python (3.11.7)
1 import re
2 from functools import lru_cache
3 from typing import Callable, List
4
5 from ._cell_widths import CELL_WIDTHS
6
7 # Regex to match sequence of the most common character ranges
8 _is_single_cell_widths = re.compile("^[\u0020-\u006f\u00a0\u02ff\u0370-\u0482]*$").match
9
10
11 @lru_cache(4096)
12 def cached_cell_len(text: str) -> int:
13 """Get the number of cells required to display text.
14
15 This method always caches, which may use up a lot of memory. It is recommended to use
16 `cell_len` over this method.
17
18 Args:
19 text (str): Text to display.
20
21 Returns:
22 int: Get the number of cells required to display text.
23 """
24 _get_size = get_character_cell_size
25 total_size = sum(_get_size(character) for character in text)
26 return total_size
27
28
29 def cell_len(text: str, _cell_len: Callable[[str], int] = cached_cell_len) -> int:
30 """Get the number of cells required to display text.
31
32 Args:
33 text (str): Text to display.
34
35 Returns:
36 int: Get the number of cells required to display text.
37 """
38 if len(text) < 512:
39 return _cell_len(text)
40 _get_size = get_character_cell_size
41 total_size = sum(_get_size(character) for character in text)
42 return total_size
43
44
45 @lru_cache(maxsize=4096)
46 def get_character_cell_size(character: str) -> int:
47 """Get the cell size of a character.
48
49 Args:
50 character (str): A single character.
51
52 Returns:
53 int: Number of cells (0, 1 or 2) occupied by that character.
54 """
55 return _get_codepoint_cell_size(ord(character))
56
57
58 @lru_cache(maxsize=4096)
59 def _get_codepoint_cell_size(codepoint: int) -> int:
60 """Get the cell size of a character.
61
62 Args:
63 codepoint (int): Codepoint of a character.
64
65 Returns:
66 int: Number of cells (0, 1 or 2) occupied by that character.
67 """
68
69 _table = CELL_WIDTHS
70 lower_bound = 0
71 upper_bound = len(_table) - 1
72 index = (lower_bound + upper_bound) // 2
73 while True:
74 start, end, width = _table[index]
75 if codepoint < start:
76 upper_bound = index - 1
77 elif codepoint > end:
78 lower_bound = index + 1
79 else:
80 return 0 if width == -1 else width
81 if upper_bound < lower_bound:
82 break
83 index = (lower_bound + upper_bound) // 2
84 return 1
85
86
87 def set_cell_size(text: str, total: int) -> str:
88 """Set the length of a string to fit within given number of cells."""
89
90 if _is_single_cell_widths(text):
91 size = len(text)
92 if size < total:
93 return text + " " * (total - size)
94 return text[:total]
95
96 if total <= 0:
97 return ""
98 cell_size = cell_len(text)
99 if cell_size == total:
100 return text
101 if cell_size < total:
102 return text + " " * (total - cell_size)
103
104 start = 0
105 end = len(text)
106
107 # Binary search until we find the right size
108 while True:
109 pos = (start + end) // 2
110 before = text[: pos + 1]
111 before_len = cell_len(before)
112 if before_len == total + 1 and cell_len(before[-1]) == 2:
113 return before[:-1] + " "
114 if before_len == total:
115 return before
116 if before_len > total:
117 end = pos
118 else:
119 start = pos
120
121
122 # TODO: This is inefficient
123 # TODO: This might not work with CWJ type characters
124 def chop_cells(text: str, max_size: int, position: int = 0) -> List[str]:
125 """Break text in to equal (cell) length strings, returning the characters in reverse
126 order"""
127 _get_character_cell_size = get_character_cell_size
128 characters = [
129 (character, _get_character_cell_size(character)) for character in text
130 ]
131 total_size = position
132 lines: List[List[str]] = [[]]
133 append = lines[-1].append
134
135 for character, size in reversed(characters):
136 if total_size + size > max_size:
137 lines.append([character])
138 append = lines[-1].append
139 total_size = size
140 else:
141 total_size += size
142 append(character)
143
144 return ["".join(line) for line in lines]
145
146
147 if __name__ == "__main__": # pragma: no cover
148
149 print(get_character_cell_size("😽"))
150 for line in chop_cells("""这是对亚洲语言支持的测试。面对模棱两可的想法，拒绝猜测的诱惑。""", 8):
151 print(line)
152 for n in range(80, 1, -1):
153 print(set_cell_size("""这是对亚洲语言支持的测试。面对模棱两可的想法，拒绝猜测的诱惑。""", n) + "|")
154 print("x" * n)
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