& flex_items, float main_available_size)
|
||
{
|
||
Vector<FlexLine> flex_lines;
|
||
|
||
// FIXME: Also support wrap-reverse
|
||
if (flex_container.computed_values().flex_wrap() == CSS::FlexWrap::Nowrap) {
|
||
FlexLine line;
|
||
for (auto& flex_item : flex_items) {
|
||
line.items.append(&flex_item);
|
||
}
|
||
flex_lines.append(line);
|
||
} else {
|
||
FlexLine line;
|
||
float line_main_size = 0;
|
||
for (auto& flex_item : flex_items) {
|
||
if ((line_main_size + flex_item.hypothetical_main_size) > main_available_size) {
|
||
flex_lines.append(line);
|
||
line = {};
|
||
line_main_size = 0;
|
||
}
|
||
line.items.append(&flex_item);
|
||
line_main_size += flex_item.hypothetical_main_size;
|
||
}
|
||
flex_lines.append(line);
|
||
}
|
||
|
||
return flex_lines;
|
||
}
|
||
|
||
// https://www.w3.org/TR/css-flexbox-1/#resolve-flexible-lengths
|
||
void FlexFormattingContext::resolve_flexible_lengths(Vector<FlexLine>& flex_lines, float main_available_size)
|
||
{
|
||
enum FlexFactor {
|
||
FlexGrowFactor,
|
||
FlexShrinkFactor
|
||
};
|
||
|
||
FlexFactor used_flex_factor;
|
||
// 6.1. Determine used flex factor
|
||
for (auto& flex_line : flex_lines) {
|
||
size_t number_of_unfrozen_items_on_line = flex_line.items.size();
|
||
|
||
float sum_of_hypothetical_main_sizes = 0;
|
||
for (auto& flex_item : flex_line.items) {
|
||
sum_of_hypothetical_main_sizes += flex_item->hypothetical_main_size;
|
||
}
|
||
if (sum_of_hypothetical_main_sizes < main_available_size)
|
||
used_flex_factor = FlexFactor::FlexGrowFactor;
|
||
else
|
||
used_flex_factor = FlexFactor::FlexShrinkFactor;
|
||
|
||
for (auto& flex_item : flex_line.items) {
|
||
if (used_flex_factor == FlexFactor::FlexGrowFactor)
|
||
flex_item->flex_factor = flex_item->box.computed_values().flex_grow_factor();
|
||
else if (used_flex_factor == FlexFactor::FlexShrinkFactor)
|
||
flex_item->flex_factor = flex_item->box.computed_values().flex_shrink_factor();
|
||
}
|
||
|
||
// 6.2. Size inflexible items
|
||
auto freeze_item_setting_target_main_size_to_hypothetical_main_size = [&number_of_unfrozen_items_on_line](FlexItem& item) {
|
||
item.target_main_size = item.hypothetical_main_size;
|
||
number_of_unfrozen_items_on_line--;
|
||
item.frozen = true;
|
||
};
|
||
for (auto& flex_item : flex_line.items) {
|
||
if (flex_item->flex_factor.has_value() && flex_item->flex_factor.value() == 0) {
|
||
freeze_item_setting_target_main_size_to_hypothetical_main_size(*flex_item);
|
||
} else if (used_flex_factor == FlexFactor::FlexGrowFactor) {
|
||
// FIXME: Spec doesn't include the == case, but we take a too basic approach to calculating the values used so this is appropriate
|
||
if (flex_item->flex_base_size > flex_item->hypothetical_main_size) {
|
||
freeze_item_setting_target_main_size_to_hypothetical_main_size(*flex_item);
|
||
}
|
||
} else if (used_flex_factor == FlexFactor::FlexShrinkFactor) {
|
||
if (flex_item->flex_base_size < flex_item->hypothetical_main_size) {
|
||
freeze_item_setting_target_main_size_to_hypothetical_main_size(*flex_item);
|
||
}
|
||
}
|
||
}
|
||
|
||
// 6.3. Calculate initial free space
|
||
auto calculate_free_space = [&]() {
|
||
float sum_of_items_on_line = 0;
|
||
for (auto& flex_item : flex_line.items) {
|
||
if (flex_item->frozen)
|
||
sum_of_items_on_line += flex_item->target_main_size;
|
||
else
|
||
sum_of_items_on_line += flex_item->flex_base_size;
|
||
}
|
||
return main_available_size - sum_of_items_on_line;
|
||
};
|
||
|
||
float initial_free_space = calculate_free_space();
|
||
|
||
// 6.4 Loop
|
||
auto for_each_unfrozen_item = [&flex_line](auto callback) {
|
||
for (auto& flex_item : flex_line.items) {
|
||
if (!flex_item->frozen)
|
||
callback(flex_item);
|
||
}
|
||
};
|
||
|
||
while (number_of_unfrozen_items_on_line > 0) {
|
||
// b Calculate the remaining free space
|
||
auto remaining_free_space = calculate_free_space();
|
||
float sum_of_unfrozen_flex_items_flex_factors = 0;
|
||
for_each_unfrozen_item([&](FlexItem* item) {
|
||
sum_of_unfrozen_flex_items_flex_factors += item->flex_factor.value_or(1);
|
||
});
|
||
|
||
if (sum_of_unfrozen_flex_items_flex_factors < 1) {
|
||
auto intermediate_free_space = initial_free_space * sum_of_unfrozen_flex_items_flex_factors;
|
||
if (AK::abs(intermediate_free_space) < AK::abs(remaining_free_space))
|
||
remaining_free_space = intermediate_free_space;
|
||
}
|
||
|
||
// c Distribute free space proportional to the flex factors
|
||
if (remaining_free_space != 0) {
|
||
if (used_flex_factor == FlexFactor::FlexGrowFactor) {
|
||
float sum_of_flex_grow_factor_of_unfrozen_items = sum_of_unfrozen_flex_items_flex_factors;
|
||
for_each_unfrozen_item([&](FlexItem* flex_item) {
|
||
float ratio = flex_item->flex_factor.value_or(1) / sum_of_flex_grow_factor_of_unfrozen_items;
|
||
flex_item->target_main_size = flex_item->flex_base_size + (remaining_free_space * ratio);
|
||
});
|
||
} else if (used_flex_factor == FlexFactor::FlexShrinkFactor) {
|
||
float sum_of_scaled_flex_shrink_factor_of_unfrozen_items = 0;
|
||
for_each_unfrozen_item([&](FlexItem* flex_item) {
|
||
flex_item->scaled_flex_shrink_factor = flex_item->flex_factor.value_or(1) * flex_item->flex_base_size;
|
||
sum_of_scaled_flex_shrink_factor_of_unfrozen_items += flex_item->scaled_flex_shrink_factor;
|
||
});
|
||
|
||
for_each_unfrozen_item([&](FlexItem* flex_item) {
|
||
float ratio = 1.0f;
|
||
if (sum_of_scaled_flex_shrink_factor_of_unfrozen_items != 0.0f)
|
||
ratio = flex_item->scaled_flex_shrink_factor / sum_of_scaled_flex_shrink_factor_of_unfrozen_items;
|
||
flex_item->target_main_size = flex_item->flex_base_size - (AK::abs(remaining_free_space) * ratio);
|
||
});
|
||
}
|
||
} else {
|
||
// This isn't spec but makes sense.
|
||
for_each_unfrozen_item([&](FlexItem* flex_item) {
|
||
flex_item->target_main_size = flex_item->flex_base_size;
|
||
});
|
||
}
|
||
// d Fix min/max violations.
|
||
float adjustments = 0.0f;
|
||
for_each_unfrozen_item([&](FlexItem* item) {
|
||
auto min_main = has_main_min_size(item->box)
|
||
? specified_main_min_size(item->box)
|
||
: 0;
|
||
auto max_main = has_main_max_size(item->box)
|
||
? specified_main_max_size(item->box)
|
||
: NumericLimits<float>::max();
|
||
|
||
float original_target_size = item->target_main_size;
|
||
|
||
if (item->target_main_size < min_main) {
|
||
item->target_main_size = min_main;
|
||
item->is_min_violation = true;
|
||
}
|
||
|
||
if (item->target_main_size > max_main) {
|
||
item->target_main_size = max_main;
|
||
item->is_max_violation = true;
|
||
}
|
||
float delta = item->target_main_size - original_target_size;
|
||
adjustments += delta;
|
||
});
|
||
// e Freeze over-flexed items
|
||
float total_violation = adjustments;
|
||
if (total_violation == 0) {
|
||
for_each_unfrozen_item([&](FlexItem* item) {
|
||
--number_of_unfrozen_items_on_line;
|
||
item->frozen = true;
|
||
});
|
||
} else if (total_violation > 0) {
|
||
for_each_unfrozen_item([&](FlexItem* item) {
|
||
if (item->is_min_violation) {
|
||
--number_of_unfrozen_items_on_line;
|
||
item->frozen = true;
|
||
}
|
||
});
|
||
} else if (total_violation < 0) {
|
||
for_each_unfrozen_item([&](FlexItem* item) {
|
||
if (item->is_max_violation) {
|
||
--number_of_unfrozen_items_on_line;
|
||
item->frozen = true;
|
||
}
|
||
});
|
||
}
|
||
}
|
||
|
||
// 6.5.
|
||
for (auto& flex_item : flex_line.items) {
|
||
flex_item->main_size = flex_item->target_main_size;
|
||
}
|
||
}
|
||
}
|
||
|
||
}
|