vindauga 0.1.5

Cross Platform Text UI library

Vindauga

Introduction

This is a pure python3 implementation of the BSD licensed C++ Turbo Vision library.

Vindauga is the old Norse precursor to the middle english word 'Window'. These are really old windows...

I needed a cross-platform TUI for python for a project, and the projects available worked on Windows or UNIX but not both. I had previously built a version of this by transliteration which was quite frankly awful, so a dust-off began.

The benefits of this version;

• No dependencies other than curses (See Windows below to have it work in a cmd/powershell window)
  • Will try in Windows Terminal when it arrives (it should work fine)
    • It does not work fine. Rendering has issues. Mouse doesn't work.
• A lot of refactoring to make the code-base somewhat consistent.
• It uses unicode by default, (so no CP437)
  • See UTF-Demo and Cyrillic Test
  • The file viewer works with UTF-8 encoded files, see UTF-Demo.
  • Unicode data entry however, is a different story, that's still an issue.
  • gettext is enabled so you can use the _() built-in, there's no extraction now though.
• Curses mouse works in DOS windows and Cygwin, putty etc.
• Some stuff is Pythonic.
  • Some is still a little clunky to use, working on that.
• You can dynamically change the "resolution" of the console window to be the size you need.
  • See vindauga_demo for how.
  • This only works in virtual terminals (including windows CMD).
• Tested on Mac, Windows, Cygwin, Putty, X-Terms
  • A lot of alt-keys are trapped on mac you have to use ESC-xxx instead.
• You can open (interactive) shell windows.

I've implemented other widgets like combo-boxes so there's some extra widgets available OOTB. I've pulled together the examples and converted them as well, so there's sample code. I've tried to keep the original class and method documentation where appropriate.

You're currently limited to 1024 width windows, you can adjust this in vindauga.types.draw_buffer or subclass DrawBuffer if it's really a problem. If you're doing linear processing of the draw buffer, then it will grow whatever size you want, but if you want them pre-allocated it's 1K.

Windows

If you want to use it from a command window, using native Python, you'll need to pip install windows-curses and it will work fine.

You'll also need to install the pywin32 libraries.

Terminal has a buffering problem with stdin echoing from cmd prompts.

Running it in Cygwin doesn't require anything, just use the cygwin python in a mintty window.

Mac

You'll want to install pasteboard for some clipboard support.

Using it

Look in the examples directory for small samples of how to use widgets. The vindauga_demo shows how to put it all together into a larger app.

For the most part, you will want to subclass Application and add your own Menu objects.

This example is pretty much as simple as it gets, although it does nothing except render a background with the default StatusLine that lets you Alt+X to quit.

# -*- coding: utf-8 -*-
from vindauga.widgets.application import Application
from vindauga.widgets.desktop import Desktop


class Demo(Application):
    """
    How to __change the background _pattern
    """
    def __init__(self):
        Desktop.DEFAULT_BACKGROUND = '╬'
        super().__init__()


if __name__ == '__main__':
    app = Demo()
    app.run()

Issues

• Events sometimes disappear, particularly mouse clicks from inside PowerShell windows. Click then tab and then the click arrives.
• The Screen class does too much and needs to be broken up to move IO into it's own hierarchy
• Lots more testing needs to be added.
• No console mouse support as yet
• I haven't collected all the module imports into __init__.py I'm not convinced either way yet.
  • That does mean a lot of import lines, but it means you're only importing what you need, and what you're using is explicit.

Contributing

Python Version

I'm targetting python 3.7+ (It should work with 3.6 with the dataclasses backport)

Class and Variable Names

• It doesn't use PEP-8 naming, for various reasons.
  • Naming is camel case
  • Classes are uppercase first; e.g. ClassName
  • Variables are lowercase first; e.g. variableName
  • Acronyms should be upper class and separated by an underscore to prevent run-on; e.g. MyHTTP_Service

Filenames

• Filenames should be all lowercase to prevent issues on case-insensitive file systems.
• It should indicate the main class defined within, with words seperated by underscores e.g. class_name.py
  • Runnable filenames (like in examples), should use dash instead of underscore e.g. my-test.py
    1. This prevents accidental importing from them
    2. Allows you to name an example after widget without conflicting names.

Hierarchy

Generally;

• Simple views should be under widgets
• Data requests things under dialogs
• Complex things under gadgets e.g things that have their own window.

Move things into submodules if they need to span multiple files

If you make a widget, add a sample use-case into examples

Debugging

Obviously using print() isn't going to work, so use the logging module and prefix your logger with vindauga. You can use postMessage from widgets.message_window to log into a Vindauga window. See info-box.py