Re: [PATCH 1/4] python/utils: add enboxify() text decoration utility

[John Snow <jsnow@redhat.com>]

On Tue, Feb 15, 2022 at 5:55 PM Eric Blake <eblake@redhat.com> wrote:
>
> On Tue, Feb 15, 2022 at 05:08:50PM -0500, John Snow wrote:
> > >>> print(enboxify(msg, width=72, name="commit message"))
> > ┏━ commit message ━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┓
> > ┃ enboxify() takes a chunk of text and wraps it in a text art box that ┃
> > ┃  adheres to a specified width. An optional title label may be given, ┃
> > ┃  and any of the individual glyphs used to draw the box may be        ┃
>
> Why do these two lines have a leading space,
>
> > ┃ replaced or specified as well.                                       ┃
>
> but this one doesn't?  It must be an off-by-one corner case when your
> choice of space to wrap on is exactly at the wrap column.
>

Right, you're probably witnessing the right-pad *and* the actual space.

> > ┗━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━━┛
> >
> > Signed-off-by: John Snow <jsnow@redhat.com>
> > ---
> >  python/qemu/utils/__init__.py | 58 +++++++++++++++++++++++++++++++++++
> >  1 file changed, 58 insertions(+)
> >
> > diff --git a/python/qemu/utils/__init__.py b/python/qemu/utils/__init__.py
> > index 7f1a5138c4b..f785316f230 100644
> > --- a/python/qemu/utils/__init__.py
> > +++ b/python/qemu/utils/__init__.py
> > @@ -15,7 +15,10 @@
> >  # the COPYING file in the top-level directory.
> >  #
> >
> > +import os
> >  import re
> > +import shutil
> > +import textwrap
> >  from typing import Optional
> >
> >  # pylint: disable=import-error
> > @@ -23,6 +26,7 @@
> >
> >
> >  __all__ = (
> > +    'enboxify',
> >      'get_info_usernet_hostfwd_port',
> >      'kvm_available',
> >      'list_accel',
> > @@ -43,3 +47,57 @@ def get_info_usernet_hostfwd_port(info_usernet_output: str) -> Optional[int]:
> >          if match is not None:
> >              return int(match[1])
> >      return None
> > +
> > +
> > +# pylint: disable=too-many-arguments
> > +def enboxify(
> > +        content: str = '',
> > +        width: Optional[int] = None,
> > +        name: Optional[str] = None,
> > +        padding: int = 1,
> > +        upper_left: str = '┏',
> > +        upper_right: str = '┓',
> > +        lower_left: str = '┗',
> > +        lower_right: str = '┛',
> > +        horizontal: str = '━',
> > +        vertical: str = '┃',
> > +) -> str:
> > +    """
> > +    Wrap some text into a text art box of a given width.
> > +
> > +    :param content: The text to wrap into a box.
> > +    :param width: The number of columns (including the box itself).
> > +    :param name: A label to apply to the upper-left of the box.
> > +    :param padding: How many columns of padding to apply inside.
> > +    """
>
> Where's theh :param docs for the 6 custom glyphs?
>

Omitted as kinda-sorta-uninteresting. I can add them if we decide we
want this series.
(It's admittedly a bit of a "Hey, what do you think of this?")

> > +    if width is None:
> > +        width = shutil.get_terminal_size()[0]
> > +    prefix = vertical + (' ' * padding)
> > +    suffix = (' ' * padding) + vertical
> > +    lwidth = width - len(suffix)
> > +
> > +    def _bar(name: Optional[str], top: bool = True) -> str:
> > +        ret = upper_left if top else lower_left
> > +        right = upper_right if top else lower_right
> > +        if name is not None:
> > +            ret += f"{horizontal} {name} "
> > +
> > +        assert width is not None
> > +        filler_len = width - len(ret) - len(right)
> > +        ret += f"{horizontal * filler_len}{right}"
> > +        return ret
> > +
> > +    def _wrap(line: str) -> str:
> > +        return os.linesep.join([
> > +            wrapped_line.ljust(lwidth) + suffix
> > +            for wrapped_line in textwrap.wrap(
> > +                    line, width=lwidth, initial_indent=prefix,
> > +                    subsequent_indent=prefix, replace_whitespace=False,
> > +                    drop_whitespace=False, break_on_hyphens=False)
>
> Always nice when someone else has written the cool library function to
> do all the hard work for you ;)  But this is probably where you have the off-by-one I called out above.
>

Yeah, I just didn't want it to eat multiple spaces if they were
present -- I wanted it to reproduce them faithfully. The tradeoff is
some silliness near the margins.

Realistically, if I want something any better than what I've done
here, I should find a library to do it for me instead -- but for the
sake of highlighting some important information, this may be
just-enough-juice.

--js