Subject: bug#51995: 29.0.50; `string-pixel-width' depends on the current window width

From: Brahimi Saifullah <[email-masked]>
Date: Sun, 21 Nov 2021 15:38:05 -0300

>He mean a REALLY long line.  Like thousands of characters.

>These examples are harmless.  Please try to test (1) with a large buffer
>that has no newline characters and (2) with 'truncate-lines' non-nil.
>'window-text-pixel-size' must be able to handle these cases gracefully
>even if it's not geared to them.

I think there's a misunderstading.
I meant that a facility should be added to `window-text-pixel-size' so
that callers like `string-pixel-width' can ask for having no (X) limit
without specifying a large number themselves.  Basically I want to use:

  (window-text-pixel-size window (point-min) (point) t)
                                                    ^^^
   (or some other value that `window-text-pixel-size' 
   should understand as meaning "no limit" for X-LIMIT)

instead of:

  (window-text-pixel-size window (point-min) (point) 123456789)

The default behavior of the function should stay the same.

>Any clients of 'window-text-pixel-size' like 'string-pixel-width' can
>easily set X-LIMIT to some sufficiently large value without affecting
>the basic functionality of 'window-text-pixel-size'.

Yes, that's the simplest solution, but I find passing a random magic number
instead of providing a simple interface to say "I don't want to use a limit"
(like Y-LIMIT already allows, as I previously mentioned) rather inelegant :)

>Please try the attached patch (if it doesn't apply, I'll send you the
>affected functions separately so you can apply the changes manually).

Can you explain how you are supposed to apply it?

I tried:

  git apply buffer-text-pixel-size.diff

But all it says is:

  error: corrupt patch at line 12

I did apply the changes manually by looking at the .diff file,
and it's seemingly working for me.  Minus one glaring issue:
`string-pixel-width' is using `buffer-size' as the X-LIMIT, but
that function returns the amount of characters in the buffer.
This means that instead of returning the pixel width, it merely
returns the amount of characters in a string.  If I change that,
everything else seems to be in good order.