snakeflex

Flexbox and CSS Grid-inspired layout utilities for tkinter and customtkinter.

snakeflex implements Flexbox inspired functionality in the context of building user interfaces with Tkinter and/or CustomTkinter and Python. It works as a drop-in layout layer over standard tkinter and customtkinter widgets, without any external dependencies.

pip install snakeflex

---

Quick start

import tkinter as tk
from snakeflex import FlexRow, FlexCol, GridFrame, Spacer

root = tk.Tk()

# Horizontal bar
bar = FlexRow(root, justify="space-between", align="center", gap=8)
bar.pack(fill="x")

title = tk.Label(bar, text="My App")
bar.add(title)
bar.add(Spacer())                           # pushes right-hand items to the edge
bar.add(tk.Button(bar, text="Settings"))
bar.add(tk.Button(bar, text="Quit", command=root.quit))

# Vertical panel
panel = FlexCol(root, align="stretch", gap=4)
panel.pack(fill="both", expand=True)

panel.add(tk.Label(panel, text="Header"))
panel.add(tk.Text(panel), grow=1)           # Text widget fills remaining height
panel.add(tk.Label(panel, text="Status"))

root.mainloop()

---

FlexRow / FlexCol

from snakeflex import FlexRow, FlexCol

Parameters

Parameter	Type	Default	Description
justify	str	"start"	Main-axis alignment: "start" "end" "center" "space-between" "space-around" "space-evenly"
align	str	"stretch"	Cross-axis alignment: "stretch" "start" "end" "center"
gap	int	0	Pixels of space between children
fg_color	str	"transparent"	Background colour (customtkinter-compatible alias for bg)
direction	str	"row"	FlexFrame only: "row" "column" "row-reverse" "column-reverse"

.add(widget, *, grow=0, align=None)

row = FlexRow(parent, justify="space-between", gap=8)
row.add(logo)
row.add(slider, grow=1)      # slider expands to fill spare space
row.add(mute_btn)

Parameter	Default	Description
grow	0	Proportional share of remaining space (like flex-grow)
align	None	Per-child cross-axis override

Returns the widget for chaining.

---

GridFrame

from snakeflex import GridFrame

Template syntax

"200px 1fr 2fr"  - fixed 200 px | 1 share | 2 shares of remaining space
"1fr 1fr 1fr"    - three equal columns
"auto 1fr"       - content-sized column + fills the rest
"48px 1fr 28px"  - fixed header | flexible content | fixed footer

Usage

layout = GridFrame(parent,
    columns="220px 1fr",
    rows="48px 1fr 28px",
    gap=4,
)
layout.add(topbar,    col=0, row=0, colspan=2)
layout.add(sidebar,   col=0, row=1)
layout.add(content,   col=1, row=1)
layout.add(statusbar, col=0, row=2, colspan=2)

Responsive breakpoints

layout.on_resize(800,
    narrow=lambda: layout.hide_col(2),   # collapse detail panel
    wide=lambda:   layout.show_col(2),
)

---

Spacer

An invisible, expanding spacer — equivalent to <div style="flex: 1" />.

bar = FlexRow(parent, justify="start", gap=8)
bar.add(logo)
bar.add(Spacer())      # everything after this is pushed right
bar.add(btn_a)
bar.add(btn_b)

When added to a FlexRow/FlexCol, Spacer defaults to grow=1.

customtkinter compatibility

All containers accept fg_color as an alias for bg and default to "transparent" so they blend seamlessly into CTk windows:

import customtkinter as ctk
from snakeflex import FlexRow

app = ctk.CTk()
bar = FlexRow(app, fg_color="transparent", gap=8)
bar.add(ctk.CTkLabel(bar, text="Hello"))
bar.add(ctk.CTkButton(bar, text="Go"), grow=1)

---

Installation

pip install snakeflex