121 lines
3.1 KiB
Python
121 lines
3.1 KiB
Python
"""
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Utilities for dealing with string containing wide characters.
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"""
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import re
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from wcwidth import wcwidth, wcswidth
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def _wc_hard_wrap(line, length):
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"""
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Wrap text to length characters, breaking when target length is reached,
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taking into account character width.
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Used to wrap lines which cannot be wrapped on whitespace.
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"""
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chars = []
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chars_len = 0
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for char in line:
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char_len = wcwidth(char)
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if chars_len + char_len > length:
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yield "".join(chars)
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chars = []
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chars_len = 0
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chars.append(char)
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chars_len += char_len
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if chars:
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yield "".join(chars)
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def wc_wrap(text, length):
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"""
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Wrap text to given length, breaking on whitespace and taking into account
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character width.
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Meant for use on a single line or paragraph. Will destroy spacing between
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words and paragraphs and any indentation.
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"""
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line_words = []
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line_len = 0
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words = re.split(r"\s+", text.strip())
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for word in words:
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word_len = wcswidth(word)
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if line_words and line_len + word_len > length:
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line = " ".join(line_words)
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if line_len <= length:
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yield line
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else:
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yield from _wc_hard_wrap(line, length)
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line_words = []
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line_len = 0
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line_words.append(word)
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line_len += word_len + 1 # add 1 to account for space between words
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if line_words:
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line = " ".join(line_words)
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if line_len <= length:
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yield line
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else:
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yield from _wc_hard_wrap(line, length)
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def trunc(text, length):
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"""
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Truncates text to given length, taking into account wide characters.
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If truncated, the last char is replaced by an ellipsis.
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"""
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if length < 1:
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raise ValueError("length should be 1 or larger")
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# Remove whitespace first so no unnecessary truncation is done.
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text = text.strip()
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text_length = wcswidth(text)
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if text_length <= length:
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return text
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# We cannot just remove n characters from the end since we don't know how
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# wide these characters are and how it will affect text length.
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# Use wcwidth to determine how many characters need to be truncated.
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chars_to_truncate = 0
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trunc_length = 0
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for char in reversed(text):
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chars_to_truncate += 1
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trunc_length += wcwidth(char)
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if text_length - trunc_length <= length:
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break
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# Additional char to make room for ellipsis
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n = chars_to_truncate + 1
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return text[:-n].strip() + '…'
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def pad(text, length):
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"""Pads text to given length, taking into account wide characters."""
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text_length = wcswidth(text)
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if text_length < length:
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return text + ' ' * (length - text_length)
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return text
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def fit_text(text, length):
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"""Makes text fit the given length by padding or truncating it."""
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text_length = wcswidth(text)
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if text_length > length:
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return trunc(text, length)
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if text_length < length:
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return pad(text, length)
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return text
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