Nemo: [Feature Request] Improve Compact View Mousewheel Scroll Behavior

[Kreevoz]

In Nemo's Compact View mode (which is awesome!), scrolling vertically with the mousewheel does not emit any scrolling behavior.
The user has to hold SHIFT + Scroll up or Down to initiate horizontal scrolling.

Feature Request:

• A toggle in the Nemo Settings, Behavior -> [ ] Use vertical scrollwheel for horizontal scrolling in Compact View

Reason for this Request:

The behavior is inconsistent and unintuitive:

- In Icon View, Shift + Vertical Scroll does: nothing
- In List View, Shift + Vertical Scroll does: nothing
- In both views, vertical scrolling initiates the main scrolling action.
Edit: Weak argument, successfully challenged.

• In all other file browsers and on other operating systems, scrolling vertically in horizontal view modes will initiate the horizontal scrolling action.
• User onboarding experience can be improved by allowing learned/expected behavior when scrolling in Compact View. Making it a settings toggle will prevent upsetting users who like the current default.

I can understand how for owners of a mouse with an additional horizontal scroll wheel, this split makes sense. The majority of users who do not have such a mouse feature get penalized by having to reach for the keyboard each time they wish to scroll in Compact View mode.

If I have overlooked a hidden or obvious means to alter this behavior (config setting, environment variable etc), then please someone tell me and I'll happily crumple up this feature request and toss it in the bin.

[Axel-Erfurt]

LMDE7 Nemo 6.4.5
In List View, Shift + Vertical Scroll does scrolling horizontal for me

[Kreevoz]

List view doesn't have a horizontal dimension for me, just a vertical list of items. How do you get to the point of needing to scroll horizontally in it?

[cplittlfield]

Activate more columns than the current window can display at once.

In compact view, the same is true, by the way, except that Shift + Scroll is not necessary. Using the scroll wheel on the mouse is sufficient.

[Kreevoz]

@cplittlfield Wait so for you, compact view natively scrolls to the right just by using the scroll wheel alone?
I'm using Nemo as a standalone file browser outside of the Mint desktop environment, would that impact how it responds to the scroll input?

[cplittlfield]

@cplittlfield Wait so for you, compact view natively scrolls to the right just by using the scroll wheel alone? I'm using Nemo as a standalone file browser outside of the Mint desktop environment, would that impact how it responds to the scroll input?

It's possible, but I'm not a dev, so I couldn't say, one way or o the other.

[Axel-Erfurt]

Click the image

[Kreevoz]

I see now what you mean, thanks for the gif.

[Kreevoz]

To make it clearer why I am riding around on this functionality.

After you two pointed it out, I agree that Shift + Scroll works in the other viewmodes where it makes sense. I'm not debating that it needs to be changed there at all. It makes sense.

But in the Compact View mode, regularly scrolling the mousewheel does nothing on my system. No activity at all. This does not seem to be what is intended, but I might completely be misunderstanding the code. Looking at it, I am seeing this:

In the nemo-icon-view.c file, there is the function: nemo_icon_view_scroll_event https://github.com/linuxmint/nemo/blob/032ce13a5a5f1edca811b367a27e8dcf31892afa/src/nemo-icon-view.c#L1819

After checking that the icon_view->details->compact mode is active, and it gets a valid scroll event, it first passes the scroll event to another function, nemo_view_handle_scroll_event in the file nemo-view.c :
https://github.com/linuxmint/nemo/blob/032ce13a5a5f1edca811b367a27e8dcf31892afa/src/nemo-view.c#L10969
This checks if the user is holding down CTRL while scrolling, so it can zoom the view instead.
-> This is not the case for simple scrolling in compact view.
So that function returns FALSE.

Back in the nemo-icon-view.c file function, we thus successfully meet the condition to step into the next block of code which includes...:
https://github.com/linuxmint/nemo/blob/032ce13a5a5f1edca811b367a27e8dcf31892afa/src/nemo-icon-view.c#L1835

This code, which seems to be meant to turn vertical scroll events into horizontal scroll events.....

... so why do I still have to hold down SHIFT? It does not even check for GDK_SHIFT_MASK in this function at all. 😯
Am I too dumb to understand this code properly? Where does it get the requirement to hold SHIFT from?

If my request is untenable and no way in hell anybody would want nemo to ever scroll sideways with a vertical mouse wheel scroll then I'm okay with modifying the code and running a modified version on my system but- it seems to be complete and should be working already. But it doesn't. 😵‍💫 Why?

[Kreevoz]

I figured it out. This is actually a Wayland related bug.
I'll file it with the nemo repository.

[FilouTech]

I have the same scroll-problem in nemo (compact view) when I use a Logitech MX Master 3.
I got a thumb wheel there, but I wanna use the normal mouse wheel to scroll horizontally.
Other mice work fine.

I solved it with a python-script for the time being.

No guarantee that this will work. Use at your own risk!
This worked for me in Linux Mint 22.3 Cinnamon.

Additional dependencies might be needed:
sudo apt install python3-pip python3-gi python3-setuptools python3-pynput python3-ewmh

Make a new file on the desktop with the name: nemo_scroll.py
Open the file with text editor and put in the following text and save it of course:

#START
import subprocess
from pynput import mouse
from ewmh import EWMH
wm = EWMH()
mouse_controller = mouse.Controller()
# Check if nemo is the active window
def is_nemo_compact_active():
    try:
        win = wm.getActiveWindow()
        if not win or 'nemo' not in str(win.get_wm_class()).lower():
            return False
        # Check if compact mode is active / selected
        cmd = ["gsettings", "get", "org.nemo.preferences", "default-folder-viewer"]
        mode = subprocess.check_output(cmd).decode("utf-8").strip().strip("'")
        return mode == "compact-view"
    except:
        return False
def on_scroll(x, y, dx, dy):
    if is_nemo_compact_active():
        # Emulate horizontal scroll
        # dy > 0 is up (becomes left), dy < 0 is down (becomes right)
        if dy > 0:
            # Scroll left
            mouse_controller.scroll(-1, 0)
        elif dy < 0:
            # Scroll right
            mouse_controller.scroll(1, 0)
with mouse.Listener(on_scroll=on_scroll) as listener:
    listener.join()
#END

To start the script open terminal and write:
python3 ~/Desktop/nemo_scroll.py &
(depending on the system language 'Desktop' might be a different name)

To stop the script open terminal and write:
pkill -f nemo_scroll.py

Hope it works!

[Kreevoz]

I had proposed a fix here, back in November: linuxmint/nemo#3636
but it has not been picked up or implemented as of yet.

Your workaround is also pretty clever! 😁 Guess we'll have to help ourselves if nobody else wants to.