Pdf.js: single page mode

[samth]

For reading presentations, it would be nice to have a singe-page/non-continuous mode. This would make scrolling keys either move to the entire next page, or not show the next page at all. Evince currently has such a mode, separate from a full screen/presentation mode.

[samth]

Just noticed that this is basically the same as #1380, so closing.

[saebekassebil]

You should reopen this, as #1380 is not the same issue. 1380 was about being able to scroll a page down in general. Your's are about having a _mode_ to enter and leave.

I'm implementing this in the presentation mode I'm working on, but as I understand it you'd like to have a seperate mode? How does one dis/enable a such mode in Evince?

[saebekassebil]

I've implemented a Presentation mode #1388 - I'm aware that it might not be what you're looking for, but it utilizes a Single Page mode, which could be easily implemented in PDF.js - Maybe you'd like to submit a pull request?

[samth]

I've reopened the issue.

To activate the mode in Evince, go to the "View" menu, and uncheck "Continuous".

[saebekassebil]

This would be a great feature, but it might be hard to let the user turn it on/off 'cause I'm not sure how much more room we can take up in the toolbar. Do you have any great ideas how this could be presented to the user? Maybe just a shortcut combination to activate/deactivate it?

_EDIT:_ Or maybe we could just use this mode, when the zoom level is set to "page-fit" - That would replicate the behavior of Adobe Reader and seems like a reasonable approach?

[yurydelendik]

@samth, not sure why this issue is opened/re-opened. pdf.js let you switch between pages using left/right keys or page up/down toolbar buttons. Could you provide a good explanation and benefits of setting this mode explicitly?

Personally, I never used this mode in evince/reader and it's always a pain when non-continuous mode set by default to use with mouse, trackpad or touchscreen.

[ericlenio]

I have a use case for this feature: for larger PDFs. Using Chrome on my (2 year old) Android phone, it's pretty easy to cause a crash with the standard tracemonkey PDF, and we have a requirement for much larger PDFs. My gut feeling is that single page mode would at least help preclude crashes. @saebekassebil: you mentioned it would be easy to implement single page mode, can you share some insights on how you'd go about that and I'll take a crack at it... by the way presentation mode doesn't quite fit what I want, I want to keep the standard viewer toolbar in play.

[allefeld]

I support this request.

I'm developing a presentation with beamer and previewing it with pdf.js (not presenting). It is a hassle to scroll up/down to have the whole slide in view. I scroll using the mouse wheel, because the keyboard focus should remain in the editor. An alternative are the page down / up buttons, but that requires more attention than simply flipping through with the wheel.

It should work roughly like this: If there is a scroll event that would move part of the current page out of the view, make it a page up / down event instead.

I'm surprised there is a discussion whether this is a useful feature. It is standard in most pdf viewers I've used (Adobe Acrobat, Okular, Foxit Reader, ...)

For example in Adobe Acrobat (old v9 for Linux):

As for how to present it in the UI, it could simply be a toggle button in the right-hand pull-down menu.

[nicola-gigante]

I was directed here from an issue in VSCode's LaTeX workshop plugin: https://github.com/James-Yu/LaTeX-Workshop/issues/1789.

When previewing presentations (made with beamer in my case), single-page mode is essential, because otherwise you cannot test how transitions will actually be shown during the presentation.

So this feature is very much needed please.