bug#56102: 29.0.50; fit-frame-to-buffer's window-text-pixel-size calculation can be incorrect when only is set to vertically

[martin rudalics]

>>> The problem appears to be the lines:
>>>
>>> (size
>>>              (window-text-pixel-size window from to max-width max-height))
>>>
>>> As the max-width will be larger than the current frame (meaning the
>>> height calculation will not take wrapping into account).

I think MAX-WIDTH should be nil here.

>>> One possible fix is to set min/max height/width based on `only' to
>>> (frame-parameter frame 'width) / (frame-parameter frame 'height) but I
>>> do not know if that is the best fix.

This would not work.  The 'height' frame parameter counts in characters
while 'window-text-pixel-size' wants pixels as X-LIMIT.  Also, the sizes
of frame and window decorations would hardly match.

>>> If that is done, then it may be possible to remove the rest of the
>>> special handling for `only' that sets width/height to nil and handles that.
>>
>> I think you're right, but I'd like to hear if Martin has any comments.
>
> Sounds good. The most minimal change I can think of is to use the
> current frame's width as max-width in the window-text-pixel-size call
> when only is set to vertically. I don't know of any reason we need to
> constrain max-height in that call because it doesn't have the same
> impact. That can be done either explicitly in that call or by changing
> max-width to be set to the current width as I described before. That
> would be asymmetrical with max-height though, which would be rather
> confusing IMO.

Please try the attached diff.

Thanks, martin

fit-frame-to-buffer.diff
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