textcharts

Beautiful text based charts for your terminal — zero dependencies.

15 chart types with Unicode box-drawing, ANSI colors, and automatic terminal width detection. Pure Python, no external dependencies, Python 3.10+.

Provenance

textcharts was extracted from the BenchBox project so the terminal charting layer could be used as a standalone library.

BenchBox remains the source of the most complete end-to-end usage examples for benchmarking and performance-analysis workflows. For canonical example-driven documentation, see the BenchBox documentation.

Install

pip install textcharts

Quick Start

from textcharts import BoxPlot, BoxPlotSeries

downtown = [1825, 1900, 1980, 2100, 2250, 2400, 2550, 2710, 2980]
riverside = [1450, 1525, 1600, 1680, 1750, 1820, 1950, 2080, 2220]
midtown = [1650, 1710, 1780, 1840, 1920, 2010, 2140, 2280, 2450]

series = [
    BoxPlotSeries(name="Downtown", values=downtown),
    BoxPlotSeries(name="Riverside", values=riverside),
    BoxPlotSeries(name="Midtown", values=midtown),
]
chart = BoxPlot(
    series=series,
    title="Apartment Rents",
    subtitle="Monthly rent distribution by neighborhood",
)
print(chart.render())

Text output (greyscale)

Apartment Rents (Value)
               Monthly rent distribution by neighborhood
────────────────────────────────────────────────────────────────────────

                         ╷     ┌─────────┬──────────┐                ╷
Downtown                 ├─────│         │          │────────────────┤
                         ╵     └─────────┴──────────┘                ╵
           ╷    ┌─────┬──────┐          ╷
Riverside  ├────│     │      │──────────┤
           ╵    └─────┴──────┘          ╵
                  ╷    ┌────┬────────┐          ╷
Midtown           ├────│    │        │──────────┤
                  ╵    └────┴────────┘          ╵
           ───────────────────────────────────────────────────────────
           1.4K                       2.2K                        3.0K
                                Value →
           median  mean    std
           ──────  ────  ─────
Downtown     2.2K  2.3K  392.7
Riverside    1.8K  1.8K  257.6
Midtown      1.9K  2.0K  269.8

Chart Types

Chart	Class	Data Model
Bar chart	BarChart	BarData
Histogram	Histogram	HistogramBar
Heatmap	Heatmap	matrix + labels
Box plot	BoxPlot	BoxPlotSeries
Line chart	LineChart	LinePoint
Scatter plot	ScatterPlot	ScatterPoint
Comparison bar	ComparisonBar	ComparisonBarData
Diverging bar	DivergingBar	DivergingBarData
Summary box	SummaryBox	SummaryStats
Percentile ladder	PercentileLadder	PercentileData
Normalized speedup	NormalizedSpeedup	SpeedupData
Stacked bar	StackedBar	StackedBarData
Sparkline table	SparklineTable	SparklineTableData
CDF chart	CDFChart	CDFSeriesData
Rank table	RankTable	RankTableData

Public API

• Chart classes: BarChart, Heatmap, LineChart, SummaryBox, etc.
• Data models: BarData, HistogramBar, LinePoint, SummaryStats, etc.
• Configuration: ChartOptions and ColorMode

CLI

Generate charts from the command line with JSON input:

# Pipe JSON data to any chart type
echo '[{"label": "Fiction", "value": 18.4}, {"label": "Comics", "value": 9.8}]' \
  | textcharts bar --title "Revenue" --no-color

# Read from a file
textcharts heatmap -f matrix.json --color-scheme sequential

# List all 15 chart types
textcharts list

# See data format and options for any chart type
textcharts scatter --help

See the input formats reference for the JSON schema of each chart type.

MCP Server

Use textcharts as an AI tool via the Model Context Protocol:

pip install textcharts[mcp]

Add to your MCP client config (Claude Desktop, Claude Code, etc.):

{
  "mcpServers": {
    "textcharts": {
      "command": "textcharts-mcp"
    }
  }
}

This exposes 17 tools: textcharts_bar, textcharts_heatmap, ..., textcharts_list, and textcharts_describe. See the MCP setup guide for full configuration options.

Configuration

from textcharts import ChartOptions, ColorMode

opts = ChartOptions(
    use_color=True,       # Auto-detect ANSI color support; set False to force plain text
    use_unicode=True,     # Unicode box-drawing characters
    width=80,             # Chart width (None for auto-detect)
    theme="dark",         # "dark" or "light"
)

use_color=True respects terminal detection and NO_COLOR. In non-interactive contexts, renders default to plain text without ANSI escapes.

Heatmaps support color_scheme="diverging" (default) or color_scheme="sequential".

Matrix-based APIs require exact dimensions:

• len(row_labels) == len(matrix)
• every matrix row length must equal len(col_labels)

Development

Install dev tools:

uv sync --group dev

Run the same checks used for release verification:

uv run --group dev ruff check src/ tests/
uv run --group dev python -m pytest -q
uv run --group dev sphinx-build -W -b html docs docs/_build/html
uv build

Project documentation lives under docs/ and is built with Sphinx.

If you want richer real-world examples beyond the standalone library docs, use the BenchBox documentation as the canonical reference for benchmark-oriented chart usage.

Golden regression snapshots live under tests/fixtures/golden/ascii/. To intentionally update them after a renderer change:

uv run --group dev python -m pytest tests/test_golden_output.py -q --update-golden

Features

• Zero dependencies — pure Python, stdlib only
• 15 chart types — from simple bars to heatmaps and CDF curves
• Terminal-aware — auto-detects width, color support, and Unicode capability
• Best/worst highlighting — automatic annotation of extreme values
• Typed — full type hints with py.typed marker (PEP 561)

License

MIT