Fresh install "No suitable graphics backend found" error message

[willbontrager]

I have installed Calibre as an "isolated" install so it does not require root access.

For testing, I'm using a CLI (SSH). The PDF never gets made. An error message is "No suitable graphics backend found" (search didn't find an instance of that phrase on the forum).

What can I do to get past this point? Thank you!

Here is a copy of a session:

[ds1363]$ /home/willbont/bontragercgi.com/calibre/calibre/ebook-convert /home/willbont/bontragercgi.com/CalibreTest/22/page.html /home/willbont/bontragercgi.com/CalibreTest/22/index.pdf
1% Converting input to HTML...
qt.webenginecontext:

GL Type: disabled
Surface Type: DefaultRenderableType
Surface Profile: NoProfile
Surface Version: 2.0
QSG RHI Backend: OpenGL
Using Supported QSG Backend: yes
Using Software Dynamic GL: no
Using Multithreaded OpenGL: no

Init Parameters:
* application-name ebook-convert
* browser-subprocess-path /home/willbont/bontragercgi.com/calibre/calibre/libexec/QtWebEngineProcess
* disable-features ConsolidatedMovementXY,InstalledApp,BackgroundFetc h,WebOTP,WebPayments,WebUSB,PictureInPicture
* disable-gpu
* disable-setuid-sandbox
* disable-speech-api
* enable-features NetworkServiceInProcess,TracingServiceInProcess
* enable-threaded-compositing
* in-process-gpu
* use-gl disabled

InputFormatPlugin: HTML Input running
on /home/willbont/bontragercgi.com/CalibreTest/22/page.html
Language not specified
Creator not specified
Building file list...
IgnoreFile("Could not read from file: / with error: [Errno 21] Is a directory: '/'")
Normalizing filename cases
Rewriting HTML links
/ is a link to a directory. Ignoring.
34% Running transforms on e-book...
Merging user specified metadata...
Detecting structure...
Auto generated TOC with 2 entries.
Flattening CSS and remapping font sizes...
Stylesheet 'https://lightfocus.com/17includes/17lightfocus.css?recache' referenced by file 'page.html' not in manifest
Source base font size is 12.00000pt
Removing fake margins...
Cleaning up manifest...
Trimming unused files from manifest...
Creating PDF Output...
67% Running PDF Output plugin
68% Parsed all content for markup transformation
70% Completed markup transformation
No suitable graphics backend found

Load of clbr://internal.invalid/book/page.html failed
[ds1363]$

[willbontrager]

In case it is needed for addressing the issue (and thank you so much!), here is the session when Calbre was installed.

[ds1363]$ wget -nv -O- https://download.calibre-ebook.com/linux-installer.sh | sh /dev/stdin install_dir=~/bontragercgi.com/calibre isolated=y
2022-08-29 14:14:15 URL:https://download.calibre-ebook.com/linux-installer.sh [33493/33493] -> "-" [1]
Using python executable: /usr/bin/python3
Installing to /home/willbont/bontragercgi.com/calibre/calibre
Downloading tarball signature securely...
Using previously downloaded calibre-6.3.0-x86_64.txz
Extracting files to /home/willbont/bontragercgi.com/calibre/calibre ...
Extracting application files...
Run "/home/willbont/bontragercgi.com/calibre/calibre/calibre" to start calibre
[ds1363]$

[gbm]

You are probly missing some of the required qt and x-11 libraries.

If you get an error Could not load the Qt platform plugin xcb you are missing some needed X11-XCB libraries, such as libxcb-xinerama0, for details see here.

On servers, if you get an error about a missing libEGL, you might need to install some OpenGL packages such as libegl1 and libopengl0

https://calibre-ebook.com/download_linux

bernie

Originally Posted by willbontrager

In case it is needed for addressing the issue (and thank you so much!), here is the session when Calbre was installed.

[ds1363]$ wget -nv -O- https://download.calibre-ebook.com/linux-installer.sh | sh /dev/stdin install_dir=~/bontragercgi.com/calibre isolated=y
2022-08-29 14:14:15 URL:https://download.calibre-ebook.com/linux-installer.sh [33493/33493] -> "-" [1]
Using python executable: /usr/bin/python3
Installing to /home/willbont/bontragercgi.com/calibre/calibre
Downloading tarball signature securely...
Using previously downloaded calibre-6.3.0-x86_64.txz
Extracting files to /home/willbont/bontragercgi.com/calibre/calibre ...
Extracting application files...
Run "/home/willbont/bontragercgi.com/calibre/calibre/calibre" to start calibre
[ds1363]$

[kovidgoyal]

conversion to pdf uses QtWebEngine, which needs a suitable graphics backend, which you are missing. Presumably this is some kind of headless VM/container?

Use the env var to tell qt webengine to disable hardware acceleration, as described at https://doc.qt.io/qt-6/qtwebengine-debugging.html

[willbontrager]

(There is a question at the end.)

I am still getting errors related to desktop integration. I don't and can't use desktop.

For the functionality I need, it would be CLI, specifically, using the PHP exec() command to interface with Calibre.

My current impression is that the latest versions of Calibre won't work that way.

The reason for the install is because I am changing servers. An older version works grand on the server I am abandoning.

I don't know what Calibre version is installed there, but many files are dated 2018 May 31. It is an isolated install. The Python version is 2.7.

Is there a way to install a previous version? Whatever version the above might be?

[kovidgoyal]

instructions for installing older versions are on the linux download page.

[DNSB]

Originally Posted by willbontrager

I don't know what Calibre version is installed there, but many files are dated 2018 May 31. It is an isolated install. The Python version is 2.7.

Is there a way to install a previous version? Whatever version the above might be?

Going by the dates on the signature file list, if the original install was from the calibre site, that could be 3.24.2 (May 26, 2018).

You might want to try calibre 3.48.