from __future__ import annotations from functools import lru_cache from typing import Callable from ._cell_widths import CELL_WIDTHS # Ranges of unicode ordinals that produce a 1-cell wide character # This is non-exhaustive, but covers most common Western characters _SINGLE_CELL_UNICODE_RANGES: list[tuple[int, int]] = [ (0x20, 0x7E), # Latin (excluding non-printable) (0xA0, 0xAC), (0xAE, 0x002FF), (0x00370, 0x00482), # Greek / Cyrillic (0x02500, 0x025FC), # Box drawing, box elements, geometric shapes (0x02800, 0x028FF), # Braille ] # A set of characters that are a single cell wide _SINGLE_CELLS = frozenset( [ character for _start, _end in _SINGLE_CELL_UNICODE_RANGES for character in map(chr, range(_start, _end + 1)) ] ) # When called with a string this will return True if all # characters are single-cell, otherwise False _is_single_cell_widths: Callable[[str], bool] = _SINGLE_CELLS.issuperset @lru_cache(4096) def cached_cell_len(text: str) -> int: """Get the number of cells required to display text. This method always caches, which may use up a lot of memory. It is recommended to use `cell_len` over this method. Args: text (str): Text to display. Returns: int: Get the number of cells required to display text. """ if _is_single_cell_widths(text): return len(text) return sum(map(get_character_cell_size, text)) def cell_len(text: str, _cell_len: Callable[[str], int] = cached_cell_len) -> int: """Get the number of cells required to display text. Args: text (str): Text to display. Returns: int: Get the number of cells required to display text. """ if len(text) < 512: return _cell_len(text) if _is_single_cell_widths(text): return len(text) return sum(map(get_character_cell_size, text)) @lru_cache(maxsize=4096) def get_character_cell_size(character: str) -> int: """Get the cell size of a character. Args: character (str): A single character. Returns: int: Number of cells (0, 1 or 2) occupied by that character. """ codepoint = ord(character) _table = CELL_WIDTHS lower_bound = 0 upper_bound = len(_table) - 1 index = (lower_bound + upper_bound) // 2 while True: start, end, width = _table[index] if codepoint < start: upper_bound = index - 1 elif codepoint > end: lower_bound = index + 1 else: return 0 if width == -1 else width if upper_bound < lower_bound: break index = (lower_bound + upper_bound) // 2 return 1 def set_cell_size(text: str, total: int) -> str: """Set the length of a string to fit within given number of cells.""" if _is_single_cell_widths(text): size = len(text) if size < total: return text + " " * (total - size) return text[:total] if total <= 0: return "" cell_size = cell_len(text) if cell_size == total: return text if cell_size < total: return text + " " * (total - cell_size) start = 0 end = len(text) # Binary search until we find the right size while True: pos = (start + end) // 2 before = text[: pos + 1] before_len = cell_len(before) if before_len == total + 1 and cell_len(before[-1]) == 2: return before[:-1] + " " if before_len == total: return before if before_len > total: end = pos else: start = pos def chop_cells( text: str, width: int, ) -> list[str]: """Split text into lines such that each line fits within the available (cell) width. Args: text: The text to fold such that it fits in the given width. width: The width available (number of cells). Returns: A list of strings such that each string in the list has cell width less than or equal to the available width. """ _get_character_cell_size = get_character_cell_size lines: list[list[str]] = [[]] append_new_line = lines.append append_to_last_line = lines[-1].append total_width = 0 for character in text: cell_width = _get_character_cell_size(character) char_doesnt_fit = total_width + cell_width > width if char_doesnt_fit: append_new_line([character]) append_to_last_line = lines[-1].append total_width = cell_width else: append_to_last_line(character) total_width += cell_width return ["".join(line) for line in lines] if __name__ == "__main__": # pragma: no cover print(get_character_cell_size("😽")) 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): print(line) for n in range(80, 1, -1): 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) + "|") print("x" * n)