Re: (save-excursion (other-window 1)) leaves me in the other window

[Sean McAfee]

Tim X <timx@nospam.dev.null> writes:

> Sean McAfee <eefacm@gmail.com> writes:
>> A native reimplementation of scroll-other-window doesn't work as I'd
>> expect:
>>
>>   (save-excursion
>>     (other-window 1)
>>     (scroll-up))
>>
>> The problem is that the current window isn't restored, which surprised
>> me considerably.  Why doesn't this work, and how would I write a
>> function to go do some stuff in the other window and then come back?
>
> As emacs already has the command to scroll the other window, I'm
> assuming your example is a simplification of what you really want to do.

True.  The situation is this:

I have a frame, split horizontally into two windows.  One window shows
text that came from an OCR process; the other window, in image-mode,
shows the (large) image that was the input to that OCR process.  What I
want to do is work in the text window, shifting the image in the other
window around as I check it against the text.  I assumed I could do
something like this:

(defmacro in-other-window (&rest body)
  `(save-excursion (other-window 1) ,@body))

And then:

(global-set-key [(shift down)]
  (lambda () (interactive) (in-other-window (image-next-line))))

...and similarly for the other three directions.

Although the documentation for save-excursion says that it saves and
restores the current buffer, it doesn't in this case.  I still don't
really know why.  I tried using save-window-excursion instead as Joe
Fineman suggested, but while that worked for image-next-line and
image-previous-line, it doesn't for image-forward-hscroll, which I need
for scrolling horizontally.  I guess the horizontal scroll amount is
something that's saved and restored by save-window-excursion.  So I
finally settled on this:

(defmacro in-other-window (&rest body)
  `(progn
     (other-window 1)
     (unwind-protect
         (progn ,@body)
       (other-window -1))))

I just have to be careful not to alter the window configuration from
within in-other-window.