Re: [Pythondialog-users] Change input method

[Florent R. <f.r...@fr...>]

Hello,

"Ebbesen  Soren" <seb...@id...> wrote:

> I have connected a DIY game controller to my Raspberry Pi. I would like to
> navigate a dialog with the output of the game controller rather than a normal
> keyboard. I've created a Python script that can read the output of the game
> controller and store it in a variable, so that part is working. I just need to
> fix something somewhere to change from the keyboard to my own custom variable
> which is triggered by the controller. Can this be done?
>
> I looked through Dialog.py but I didn't see anything about keyboard events.

Correct, this is handled at ncurses level, on which dialog is based
(maybe directly in dialog sometimes too, but I don't think so).

> Maybe the right place to fix this is not even in pythondialog but rather in
> the underlying dialog utility?

I don't think you need to modify dialog for this.

> I've actually made it work using pygame and ncurses directly but I would like
> to take advantage of the features of pythondialog to build a proper dialog.

I think there are mainly two ways to do what you want:
  - send appropriate byte sequences to the controlling terminal. I would
    try writing to a device returned by os.ttyname(). You should be able
    to obtain the codes for arrow keys for instance with something like:

      cat >/tmp/whatever

    Then type Ctrl-V followed by the key you are interested in, then
    Enter, Ctrl-D to close the file, then inspect /tmp/whatever with a
    hex editor or od(1).

    Another approach at the same level would be to use pseudo-terminals
    (pty), I believe. Python has os.openpty() and a 'pty' module for
    this.

    I have no experience with this kind of stuff, so I can't promise it
    works this way.

  - simulate the keyboard events at kernel or X server level. I have
    good experience sending mouse events to the Linux kernel using
    python-evdev:

      http://python-evdev.readthedocs.org/en/latest/

    but it can also send keyboard events. There are other modules doing
    the same, I only know this one works. This approach requires write
    permissions to /dev/uinput; you may want to use an udev rule such
    as:

      SUBSYSTEM=="misc", KERNEL=="uinput", GROUP="your-group", MODE="0664"

    to automatically set this up at each boot.

    There are also many tools/hacks to simulate events at the X server
    level (xdo, PyAutoGUI...) but my attempts with this approach have
    not been successful. I remember trying XSendEvent and
    XTestFakeKeyEvent in C++ as well as xdo from the command line, but
    this didn't work well for me.

Finally, unsuitable for dialog, but using D-Bus to control other
programs can be very effective. Using the following simple patch: