Continuous image scrolling (was: What improvements would be truly useful?)

[Juri Linkov]

>>> What would improve my user experience would be improvements to the
>>> display engine that will allow a better document viewing capabilities
>>> in something like pdf-tools (like continuous scrolling).
>>
>> Continuous scrolling can be easily implemented with a simple hack
>> to insert adjacent images for the previous/next pdf pages in
>> the same DocView buffer.
>
> I've looked into implementing this feature and it is not as simple as it
> seems. The hack you mention is precisely that: a hack, and a very cranky
> one. AFAIK there is no way of implementing continous scrolling with
> adjacent images if you care at all about robustness and user experience.
> And the fact that people is asking for this feature for years and, to
> this day, nobody implemented it, seems to confirm my impressions.

I just realized we already have continuous image scrolling mode:

1. visiting a PDF file generates PNG images in the temporary directory
2. C-x d /tmp/docview1000/... RET
3. M-x iimage-mode RET
4. enjoy continuous image scrolling mode directly in dired
   (the same logic could be later incorporated into doc-view.el)

I tried this with a directory containing ca 1000 pages/images
and there is no performance degradation while continuously scrolling
all these 1000 images.