PancakeKit

PancakeKit is a lightweight browser UI for Python scripts. Add small UI components (“toppings”) to a page (Pancake), then serve it locally.

Installation

pip install pancakekit

Quick start

from pancakekit import Pancake

def fibonacci(n=10):
    return (fibonacci(n - 1) + fibonacci(n - 2)) if n >= 2 else n

cake = Pancake()     # 1) create a page
cake.add(fibonacci)  # 2) add a function (auto UI)
cake.serve()         # 3) start the server

Open http://127.0.0.1:8000/.

Interactive mode

In interactive environments (REPL/IPython), Pancake() starts the server automatically by default.

from pancakekit import *

cake = Pancake()  # auto-serve in interactive mode

# To opt out:
# cake = Pancake(auto_serve_in_interactive_mode=False)
# cake.serve()

You can also start a ready-to-use interactive session from the command line:

python -m pancakekit

Or load an existing script and auto-register callables:

python -m pancakekit path/to/your_script.py

Values and events

Most toppings expose their state through .value.

from pancakekit import *

cake = Pancake()
age = cake.add(Input("Age", default=20), name="age")
age.value_changed = lambda v: cake.show_message({"age": v})

You can access toppings by name:

from pancakekit import *

cake = Pancake()
cake.add(Input("Count", default=0), name="count")
cake["count"].value += 1

Buttons: clicked and long-press pressed

from pancakekit import *

cake = Pancake()
btn = cake.add(Button("Hold me"))

btn.clicked = lambda _v: cake.show_message("clicked")
btn.pressed = lambda _v: cake.show_message("pressed")

Long-press behavior:

• pressed starts after ~0.5s hold, then repeats while held down
• repeats after the previous handler finishes, with ~0.1s delay
• if clicked is not set but pressed is set, pressed fires immediately on pointer down

Honeycomb (script editor)

Each Pancake has a built-in Honeycomb card.

• Toggle: Shift + Enter
• Run: Cmd/Ctrl + Enter
• Recall saved scripts: Cmd/Ctrl + ↑ / ↓ (when Honeycomb is open)

Inside Honeycomb, the current page is available as the reserved name cake.

Built-in toppings

Inputs

• Input(label, default=None, placeholder=None)
• DictInput(default: dict, horizontal: bool = False)
• Slider(label, range_min, range_max, value=None, step=1.0)
• Select(label, options, value=None, placeholder=None, with_clear=False, allow_none=None, disabled=False)
• Switch(label="", value=False, disabled=False)
• RadioGroup(label, options, value=None, orientation="vertical", appearance=None, allow_none=False, disabled=False)

Display

• Label(text=""), Text(text=""), Paragraph(text="")
• ImageView(image: PIL.Image | str), ImageCard(image: PIL.Image | str)
• Table(df: pandas.DataFrame | dict)
• ProgressBar(value=0, label=None, max_value=100, show_value=True)

Layout / containers

• Row(), Column(), Group(...)
• Card(...), FloatingCard(...) (floating draggable cards)
• GridPanel(size=(rows, cols), status_dict=None, style=None)

Multiple pages with Plate

from pancakekit import *

plate = Plate()

class Crape(Pancake):
    def decorate(self):
        b = self.add(Button("Go to Waffle"))
        b.clicked = lambda _v: plate.go_to("Waffle")

class Waffle(Pancake):
    def decorate(self):
        b = self.add(Button("Go to Crape"))
        b.clicked = lambda _v: plate.go_to("Crape")

Crape(plate)
Waffle(plate)
plate.serve()

Making a custom topping

from pancakekit import Topping, Tag

class MyLabel(Topping):
    def prepare(self, text):
        self.value = text
        self.label = Tag("label", style={"text-shadow": "1px 1px 1px #bbb"}, value_ref=self)

    def html(self):
        return self.label.render()

Useful hooks:

• prepare(self, *args, **kwargs) (one-time setup)
• html(self) (render HTML)
• value_getter(self) / value_preprocessor(self, value) / web_value_proprocessor(self, tag, value)
• event_preprocessor(self, event)