MoonChartSVG

MoonChartSVG is a zero-dependency SVG chart library written in pure MoonBit. It provides builder APIs for bar, line, area, scatter, pie, donut, radar, stacked bar, and horizontal bar charts.

Install

moon add Mitsuha11zz/MoonChartSVG

Quick Start

let svg = @MoonChartSVG.BarChart::new()
  .title("Monthly Sales")
  .x_labels(["Jan", "Feb", "Mar", "Apr"])
  .series(@MoonChartSVG.Series::new("Product A", [120.0, 200.0, 150.0, 180.0]))
  .series(@MoonChartSVG.Series::new("Product B", [80.0, 130.0, 170.0, 140.0]))
  .render()

render() returns a complete standalone <svg> document. It can be written to a file, embedded in HTML, or composed with the included dashboard helpers.

Highlights

• Nine chart types with a consistent builder API
• Pure SVG output with no browser or runtime dependency
• Automatic axis scaling and a built-in Tableau-style palette
• Responsive multi-row legends for narrow canvases
• XML escaping for titles, labels, colors, and generated attributes
• Stable pie, donut, and radar coordinates across all angle quadrants
• Defensive copies in builders so earlier chart values stay unchanged
• Graceful handling of empty and non-positive pie or donut data
• CSV parsing, descriptive statistics, themes, and HTML wrappers

Demo

moon run cmd/main

The command prints complete examples for every chart type, a composed SVG dashboard, theme usage, and CSV-driven data.

Validation

moon check --deny-warn --target all
moon fmt --check
moon info --target all
moon test --deny-warn --target all
moon coverage analyze

The current MoonBit CLI does not accept --deny-warn for moon fmt or moon info; moon fmt --check and a clean moon info run are the supported equivalent checks. The current suite contains 93 tests.

Data Behavior

• Pie and donut slices with values less than or equal to zero are ignored.
• A pie or donut whose positive total is zero renders an empty SVG chart.
• A single 100% pie uses two SVG half-arcs; a donut uses paired outer and inner half-arcs so both render consistently across SVG engines.
• Donut hole ratios are clamped to the range 0.0..0.95.
• Radar grid levels are clamped to at least one.
• Radar values missing from a series are rendered as zero.
• CSV input supports quoted fields, escaped quotes, embedded newlines, and CRLF records.
• Empty statistical inputs return 0.0 instead of dividing by zero or indexing an empty array.
• User-provided SVG text and attributes are XML escaped.

License

Apache-2.0