NebulaTk

NebulaTk is an early-stage, Tkinter-style GUI toolkit with a custom widget/rendering pipeline. Widgets are composed into Pillow images and displayed through an OpenGL window backend.

Questions, bug reports, and feature requests: ctrl.alt.op@gmail.com or through this GitHub repo

Current status

• Project is in active early development.
• The current Window() path in this branch supports render_mode="image_gl" only, but might be expanded for vulkan later.
• Rendering currently depends on a GLFW + PyOpenGL backend.

Installation

From the repository root:

pip install -e .

For development and tests:

pip install -r requirements.txt

Quick start

import nebulatk as ntk

window = ntk.Window(title="NebulaTk")
ntk.Button(window, text="Hello NebulaTk").place(20, 20)

You can also run included examples:

python examples/example.py
python examples/relativeplace.py
python examples/word_collage.py
python examples/defaults_theme_toggle.py

Note: example scripts may reference local assets under examples/Images/. If those assets are missing in your checkout, update image paths or provide your own files.

Defaults, themes, and styles

NebulaTk supports file-backed defaults through nebulatk/defaults.py. This lets you:

• Define app-wide default colors/fonts in a Python module.
• Define named reusable styles (for example button_1, button_2).
• Inherit styles from other styles with extends.
• Switch defaults at runtime and update all widgets that are still default-bound.

1) Create a defaults file

Create a Python file (for example my_defaults_light.py):

DEFAULTS = {
    "default_text_color": "#101010",
    "default_fill": "#ffffff",
    "default_border": "#222222",
    # -1 means "auto size", dynamically recomputed for default-bound widgets
    "default_font": ("Helvetica", -1, "normal"),
    # Used by Window(background_color="default") and by default Window()
    "default_window_background": "#f4f7ff",
}

STYLES = {
    "button_1": {
        "fill": "#d7e8ff",
        "text_color": "#112244",
        "border": "#4477aa",
        "border_width": 2,
    },
    "button_2": {
        "extends": "button_1",
        "fill": "#e9f6d2",
    },
}

You can also use:

• PROFILE = {"defaults": {...}, "styles": {...}} in one object, or
• lowercase defaults/styles.

2) Load defaults when creating a window

import nebulatk as ntk

window = ntk.Window(
    title="Themed App",
    defaults_file="my_defaults_light.py",
)

3) Use default-bound widget values

Properties set to "default" (or font=None/font="default") are owned by the defaults system and update when defaults change.

btn = ntk.Button(
    window,
    text="Save",
    fill="default",
    border="default",
    text_color="default",
    font="default",
).place(20, 20)

For image-backed widgets, default fill and default border are transparent by design so image edges are not covered.

4) Apply named styles

Use style references from window.defaults:

primary = ntk.Button(
    window,
    text="Primary",
    style=window.defaults.button_1,
    width=160,
    height=44,
).place(20, 80)

secondary = ntk.Button(
    window,
    text="Secondary",
    style=window.defaults.button_2,
    width=160,
    height=44,
).place(20, 140)

You may also pass a style name string directly:

ntk.Button(window, text="Inline Name", style="button_1").place(200, 80)

5) Override style/default values per widget

If you set a concrete value, that property is no longer default-bound for that widget and will not be changed by later theme switches.

danger = ntk.Button(
    window,
    text="Delete",
    style=window.defaults.button_1,
    fill="#aa0000",  # explicit override
).place(20, 200)

In this example, danger.fill remains #aa0000 after defaults are switched, while other style/default-bound fields still update.

6) Switch themes at runtime

Use window.set_defaults(...) to load a different defaults file:

is_dark = False

def toggle_theme():
    global is_dark
    is_dark = not is_dark
    target = "my_defaults_dark.py" if is_dark else "my_defaults_light.py"
    window.set_defaults(target)

ntk.Button(window, text="Toggle Theme", command=toggle_theme).place(20, 260)

When switched, all widgets that still use default-bound values (including style-bound fields) are updated automatically across the app.

7) Dynamic default font sizing behavior

If a widget is using the default font with size -1, NebulaTk recomputes the font size when widget size/text constraints change (for example resize/reflow). Once you set an explicit font size (for example ("Helvetica", 13, "normal")), that widget stops auto-resizing its font and keeps the explicit size.

Running tests

From the project root:

pytest

Public API highlights

Top-level imports exposed by nebulatk include:

• Window
• FileDialog
• Widgets: Button, Label, Entry, Frame, Slider, Container
• Utility modules: colors_manager, fonts_manager, image_manager, bounds_manager, standard_methods, animation_controller, rendering, file_manager

Many widget methods are chainable, for example:

ntk.Button(window, text="Chainable").place(10, 10).hide().show()

Project layout

• nebulatk/ - main package source
• nebulatk/widgets/ - widget classes and base components
• examples/ - runnable usage demos
• tests/ - pytest test suite

Notes

• This project is not a drop-in implementation of Tk's internal event/render loop.
• The window/rendering architecture uses both threading and multiprocessing internally.