| | """ |
| | This module provides functions for justifying Unicode text in a monospaced |
| | display such as a terminal. |
| | |
| | We used to have our own implementation here, but now we mostly rely on |
| | the 'wcwidth' library. |
| | """ |
| |
|
| | from unicodedata import normalize |
| |
|
| | from wcwidth import wcswidth, wcwidth |
| |
|
| | from ftfy.fixes import remove_terminal_escapes |
| |
|
| |
|
| | def character_width(char: str) -> int: |
| | r""" |
| | Determine the width that a character is likely to be displayed as in |
| | a monospaced terminal. The width for a printable character will |
| | always be 0, 1, or 2. |
| | |
| | Nonprintable or control characters will return -1, a convention that comes |
| | from wcwidth. |
| | |
| | >>> character_width('θ»') |
| | 2 |
| | >>> character_width('A') |
| | 1 |
| | >>> character_width('\N{ZERO WIDTH JOINER}') |
| | 0 |
| | >>> character_width('\n') |
| | -1 |
| | """ |
| | return int(wcwidth(char)) |
| |
|
| |
|
| | def monospaced_width(text: str) -> int: |
| | r""" |
| | Return the number of character cells that this string is likely to occupy |
| | when displayed in a monospaced, modern, Unicode-aware terminal emulator. |
| | We refer to this as the "display width" of the string. |
| | |
| | This can be useful for formatting text that may contain non-spacing |
| | characters, or CJK characters that take up two character cells. |
| | |
| | Returns -1 if the string contains a non-printable or control character. |
| | |
| | >>> monospaced_width('γ‘γγΆε°θΏγ') |
| | 12 |
| | >>> len('γ‘γγΆε°θΏγ') |
| | 6 |
| | >>> monospaced_width('owl\N{SOFT HYPHEN}flavored') |
| | 11 |
| | >>> monospaced_width('example\x80') |
| | -1 |
| | |
| | A more complex example: The Korean word 'ibnida' can be written with 3 |
| | pre-composed characters or 7 jamo. Either way, it *looks* the same and |
| | takes up 6 character cells. |
| | |
| | >>> monospaced_width('μ
λλ€') |
| | 6 |
| | >>> monospaced_width('\u110b\u1175\u11b8\u1102\u1175\u1103\u1161') |
| | 6 |
| | |
| | The word "blue" with terminal escapes to make it blue still takes up only |
| | 4 characters, when shown as intended. |
| | >>> monospaced_width('\x1b[34mblue\x1b[m') |
| | 4 |
| | """ |
| | |
| | |
| | |
| | |
| | |
| | return int(wcswidth(remove_terminal_escapes(normalize("NFC", text)))) |
| |
|
| |
|
| | def display_ljust(text: str, width: int, fillchar: str = " ") -> str: |
| | """ |
| | Return `text` left-justified in a Unicode string whose display width, |
| | in a monospaced terminal, should be at least `width` character cells. |
| | The rest of the string will be padded with `fillchar`, which must be |
| | a width-1 character. |
| | |
| | "Left" here means toward the beginning of the string, which may actually |
| | appear on the right in an RTL context. This is similar to the use of the |
| | word "left" in "left parenthesis". |
| | |
| | >>> lines = ['Table flip', '(β―Β°β‘Β°)β―οΈ΅ β»ββ»', 'γ‘γγΆε°θΏγ'] |
| | >>> for line in lines: |
| | ... print(display_ljust(line, 20, 'β')) |
| | Table flipββββββββββ |
| | (β―Β°β‘Β°)β―οΈ΅ β»ββ»βββββββ |
| | γ‘γγΆε°θΏγββββββββ |
| | |
| | This example, and the similar ones that follow, should come out justified |
| | correctly when viewed in a monospaced terminal. It will probably not look |
| | correct if you're viewing this code or documentation in a Web browser. |
| | """ |
| | if character_width(fillchar) != 1: |
| | raise ValueError("The padding character must have display width 1") |
| |
|
| | text_width = monospaced_width(text) |
| | if text_width == -1: |
| | |
| | return text |
| |
|
| | padding = max(0, width - text_width) |
| | return text + fillchar * padding |
| |
|
| |
|
| | def display_rjust(text: str, width: int, fillchar: str = " ") -> str: |
| | """ |
| | Return `text` right-justified in a Unicode string whose display width, |
| | in a monospaced terminal, should be at least `width` character cells. |
| | The rest of the string will be padded with `fillchar`, which must be |
| | a width-1 character. |
| | |
| | "Right" here means toward the end of the string, which may actually be on |
| | the left in an RTL context. This is similar to the use of the word "right" |
| | in "right parenthesis". |
| | |
| | >>> lines = ['Table flip', '(β―Β°β‘Β°)β―οΈ΅ β»ββ»', 'γ‘γγΆε°θΏγ'] |
| | >>> for line in lines: |
| | ... print(display_rjust(line, 20, 'β')) |
| | ββββββββββTable flip |
| | βββββββ(β―Β°β‘Β°)β―οΈ΅ β»ββ» |
| | ββββββββγ‘γγΆε°θΏγ |
| | """ |
| | if character_width(fillchar) != 1: |
| | raise ValueError("The padding character must have display width 1") |
| |
|
| | text_width = monospaced_width(text) |
| | if text_width == -1: |
| | return text |
| |
|
| | padding = max(0, width - text_width) |
| | return fillchar * padding + text |
| |
|
| |
|
| | def display_center(text: str, width: int, fillchar: str = " ") -> str: |
| | """ |
| | Return `text` centered in a Unicode string whose display width, in a |
| | monospaced terminal, should be at least `width` character cells. The rest |
| | of the string will be padded with `fillchar`, which must be a width-1 |
| | character. |
| | |
| | >>> lines = ['Table flip', '(β―Β°β‘Β°)β―οΈ΅ β»ββ»', 'γ‘γγΆε°θΏγ'] |
| | >>> for line in lines: |
| | ... print(display_center(line, 20, 'β')) |
| | βββββTable flipβββββ |
| | βββ(β―Β°β‘Β°)β―οΈ΅ β»ββ»ββββ |
| | ββββγ‘γγΆε°θΏγββββ |
| | """ |
| | if character_width(fillchar) != 1: |
| | raise ValueError("The padding character must have display width 1") |
| |
|
| | text_width = monospaced_width(text) |
| | if text_width == -1: |
| | return text |
| |
|
| | padding = max(0, width - text_width) |
| | left_padding = padding // 2 |
| | right_padding = padding - left_padding |
| | return fillchar * left_padding + text + fillchar * right_padding |
| |
|