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https://github.com/pfalcon/picotui

Lightweight, pure-Python Text User Interface (TUI) widget toolkit with minimal dependencies. Dedicated to the Pycopy project.
https://github.com/pfalcon/picotui

curses micropython minimalist pycopy python suckless terminal tui unbloated

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Lightweight, pure-Python Text User Interface (TUI) widget toolkit with minimal dependencies. Dedicated to the Pycopy project.

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README 

        
picotui

=======



Picotui is a Text User Interface (TUI) widget library for Python3.

It is known to work with CPython3 and

`Pycopy `_ (Unix version is

officially supported for the latter), but should work with any

Python3 implementation which allows to access stdin/stdout file

descriptors.



You can learn more about it with the help of a virtual Q&A session:



Q: There're a few TUI libraries for Python, why yet another one?



A: Urwid is one well-known such TUI library. Here's an entry from its

FAQ: "How do I create drop-downs, floating windows, and scroll bars? -

You need to start writing some fairly complex widgets. This

functionality hasn't been added to Urwid yet." So, Urwid is a

widget library which doesn't have dropdowns. Version 0.8.0 of

Urwid was imported into SVN (and later Git) in 2004. Urwid doesn't

have dropdowns and stuff for 10+ years.



Q: Hey, but you cut off the answer from Urwid FAQ. It says: "but if you

are willing to write it, we do accept patches". Why didn't you implement

those widgets for Urwid and contribute them?



A: Why didn't you? No, wait, that's not productive. I didn't implement

them for Urwid because I don't like its architecture and the fact that

its widget set is rather weak (so it's hard to write new widgets - there

are not enough examples to start from). And don't get me wrong, but the

fact that nobody wrote those widgets for Urwid during 10+ years, got to

mean something. However, I tried to hack on another, less, but still

known Python TUI library - Npyscreen. Its widget set is much more

advanced and usable. But - it still has some architectural choices

which makes extending it and overriding some behaviors problematic.

I also found its project management a bit unresponsive. So, after making

a dozen of commits to my fork, I thought it's time to get some breath and

started picotui.



Q: So, sun must shine bright in the picotui land, and it must be the best

library out there?



A: Alas, no. Let me start with the fact that most TUI libraries are based

on ``curses`` library for terminal screen management. It makes sure that if

you update a screen, only the minimal set of updates is made. This was

very important at the era of 300 baud serial connections. Let's count:

300 baud is about 30 bytes/s, and the standard VT100 screen is 80*24 = ~2K.

Double that for attributes. So, transferring a complete screen to show

to user would take 2 mins. If you draw the same screen twice (no changes in

content), it would take 4 mins. ``curses`` library cuts that back to mere 2

mins. So, alas, ``picotui`` doesn't use curses. That's based on the fact

that picotui wants to be compatible with Pycopy, and its philosophy

is minimalism - if it's possible to do screen output without ``curses``,

let's do just that. It's also grounded in the fact that nobody uses

300 baud modems any longer, most apps are run in a local terminal emulator

with instant updates, most of the remaining are run over LANs which

also offer fast updates. The modern basic serial connection speed is

115200 which is still too slow for real-time fullscreen updates though.

That's why I say "alas". Beyond the optimized screen updates, ``picotui``

lacks many other things too: e.g., double-buffering (so redrawing the

previous screen content behind pop-ups is up to you), it lacks geometry

managers, so calculating coordinates is up to you, etc. Yes, just like

that - I lacked widgets the most, and that's what I implemented. The rest

is just KISS.



Q: But that's really sad!



A: Indeed, it is. The only good news is that now you have a choice: if

you want your app work well with 300 baud modems, you can use other

libraries, and if you want widgets, you can use `picotui`.



Q: So many words, where's a mandatory screenshot?



A: Sure:



.. image:: https://raw.githubusercontent.com/pfalcon/picotui/master/picotui.png



Documentation

-------------



Picotui is an experimental WIP project, and the best documentation currently

is the source code (https://github.com/pfalcon/picotui/tree/master/picotui)

and examples (see below).



Examples

--------



* example_widgets.py - Shows repertoire of widgets, inside a dialog.

* example_menu.py - Shows a "fullscreen" application with a main menu.

* example_dialogs.py - Shows some standard dialogs.

* examples/ - More assorted examples.



Known Issues

------------



Pay attention to what Unicode font you use in your console. Some Linux

distributions, e.g. Ubuntu, are known to have a broken Unicode font

installed by default, which causes various visual artifacts (specifically,

Ubuntu Mono font isn't really monospace - many Unicode pseudographic

characters have double (or so) width, box-drawing symbols have gaps, etc.)