tui-ui
Lay out a terminal screen the way you lay out a web page: nested boxes with margin,
border, and padding; rows and columns that flex with fr units; and drop-in widgets
(panels, tables, cards, meters, tabs, trees). You compose a tree of renderables, and
the engine resolves sizes, composites cell grids, and serializes once to a
tmux-safe ANSI frame. Everything is display-cell accurate, so CJK, emoji, and
box-drawing never desync your columns.
Pure Python stdlib (optional pyfiglet for the Banner, optional wcwidth for an
authoritative width — a stdlib fallback covers the same edge cases). Output is a
plain string you can print, pipe, feed to the fx play loop, or render to PNG with
the SmartCLI pyte harness.
When to use
- Building a status page / dashboard / control panel that should look designed, not dumped.
- You need boxes, tables, or columns that line up — especially with wide glyphs.
- You want web mental models (box model, flexbox rows, a grid, cards) in a TUI.
- Adding a new reusable terminal widget to a shared catalog.
- Do NOT use for full-screen interactive apps with input loops — that is drive-tui's job. tui-ui produces frames; something else owns the terminal.
Setup
Run from the skill directory skills/tui-ui as a package:
python -m ui widgets # list widgets
python -m ui demo <name> --width 60 --height 12 # render one widget
python -m ui gallery --width 100 --height 30 # the showcase dashboard "page"
python -m ui demo table --theme synthwave # --theme applies a palette
python -m ui sixel image.png --cols 40 --rows 20 # TRUE-graphics bitmap (sixel)
python -m ui sixel --probe # does this terminal support sixel?
Beyond sub-cell glyphs, tui-ui can emit true bitmap graphics via Sixel for
terminals that support it (Windows Terminal ≥1.22, xterm, WezTerm, mlterm): the
ui.sixel module encodes any RGB pixel grid — including a SubcellRaster.px
buffer, via raster_to_sixel(raster) — to a DCS escape string
(encode_sixel(pixels) / print_sixel(...)). supports_sixel() runs a DA1 probe
(returns True/False/None-unknown). This is the graphics-protocol escape hatch above
the half/quad/sextant/braille sub-cell rendering; the sub-cell path still works on
every terminal, sixel is the upgrade where available.
Or by path from anywhere (a PEP-366 prelude bootstraps the package):
python skills/tui-ui/ui/cli.py gallery
On Windows set PYTHONIOENCODING=utf-8 (or the CLI auto-reconfigures stdout) so
box/CJK glyphs encode. The CLI renders once and exits — bounded, no loop.
The box model (ui/box.py)
A Box wraps content in the CSS nesting order margin → border → padding →
content. Borders are cells (1 per present side), padding is the CSS 4-tuple
(top, right, bottom, left), and box-sizing defaults to border-box: the
requested width/height IS the border box, and content = width − gutter where
gutter = padding + border per axis.
from ui import Box
Box(content="hello",
width=24, height=5, # int cells | "auto" | Fr(2)/"2fr" | "50%"
border="rounded", # single | rounded | heavy | double | ascii | none
padding=(0, 1), # int | (v,h) | (t,r,b,l)
margin=0,
title="Title", title_align="left", # left | center | right
align="left", valign="top", # content alignment inside the padding box
fg=(210,216,228), bg="#0e1016", border_fg="#4a5a82")
Box.measure(w, h) -> (w, h) reports the natural outer size; Box.render(w, h) -> Canvas draws it into an exact region. Content taller/wider than the region is
clipped to the content box so it never overwrites the border.
Layout (ui/layout.py)
Containers share the widget protocol (measure / render), so they nest freely.
VStack(children, gap, align, valign)— stack top→bottom; cross axis is width.HStack(children, gap, valign)— flex row left→right;frchildren share width.Grid(cells, cols, rows, col_gap, row_gap)— rows × cols;grid(cells, ncols=3)is the shortcut.Page(child, width, height)— the fixed-size root;page.to_ansi()is your frame.
fr / fractional distribution is the load-bearing algorithm. Never round each
track independently (that drifts ±1). The engine uses Rich's carry-remainder method,
so resolve_tracks(10, [Fr(1),Fr(1),Fr(1)], ...) == [3, 3, 4] exactly and cumulative
offsets never drift. Fixed/auto tracks are measured and subtracted first; the
remainder is shared among fr tracks by weight; overflowing fixed tracks shrink
largest-first to fit.
Compose a "page"
A dashboard is just a tree of boxes and widgets handed to a Page:
from ui import Page, VStack, HStack, Box, Fr, get_theme
from ui.widgets import Banner, Badge, Table, Meter, ProgressBar, Tabs, Tree
t = get_theme("dashboard")
def panel(content, title, **kw):
return Box(content, border="single", title=title, padding=(0,1),
bg=t.bg, fg=t.fg, border_fg=t.border, **kw)
page = Page(
VStack([
Box(Banner("DASH", theme=t), border="rounded", border_fg=t.accent, height=8),
HStack([panel(Meter(theme=t), "Resources"), # auto width
panel(Table(theme=t), "Services", width=Fr(1))], gap=1), # flex fill
panel(ProgressBar(0.73, label="Deploy", theme=t), "Progress", height=3),
], gap=0, bg=t.bg),
width=100, height=30, bg=t.bg)
print(page.to_ansi())
See ui/cli.py:_build_gallery for the full showcase (banner, badge status row, a
two-panel middle region, tabs, and a progress footer). Themes live in
ui/core.py (dashboard, synthwave, forest, mono, amber); each carries
semantic slots (bg fg muted border accent ok warn err) plus gradient stops.
Widget catalog
python -m ui widgets lists them; each has a sample(theme) used by demo/gallery.
| key | what it renders |
|---|---|
panel | Bordered frame with title + word-wrapped body |
table | Auto-sized data table with borders, bold header, status coloring |
card | Composite: title + body + key/value list + badge footer |
progress | Progress bar, 1/8-cell precision (█▉▊▋▌▍▎▏), gradient fill + percent |
meter | Multi-row labelled bar chart (CPU/MEM/DISK style) |
tabs | Tab strip with the active tab underlined + a content pane |
kv | Two-column key/value (definition) list; keys padded, values wrap |
tree | DFS tree with ├──/└──/│ guide glyphs |
rule | Horizontal divider with an optional aligned title |
badge | Inline status pill / chip (ok/warn/err/accent) |
banner | Big FIGlet text (needs pyfiglet; degrades to a bold label) |
Plus 4 shader/raster-backed extras shipped in ui/widgets_ext/ (the effort-replica primitives + a sub-cell chart; also in python -m ui widgets):
| key | what it renders |
|---|---|
gradient_rule | Solid rule filled with a per-cell truecolor gradient |
radial_glow | Localized rounded/pulsing radial glow (background light field) |
slider_track | Thin solid slider rail with a marker + tick labels |
braille_chart | Smooth sub-cell line chart of a data series (braille 2×4 px/cell) |
Add a widget (the recipe)
Drop a module in ui/widgets_ext/ — registry.load_all() discovers it, no wiring.
# ui/widgets_ext/spark.py
from ui.registry import register
from ui.widgets import Widget
from ui.core import Canvas
@register
class Spark(Widget):
key = "spark" # registry key (python -m ui demo spark)
summary = "Inline sparkline" # shown by `widgets`
def __init__(self, values=(1,3,2,5,4), *, theme=None):
super().__init__(theme)
self.values = list(values)
def measure(self, avail_w, avail_h): # (width_wanted, height_wanted)
return (len(self.values), 1)
def render(self, region_w, region_h): # -> exact-size Canvas
cv = Canvas(region_w, max(1, region_h), bg=self.theme.bg)
bars = "▁▂▃▄▅▆▇█"; hi = max(self.values) or 1
for i, v in enumerate(self.values[:region_w]):
cv.set(i, 0, bars[min(7, v*7//hi)], fg=self.theme.accent, bg=self.theme.bg)
return cv
@classmethod
def sample(cls, theme): # used by demo/gallery
return cls(theme=theme)
Contract every widget honors: measure(avail_w, avail_h) -> (w, h) and
render(region_w, region_h) -> Canvas of exactly that region. Set class attrs
width/height (int / Fr / "auto") if a parent stack should size it specially.
Then: python -m ui widgets (it appears) and python -m ui demo spark.
Width & alignment (why columns don't misalign)
The engine never uses len(). ui.core.width(s) returns display cells: CJK /
fullwidth → 2, combining marks → 0, ANSI stripped to 0, and the emoji edge cases
handled — ZWJ sequences (👩💻=2), VS16 (♀️=2), regional-indicator flag pairs
(🇯🇵=2). Canvas.put_text is wide-aware: a double-width glyph occupies its cell
plus a continuation cell that is never serialized, so a CJK char can't shove the
columns behind it. blit heals any wide glyph it cuts at a seam.
tmux safety & rendering to PNG
to_ansi() emits only CSI SGR color runs (\x1b[…m, run-length like fx) and
newlines — no cursor moves, no alt-screen, no scroll region. A frame is therefore
composable and safe to print inside a tmux pane; tmux re-parses it through its own VT
layer identically. There is no real tmux/docker/WSL on this box, so rendering is
verified with pyte (a faithful VT emulator) → PNG via PIL — the standard
no-tmux snapshot method. Always label such captures as pyte-simulation, not a
real-tmux capture (see tools/screenshot/shot.py:RENDER_LABEL).
import sys; sys.path[:0] = ["tools/screenshot", "skills/tui-ui"]
import shot
from ui import get_theme; from ui.cli import _build_gallery
ansi = _build_gallery(get_theme("dashboard"), 100, 30).to_ansi()
screen = shot.render_bytes_to_screen(shot.render_frame_to_bytes(ansi), 100, 30)
shot.screen_to_png(screen, "out.png") # faithful cell-grid render
Knowledge base — look before you build
Before recreating or inventing any effect, consult the SmartCLI knowledge graph at
D:/Project/SmartCLI/knowledge/INDEX.md — 95 sourced concept notes + 27 case studies,
organized around one discipline: pick your lane.
- Replica (reproduce a real, existing UI/animation/screenshot): measure ground truth
first, never head-canon. Start at [[hard-lessons]] (mirrors
references/HARD-LESSONS.md) and the worked case [[effort-selector]] (measured palette/geometry/animation for the/effortpicker) → drive-and-capture, quantify scale + form, extract exact params, build against truth, verify on the real run path. - Creative (design a new widget/effect): compose primitives. Start at [[rendering-model]]
(mirrors
references/RENDERING-MODEL.md, the four-primitive kernel) and ask "which primitives compose this?" before writing a bespoke widget.
Recreating a REAL effect — read this first
Before recreating any effect that already exists (a real CLI's UI, an animation, a
screenshot), read references/HARD-LESSONS.md and follow its 10 rules. It is the
distilled record of a replica that took a dozen wrong iterations because of guessing
instead of measuring. The non-negotiable core:
- Get ground truth first — never approximate from imagination. If the real program
exists, drive it with
smartcli_core.PtySession, capture the actual rendered per-cell bytes/colors, and for animations capture multiple PNG frames and study them. Reverse-engineer exact constants from source when available. - Confirm scale and shape before writing render code — how many rows/cols the effect occupies, 1-D vs 2-D, static vs animated, and how it moves (measure the moving edge across frames, don't guess). A ripple that is really an 8-row rectangle will never be reproduced as a 1-row bar.
- Verify on the REAL run path, never on a self-satisfying preview. Run the script's
own full startup (
python script.py, no monkeypatches), capture stderr, and use SmartCLI to drive your own script and diff its real output against ground truth. A missing import or anisatty()early-return produces a blank/crash the PNG preview won't show. - You have the tools to look — use them. You are an agent CLI with PTY + screen capture + PNG rendering. Don't ask the user what it looks like; go capture it.
Replica smoke workflow
When recreating a screenshot-driven CLI/TUI, do not finish after visual intuition or one
happy-path preview. Create a bounded --once frame mode in the target program, then
render a matrix through tools/screenshot/shot.py or tools/screenshot/cli.py.
Minimum checks for a screenshot replica:
- Cover every visible state in the reference, plus separate animation frames for each distinct animated backdrop or transition shape.
- Render at the reference size and at least two stress sizes, such as
80x24and a wider/taller terminal. - Assert the stream contains truecolor ANSI when color is part of the design, has no
U+FFFD, and includes the key visible labels from the reference. - Inspect the generated PNG contact set manually before handoff; pyte checks catch blanks, clipping, color presence, and mojibake, but not taste, exact spacing, or whether an active color reads like the reference.
- Run one real Windows Terminal interactive smoke for input semantics, alt-screen restoration, cursor restoration, and resize behavior. Pyte is not a substitute for keyboard/input-loop verification.
For interactive replicas, make Enter and Esc behavior observable: emit the selected
value or use distinct exit status/cancel semantics after leaving the alt screen. Keep
--once non-interactive and deterministic so reports can reproduce the PNG set.
Self-test (bounded, no loop)
python self_test.py renders the 100×30 dashboard once and asserts: 30 rows each
exactly 100 cells (no fr drift), box-drawing glyphs present, truecolor SGR present,
width() edge cases correct, and a CJK table row's vertical bars land on the SAME
columns as an ASCII row (proving wide-char alignment). Exit 0 = pass. It also passes
cleanly at sizes (40,12), (80,24), (120,40), (200,50).
File map
ui/core.py—Canvas,Cell,width(), color/SGR helpers, box-glyph tables,Themes.ui/box.py— the CSS box model (Box,Fr, dim resolution, clipping).ui/layout.py—VStack/HStack/Grid/Page+ carry-remainderfrresolution.ui/widgets.py— the 11 core web-style widgets.ui/widgets_ext/— 4 shipped extras (gradient_rule,radial_glow,slider_track,braille_chart) + drop a module here to add your own.ui/registry.py—@register+ folder discovery.ui/cli.py—widgets/demo/gallery(+--width --height --theme).ui/field.py— CellField shader engine (Ripple/RadialGlow/LinearGradient/Plasma+ ASPECT dist).self_test.py— bounded render assertions.references/HARD-LESSONS.md— read before any replica: 10 rules from a dozen failed iterations (knowledge twin: [[hard-lessons]]).references/RENDERING-MODEL.md— first-principles: cell grid, shader fields, sub-cell, box algebra (knowledge twin: [[rendering-model]]).examples/effort_selector.py— worked replica of a real /effort-style selector (ground-truth-driven; measured constants: [[effort-selector]]).D:/Project/SmartCLI/knowledge/INDEX.md— the knowledge graph: look here before building (replica vs creative lanes).