bug#67533: SVG images confound position pixel measurements

[Eli Zaretskii]

> From: JD Smith <jdtsmith@gmail.com>
> Date: Sun, 3 Dec 2023 10:49:37 -0500
> 
> BTW, in case anyone is wondering where window-text-pixel-size with a negative 
> pixel FROM offset is needed, Po Lu's pixel-scroll-precision-up-page is using 
> precisely this approach to measure the content above window-start (so as to 
> smoothly scroll up with high performance):
> 
>         (let* ((start (window-start))
>                (dims (window-text-pixel-size nil (cons start (- delta))
>                                              start nil nil nil t))
> 

I know very well why that feature was added.  My questions was not
about negative offsets in general, but about negative offsets when
FROM is in the first line of the buffer, i.e. when there's no text at
all above that line.