[GUI Plugin] Generate Cover

[slimcat]

I have an update on the font issue in the Generate Cover plugin, as well as a relatively easy workaround that works in Calibre 8.

The same issue (some fonts not showing up in the menu and other fonts not working) happens in Calibre’s Ebook Editor in the Editor Settings font picker. The failures are identical to Generate Cover and visible in the menu itself. I submitted a bug report and Kovid’s response was that it’s not a Calibre problem, it’s a Qt problem. I’m not a developer, so I wasn’t familiar with Qt, but apparently it’s the framework Calibre is built on. Bottom line: a fix is not coming from Calibre.

While rolling back to Calibre 7 may fix this issue on Windows, that doesn’t work on Mac. And even if it did, I use the Generate Cover plugin a lot, so jumping back and forth between different Calibre versions would be super inconvenient (and I wouldn’t be willing to stick to an outdated version of Calibre, especially since God knows when/if this will be fixed in Qt).

But there’s a very quick and simple hack to get specific fonts working correctly (and added to the menu if they’re missing) using the free, open-source app FontForge: https://fontforge.org/en-US/.

It only takes a minute or two and works on all static, user-installed fonts (~/Library/Fonts or /Library/Fonts). It doesn’t work on variable fonts, Adobe Creative Cloud-activated fonts, or system fonts.

This is how to do it on Mac, but I assume the steps are similar on Windows:

1. Make a copy of the font and add Calibre to the file name (e.g. Your-Font-Name.otf → Your-Font-Name-Calibre.otf)

2. Open the Calibre copy of the font in FontForge.

3. Go to Element → Font Info.

4. Edit the first 3 fields in PS Names so they match. Fontname can’t have any spaces, but it will match the others if the words are the same.

• Fontname: Your-Font-Name-Calibre
• Family Name: Your Font Name Calibre
• Name for Humans: Your Font Name Calibre

5. Review/edit the following four TTF Names. Family, Fullname, and Preferred Family (if it appears) must match. If your font is already in the Generate Cover menu, leave the Styles string alone. If you’re trying to add a font that’s missing, you’ll also (usually) need to change Styles (Subfamily) to Regular.

• Family: Your Font Name Calibre
• Styles (SubFamily): Regular
• Fullname: Your Font Name Calibre
• Preferred Family: Your Font Name Calibre

Leave everything else as is. Click OK when finished.

6. Click Change in the popup that appears asking to change the UniqueID.

7. Go to File → Generate Fonts

8. In the Generate Fonts window:

• Choose a save location (usually ~/Library/Fonts)
• Make sure the file name matches the name you created at the start
• Select the correct format: OpenType (CFF) for OTF fonts, TrueType for TTF
• Click Generate
• In the popup that appears saying the file already exists, click Replace (you’re just replacing the copy you made with your new edited version)

(For TTF fonts, you may get a Non-standard Em-Size popup. For both TTF and OTF fonts, you may get a warning about Windows kerning. You can safely ignore both. If you test the original, unedited font, you’ll see the same alerts.)

That’s all you have to do.

There’s no confirmation message from FontForge, but you can confirm it worked by looking in your fonts folder. If the font was successfully regenerated, you'll see a new modified date. Relaunch Calibre if it's open. Your new, working font will be in the Generate Cover font menu and ready to use.

For a walkthrough, screenshots are here: https://imgur.com/a/workaround-gener...-issue-QLAo9N1

[Saiyuki_Eiri]

Originally Posted by slimcat

I have an update on the font issue in the Generate Cover plugin, as well as a relatively easy workaround that works in Calibre 8.

The same issue (some fonts not showing up in the menu and other fonts not working) happens in Calibre’s Ebook Editor in the Editor Settings font picker. The failures are identical to Generate Cover and visible in the menu itself. I submitted a bug report and Kovid’s response was that it’s not a Calibre problem, it’s a Qt problem. I’m not a developer, so I wasn’t familiar with Qt, but apparently it’s the framework Calibre is built on. Bottom line: a fix is not coming from Calibre.

While rolling back to Calibre 7 may fix this issue on Windows, that doesn’t work on Mac. And even if it did, I use the Generate Cover plugin a lot, so jumping back and forth between different Calibre versions would be super inconvenient (and I wouldn’t be willing to stick to an outdated version of Calibre, especially since God knows when/if this will be fixed in Qt).

But there’s a very quick and simple hack to get specific fonts working correctly (and added to the menu if they’re missing) using the free, open-source app FontForge: https://fontforge.org/en-US/.

It only takes a minute or two and works on all static, user-installed fonts (~/Library/Fonts or /Library/Fonts). It doesn’t work on variable fonts, Adobe Creative Cloud-activated fonts, or system fonts.

This is how to do it on Mac, but I assume the steps are similar on Windows:

1. Make a copy of the font and add Calibre to the file name (e.g. Your-Font-Name.otf → Your-Font-Name-Calibre.otf)

2. Open the Calibre copy of the font in FontForge.

3. Go to Element → Font Info.

4. Edit the first 3 fields in PS Names so they match. Fontname can’t have any spaces, but it will match the others if the words are the same.

• Fontname: Your-Font-Name-Calibre
• Family Name: Your Font Name Calibre
• Name for Humans: Your Font Name Calibre

5. Review/edit the following four TTF Names. Family, Fullname, and Preferred Family (if it appears) must match. If your font is already in the Generate Cover menu, leave the Styles string alone. If you’re trying to add a font that’s missing, you’ll also (usually) need to change Styles (Subfamily) to Regular.

• Family: Your Font Name Calibre
• Styles (SubFamily): Regular
• Fullname: Your Font Name Calibre
• Preferred Family: Your Font Name Calibre

Leave everything else as is. Click OK when finished.

6. Click Change in the popup that appears asking to change the UniqueID.

7. Go to File → Generate Fonts

8. In the Generate Fonts window:

• Choose a save location (usually ~/Library/Fonts)
• Make sure the file name matches the name you created at the start
• Select the correct format: OpenType (CFF) for OTF fonts, TrueType for TTF
• Click Generate
• In the popup that appears saying the file already exists, click Replace (you’re just replacing the copy you made with your new edited version)

(For TTF fonts, you may get a Non-standard Em-Size popup. For both TTF and OTF fonts, you may get a warning about Windows kerning. You can safely ignore both. If you test the original, unedited font, you’ll see the same alerts.)

That’s all you have to do.

There’s no confirmation message from FontForge, but you can confirm it worked by looking in your fonts folder. If the font was successfully regenerated, you'll see a new modified date. Relaunch Calibre if it's open. Your new, working font will be in the Generate Cover font menu and ready to use.

For a walkthrough, screenshots are here: https://imgur.com/a/workaround-gener...-issue-QLAo9N1

IT WORKED! Thank you so much! I like to use Adobe Garamond Pro Bold as a Title Font for my Covers, so I thought it won't work, but it did! I simply name all the font as Calibre Titles (removed completely the Adobe part), followed your instrucstions et voilà! Finally I will be able to keep reading on my kindle

[slimcat]

Originally Posted by Saiyuki_Eiri

IT WORKED! Thank you so much! I like to use Adobe Garamond Pro Bold as a Title Font for my Covers, so I thought it won't work, but it did! I simply name all the font as Calibre Titles (removed completely the Adobe part), followed your instrucstions et voilà! Finally I will be able to keep reading on my kindle

So glad it worked for you!

Adobe fonts work with this hack as long as you have the actual font files and they're installed locally, rather than activated through Creative Cloud.

[kiwidude]

Release Notes
https://github.com/kiwidude68/calibr...te_cover-2.3.7

[Tharos]

By default, the plugin offers to use the current cover, which is located in the same directory (as cover.jpg) as the ebook.

Is it possible to make an additional adjustment here so that a different image from the directory can be used? If I understand correctly, Calibre renames an added image so that it has the same name as the ebook file.

I am asking because once the existing cover has been changed, I cannot use it again if information about the ebook changes later and I would like to have that information on the cover as well.

[bondo]

I have a feature request...
It would be nice if I could select a background image to use for a cover.
A static one that would be used for every cover and a dynamic one that would override the static background for an individual book.

thanks

[RUATXNJR06]

Is it possible to add my own book cover edits to my Calibre rotation of book covers possible?

[compurandom]

Originally Posted by bondo

I have a feature request...
It would be nice if I could select a background image to use for a cover.
A static one that would be used for every cover and a dynamic one that would override the static background for an individual book.

For the second one, I just set the book cover with the image I want, and then have "current cover" set as the default.. although that's not exactly a background image.

[JSWolf]

Originally Posted by bondo

I have a feature request...
It would be nice if I could select a background image to use for a cover.
A static one that would be used for every cover and a dynamic one that would override the static background for an individual book.

thanks

You need to actually have a cover image so the reading software can actually pull out the cover.

[regina3264]

Hi, I'm going to be very upfront about the fact that I am a complete idiot, and this is undoubtedly somehow my fault, but I'm hoping someone smarter than me will be able to help me figure it out.

My laptop died a bitter and sudden death and I wasn't able to export all of my Calibre settings, though I do have my libraries. So I've been trying to set up all the plugins and everything I had before, and it's all gone fine, except Generate Cover, which just...doesn't appear when I install it. I can find it on the list of installed plugins, but not as a menu option, and when I try to customize it, it says I need to restart Calibre before I can customize this plugin.

No matter how many times I restart Calibre, I get the same message. The plugin still won't show up on the menu, and won't let me customize it. I've uninstalled it, reinstalled it, restarted Calibre a thousand times, restarted my entire computer several times, tried downloading the zip version and loading it that way...nothing is working.

I absolutely cannot figure out what I've done wrong, and I'm not even getting error messages that could give me (or someone, at least) a clue. Does anyone know what I screwed up, and how I could fix it?

Thanks in advance!

[PeterT]

One useful approach is to start calibre in debug mode (on preferences menu), and then shut calibre down and post the resulting log file. In cases like this there will often be an error message from the plugin showing why it's not initializing properly.

[regina3264]

Originally Posted by PeterT

One useful approach is to start calibre in debug mode (on preferences menu), and then shut calibre down and post the resulting log file. In cases like this there will often be an error message from the plugin showing why it's not initializing properly.

Hi, thank you! Okay, I did this, and I got the debug log, but I can't pretend to understand this, so:

Spoiler:

ApplicationPaletteChange event ignored
Using calibre Qt style: True
Traceback (most recent call last):
File "calibre\gui2\ui.py", line 134, in __init__
File "calibre\gui2\ui.py", line 152, in init_iaction
File "calibre\customize\__init__.py", line 678, in load_actual_plugin
File "importlib\__init__.py", line 88, in import_module
File "<frozen importlib._bootstrap>", line 1398, in _gcd_import
File "<frozen importlib._bootstrap>", line 1371, in _find_and_load
File "<frozen importlib._bootstrap>", line 1342, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 938, in _load_unlocked
File "calibre\customize\zipplugin.py", line 219, in exec_module
File "calibre_plugins.generate_cover.action", line 17, in <module>
File "<frozen importlib._bootstrap>", line 1371, in _find_and_load
File "<frozen importlib._bootstrap>", line 1342, in _find_and_load_unlocked
File "<frozen importlib._bootstrap>", line 938, in _load_unlocked
File "calibre\customize\zipplugin.py", line 219, in exec_module
File "calibre_plugins.generate_cover.config", line 108, in <module>
File "calibre\utils\config.py", line 320, in __init__
File "calibre\utils\config.py", line 349, in refresh
File "calibre\utils\config_base.py", line 377, in read_data
File "calibre\utils\config_base.py", line 360, in retry_on_fail
File "calibre\utils\config_base.py", line 375, in r
PermissionError: [Errno 13] Permission denied: 'C:\\Users\\dani_\\AppData\\Roaming\\calibre\\plug ins\\Generate Cover.json'
EpubMerge: DEBUG: 2026-04-03 17:09:58,724: calibre_plugins.epubmerge.epubmerge_plugin(156): macmenuhack file_path:C:\Users\dani_\AppData\Roaming\calibre\p lugins\fanficfare_macmenuhack.txt
calibre Debug log
calibre 9.6 embedded-python: True
Windows-11-10.0.26200-SP0 Windows ('64bit', 'WindowsPE')
('Windows', '11', '10.0.26200')
Python 3.14.2
Windows: ('11', '10.0.26200', 'SP0', 'Multiprocessor Free')
Interface language: None
EXE path: C:\Program Files\Calibre2\calibre-debug.exe
Successfully initialized third party plugins: BookFusion Plugin (0, 8, 1) && Count Pages (1, 15, 1) && EpubMerge (3, 2, 0) && FanFicFare (4, 56, 0) && Generate Cover (2, 3, 7) && Goodreads (1, 8, 4)
calibre 9.6 embedded-python: True
Windows-11-10.0.26200-SP0 Windows ('64bit', 'WindowsPE')
('Windows', '11', '10.0.26200')
Python 3.14.2
Windows: ('11', '10.0.26200', 'SP0', 'Multiprocessor Free')
Interface language: None
EXE path: C:\Program Files\Calibre2\calibre-debug.exe
Successfully initialized third party plugins: BookFusion Plugin (0, 8, 1) && Count Pages (1, 15, 1) && EpubMerge (3, 2, 0) && FanFicFare (4, 56, 0) && Generate Cover (2, 3, 7) && Goodreads (1, 8, 4)
QPA platform: windows
devicePixelRatio: 1.5
logicalDpi: 96.0 x 96.0
physicalDpi: 92.89142857142856 x 96.25263157894736
[0.00] Starting up...
[0.00] Showing splash screen...
[1.17] splash screen shown
[1.17] Initializing db...
[1.28] db initialized
[1.28] Constructing main UI...
[2.92] GUI main window shown
[3.00] main UI initialized...
[3.00] Hiding splash screen
[3.00] splash screen hidden
[3.00] Started up in 3.00 seconds with 2510 books
[66.97] Shutdown starting...
[67.02] Shutdown message shown...
[67.02] Grid view shutdown
[67.02] Bookshelf view shutdown
[67.02] Actions shutdown
[67.22] Various services shutdown
[67.22] Metadata backup shutdown
[67.23] Current database closed
[67.24] Windows hidden
[67.28] Waiting for overseers, mdns, and live to shutdown
[67.28] Waiting for device manager to shutdown
[67.28] Shutdown complete in 0.31, quitting...

[theducks]

PermissionError: [Errno 13] Permission denied: 'C:\\Users\\dani_\\AppData\\Roaming\\calibre\\plug ins\\Generate Cover.json'
Why would one plugin have a permissions issue? did the json file come from some other install?

[BetterRed]

Not the first instance in recent weeks (# 35) ==>> https://www.mobileread.com/forums/sh...onError&page=3

BR

[regina3264]

Originally Posted by theducks

PermissionError: [Errno 13] Permission denied: 'C:\\Users\\dani_\\AppData\\Roaming\\calibre\\plug ins\\Generate Cover.json'
Why would one plugin have a permissions issue? did the json file come from some other install?

OMG, I have absolutely no idea how or why it would do that - I downloaded it direct from the plugins page, and also tried downloading the zip file and loading it from that, and they both had the same problem, BUT!!!

Your comment caused me to try running Calibre as administrator and IT WORKED!

Thank you so much!