Feature request: continuous view

[oscarfv]

Is it feasible to implement viewing the top of the next page when you reach the end of the current page? While reading e-books and scrolling down with Space as you advance it is unpleasant that when the bottom of the page is reached the line that was previously at the bottom of the screen now it can be located anywhere depending on the zoom level etc. Other pdf viewers solve this by showing the top of the next page below the current one and thus always advancing the same amount of space on each scroll operation.

Ditto for scrolling up.

[politza]

We could have a fixed-scroll-mode.

Displaying more than one page/image per window is not going to happen
anytime soon.

[oscarfv]

How would work that fixed-scroll-mode?

If Emacs could do the same amount of scrolling every time Space is hitted, it would be good enough for now. Maybe adding empty lines after the image?

[politza]

How would work that fixed-scroll-mode?

Like you described.

[titaniumbones]

Right now the lack of a continuous mode is the only thing that I miss from other viewers. From what you say, this is unlikely to work -- I guess because the buffer is only capable of displaying one image at a time? And is that a fundamental constraint?

In any case I find the jump fro mthe bottom of one page to the top of the next hard to follow. It's too bad because otherwise pdf-tools is already way better than any other viewer!

[politza]

Matt Price notifications@github.com writes:

[...] the buffer is only capable of displaying one image at a time?
And is that a fundamental constraint? [...]

No, but there are some difficulties to overcome. I already have an idea
how, but haven't found the energy to go ahead. I could elaborate, If
you care.

[thisirs]

I'd love the see this feature implemented... This is actually the only thing that keeps me from switching to pdf-tools (which is great btw ;))

[antoine-levitt]

+1 on the comments, this package is great and I'd love to switch to it, but the lack of continuous scrolling is what's keeping me back.

[clubfed]

+1

[Compro-Prasad]

I think that it would be better if you could elaborate so that someone could get how to solve this problem and submit a merge request.

[guilhermemtr]

I also feel that it would be a great new feature to pdf-tools (I actually subscribed to this issue waiting for updates on this feature).

This is what I think is meant by the feature request (illustrated with images, using evince):
Image 1:

Image 2:

Basically, it would be great to be able to scroll the whole document (instead of only having the page by page display), and have the pages appearing as if they were only one very long page (but keeping the delimiters, as in the images).

[politza]

Generally speaking, there are two issues:

1. Large parts of the software (including image-mode) assume a one-to-one correspondence between a displayed page and its window.
2. Emacs is not easily convinced to scroll an image, such that its display starts in the middle of it, in case would completely fits into the window.

[Compro-Prasad]

Can't we display a limited number of images vertically(max 4 pages) in the same buffer and scroll it normally. When we hit the next page or the next next page we can remove images above and add new ones below. I mean it may be something like (save-excursion (redisplay-images)) .

[Compro-Prasad]

Spacemacs accomplishes a scrolling behaviour by remapping the keys but with no continuous effect.

[guilhermemtr]

If I programmed in el I would do the request, but I don't.
Maybe, here is a way to do it:

Use 5 images [0,1,2,3,4].
When the user scrolls out of image[2], start loading image[0] or [4] (depending if it's a scroll up or down).
When the user is reaching the bottom half of [3] (or top-half of [1]): shift the image array down (or up)*, load the new image in [4] (or [0]) and make the pdf shift the view to make a smoother transition (and hopefully seemless)

*e.g. [img1,img2,img3,img4,img5] -> [img2,img3,img4,img5,img??]
Is this doable?
I'm not aware of the implementation details so it might be completely out.

[hisnawi]

Any updates on this?

[pprw]

+1 on this feature request. I personally want also to see double page mode on pdf-tools (see #303).

[Compro-Prasad]

I think we should have a feature request in Emacs for an infinite background scroll mode. Which would help in solving this issue.