Re: line-pixel-height beyond eol

[Eli Zaretskii <eliz@gnu.org>]

> From: Tak Kunihiro <tkk@misasa.okayama-u.ac.jp>
> Date: Tue, 12 Sep 2017 19:12:23 +0900
> Cc: Kunihiro Tak <tkk@misasa.okayama-u.ac.jp>
> 
> I want to scroll pixel-wise with auto-hscroll-mode off.
> 
> When auto-hscroll-mode is nil, `hollow’ cursor can go over the end
> of line with an inline image.  As soon as the image is scrolled out to
> the left, on display, height of line shrinks to frame-char-height.

The display engine only renders what's on the screen.

> Since point is on the line, the function `line-pixel-height’ returns
> height of image instead of that of text.

Correct.  line-pixel-height is not documented to depend on what is
displayed on the screen, it reports the dimensions of the line as a
whole.

> Is there a way to obtain the height in pixels of the line at the `hollow’
> point in the selected window?  Or is there a way to maintain the height of
> a line even when an image is horizontally scrolled out?

I don't think I understand what value you want to obtain.  Can you
elaborate, and perhaps also explain what do you want to do with that
value and why?