# Asynchronous Tkinter Mainloop
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<!---->
Implementation of asynchronous `mainloop` for tkinter, the use of which allows using `async` handler functions.
It is intended to be as simple to use as possible. No fancy unusual syntax or constructions - just use an alternative
function instead of `root.mainloop()` and wrap asynchronous handlers into a helper function.
> Please, fill free to [report bugs](https://github.com/insolor/async-tkinter-loop/issues), add [pull requests](https://github.com/insolor/async-tkinter-loop/pulls) or [share your thoughts / ask questions, etc.](https://github.com/insolor/async-tkinter-loop/discussions) about the module.
Based on ideas from:
* my answer on ru.stackoverflow.com: <https://ru.stackoverflow.com/a/1043146>
* answer of [Terry Jan Reedy](https://stackoverflow.com/users/722804) on stackoverflow.com:
<https://stackoverflow.com/a/47896365>
* answer of [jfs](https://ru.stackoverflow.com/users/23044) on ru.stackoverflow.com:
<https://ru.stackoverflow.com/a/804609>
## Installation
### Release version
Install the package with the following command:
```
pip install async-tkinter-loop
```
or
```
pip install async-tkinter-loop[examples]
```
- `[examples]` part is needed to install optional dependencies (such as `httpx` and `pillow`) to run some of the
examples. If you're not going to run examples, remove the `[examples]` part from the command
- Use `pip3` instead of `pip` on Linux systems to install the package for python3 (not python2)
- Probably you'll want to create a virtual environment for experiments with this library, but this is optional.
- If you want to try examples, download the entire repository as an archive (green "code" button on
[the github page](https://github.com/insolor/async-tkinter-loop) →
"Download ZIP"), unpack, run any example (of course, you need to install optional dependencies)
### Development version
1. Install [Poetry](https://python-poetry.org), e.g., with `pip install poetry` (`pip3 install poetry`) command
(other possible ways of installation see [here](https://python-poetry.org/docs/#installation))
2. Download and unpack or clone [the repository](https://github.com/insolor/async-tkinter-loop).
3. Run the command `poetry install` or `poetry install -E examples` (the later command installs optional dependencies
needed to run some examples). This command will create `.venv` directory with a virtual environment and
install dependencies into it.
- Run any example with `poetry run python examples/sparks.py` (insert a file name of an example).
- Or activate the virtual environment with `poetry shell` and run an example with `python examples/sparks.py`
command. You can also open the directory with the project in some IDE (e.g., PyCharm or VS Code)
and select Python interpreter from the virtual environment as a project interpreter,
then run examples directly from the IDE.
## Some examples
Basic example:
```python
import asyncio
import tkinter as tk
from async_tkinter_loop import async_handler, async_mainloop
async def counter():
i = 0
while True:
i += 1
label.config(text=str(i))
await asyncio.sleep(1.0)
root = tk.Tk()
label = tk.Label(root)
label.pack()
tk.Button(root, text="Start", command=async_handler(counter)).pack()
async_mainloop(root)
```
Also, `async_handler` function can be used as a decorator (but it makes a decorated function syncroneous):
```python
import asyncio
import tkinter as tk
from async_tkinter_loop import async_handler, async_mainloop
@async_handler
async def counter():
i = 0
while True:
i += 1
label.config(text=str(i))
await asyncio.sleep(1.0)
root = tk.Tk()
label = tk.Label(root)
label.pack()
tk.Button(root, text="Start", command=counter).pack()
async_mainloop(root)
```
A more practical example, downloading an image from the Internet with [httpx](https://github.com/encode/httpx)
(you can use [aiohttp](https://github.com/aio-libs/aiohttp) as well)
and displaying it in the Tkinter window:
```python
import tkinter as tk
from io import BytesIO
import httpx
from PIL import Image, ImageTk
from async_tkinter_loop import async_handler, async_mainloop
async def load_image(url):
button.config(state=tk.DISABLED)
label.config(text="Loading...", image="")
async with httpx.AsyncClient() as client:
response = await client.get(url, follow_redirects=True)
if response.status_code != 200:
label.config(text=f"HTTP error {response.status_code}")
else:
content = response.content
pil_image = Image.open(BytesIO(content))
image = ImageTk.PhotoImage(pil_image)
label.image = image
label.config(image=image, text="")
button.config(state=tk.NORMAL)
url = "https://picsum.photos/800/640"
root = tk.Tk()
root.geometry("800x640")
button = tk.Button(root, text="Load an image", command=async_handler(load_image, url))
button.pack()
label = tk.Label(root)
label.pack(expand=1, fill=tk.BOTH)
async_mainloop(root)
```
More examples see in the [`examples`](https://github.com/insolor/async-tkinter-loop/tree/main/examples) directory.
## Similar projects
* [Starwort/asynctk](https://github.com/Starwort/asynctk) ([on PyPi](https://pypi.org/project/asynctk/))
* [gottadiveintopython/asynctkinter](https://github.com/gottadiveintopython/asynctkinter) ([on PyPi](https://pypi.org/project/asynctkinter/))
* [Lucretiel/tkinter-async](https://github.com/Lucretiel/tkinter-async)
* [fluentpython/asyncio-tkinter](https://github.com/fluentpython/asyncio-tkinter)