ladybird/Userland/Libraries/LibWeb/Layout/FormattingContext.h
Andreas Kling f0560fd087 LibWeb: Support <svg> elements with display: block
There are a couple of things that went into this:

- We now calculate the intrinsic width/height and aspect ratio of <svg>
  elements based on the spec algorithm instead of our previous ad-hoc
  guesswork solution.

- Replaced elements with automatic size and intrinsic aspect ratio but
  no intrinsic dimensions are now sized with the stretch-fit width
  formula.

- We take care to assign both used width and used height to <svg>
  elements before running their SVG formatting contexts. This ensures
  that the inside SVG content is laid out with knowledge of its
  viewport geometry.

- We avoid infinite recursion in tentative_height_for_replaced_element()
  by using the already-calculated used width instead of calling the
  function that calculates the used width (since that may call us right
  back again).
2023-05-20 08:49:42 +02:00

138 lines
6 KiB
C++

/*
* Copyright (c) 2020-2022, Andreas Kling <kling@serenityos.org>
*
* SPDX-License-Identifier: BSD-2-Clause
*/
#pragma once
#include <AK/OwnPtr.h>
#include <LibWeb/Forward.h>
#include <LibWeb/Layout/AvailableSpace.h>
#include <LibWeb/Layout/LayoutState.h>
namespace Web::Layout {
class FormattingContext {
public:
virtual ~FormattingContext();
enum class Type {
Block,
Inline,
Flex,
Grid,
Table,
SVG,
InternalReplaced, // Internal hack formatting context for replaced elements. FIXME: Get rid of this.
InternalDummy, // Internal hack formatting context for unimplemented things. FIXME: Get rid of this.
};
virtual void run(Box const&, LayoutMode, AvailableSpace const&) = 0;
// This function returns the automatic content height of the context's root box.
virtual CSSPixels automatic_content_width() const = 0;
// This function returns the automatic content height of the context's root box.
virtual CSSPixels automatic_content_height() const = 0;
Box const& context_box() const { return m_context_box; }
FormattingContext* parent() { return m_parent; }
FormattingContext const* parent() const { return m_parent; }
Type type() const { return m_type; }
bool is_block_formatting_context() const { return type() == Type::Block; }
virtual bool inhibits_floating() const { return false; }
[[nodiscard]] static Optional<Type> formatting_context_type_created_by_box(Box const&);
static bool creates_block_formatting_context(Box const&);
static CSSPixels compute_width_for_replaced_element(LayoutState const&, ReplacedBox const&, AvailableSpace const&);
static CSSPixels compute_height_for_replaced_element(LayoutState const&, ReplacedBox const&, AvailableSpace const&);
OwnPtr<FormattingContext> create_independent_formatting_context_if_needed(LayoutState&, Box const& child_box);
virtual void parent_context_did_dimension_child_root_box() { }
CSSPixels calculate_min_content_width(Layout::Box const&) const;
CSSPixels calculate_max_content_width(Layout::Box const&) const;
CSSPixels calculate_min_content_height(Layout::Box const&, AvailableSize const& available_width) const;
CSSPixels calculate_max_content_height(Layout::Box const&, AvailableSize const& available_width) const;
CSSPixels calculate_fit_content_height(Layout::Box const&, AvailableSpace const&) const;
CSSPixels calculate_fit_content_width(Layout::Box const&, AvailableSpace const&) const;
CSS::Length calculate_inner_width(Layout::Box const&, AvailableSize const&, CSS::Size const& width) const;
CSS::Length calculate_inner_height(Layout::Box const&, AvailableSize const&, CSS::Size const& height) const;
virtual CSSPixels greatest_child_width(Box const&) const;
CSSPixels containing_block_width_for(Box const& box) const { return containing_block_width_for(box, m_state); }
CSSPixels containing_block_height_for(Box const& box) const { return containing_block_height_for(box, m_state); }
static CSSPixels containing_block_width_for(Box const&, LayoutState const&);
static CSSPixels containing_block_height_for(Box const&, LayoutState const&);
[[nodiscard]] CSSPixels calculate_stretch_fit_width(Box const&, AvailableSize const&) const;
[[nodiscard]] CSSPixels calculate_stretch_fit_height(Box const&, AvailableSize const&) const;
[[nodiscard]] static CSSPixels calculate_stretch_fit_width(Box const&, AvailableSize const&, LayoutState const&);
[[nodiscard]] static CSSPixels calculate_stretch_fit_height(Box const&, AvailableSize const&, LayoutState const&);
virtual bool can_determine_size_of_child() const { return false; }
virtual void determine_width_of_child(Box const&, AvailableSpace const&) { }
virtual void determine_height_of_child(Box const&, AvailableSpace const&) { }
virtual CSSPixelPoint calculate_static_position(Box const&) const;
bool can_skip_is_anonymous_text_run(Box&);
protected:
FormattingContext(Type, LayoutState&, Box const&, FormattingContext* parent = nullptr);
static bool should_treat_width_as_auto(Box const&, AvailableSpace const&);
static bool should_treat_height_as_auto(Box const&, AvailableSpace const&);
OwnPtr<FormattingContext> layout_inside(Box const&, LayoutMode, AvailableSpace const&);
void compute_inset(Box const& box);
struct SpaceUsedByFloats {
CSSPixels left { 0 };
CSSPixels right { 0 };
};
struct ShrinkToFitResult {
CSSPixels preferred_width { 0 };
CSSPixels preferred_minimum_width { 0 };
};
static CSSPixels tentative_width_for_replaced_element(LayoutState const&, ReplacedBox const&, CSS::Size const& computed_width, AvailableSpace const&);
static CSSPixels tentative_height_for_replaced_element(LayoutState const&, ReplacedBox const&, CSS::Size const& computed_height, AvailableSpace const&);
CSSPixels compute_auto_height_for_block_formatting_context_root(Box const&) const;
ShrinkToFitResult calculate_shrink_to_fit_widths(Box const&);
void layout_absolutely_positioned_element(Box const&, AvailableSpace const&);
void compute_width_for_absolutely_positioned_element(Box const&, AvailableSpace const&);
void compute_width_for_absolutely_positioned_non_replaced_element(Box const&, AvailableSpace const&);
void compute_width_for_absolutely_positioned_replaced_element(ReplacedBox const&, AvailableSpace const&);
enum class BeforeOrAfterInsideLayout {
Before,
After,
};
void compute_height_for_absolutely_positioned_element(Box const&, AvailableSpace const&, BeforeOrAfterInsideLayout);
void compute_height_for_absolutely_positioned_non_replaced_element(Box const&, AvailableSpace const&, BeforeOrAfterInsideLayout);
void compute_height_for_absolutely_positioned_replaced_element(ReplacedBox const&, AvailableSpace const&, BeforeOrAfterInsideLayout);
Type m_type {};
FormattingContext* m_parent { nullptr };
JS::NonnullGCPtr<Box const> m_context_box;
LayoutState& m_state;
};
}