While, I admit, likely of little utility really, this library aims to show one possible way of writing and "shipping" a custom widget for Textual. Key here is that the library contains and provides a custom widget which can be imported and used in an application; but it also provides a simple application that can be run to see the widget in action.

This library is just a thin wrapper around https://qrenco.de/. Each time you create a QR code the content you encode is sent to that website. It also means, of course, that this is only usable with a working net connection. Please keep these things in mind if you do decide to actually use this for something.

The library itself can be installed with pip:

$ pip install textual-qrcode

or with your Python environment manager of choice.

The demo/test application can be run like this:

$ python -m textual_qrcode

When you've finished testing, press Ctrl+C to quit.

To make use of the QRCode widget, import it into your code:

from textual_qrcode import QRCode

The widget itself takes all of the arguments that a normal Textual Widget takes, but has the addition of an initial positional argument which is some text to encode. An example use of it could look like:

    def compose( self ) -> ComposeResult:
        yield Header()
        yield QRCode( "https://textual.textualize.io/" )
        yield Footer()

The widget also has a encode method, that lets you update the QR code to display something else. For example:

self.query_one( QRCode ).encode( "Now I've changed it to this" )

The widget will send out one of two messages when an attempt is made to encode some content. If the content was encoded fine a QRCode.Encoded message is sent out, which can be caught like this:

def on_qrcode_encoded( self, event: QRCode.Encoded ) -> None:
    # Do something now that the QR code was updated fine.

If there is an error encoding the content QRCode.Error will be sent out. this can be used like this:

def on_qrcode_error( self, event: QRCode.Error ) -> None:
    # Do something about the error.

In both cases the event sent out has a qr_code property which is the QRCode widget involved.