Re: line-pixel-height beyond eol

[Tak Kunihiro <tkk@misasa.okayama-u.ac.jp>]

Thank you for the response.

>> 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?

With Eww, I often meet pages with wide images.  I want to scroll
pixel-wisely the buffers with auto-hscroll-mode off even when
(current-column) is a large number.

The building block of pixel-wise scrolling is described as below.

  (progn (vertical-motion 1)
         (dolist (vs (number-sequence 1 (1- (frame-char-height))))
           (set-window-vscroll nil vs t) (sit-for 0.01))
         (scroll-up 1))

To determine when to flush in a buffer of lines with different height,
I have to know
  - height of line in pixel of the top line on screen.
I think that, on XXX condition, I rather should obtain it as
frame-char-height instead of line-pixel-height.  I cannot find how to
describe the XXX condition.

Also, to avoid unexpected jump, I want to calculate margin to move the
`hollow’ cursor by vertical-motion.  Here the `hollow’ cursor is
defined as a cursor shown up when (current-column) is large, that can
go over the end of line.  I want to know following two valuse, that
are
  - height of line in pixel where the `hollow’ cursor is
  - y position of the `hollow’ cursor instead of (cdr (posn-x-y (posn-at-point))).
I have no idea how to get those.

Please give me suggestions!