Smooth image scrolling

[Michael Heerdegen <michael_heerdegen@web.de>]

Hello,

sorry to bring up again this old topic, but I couldn't find a solution
that I liked.

I have experimented with Calc and making the output buffer show the
results as an image (gotten from tex'ing the latex form of the result).

Normally, the calc buffers are only a few lines tall, and one image may
be quite as large, or even larger.  Everything is narrow.

Normal mouse-whell scrolling just jumps past the image, so you have no
chance to see the second half of it.  Even if I scroll in one-line
steps.

So I experimented with scrolling by changing the window's vscroll (as
image-mode uses to do).  Oh, pixel-scroll-mode doesn't behave much
nicer, so that didn't help.

But now changing the windows vscroll comes with new problems.  When
increasing the window's vscroll (say, by one) moves the cursor out of
view, Emacs (redisplay I guess) moves it back into the visible buffer
part (it doesn't change point), and what I get is actually scrolling
backwards.

I then tried to adjust point manually, which is not that simple.  But
even then - when I want to get back to standard scrolling (say I have
now scrolled past the first image), Emacs silently undoes the vscroll
setting, again scrolling backwards in effect.  So I would have to handle
that effect as well, probably reimplementing more or less the whole
scrolling algorithms.

Do I miss something, or is this really ... a bit hard to achieve?

TIA,

Michael.