jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2022, Andreas Kling <kling@serenityos.org>
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7#pragma once
8
9#include <AK/HashMap.h>
10#include <LibGfx/Point.h>
11#include <LibWeb/Layout/Box.h>
12#include <LibWeb/Layout/LineBox.h>
13#include <LibWeb/Painting/PaintableBox.h>
14
15namespace Web::Layout {
16
17enum class SizeConstraint {
18 None,
19 MinContent,
20 MaxContent,
21};
22
23class AvailableSize;
24class AvailableSpace;
25
26struct LayoutState {
27 LayoutState()
28 : m_root(*this)
29 {
30 }
31
32 explicit LayoutState(LayoutState const* parent)
33 : m_parent(parent)
34 , m_root(find_root())
35 {
36 used_values_per_layout_node.resize(m_root.used_values_per_layout_node.size());
37 }
38
39 LayoutState const& find_root() const
40 {
41 LayoutState const* root = this;
42 for (auto* state = m_parent; state; state = state->m_parent)
43 root = state;
44 return *root;
45 }
46
47 struct UsedValues {
48 NodeWithStyleAndBoxModelMetrics const& node() const { return *m_node; }
49 void set_node(NodeWithStyleAndBoxModelMetrics&, UsedValues const* containing_block_used_values);
50
51 CSSPixels content_width() const { return m_content_width; }
52 CSSPixels content_height() const { return m_content_height; }
53 void set_content_width(CSSPixels);
54 void set_content_height(CSSPixels);
55
56 // NOTE: These are used by FlexFormattingContext to assign a temporary main size to items
57 // early on, so that descendants have something to resolve percentages against.
58 void set_temporary_content_width(CSSPixels);
59 void set_temporary_content_height(CSSPixels);
60
61 bool has_definite_width() const { return m_has_definite_width && width_constraint == SizeConstraint::None; }
62 bool has_definite_height() const { return m_has_definite_height && height_constraint == SizeConstraint::None; }
63
64 // Returns the available space for content inside this layout box.
65 // If the space in an axis is indefinite, and the outer space is an intrinsic sizing constraint,
66 // the constraint is used in that axis instead.
67 AvailableSpace available_inner_space_or_constraints_from(AvailableSpace const& outer_space) const;
68
69 void set_content_offset(CSSPixelPoint);
70 void set_content_x(CSSPixels);
71 void set_content_y(CSSPixels);
72
73 CSSPixelPoint offset;
74
75 SizeConstraint width_constraint { SizeConstraint::None };
76 SizeConstraint height_constraint { SizeConstraint::None };
77
78 CSSPixels margin_left { 0 };
79 CSSPixels margin_right { 0 };
80 CSSPixels margin_top { 0 };
81 CSSPixels margin_bottom { 0 };
82
83 CSSPixels border_left { 0 };
84 CSSPixels border_right { 0 };
85 CSSPixels border_top { 0 };
86 CSSPixels border_bottom { 0 };
87
88 CSSPixels padding_left { 0 };
89 CSSPixels padding_right { 0 };
90 CSSPixels padding_top { 0 };
91 CSSPixels padding_bottom { 0 };
92
93 CSSPixels inset_left { 0 };
94 CSSPixels inset_right { 0 };
95 CSSPixels inset_top { 0 };
96 CSSPixels inset_bottom { 0 };
97
98 Vector<LineBox> line_boxes;
99
100 CSSPixels margin_box_left() const { return margin_left + border_left + padding_left; }
101 CSSPixels margin_box_right() const { return margin_right + border_right + padding_right; }
102 CSSPixels margin_box_top() const { return margin_top + border_top + padding_top; }
103 CSSPixels margin_box_bottom() const { return margin_bottom + border_bottom + padding_bottom; }
104
105 CSSPixels margin_box_width() const { return margin_box_left() + content_width() + margin_box_right(); }
106 CSSPixels margin_box_height() const { return margin_box_top() + content_height() + margin_box_bottom(); }
107
108 CSSPixels border_box_left() const { return border_left + padding_left; }
109 CSSPixels border_box_right() const { return border_right + padding_right; }
110 CSSPixels border_box_top() const { return border_top + padding_top; }
111 CSSPixels border_box_bottom() const { return border_bottom + padding_bottom; }
112
113 CSSPixels border_box_width() const { return border_box_left() + content_width() + border_box_right(); }
114 CSSPixels border_box_height() const { return border_box_top() + content_height() + border_box_bottom(); }
115
116 Optional<Painting::PaintableBox::OverflowData> overflow_data;
117
118 Painting::PaintableBox::OverflowData& ensure_overflow_data()
119 {
120 if (!overflow_data.has_value())
121 overflow_data = Painting::PaintableBox::OverflowData {};
122 return *overflow_data;
123 }
124
125 Optional<LineBoxFragmentCoordinate> containing_line_box_fragment;
126
127 void add_floating_descendant(Box const& box) { m_floating_descendants.set(&box); }
128 auto const& floating_descendants() const { return m_floating_descendants; }
129
130 private:
131 AvailableSize available_width_inside() const;
132 AvailableSize available_height_inside() const;
133
134 Layout::NodeWithStyleAndBoxModelMetrics* m_node { nullptr };
135
136 CSSPixels m_content_width { 0 };
137 CSSPixels m_content_height { 0 };
138
139 bool m_has_definite_width { false };
140 bool m_has_definite_height { false };
141
142 HashTable<Box const*> m_floating_descendants;
143 };
144
145 CSSPixels resolved_definite_width(Box const&) const;
146 CSSPixels resolved_definite_height(Box const&) const;
147
148 void commit();
149
150 // NOTE: get_mutable() will CoW the UsedValues if it's inherited from an ancestor state;
151 UsedValues& get_mutable(NodeWithStyleAndBoxModelMetrics const&);
152
153 // NOTE: get() will not CoW the UsedValues.
154 UsedValues const& get(NodeWithStyleAndBoxModelMetrics const&) const;
155
156 Vector<OwnPtr<UsedValues>> used_values_per_layout_node;
157
158 // We cache intrinsic sizes once determined, as they will not change over the course of a full layout.
159 // This avoids computing them several times while performing flex layout.
160 struct IntrinsicSizes {
161 Optional<CSSPixels> min_content_width;
162 Optional<CSSPixels> max_content_width;
163
164 // NOTE: Since intrinsic heights depend on the amount of available width, we have to cache
165 // three separate kinds of results, depending on the available width at the time of calculation.
166 HashMap<CSSPixels, Optional<CSSPixels>> min_content_height_with_definite_available_width;
167 HashMap<CSSPixels, Optional<CSSPixels>> max_content_height_with_definite_available_width;
168 Optional<CSSPixels> min_content_height_with_min_content_available_width;
169 Optional<CSSPixels> max_content_height_with_min_content_available_width;
170 Optional<CSSPixels> min_content_height_with_max_content_available_width;
171 Optional<CSSPixels> max_content_height_with_max_content_available_width;
172 };
173
174 HashMap<NodeWithStyleAndBoxModelMetrics const*, NonnullOwnPtr<IntrinsicSizes>> mutable intrinsic_sizes;
175
176 LayoutState const* m_parent { nullptr };
177 LayoutState const& m_root;
178};
179
180CSSPixelRect absolute_content_rect(Box const&, LayoutState const&);
181CSSPixelRect margin_box_rect(Box const&, LayoutState const&);
182CSSPixelRect margin_box_rect_in_ancestor_coordinate_space(Box const& box, Box const& ancestor_box, LayoutState const&);
183CSSPixelRect border_box_rect(Box const&, LayoutState const&);
184CSSPixelRect border_box_rect_in_ancestor_coordinate_space(Box const& box, Box const& ancestor_box, LayoutState const&);
185CSSPixelRect content_box_rect(Box const&, LayoutState const&);
186CSSPixelRect content_box_rect_in_ancestor_coordinate_space(Box const& box, Box const& ancestor_box, LayoutState const&);
187CSSPixels box_baseline(LayoutState const& state, Box const& box);
188
189}