ladybird/Userland/Libraries/LibWeb/Layout/FlexFormattingContext.h
Andreas Kling b079f4d590 LibWeb: Make flexbox special definite size cases explicit
The CSS-FLEXBOX-1 spec has a bunch of special cases where sizes are
considered definite after reaching a specific point of the layout
algorithm.

Before this change, we were relying on set_content_width/height also
implicitly marking those content sizes as definite.

To prepare for that implicit behavior going away, this patch makes
the special cases explicit.
2024-02-21 17:54:05 +01:00

241 lines
11 KiB
C++

/*
* Copyright (c) 2021-2024, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <LibWeb/Layout/Box.h>
#include <LibWeb/Layout/FormattingContext.h>
namespace Web::Layout {
class FlexFormattingContext final : public FormattingContext {
public:
FlexFormattingContext(LayoutState&, Box const& flex_container, FormattingContext* parent);
~FlexFormattingContext();
virtual bool inhibits_floating() const override { return true; }
virtual void run(Box const&, LayoutMode, AvailableSpace const&) override;
virtual CSSPixels automatic_content_width() const override;
virtual CSSPixels automatic_content_height() const override;
Box const& flex_container() const { return context_box(); }
virtual CSSPixelPoint calculate_static_position(Box const&) const override;
private:
[[nodiscard]] bool should_treat_main_size_as_auto(Box const&) const;
[[nodiscard]] bool should_treat_cross_size_as_auto(Box const&) const;
[[nodiscard]] bool should_treat_main_max_size_as_none(Box const&) const;
[[nodiscard]] bool should_treat_cross_max_size_as_none(Box const&) const;
[[nodiscard]] CSSPixels adjust_main_size_through_aspect_ratio_for_cross_size_min_max_constraints(Box const&, CSSPixels main_size, CSS::Size const& min_cross_size, CSS::Size const& max_cross_size) const;
[[nodiscard]] CSSPixels calculate_main_size_from_cross_size_and_aspect_ratio(CSSPixels cross_size, CSSPixelFraction aspect_ratio) const;
[[nodiscard]] CSSPixels calculate_cross_size_from_main_size_and_aspect_ratio(CSSPixels main_size, CSSPixelFraction aspect_ratio) const;
void dump_items() const;
struct DirectionAgnosticMargins {
CSSPixels main_before { 0 };
CSSPixels main_after { 0 };
CSSPixels cross_before { 0 };
CSSPixels cross_after { 0 };
bool main_before_is_auto { false };
bool main_after_is_auto { false };
bool cross_before_is_auto { false };
bool cross_after_is_auto { false };
};
struct FlexItem {
JS::NonnullGCPtr<Box> box;
LayoutState::UsedValues& used_values;
Optional<CSS::FlexBasis> used_flex_basis {};
bool used_flex_basis_is_definite { false };
CSSPixels flex_base_size { 0 };
CSSPixels hypothetical_main_size { 0 };
CSSPixels hypothetical_cross_size { 0 };
CSSPixels hypothetical_cross_size_with_margins() { return hypothetical_cross_size + margins.cross_before + margins.cross_after + borders.cross_after + borders.cross_before + padding.cross_after + padding.cross_before; }
CSSPixels target_main_size { 0 };
bool frozen { false };
Optional<double> flex_factor {};
double scaled_flex_shrink_factor { 0 };
double desired_flex_fraction { 0 };
CSSPixels outer_hypothetical_main_size() const
{
return hypothetical_main_size + margins.main_before + margins.main_after + borders.main_before + borders.main_after + padding.main_before + padding.main_after;
}
CSSPixels outer_target_main_size() const
{
return target_main_size + margins.main_before + margins.main_after + borders.main_before + borders.main_after + padding.main_before + padding.main_after;
}
CSSPixels outer_flex_base_size() const
{
return flex_base_size + margins.main_before + margins.main_after + borders.main_before + borders.main_after + padding.main_before + padding.main_after;
}
// The used main size of this flex item. Empty until determined.
Optional<CSSPixels> main_size {};
// The used cross size of this flex item. Empty until determined.
Optional<CSSPixels> cross_size {};
CSSPixels main_offset { 0 };
CSSPixels cross_offset { 0 };
DirectionAgnosticMargins margins {};
DirectionAgnosticMargins borders {};
DirectionAgnosticMargins padding {};
bool is_min_violation { false };
bool is_max_violation { false };
CSSPixels add_main_margin_box_sizes(CSSPixels content_size) const
{
return content_size + margins.main_before + margins.main_after + borders.main_before + borders.main_after + padding.main_before + padding.main_after;
}
CSSPixels add_cross_margin_box_sizes(CSSPixels content_size) const
{
return content_size + margins.cross_before + margins.cross_after + borders.cross_before + borders.cross_after + padding.cross_before + padding.cross_after;
}
};
struct FlexLine {
Vector<FlexItem&> items;
CSSPixels cross_size { 0 };
Optional<CSSPixels> remaining_free_space;
double chosen_flex_fraction { 0 };
double sum_of_flex_factor_of_unfrozen_items() const;
double sum_of_scaled_flex_shrink_factor_of_unfrozen_items() const;
};
CSSPixels main_gap() const;
CSSPixels cross_gap() const;
[[nodiscard]] bool has_definite_main_size(LayoutState::UsedValues const&) const;
[[nodiscard]] bool has_definite_cross_size(LayoutState::UsedValues const&) const;
[[nodiscard]] bool has_definite_main_size(FlexItem const& item) const { return has_definite_main_size(item.used_values); }
[[nodiscard]] bool has_definite_cross_size(FlexItem const& item) const { return has_definite_cross_size(item.used_values); }
[[nodiscard]] CSSPixels inner_main_size(LayoutState::UsedValues const&) const;
[[nodiscard]] CSSPixels inner_cross_size(LayoutState::UsedValues const&) const;
[[nodiscard]] CSSPixels inner_main_size(FlexItem const& item) const { return inner_main_size(item.used_values); }
[[nodiscard]] CSSPixels inner_cross_size(FlexItem const& item) const { return inner_cross_size(item.used_values); }
bool has_main_min_size(Box const&) const;
bool has_cross_min_size(Box const&) const;
CSSPixels specified_main_max_size(Box const&) const;
CSSPixels specified_cross_max_size(Box const&) const;
bool is_cross_auto(Box const&) const;
CSSPixels specified_main_min_size(Box const&) const;
CSSPixels specified_cross_min_size(Box const&) const;
bool has_main_max_size(Box const&) const;
bool has_cross_max_size(Box const&) const;
CSSPixels automatic_minimum_size(FlexItem const&) const;
CSSPixels content_based_minimum_size(FlexItem const&) const;
Optional<CSSPixels> specified_size_suggestion(FlexItem const&) const;
Optional<CSSPixels> transferred_size_suggestion(FlexItem const&) const;
CSSPixels content_size_suggestion(FlexItem const&) const;
CSS::Size const& computed_main_size(Box const&) const;
CSS::Size const& computed_main_min_size(Box const&) const;
CSS::Size const& computed_main_max_size(Box const&) const;
CSS::Size const& computed_cross_size(Box const&) const;
CSS::Size const& computed_cross_min_size(Box const&) const;
CSS::Size const& computed_cross_max_size(Box const&) const;
CSSPixels get_pixel_width(Box const&, CSS::Size const&) const;
CSSPixels get_pixel_height(Box const&, CSS::Size const&) const;
bool flex_item_is_stretched(FlexItem const&) const;
void set_main_size(Box const&, CSSPixels size);
void set_cross_size(Box const&, CSSPixels size);
void set_offset(Box const&, CSSPixels main_offset, CSSPixels cross_offset);
void set_main_axis_first_margin(FlexItem&, CSSPixels margin);
void set_main_axis_second_margin(FlexItem&, CSSPixels margin);
void set_has_definite_main_size(FlexItem&);
void set_has_definite_cross_size(FlexItem&);
void copy_dimensions_from_flex_items_to_boxes();
void generate_anonymous_flex_items();
void determine_available_space_for_items(AvailableSpace const&);
void determine_flex_base_size_and_hypothetical_main_size(FlexItem&);
void collect_flex_items_into_flex_lines();
void resolve_flexible_lengths();
void resolve_flexible_lengths_for_line(FlexLine&);
void resolve_cross_axis_auto_margins();
void determine_hypothetical_cross_size_of_item(FlexItem&, bool resolve_percentage_min_max_sizes);
void calculate_cross_size_of_each_flex_line();
void handle_align_content_stretch();
CSS::AlignItems alignment_for_item(Box const&) const;
void determine_used_cross_size_of_each_flex_item();
void distribute_any_remaining_free_space();
void align_all_flex_items_along_the_cross_axis();
void determine_flex_container_used_cross_size();
void align_all_flex_lines();
bool is_row_layout() const { return m_flex_direction == CSS::FlexDirection::Row || m_flex_direction == CSS::FlexDirection::RowReverse; }
bool is_single_line() const { return flex_container().computed_values().flex_wrap() == CSS::FlexWrap::Nowrap; }
bool is_direction_reverse() const { return m_flex_direction == CSS::FlexDirection::ColumnReverse || m_flex_direction == CSS::FlexDirection::RowReverse; }
void populate_specified_margins(FlexItem&, CSS::FlexDirection) const;
void determine_intrinsic_size_of_flex_container();
[[nodiscard]] CSSPixels calculate_intrinsic_main_size_of_flex_container();
[[nodiscard]] CSSPixels calculate_intrinsic_cross_size_of_flex_container();
[[nodiscard]] CSSPixels calculate_cross_min_content_contribution(FlexItem const&, bool resolve_percentage_min_max_sizes) const;
[[nodiscard]] CSSPixels calculate_cross_max_content_contribution(FlexItem const&, bool resolve_percentage_min_max_sizes) const;
[[nodiscard]] CSSPixels calculate_main_min_content_contribution(FlexItem const&) const;
[[nodiscard]] CSSPixels calculate_main_max_content_contribution(FlexItem const&) const;
[[nodiscard]] CSSPixels calculate_min_content_main_size(FlexItem const&) const;
[[nodiscard]] CSSPixels calculate_max_content_main_size(FlexItem const&) const;
[[nodiscard]] CSSPixels calculate_min_content_cross_size(FlexItem const&) const;
[[nodiscard]] CSSPixels calculate_max_content_cross_size(FlexItem const&) const;
[[nodiscard]] CSSPixels calculate_fit_content_main_size(FlexItem const&) const;
[[nodiscard]] CSSPixels calculate_fit_content_cross_size(FlexItem const&) const;
[[nodiscard]] CSSPixels calculate_width_to_use_when_determining_intrinsic_height_of_item(FlexItem const&) const;
virtual void parent_context_did_dimension_child_root_box() override;
CSS::FlexBasis used_flex_basis_for_item(FlexItem const&) const;
LayoutState::UsedValues& m_flex_container_state;
Vector<FlexLine> m_flex_lines;
Vector<FlexItem> m_flex_items;
CSS::FlexDirection m_flex_direction {};
struct AxisAgnosticAvailableSpace {
AvailableSize main;
AvailableSize cross;
AvailableSpace space;
};
Optional<AxisAgnosticAvailableSpace> m_available_space_for_items;
};
}