How can I change the "stack" (folder) icon in the dock?

Question

I'm trying to change the icon of the "stack" (folders) in the dock (Plank). I made a folder in Home and put on the links that I wanted on. Then, I dragged that folder to Plank. This makes a shortcut to the selected folder on Plank. My question is: How I can change that icon?

Answer 1

Changing dock folder icon is not possible in Plank, but in order to get "stacking", the folder-on-dock--with-no-icon is not the only solution.

Instead of having a folder button in the dock without a real icon, we can have a normal launcher with multiple "Desktop Actions" - and WITH proper icon(s).

The practical difference is that with a no-icon dock folder you left-click to get the list of launchers, while here you will have to right-click the dock icon.

We are familiar with desktop actions, as they are present in other dock launchers as right-click options like those of Firefox or Chromium (to start a new window in incognito mode or temporary profile) or of media players like Clementine or Deadbeef (Play, Pause, Stop, Previous, Next).

Right-clicking the Clementine launcher you get this:

The number and type of actions accessible with double-click is set by editing the corresponding desktop file. Usually those actions lack icons, but those can be added once a Icon= line is put under each action as below.

The form of such a file should be like this:

[Desktop Entry]
Icon=
Name=
Actions=FIRST-ACTION;SECOND-ACTION
Type=Application

[Desktop Action FIRST-ACTION]
Name=
Exec=
Icon=

[Desktop Action SECOND-ACTION]
Name=
Exec=
Icon=

The Exec= line under [Desktop Entry] category (to run a program with a single left click like normal dock launchers) is not absolutely necessary, but it is useful and it can also be added, and I would use that for the most important of the programs or commands in this group (Music/Noise in the example below).

I will give an example for a "stack" of audio players. For this I will create the launcher .desktop file (using gedit text editor):

gedit ~/.local/share/applications/play_music.desktop

With these lines:

[Desktop Entry]
Icon=multimedia-audio-player
Name=Play music
Icon=multimedia-audio-player
Actions=vlc;deadbeef;clementine;banshee;pavucontrol
Type=Application

[Desktop Action vlc]
Name=Play VLC
Exec=vlc 
Icon=vlc

[Desktop Action deadbeef]
Name=Play Deadbeef
Exec=deadbeef
Icon=deadbeef

[Desktop Action clementine]
Name=Play Clementine
Exec=clementine
Icon=clementine


[Desktop Action banshee]
Name=Play Banshee
Exec=banshee
Icon=banshee

[Desktop Action pavucontrol]
Name=PulseAudio Volume Control
Exec=pavucontrol
Icon=multimedia-volume-control

To make the file executable:

chmod +x ~/.local/share/applications/play_music.desktop

The Icon= line under Desktop Entry category will get the main dock icon (in this case the Music/Noise one); the icons for each desktop action are those in each desktop action group. (In case new icons are needed: find the proper png icon with any name, put the icon in ~/.local/share/icons and edit the file above to have the same name as the icon in the line Icon=).

For each program that you want to access in this way you can add one or more such actions.

My desktop file above will give this:

Answer 2

It's not possible to change. This is currently drawn by cairo code in Plank. It is not an external asset and it can't be styled with Gtk.CSS

Answer 3

It is possible, but you need Nautilus:

Open Nautilus and find your folder > right click on it and select properties > click on the folder icon at the top right of the properties window > choose your new icon.

Once you have done that add your folder to the dock (remove it first if it is already there).