bug#4896: DocView: Continuous mode

[Juri Linkov <juri@jurta.org>]

Most of my attempts to use DocView often end up by resorting to
stand-alone PDF viewers.  The reason is a single missing feature
that would be easy to implement in DocView.

What I mean is the continuous page mode where you can scroll through
document pages without having to use the previous-page and next-page keys.

With smooth scrolling, navigation keys like C-p/<up> and C-n/<down>
on reaching the beginning/end of the current page should advance to the
previous/next page.

Using the mouse in the continuous mode requires advancing to another
page on the page edges.

Any opinions on implementing this?

Also please consider the following comments on the current keys
in DocView:

<C-home> doesn't move to the top the document like `M-<' does.
and <C-end> doesn't move to the bottom the document like `M->' does.
But in normal buffers, <C-home> is equivalent to `M-<', and
<C-end> is equivalent to `M->'.

`M->' doesn't move to the end of the document, it moves to the beginning
of the last page, but not to the end of the last page.  However, as I see
in other PDF viewers, <C-end> moves to the beginning of the last page.
So maybe in DocView it should do the same.

After rebinding <C-home>/<C-end> there will be no keys to move to the
beginning/end of the current page (image).  Maybe logically suitable
keys are: `C-a'/<home> and `C-e'/<end>?

-- 
Juri Linkov
http://www.jurta.org/emacs/