View does not move upon consecutive slide deletion

[Scafir]

Desciption

The view does not move upon consecutive slide deletion. This is a problem when deleting many slides, because we may end up way further than the last deleted slide.
What happens is that when we delete slide number N to slide number N+K, the view stays at slide number N+K, which is now an unseen slide.

To Reproduce

Steps to reproduce the behavior:

1. Open any long document.
2. Select many consecutive slides and delete them.
3. We end up ahead in the document.

Expected behavior

I would expect that when we delete slide number N to slide number N+K, the view moves at slide number N, so that we can see the splice.

Input files

N/A

Screenshots

N/A

System and Versions

• PDF Arranger version 1.7.1, flatpack
• Pikedpdf version: Not installed. Included in the flatpack?
• Fedora 34

[angsch]

I am not sure if there is something intricate with different pages sizes, but the page deletion does not have a call to scroll_to_selection.

    def on_action_delete(self, _action, _parameter, _unknown):
        """Removes the selected elements in the IconView"""

        self.clear_selected()
+       self.scroll_to_selection()

[Scafir]

Do all your pages have the same dimensions? To me it looks more like the scroll-area is too long if the pages have different dimensions than an error when deleting pages. Actually, the scroll area doesn't need to be longer than necessary in order to make the scroll-slider easier to use. If that is fixed, the scroll-back is fixed as well.

All pages dimensions are the same. I am not sure I correctly the second part of your comment though...
Another thing I should have mentioned is that my view is zoomed a lot, so all slides are in a single column and I can only see two or three at a time (so I can take a good look at them).
Here is the document, if it happens to be useful.

[dreua]

Sorry for the confusion, it seems like I found another issue while trying to reproduce yours and didn't take enough care reading your report. I'll hide my earlier comment and create another issue for what I found.

I'll also take @angsch 's suggestion as a PR, which works great by the way, and commit it straight to main. Thanks to both of you 👍

[dreua]

Looks like I fell straight into a rabbit-hole here: The self.scroll_to_selection() is nice for big one column views, but I don't like it for cases with low zoom level (big grid of small thumbnails) where the destination is already in view and the scrolling is unnecessary, unexpected and distracting. Unfortunately the methods I tried to avoid that don't work. A proper fix is beyond my available time right now, any help is welcome.

[kbengs]

One possible way to do it could be to read if the selected page is in the visible range get_visible_range2() and only scroll_to_selection() if it is not in visible range. But a more proper fix would maybe be to fix 506 first.

[dreua]

I'll need to revisit this, #609 should have made this much easier, thanks @kbengs !

[kbengs]

@dreua are you working on this or do you mind if I try to fix it?

[dreua]

I intended to but apart from the first findings here didnt, sorry. Im happy if you take it :)

[dreua]

Thank you!