__init__.py 文件源码

def strcrop(string, width, tail=None):
    """Return `string` cropped to `width`, considering wide characters

    If `tail` is not None, it must be a string that is appended to the cropped
    string.
    """
    def widechar_indexes(s):
        for i,c in enumerate(s):
            if unicodedata.east_asian_width(c) in 'FW':
                yield i

    if strwidth(string) <= width:
        return string  # string is already short enough

    if tail is not None:
        width -= strwidth(tail)  # Account for tail in final width

    indexes = list(widechar_indexes(string)) + [len(string)]
    if not indexes:
        return string[:width]  # No wide chars, regular cropping is ok

    parts = []
    start = 0
    end = 0
    currwidth = strwidth(''.join(parts))

    while indexes and currwidth < width and end < len(string):
        end = indexes.pop(0)
        if end > 0:
            parts.append(string[start:end])
            currwidth = strwidth(''.join(parts))
            start = end

    if currwidth > width:
        excess = currwidth - width
        parts[-1] = parts[-1][:-excess]

    if tail is not None:
        parts.append(tail)

    return ''.join(parts)