[GUI plugin] Palette Switcher

[dunhill]

Palette Switcher is a Calibre interface plugin that lets you manage and apply custom color palettes to the Calibre GUI. It provides a modular and reproducible way to change the look and feel of Calibre

Features
Adds a toolbar icon to access the palette manager.

Automatically detects .calibre-palette files stored in Calibre’s configuration directory.

Lets you select and apply a palette from a popup window.

Applies colors using Qt’s QPalette system.

Supports importing and exporting palettes for easy sharing.

Optionally auto‑applies the last used palette at startup.

Works with multiple variants: light, dark, custom, or any palette you add manually.

Can be extended with .qss style sheets for additional UI tweaks (e.g., scrollbars).

File Structure
Palettes are stored in the palettes/ subdirectory inside Calibre’s configuration folder:

Linux: ~/.config/calibre/palettes

Windows: %APPDATA%\calibre\palettes

Files must use the .calibre-palette extension.

Combined palette files can include both light and dark specifications.

Optional .qss style sheets can be placed in the plugin’s resources/ folder (e.g., scrollbar-dark.qss, scrollbar-light.qss).

Installation
Download the plugin ZIP file.

In Calibre, go to Preferences > Advanced > Plugins.

Click Load plugin from file and select the ZIP.

Restart Calibre. The Palette Switcher icon will appear in the toolbar.

Compatibility
Requires Calibre 6.25 or later.

Should work on Windows, macOS, and Linux.

Tested primarily on Linux — feedback from macOS and Windows users is welcome.

License
This plugin is released under the GNU GPL v3 license.

Credits
Special thanks to Comfy.n for their help in making the plugin work.

Release notes:

Spoiler:

8/02/26 Version 1.0.4 Added a button to delete the selected color palette


Version 1.0.3
A button has been added to reset Calibre's default color palette settings. This was requested by JSWolf.

Version 1.0.2
Instantly switch (with a simple selection) between palette files, supports importing from zip files, and skips duplicate palettes.
Comfy.n Update

Version 1.0.0
Thanks to the help of Comfy.n, this plugin was released.
Translation support added
Internal fixes

[dunhill]

for future use

[Comfy.n]

That's a good starting point, I think.

I prefer the version with automatic palette refresh upon selection.

I managed to make a big archive containing all palette files posted in the Color Palettes thread, imported them with a single click, and now I'm enjoying several themes I hadn't tried before.

Congratulations on your first plugin and thanks for the credits.

[dunhill]

Originally Posted by Comfy.n

That's a good starting point, I think.

I prefer the version with automatic palette refresh upon selection.

I managed to make a big archive containing all palette files posted in the Color Palettes thread, imported them with a single click, and now I'm enjoying several themes I hadn't tried before.

Congratulations on your first plugin and thanks for the credits.

That was the idea behind the add-on; I'm reviewing your file.
Thanks again. Imagine, it's midnight and I'm working flat out here.

[Comfy.n]

I'm trying to figure how some themes are able to style the border outline of the *native* calibre scrollbar handle. I didn't know this is possible.

[dunhill]

Originally Posted by Comfy.n

I'm trying to figure how some themes are able to style the border outline of the *native* calibre scrollbar handle. I didn't know this is possible.

It could be specific to the palette file that QSS is handling, or something

QScrollBar:vertical { border: 1px solid #444; background: #2b2b2b; width: 12px; margin: 0px 0px 0px 0px; } QScrollBar::handle:vertical { background: #888; min-height: 20px; border: 1px solid #555; }

[dunhill]

Here's an improved version that can instantly switch (with just a select) between palette files, supports importing from zip files, and skips duplicate palettes.
Comfy.n Update

[BetterRed]

both

I couldn't be bothered with palettes until now. I've long wanted to use different palettes for each of the calibre installs I dodge between.

What I'd like now is a palette browser - wading through 5 pages of posts in the Colour palettes thread and fishing around elsewhere is tedious. For me it doesn't have to be a calibre plugin, it fact I'd rather it wasn't, maybe a github page of some sort… or DeviantArt maybe.

Anyway - thanks again.

BR

[Terisa de morgan]

I've used it now and it works prefectly. Just a doubt... how do you go back to the default dark or light theme?

--- Forget about it, I found it. Thank you.

[BetterRed]

Originally Posted by Terisa de morgan

I've used it now and it works prefectly. Just a doubt... how do you go back to the default dark or light theme?

--- Forget about it, I found it. Thank you.

Care to share.

BR

[Terisa de morgan]

Preferences -> Look & Feel -> Main Interface -> Adjust Colors -> Restore defaults.

[JSWolf]

Originally Posted by Comfy.n

That's a good starting point, I think.

I prefer the version with automatic palette refresh upon selection.

I managed to make a big archive containing all palette files posted in the Color Palettes thread, imported them with a single click, and now I'm enjoying several themes I hadn't tried before.

Congratulations on your first plugin and thanks for the credits.

Would you mind posting this archive please? Thanks.

[JSWolf]

@dunhill, would you mind adding a return to default button? I know you can do it in calibre's preferences, I see many people no knowing you can do this and/or how.

[Comfy.n]

Originally Posted by JSWolf

Would you mind posting this archive please? Thanks.

Sure, it's attached.

[Comfy.n]

And this is a compact archive that contains only the .palette files.

(the larger archive contains other files their authors chose to share on their original posts, such as readme.txt files and screenshots)