/src/serenity/Userland/Libraries/LibGfx/TextDirection.h
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1 | | /* |
2 | | * Copyright (c) 2021, Idan Horowitz <idan.horowitz@serenityos.org> |
3 | | * |
4 | | * SPDX-License-Identifier: BSD-2-Clause |
5 | | */ |
6 | | |
7 | | #pragma once |
8 | | |
9 | | #include <AK/Array.h> |
10 | | #include <AK/Utf32View.h> |
11 | | #include <AK/Vector.h> |
12 | | |
13 | | namespace Gfx { |
14 | | |
15 | | enum class BidirectionalClass { |
16 | | STRONG_LTR, |
17 | | STRONG_RTL, |
18 | | WEAK_NUMBERS, |
19 | | WEAK_SEPARATORS, |
20 | | NEUTRAL, |
21 | | }; |
22 | | |
23 | | extern Array<BidirectionalClass, 0x1F000> const char_bidi_class_lookup_table; |
24 | | |
25 | | constexpr BidirectionalClass get_char_bidi_class(u32 ch) |
26 | 0 | { |
27 | 0 | if (ch >= char_bidi_class_lookup_table.size()) |
28 | 0 | return BidirectionalClass::STRONG_LTR; |
29 | 0 | return char_bidi_class_lookup_table[ch]; |
30 | 0 | } |
31 | | |
32 | | // FIXME: These should be parsed from the official BidiMirroring.txt that specifies the mirroring character for each character (this function doesn't take into account a large amount of characters) |
33 | | constexpr u32 get_mirror_char(u32 ch) |
34 | 0 | { |
35 | 0 | if (ch == 0x28) |
36 | 0 | return 0x29; |
37 | 0 | if (ch == 0x29) |
38 | 0 | return 0x28; |
39 | 0 | if (ch == 0x3C) |
40 | 0 | return 0x3E; |
41 | 0 | if (ch == 0x3E) |
42 | 0 | return 0x3C; |
43 | 0 | if (ch == 0x5B) |
44 | 0 | return 0x5D; |
45 | 0 | if (ch == 0x7B) |
46 | 0 | return 0x7D; |
47 | 0 | if (ch == 0x7D) |
48 | 0 | return 0x7B; |
49 | 0 | if (ch == 0xAB) |
50 | 0 | return 0xBB; |
51 | 0 | if (ch == 0xBB) |
52 | 0 | return 0xAB; |
53 | 0 | if (ch == 0x2039) |
54 | 0 | return 0x203A; |
55 | 0 | if (ch == 0x203A) |
56 | 0 | return 0x2039; |
57 | 0 | return ch; |
58 | 0 | } |
59 | | |
60 | | enum class TextDirection { |
61 | | LTR, |
62 | | RTL, |
63 | | }; |
64 | | |
65 | | constexpr TextDirection bidi_class_to_direction(BidirectionalClass class_) |
66 | 0 | { |
67 | 0 | VERIFY(class_ != BidirectionalClass::NEUTRAL); |
68 | 0 | if (class_ == BidirectionalClass::STRONG_LTR || class_ == BidirectionalClass::WEAK_NUMBERS || class_ == BidirectionalClass::WEAK_SEPARATORS) |
69 | 0 | return TextDirection::LTR; |
70 | 0 | return TextDirection::RTL; |
71 | 0 | } |
72 | | |
73 | | // Assumes the text has a homogeneous direction |
74 | | template<typename TextType> |
75 | | constexpr TextDirection get_text_direction(TextType text) |
76 | 0 | { |
77 | 0 | for (u32 code_point : text) { |
78 | 0 | auto char_direction = get_char_bidi_class(code_point); |
79 | 0 | if (char_direction != BidirectionalClass::NEUTRAL) |
80 | 0 | return bidi_class_to_direction(char_direction); |
81 | 0 | } |
82 | 0 | return TextDirection::LTR; |
83 | 0 | } |
84 | | |
85 | | class DirectionalRun { |
86 | | public: |
87 | | DirectionalRun(Vector<u32> code_points, u8 embedding_level) |
88 | 0 | : m_code_points(move(code_points)) |
89 | 0 | , m_embedding_level(embedding_level) |
90 | 0 | { |
91 | 0 | } |
92 | | |
93 | 0 | [[nodiscard]] Utf32View text() const { return { m_code_points.data(), m_code_points.size() }; } |
94 | 0 | [[nodiscard]] u8 embedding_level() const { return m_embedding_level; } |
95 | 0 | [[nodiscard]] TextDirection direction() const { return (m_embedding_level % 2) == 0 ? TextDirection::LTR : TextDirection::RTL; } |
96 | | |
97 | 0 | Vector<u32>& code_points() { return m_code_points; } |
98 | | |
99 | | private: |
100 | | Vector<u32> m_code_points; |
101 | | u8 m_embedding_level; |
102 | | }; |
103 | | |
104 | | } |