Question/Feature request: Item activated on mouse hover (mouseover, hover selection)

[mrpauloen]

Hello Linux Community,

I am currently working on a project to modify Nemo 6.4.3, on Linux Mint 22.1 Xia Cinnamon v: 6.4.6 (and potentially Nautilus, given their shared codebase) to introduce a hover-to-select functionality. This feature would allow files and folders to be highlighted (selected) when the mouse hovers over them, specifically when the "single-click to open" option is enabled.

What I’m Trying to Achieve:

• When "single-click to open items" is active, hovering over a file/folder would highlight it as if it were clicked.
• This behavior is similar to what is found in Windows File Explorer (short preview video below) or PCManFM, where elements become active on hover, enabling operations like renaming (via F2) without the need for an explicit click.

What I've Found So Far:

1. Settings & Components:

   • I located the click behavior settings in nemo-file-management-properties.c:

     static const char * const click_behavior_components[] = {
         "single_click_radiobutton",
         "double_click_radiobutton",
         NULL
     };
     
     static const char * const click_behavior_values[] = {
         "single",
         "double",
         NULL
     };

   • These settings determine the click behavior, but I haven't been able to find a direct way to link them to hover-based selection.

2. Code Exploration:

   • I explored files like nemo-list-view.c, nemo-icon-view.c, and nemo-icon-view-container.c.
   • Functions such as motion_notify_event, enter_notify_event, and leave_notify_event were not explicitly found or connected in ways that handle hover-selection.
   • Nemo includes <gtk/gtk.h>, but I couldn’t find any direct use of GtkIconView or related properties like activate-on-single-click or selection-mode.

3. GTK Documentation Insights:

   • I found properties in GTK such as :hover-selection for GtkTreeView and activate-on-single-click for GtkIconView, but Nemo doesn’t seem to implement these directly.
   • I’m wondering if Nemo uses custom components or if there's a GTK-based way to implement this functionality.

My Questions to the Community:

1. Is there a native or recommended way to implement hover-to-select in Nemo or Nautilus?
2. Could this be achieved by leveraging existing GTK properties like :hover-selection or activate-on-single-click?
3. Are there any internal signals or methods in Nemo/Nautilus that could help link hover events to selection?
4. Would modifying the core code (e.g., nemo-list-view.c) be sufficient, or is there a deeper architectural layer I should explore?

Why This Matters:

This feature would significantly enhance usability for those accustomed to hover-based file selection in other file managers. It would allow for smoother workflows and reduce unnecessary clicks, aligning Nemo with the behavior found in Windows and PCManFM.

I will provide additional screenshots to clarify the intended functionality.

---

Thank you in advance for any insights, suggestions, or guidance! Your expertise will be invaluable in navigating this challenge.

Best regards,

A passionate developer exploring the depths of Nemo/Nautilus customization.

windows.item.activated.on.mouseover.hover.webm

[mtwebster]

Hi, single-click activation isn't for me, but I could see the sense in having 'hover selection' when using it.

Icon view

This is implemented entirely in nemo - there was no GtkIconView yet when it was first written (late 90s). There are a couple of layers - starting in eel-canvas.c, nemo-icon-container.c -> nemo-icon-view-container.c.

You might have a look at nemo-icon-canvas-item.c which manages the rendering of individual icon items. It has an event handler that might be useful - you could possibly tie 'is_prelit' to being selected when in single-click mode...

... How would multi-select work? Or is that not necessary?

List view

Here you may be able to just use existing GtkTreeView functionality, but I would be surprised if it 'just worked' - there's a lot of custom behavior that may be overriding things.

---

Nautilus' code base has changed pretty significantly since Nemo was forked - I doubt there will be much similarity between the two if you attempt to implement it for both apps (if they're even receptive to it in the first place...).

We could probably clean up a lot of code (and maybe fix some bugs also) by porting nemo to use GtkIconView instead of our own implementation, but it would be a huge amount of work, and there's no guarantee it would perform as well, or enable us to keep all of our features, so we've never attempted it. Quite a bit of nautilus/nemo code has ended up being added to Gtk over the years - for instance, there is now a GtkPlacesSidebar that replaced NautilusPlacesSidebar. Unfortunately it's inferior to NemoPlacesSidebar (at least in our opinions for now).

I probably haven't answered everything, feel free to keep bugging us :) but hopefully this gives you a bit more understanding for now.

[Jopp-gh]

How would multi-select work

I've the same question as Mr Webster.
Moreover, selection on hover is usually a feature of applications with a million buttons, like blender 3d.

I see this feature more as a quick way to navigate folders with the cursor focus on the folder icon or a quick way to rename folders/files, with the cursor focus on the name label