bug#9092: movement cursor in speedbar

bug#9092: movement cursor in speedbar

[Juanma Barranquero]

emacs -Q -f speedbar

The cursor is at the bottom of the speedbar window.

<up>    ; the cursor moves over the icon in the previous line
<up>
...
<up>    ; the cursor moves over the icons normally
<right> <left>  ; the cursor is again over the icon
<down>   ; now the cursor moves to the space next to the icon.

and from that moment on, even if you move over the icon, the cursor
moves back outside it.

According to Eli, line-move-visual tells vertical-motion which column
the cursor should move to, and that does not work too well with stuff
that isn't text, like an image or a stretch glyph (like the one for
`(space :align-to NN)') display property.

    Juanma

bug#9092: movement cursor in speedbar

[Lars Ingebrigtsen]

Juanma Barranquero <lekktu@gmail.com> writes:

> emacs -Q -f speedbar
>
> The cursor is at the bottom of the speedbar window.
>
> <up>    ; the cursor moves over the icon in the previous line
> <up>
> ...
> <up>    ; the cursor moves over the icons normally
> <right> <left>  ; the cursor is again over the icon
> <down>   ; now the cursor moves to the space next to the icon.
>
> and from that moment on, even if you move over the icon, the cursor
> moves back outside it.

This behaviour is still present in Emacs 28.

> According to Eli, line-move-visual tells vertical-motion which column
> the cursor should move to, and that does not work too well with stuff
> that isn't text, like an image or a stretch glyph (like the one for
> `(space :align-to NN)') display property.

Speedbar seems to have some invisible characters at the start, and then
an image, and I think that's what's confusing Emacs here.  If it has
been just an image, Emacs usually handles that fine.

Here's a simpler recipe to reproduce:

(dotimes (i 5)
  (insert (propertize "a" 'invisible t)
	  (propertize "c" 'display
		      (find-image '((:type xpm :file "search.xpm"))))
	  (format " foo %s\n" i)))

If we don't have the invisible text before the image, then motion
commands work as expected.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#9092: movement cursor in speedbar

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Date: Tue, 08 Dec 2020 15:46:21 +0100
> Cc: 9092@debbugs.gnu.org
> 
> (dotimes (i 5)
>   (insert (propertize "a" 'invisible t)
> 	  (propertize "c" 'display
> 		      (find-image '((:type xpm :file "search.xpm"))))
> 	  (format " foo %s\n" i)))
> 
> If we don't have the invisible text before the image, then motion
> commands work as expected.

Yes, the invisible text immediately before the image was the trigger
here.

Should be fixed now on the master branch.

bug#9092: movement cursor in speedbar

[Lars Ingebrigtsen]

Eli Zaretskii <eliz@gnu.org> writes:

> Yes, the invisible text immediately before the image was the trigger
> here.
>
> Should be fixed now on the master branch.

Yup; works great, so I'm closing this bug report.

-- 
(domestic pets only, the antidote for overdose, milk.)
   bloggy blog: http://lars.ingebrigtsen.no

bug#9092: movement cursor in speedbar

[Eli Zaretskii]

> From: Lars Ingebrigtsen <larsi@gnus.org>
> Cc: lekktu@gmail.com,  9092@debbugs.gnu.org
> Date: Thu, 17 Dec 2020 12:21:07 +0100
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> > Yes, the invisible text immediately before the image was the trigger
> > here.
> >
> > Should be fixed now on the master branch.
> 
> Yup; works great, so I'm closing this bug report.

FTR, this also fixed posn-at-point and pos-visible-in-window-p, which
were reporting incorrect information when cursor was placed on the
image that follows invisible text at BOL.