Re: move_it_vertically_backward question

[Po Lu]

Eli Zaretskii <eliz@gnu.org> writes:

> Look at the code: when DY is non-positive, move_it_vertically
> delegates to move_it_vertically_backwards.

Thanks.

> Anyway, I don't necessarily object that we should do this always, but
> then we should document that when FROM is a cons cell, that specifies
> the beginning of the screen line at that pixel offset.

I will document that.

> When window-start is inside a display property or overlay (i.e., the
> first thing shown in the window is the result of that display
> property/overlay), starting from the underlying buffer position will
> almost definitely affect the results, because that buffer position
> could be at a very different position on the screen.  For example,
> what happens if window-start position has a before-string, and that
> string has a 'display' property specifying an image?  This should
> display the image as the first display element at the window
> beginning, and the buffer position of window-start will then be to the
> right and possibly also at a different Y coordinate.

Hmm, perhaps that condition should be removed in this case then.

Thanks.