bug#14567: Scrolling of large images

[Eli Zaretskii <eliz@gnu.org>]

> From: Thierry Volpiatto <thierry.volpiatto@gmail.com>
> Date: Sun, 16 Jun 2013 08:18:57 +0200
> 
> Thierry Volpiatto <thierry.volpiatto@gmail.com> writes:
> 
> > Eli Zaretskii <eliz@gnu.org> writes:
> >
> >>> Date: Sat, 15 Jun 2013 14:26:13 +0300
> >>> From: Eli Zaretskii <eliz@gnu.org>
> >>> Cc: 14567@debbugs.gnu.org
> >>> 
> >>> > From: Thierry Volpiatto <thierry.volpiatto@gmail.com>
> >>> > Date: Sat, 15 Jun 2013 13:13:05 +0200
> >>> > 
> >>> > however it would be great to be able to scroll horizontally too.
> >>> 
> >>> That's a much larger project, since we lack infrastructure to scroll
> >>> horizontally by pixels.
> >>
> >> Actually, I see that I was wrong: set-window-hscroll can do the job.
> >> The only problem is to get C-f/C-b and <left>/<right> keys invoke that
> >> function when appropriate.  Patches are welcome.
> >
> > I don't understand how to use this, it is actually setting the number of
> > column where to start scrolling, and it seems an image have only one
> > column?
> >
> > Though only setting `auto-hscroll-mode' to nil let move with C-f/b and
> > left/right as expected, may be this value should be let-bounded when
> > image-mode is detected?
> 
> I saw auto-hscroll-mode was already used, but have no effect, when
> moving it to image-mode and make it buffer-local, it is working.
> However, navigation in image looks a little slower than scrolling
> vertically, but maybe I am wrong.
> 
> 
> diff --git a/lisp/image-mode.el b/lisp/image-mode.el
> index 30dfd04..fdede81 100644
> --- a/lisp/image-mode.el
> +++ b/lisp/image-mode.el

I'm confused: didn't you want C-f/C-b and the arrows to scroll images
in modes other than image-mode?  I mentioned image-mode only as
example of usage of set-window-hscroll, since image-mode already binds
the movement keys to a command that scrolls the image horizontally.
The idea was to use something similar in other modes, when an image is
present in the window.

Wasn't that what you wanted?  If so, why are you suggesting changes to
image-mode?