Is there a simple way to get the pen pressure data from a usb tablet using python on Linux?
You can do it by reading input events on the input device node. I wrote some modules to do this. you can find it in the Pycopia project.
The disadvantage of this is that your program must run as root.
The powerdroid project also uses this, but that's old code now. You can see another example of synthesizing touch input in the devices module. It probably won't work anymore, but you might start with that.
Try using PySide, it's a QT Wrapper here: QTabletEvent.
Or you can use Python and PyGame: Here.
Related
I am having an issue with PIL (python image library). Same code running on standard raspbian and the same on custom Yocto OS don't have the same output. The yocto one is deformed, especially the 0 character
I am using python 2.7 and PIL 1.1.7.
I tested increasing gpu_mem to 128Mb on the yocto, use vc4graphics but this is not changing anything. I guess there's something I don't think about as I'm inexperienced with image rendering.
I would like to understand how to debug this.
Raspbian:
Custom Yocto:
Thanks
Well, there are too many assumptions to say anything definitely.
Are both systems using same graphical backend?
If not, you should probably match them.
It's not "Yocto OS", it's usual Linux, Yocto is just a tool to improve work-flow of building Linux.
What LCD are you using?
Usually when you are developing for board, with some new model of lcd, you also get a datasheet from vendor to tweak different parameters. I had the same problem with display not being crisp, look for lcd display section of .dts file. There should be parameters like "bits-per-pixel", which you should match to what is advised in a data-sheet.
In your case since you have 2 systems with one having a clear image and one having a fuzzy one, I can advice to look for .dts file on both systems and match lcd sections for them. Just an example of a path to .dts file in Yocto
build/tmp/work-shared/imx6ulevk/kernel-source/arch/arm/boot/dts/imx6ul-14x14-evk.dts
Find .dts files for both systems, look for what's different in lcd display section and copy raspbian lcd parameters to your Yocto .dts file.
I'm trying to capture my screen using Python because I'll use it on OpenCV, but I couldn't find a way to make it work on Gnome, since Gnome uses Wayland and all libraries that I've found only work with X11.
For now I'm not considering change my interface. I'm searching a solution to this problem.
Does someone know a solution?
To be more specific, I'll use the images to train an AI and so I need they continuously.
EDIT:
I've found this but how can I pass frames to OpenCV in Python instead of save a video file?
The proper way to do screencasting these days is by using the Screencast portal, which is part of XDG desktop portals and is already supported by GNOME, KDE, wlroots (and more). As an added advantage, this will also work in containerized formats like Flatpaks.
You can find an example on how to do screencasting in Pyhon using this snippet, created by one of the Mutter maintainers. If you look for parse_launch(), you will see a GStreamer pipeline which you can modify to include the GStreamer OpenCV elements that can do the processing for you.
Note: in your edit, you link to a predecessor of that portal, which is GNOME-specifc, internal API, so I wouldn't rely on it ;-)
I'm wondering is that possible to control lights connected to Enttec Open DMX USB via Python shell. If it is, how to?
The Open Lighting Project (formerly known as opendmx) provides a Python API, as part of their Open Lighting Architecture (OLA), for use the OpenDMX USB on OSX and Linux. If you're on Windows then I've not found anything apart from the code from Enttec's website which uses the FTD2XX.DLL libraries.
However it should be noted that one cannot use normal serial based libraries (pyserial etc). Basically OLA either needs to use a special kernel module on Linux, or use the generic FTDI non-serial kernel driver in combination with libftdi on Mac or Linux - for details see their device specific page. There is now pre-built support for Raspberry Pi's on the OLA website.
The communication and protocols used are completely different from Enttec Pro range (which one can just control using simple serial commands with something like pyserial, though OLA also talks to them too).
I know this is quite an old post, however DmxPy has worked very well for me the last few months. It only works for Python 2 but I know there's some Python 3 ports out there.
It's stupid simple to use. I personally use it in my companies quality control software. While it only work for DMX (not RDM) I think it's much easier to use than OLA's Python Wrapper. It works flawlessly with our ENTTEC as well!
UPDATE: Here's my Python 3 port: https://github.com/trevordavies095/DmxPy
I had the exact same problem, so I wrote a simple python programm for all those that are running windows; have a look: https://github.com/Coronon/PyOpenDmxUsb
It uses a C# Server (Because their C# interface was the only one that worked for me) and a Python Client and is super easy to use.
It is compatible with the non pro version too. (The Pro Version is way easier to use and I would use the AcceptedAnswer instead [But the normal one isnt supported])
Edit: This may be 'advertisement' but my project is Open-Source and super easy to use, so I believe this can be useful to others :)
I googled and search stackoverflow before asking this question
Answers that I don't expect:
wxWidgets is the best Python GUIUse TkInter (BIM) for GUI development.
Q. How to make a GUI without using any module/library? i.e make a GUI from scratch. Modules like tkinter not allowed.
I've made several GUIs from scratch using SDL which is a low level drawing library. The advantage of doing that is that it will look exactly the same on any platform down to the pixel and you can get it to work on embedded systems. Full screen GUIs are really easy too. Disadvantages are that it is a lot of work.
In python the pygame library wraps SDL so you would use that, and in fact that is how I made the GUI for a lab instrument which had a large colour LCD screen. The controller ran linux, but not X-windows.
pygame is an extra library, yes, but I can't think of a way of making a GUI with only what python provides.
The easiest GUI to make without "module/library" is a web-based one. I.e. generate HTML with Javascript from your Python code, and let the Javascript interact via AJAX with your Python app. This can be implemented without too much effort with just the standard Python library (and some JS code, of course), or with modules that don't require "heavy" installation of platform-specific extensions.
First things first, I am a Python beginner, with a typical C++/Java background for object oriented stuff.
I was convinced to try Python for this current endeavor I am working on, and so far I like it. One issue I am having though is finding a good mp3 module.
I have tried TkSnack, which installed and ran fine with no errors(as long as my audio device wasn't busy) but it could never actually produce a sound, it just did nothing... I went online for help, and was disappointed with the amount of documentation.
So I decided to switch. I tried PyMad because it is in the standard repositories for Ubuntu as well. There was even less documentation on this, but I could make it play a sound. The only problem is that it requires a loop to constantly write/play the audio buffer. This makes it particularly hairy to handle playback control(in my opinion) cause I would have to run this in a separate thread or process, and somehow control the seek position for pause and such. This is a little too low level for why I am using Python. I liked the simplicity of TkSnack for its easy commands like "mysound.play()" or "mysound.pause()" rather than controlling a loop.
I also looked at pyMedia, which looks like it is the most up to date with documentation, but I can't get it to install on my machine. I get a "gcc exited with value 1" error or something like that when running the "python setup.py build" command.
So I am looking for any suggestions or help on one of these modules, or a completely different one, that is high level and easy to use for mp3s(and preferably other formats too) I am trying to have basic playback control(pause, stop, skip, seek) and I may also be streaming files too eventually(if I ever get there).
EDIT: I like the python bindings for Gstreamer, but is this a cross-platform solution?? I forgot to mention that as a requirement. But I always just associated GStreamer with Linux, would this work on other OSs?
EDIT: Wikipedia says yes.
Sorry I can't help you with PyMad or pyMedia, but I have other suggestions.
Existing music players written in Python:
Exaile
FUPlayer
Listen
All of the above use the Python bindings for the GStreamer multimedia framework. Docs for the bindings are scarce, but check here, here, here, and examples from the source distribution here.
I just had to deal with this, and from my research I think your best bets are pyglet and pygame. They're interface packages with built-in a/v support.