Re: Displaying scrollable images in a grid-layout

[Eli Zaretskii <eliz@gnu.org>]

> From: Andreas Politz <politza@hochschule-trier.de>
> Date: Tue, 14 Apr 2015 21:29:04 +0200
> 
> Eli Zaretskii <eliz@gnu.org> writes:
> 
> >> Try this:
> >> 
> >>      (defun show-data-dir-images (&optional ncolumns)
> >> [...]
> 
> > After running this function, this works for me:
> >
> >    (set-window-vscroll nil N t)
> >
> > as long as (a) point is not on the first screen line shown in the
> > window, and (b) N is no more than 24, which AFAICS is the pixel size
> > of the small images created by the above function.
> 
> Yes but the whole point is to display only half of an image at the top.

Like I said: it works for me under the conditions described above.

> This recipe is not ideal. In the real application I would have 2 images
> (pages of a PDF) side by side, filling e.g 3/4 of the windows vertical
> space.  Below these images are another 2 which are only 1/4-way visible.
> Now I want to scroll these 4 images up by let's say the equivalent of
> next-screen-context-lines in pixels.

Can you explain why such a partial scroll is a good idea?  We can show
the entire line, and yet you want us to show only part of it?

> Would this be a feature supported by Emacs ?

Like I said, it goes against the current redisplay strategy to show
full lines whenever possible.  So it would be possible to support that
under some option, but it would need a lot of non-trivial changes.