How to unimport Tcl/Tk after running a Tkinter program - python

We are creating a program that uses two different libraries sequentially: Tkinter and WxPython. Once the script for Tkinter is initialized, the backend library Tcl/Tk prevents the execution of any Wx functions. We want to be able to remove all traces of memory of Tcl/Tk before we launch our script that uses Wx.
We have tried deleting all associated Tkinter references using the sys module, but we have had no success. We have also tried using the multiprocessing module to isolate the frameworks to separate processes, but this was unachievable as a GUI cannot be initialized through a sub-process.
Our goal is to package this into a single standalone application.

Related

Is it impossible to create GUI in python without tkinter?

I wanna know, Is it possible to create GUI in python without using tkinter?
Tk isn't technically making the GUI, it's delegating to a C library; and that's exactly what you can do too. For simplicity however, it's pretty much standard to use TkInter, or some other framework (i recommend PySimpleGUI) that takes care of the Tk interaction for you
easygui is the easiest GUI python that I have used. Designs are prebuilt for you already. Examples of easygui can. be found here https://pypi.org/project/easygui/
You can also use Flask where the frontend will be the web browser.
Tcl/Tk is an external library although it comes as part of the standard python install and it is an external library. you can use other framework to do that .
Fundamentally, Python can’t talk to any GUI system without an external module. Since the most fundamental GUI libraries on any platform are usually C-based, that requires, at minimum, importing a library like ctypes which itself is minimal and allows you to load system GUI libraries (in dlls or delis, depending on your platform).It is possible, in theory at least, to drive a GUI solely from ctypes, but it’s not very practical .

Using cv2.WINDOW_GUI_EXPANDED to be able to use zoom with imshow()

I need to be able to zoom in and out of an image I show using cv2.imshow().
I read that this can be done by adding a flag that enables an expanded gui display.
cv2.namedWindow('image',cv2.WINDOW_GUI_EXPANDED)
However, running this does not seem to make a difference, and I don't see any buttons on the gui window I create. Is there anything I need to install and how should I run it? I'm not getting any errors.
Thank you.
imshow zooming should work via built-in mouse events without WINDOW_GUI_EXPANDED.
For imshow or your particular use case, there are two requirements for zooming to work:
OpenCV is compiled with Qt library support
A thread is currently free to handle the window events (cv.waitKey(0) blocking in the main thread, or cv.startWindowThread() to spool up a background thread for window events)
I was never able to get QT support to work in windows with python. It works seamlessly in linux. And by building from source on windows with c++, it also works.
I believe that for python you need to install by copying the pyd file in C:\opencv\build\python\cv2\python-3 to your packages folder. Or you need to compile with the global python directories specified in the cmake config.

Embedding IPython console in Tkinter frame

I was working on a PyQt application that had an embedded JupyterWidget that would allow a user to use an IPython console to interact with certain variables that were being displayed. However, it was recently suggested that we switch to Tkinter graphics instead of Qt because of Tkinter's out of the box support in Python.
Is there a Tkinter equivalent implementation of the JupyterWidget in PyQt? The best I can seem to find is https://github.com/ipython/ipython/wiki/Trash:-Old-Embedding-Tkinter but this uses a very old version of IPython where almost all of the function calls are deprecated or removed entirely.
I had also tried this but was unable to make it so that changes in the subprocess' variables were reflected in the overall program.

Detecting active windows in python with KDE

I'm writing a small python script that tracks how I'm dividing my time between programs. It needs to detect the currently active window (ideally, the application controlling that window, but I can make do with just the window title), as well as idle time.
At the moment, I'm using KIdleTime to determine how long I've been not touching my computer, which works fine by itself.
I also try to use wnck to determine which windows are active, and again, this works fine by itself.
It's when I try to combine the two into one program that I run into troubles. Since wnck is a gnome library and KIdleTime is a KDE library, they need to be run on their own threads for the window change and idle timeout signals to fire.
I'm having trouble finding a way to do this in python - if I use the threading module to try to run one of them on a separate thread, the KDE library complains that it's not on the main thread, or the Gnome library has an impressive meltdown and eats all the memory it can get (incidentally, ulimit was very useful in this case, I can recommend it).
So, I have four options:
Find a KDE library that can detect
when the window is changed - I would
have thought that dbus would expose
this in kwin, but it doesn't seem
to.
Find a way of running both the kde and gnome libraries at the same
time.
Find an equivalent of KIdleTime that runs on the Gnome event thread.
Use timers to poll KIdleTime from within the Gnome thread (which is
what I'm doing now, but is far from ideal, it leads to imprecision in
determining idle times).
Can anyone offer me a solution?
One can use the wxPython GUI toolkit for this purpose.
It has a method for getting the active window.
It has a timer class, althou there are multiple ways you could use.
Of course, you can forget about QT, Gnome, and all other graphical libraries.
Here is what wx can do.

Create a directly-executable cross-platform GUI app using Python

Python works on multiple platforms and can be used for desktop and web applications, thus I conclude that there is some way to compile it into an executable for Mac, Windows and Linux.
The problem being I have no idea where to start or how to write a GUI with it, can anybody shed some light on this and point me in the right direction please?
First you will need some GUI library with Python bindings and then (if you want) some program that will convert your python scripts into standalone executables.
Cross-platform GUI libraries with Python bindings (Windows, Linux, Mac)
Of course, there are many, but the most popular that I've seen in wild are:
Tkinter - based on Tk GUI toolkit (de-facto standard GUI library for python, free for commercial projects)
WxPython - based on WxWidgets (popular, free for commercial projects)
Qt using the PyQt bindings or Qt for Python. The former is not free for commercial projects. The latter is less mature, but can be used for free.
Complete list is at http://wiki.python.org/moin/GuiProgramming
Single executable (all platforms)
PyInstaller - the most active(Could also be used with PyQt)
fbs - if you chose Qt above
Single executable (Windows)
py2exe - used to be the most popular
Single executable (Linux)
Freeze - works the same way like py2exe but targets Linux platform
Single executable (Mac)
py2app - again, works like py2exe but targets Mac OS
Another system (not mentioned in the accepted answer yet) is PyInstaller, which worked for a PyQt project of mine when py2exe would not. I found it easier to use.
http://www.pyinstaller.org/
Pyinstaller is based on Gordon McMillan's Python Installer. Which is no longer available.
An alternative tool to py2exe is bbfreeze which generates executables for windows and linux. It's newer than py2exe and handles eggs quite well. I've found it magically works better without configuration for a wide variety of applications.
There's also PyGTK, which is basically a Python wrapper for the Gnome Toolkit. I've found it easier to wrap my mind around than Tkinter, coming from pretty much no knowledge of GUI programming previously. It works pretty well and has some good tutorials. Unfortunately there isn't an installer for Python 2.6 for Windows yet, and may not be for a while.
Since python is installed on nearly every non-Windows OS by default now, the only thing you really need to make sure of is that all of the non-standard libraries you use are installed.
Having said that, it is possible to build executables that include the python interpreter, and any libraries you use. This is likely to create a large executable, however.
MacOS X even includes support in the Xcode IDE for creating full standalone GUI apps. These can be run by any user running OS X.
For the GUI itself:
PyQT is pretty much the reference.
Another way to develop a rapid user interface is to write a web app,
have it run locally and display the app in the browser.
Plus, if you go for the Tkinter option suggested by lubos hasko
you may want to try portablepy to have your app run on Windows environment
without Python.
I'm not sure that this is the best way to do it, but when I'm deploying Ruby GUI apps (not Python, but has the same "problem" as far as .exe's are concerned) on Windows, I just write a short launcher in C# that calls on my main script. It compiles to an executable, and I then have an application executable.
PySimpleGUI wraps tkinter and works on Python 3 and 2.7. It also runs on Qt, WxPython and in a web browser, using the same source code for all platforms.
You can make custom GUIs that utilize all of the same widgets that you find in tkinter (sliders, checkboxes, radio buttons, ...). The code tends to be very compact and readable.
#!/usr/bin/env python
import sys
if sys.version_info[0] >= 3:
import PySimpleGUI as sg
else:
import PySimpleGUI27 as sg
layout = [[ sg.Text('My Window') ],
[ sg.Button('OK')]]
window = sg.Window('My window').Layout(layout)
button, value = window.Read()
As explained in the PySimpleGUI Documentation, to build the .EXE file you run:
pyinstaller -wF MyGUIProgram.py
!!! KIVY !!!
I was amazed seeing that no one mentioned Kivy!!!
I have once done a project using Tkinter, although they do advocate that it has improved a lot, it still gives me a feel of windows 98, so I switched to Kivy.
I have been following a tutorial series if it helps...
Just to give an idea of how kivy looks, see this (The project I am working on):
And I have been working on it for barely a week now !
The benefits for Kivy you ask? Check this
The reason why I chose this is, its look and that it can be used in mobile as well.
# I'd use tkinter for python 3
import tkinter
tk = tkinter.Tk()
tk.geometry("400x300+500+300")
l = Label(tk,text="")
l.pack()
e = Entry(tk)
e.pack()
def click():
e['text'] = 'You clicked the button'
b = Button(tk,text="Click me",command=click)
b.pack()
tk.mainloop()
# After this I would you py2exe
# search for the use of this module on stakoverflow
# otherwise I could edit this to let you know how to do it
py2exe
Then you should use py2exe, for example, to bring in one folder all the files needed to run the app, even if the user has not python on his pc (I am talking of windows... for the apple os there is no need of an executable file, I think, as it come with python in it without any need of installing it.
Create this file
Create a setup.py
with this code:
from distutils.core import setup
import py2exe
setup(console=['l4h.py'])
save it in a folder
Put your program in the same folder of setup.py
put in this folder the program you want to make it distribuitable:
es: l4h.py
ps: change the name of the file (from l4h to anything you want, that is an example)
Run cmd from that folder (on the folder, right click + shift and choose start cmd here)
write in cmd:>python setup.py py2exe
in the dist folder there are all the files you need
you can zip it and distribute it
Pyinstaller
Install it from cmd
**
pip install pyinstaller
**
Run it from the cmd from the folder where the file is
**
pyinstaller file.py
**
Update
Read this post to make an exe on windows with pyinstaller the proper way and with one file and images in it https://pythonprogramming.altervista.org/auto-py-to-exe-only-one-file-with-images-for-our-python-apps/
You don't need to compile python for Mac/Windows/Linux. It is an interpreted language, so you simply need to have the Python interpreter installed on the system of your choice (it is available for all three platforms).
As for a GUI library that works cross platform, Python's Tk/Tcl widget library works very well, and I believe is sufficiently cross platform.
Tkinter is the python interface to Tk/Tcl
From the python project webpage:
Tkinter is not the only GuiProgramming
toolkit for Python. It is however the
most commonly used one, and almost the
only one that is portable between
Unix, Mac and Windows
You can use appJar for basic GUI development.
from appJar import gui
num=1
def myfcn(btnName):
global num
num +=1
win.setLabel("mylabel", num)
win = gui('Test')
win.addButtons(["Set"], [myfcn])
win.addLabel("mylabel", "Press the Button")
win.go()
See documentation at appJar site.
Installation is made with pip install appjar from command line.
There's three things you could do:
The first thing is to find a GUI Designer that can launch its code as standalone applications like .exe files. I use a version of MatDeck (for people using GUI Designers I recommend MD Python Designer) as I believe(I use another version so I'm not too sure.) it allows me to convert the code to a standalone applications and by having it as such, there is no need to install the software on every PC that's going to run the program.
The second option is partially bypassing the problem, launch the GUI as a web page. This would give you the most compatibility as most if not all OS can utilize it. Once again, you would need a GUI Designer that can convert its components into a web compatible format, I've done it once and I used the same version of MatDeck(Visionary Deck), I would not recommend MD Python Designer this time as I don't know if it can turn its GUIs into websites using web assembly whereas Visionary Deck I've tried and tested. As with all things there are most likely other software this is just one I use frequently because I work a lot with Mathematics and Physics.
The third option is also kind of bypassing the problem but do it in Tkinter and just ensure you have a Python IDE or just plain old Python and run the code, this will launch the GUI. This is a good solution and maybe the simplest but I wouldn't class it as the shortest or the best. If you only plan to switch between a few operating systems and computers this will probably be your best bet.

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