Python Required

[jiapei100]

Is your feature request related to a problem? Please describe.
It looks by strictly following meson manual, there is no such a python wrapper built out??? I wonder how I can use Aravis via Python.

Describe the solution you'd like
Successfully call the following couple of lines:

➜  ~ python
Python 3.8.10 (default, Jun  2 2021, 10:49:15) 
[GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import Aravis

Describe alternatives you've considered

• Tested under the test folder already, the direct command:

➜  python ls
arv-buffer-test.py  arv-camera-test.py  arv-enum-test.py  arv-evaluator-test.py  arv-feature-test.py  arv-genicam-test.py  arv-single-buffer-test.py
➜  python python arv-camera-test.py 
Traceback (most recent call last):
  File "arv-camera-test.py", line 14, in <module>
    gi.require_version ('Aravis', '0.8')
  File "~/.local/lib/python3.8/site-packages/gi/__init__.py", line 126, in require_version
    raise ValueError('Namespace %s not available' % namespace)
ValueError: Namespace Aravis not available

• Tried python-aravis, but failed to install that python package.

Additional context
N/A

[EmmanuelP]

Hi,

In order to be able to import Aravis directly, you have to proceed to a system wide installation in /usr. By default, meson installs everything in /usr/ocal.

Alternatively, you can tell python the path to the Aravis modules, using GI_TYPELIB_PATH and LD_LIBRARY_PATH environment variables.

https://stackoverflow.com/questions/19156974/how-to-get-python-to-recognize-find-homebrew-installed-gi-repository-pygobjects

`

[jiapei100]

@EmmanuelP
Thank you..

I successfully installed Aravis again, using ➜ aravis-0.8.15 meson --prefix /usr --buildtype=plain builddir.
And, I did ➜ export GI_TYPELIB_PATH="/usr/lib/x86_64-linux-gnu/girepository-1.0"

As for LD_LIBRARY_PATH, it does have included /usr/lib/x86_64-linux-gnu .
Still, import Aravis does NOT work.

Any more suggestions?

[EmmanuelP]

On some systems, you have to run ldconfig as root after a library installation.

[jiapei100]

@EmmanuelP
Tried...

➜  ~ lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 20.04.2 LTS
Release:	20.04
Codename:	focal
➜  ~ echo $GI_TYPELIB_PATH                        
/usr/lib/x86_64-linux-gnu/girepository-1.0
➜  ~ ls /usr/lib/x86_64-linux-gnu/girepository-1.0/Aravis-0.8.typelib 
/usr/lib/x86_64-linux-gnu/girepository-1.0/Aravis-0.8.typelib
➜  ~ python --version
Python 3.8.10
➜  ~ python
Python 3.8.10 (default, Jun  2 2021, 10:49:15) 
[GCC 9.4.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import Aravis
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ModuleNotFoundError: No module named 'Aravis'
>>> 

[EmmanuelP]

Aravis python binding is provided by gobject introspection. You can not directly import Aravis. Here are the needed steps:

import gi
gi.require_version ('Aravis', '0.8')
from gi.repository import Aravis

[jiapei100]

@EmmanuelP
Great ... Thank you ...
Any more documentation for Aravis Python? And, any sample code of Aravis Python?

Thank you ....

[EmmanuelP]

Not much documentation I'm afraid. There is this page about Aravis openCV and Python, but a it outdated.

https://kushalvyas.github.io/gige_ubuntu.html

[jiapei100]

@EmmanuelP

1. How to call these 2 functions?

camera.set_gain_auto()
camera.set_exposure_time_auto()

Both of these 2 functions require 2 parameters:

xception has occurred: TypeError
Aravis.Camera.set_gain_auto() takes exactly 2 arguments (1 given)
  File "....../arv-camera-test.py", line 34, in <module>
    camera.set_gain_auto()

2. Why there is ALWAYS such an ERROR while writing into USB3Vision camera?

Exception has occurred: GError
arv-device-error-quark: USB3Vision write_memory error (access-denied) (5)
  File "....../arv-camera-test.py", line 31, in <module>
    camera.set_region (0,0,1440,1080)

[jiapei100]

What's more, @EmmanuelP
How to let Aravis automatically find multiple cameras?
I mean camera2 = Aravis.Camera.new (None) ONLY finds the very FIRST camera, but NOT the other cameras.

[EmmanuelP]

Hi,

Github issues is not the right place for these questions. Please use the Aravis discourse instance.

https://aravis-project.discourse.group/c/using-aravis/8