AstroChart — Source Code Reference

Library: AstroChart (a.k.a. AstroDraw) Description: A free and open-source JavaScript/TypeScript library for generating SVG charts to display planets in astrology. Doc site: https://astrodraw.github.io/ GitHub repo: https://github.com/AstroDraw/AstroChart Branch: main

Repository Structure

The source code lives under project/ (not src/). Build output (the bundle consumed end-users) is in dist/.

AstroChart/
├── dist/
│   ├── astrochart.js              # Webpack-bundled build (99KB) — what the docs site loads
│   └── project/                   # Sub-bundle for project-mode imports
├── project/
│   ├── src/                       # TypeScript source
│   │   ├── index.ts               (172B)   — Public API entry, re-exports Chart
│   │   ├── chart.ts               (4KB)    — Chart class, public entry point
│   │   ├── svg.ts                 (84KB)   — SVG drawing primitives + all planet/zodiac glyphs
│   │   ├── radix.ts               (19KB)   — Radix chart composition (drawBg, drawUniverse, drawPoints...)
│   │   ├── transit.ts             (13KB)   — Transit chart overlay
│   │   ├── aspect.ts              (8KB)    — Aspect calculation engine
│   │   ├── zodiac.ts              (10KB)   — Zodiac logic, dignities, retrograde
│   │   ├── settings.ts            (8KB)    — Default config (colors, ratios, symbols, scale)
│   │   ├── utils.ts               (12KB)   — Geometry: getPointPosition, getRulerPositions, collision
│   │   ├── animation/
│   │   │   ├── animator.ts        (5KB)    — Animated chart transitions
│   │   │   └── timer.ts           (1KB)    — Animation timing helper
│   │   └── *.test.ts              — Jest test suite
│   ├── examples/                  — Usage examples
│   └── __tests__/                 — Additional tests
├── website/                       # Docusaurus doc site source (what renders astrodraw.github.io)
├── docs/                          # Doc site content (markdown)
├── doc/                           # Older documentation
├── package.json
├── tsconfig.json
├── webpack.config.js
└── jest.config.js

Chart Rendering Flow

Public API

// project/src/chart.ts
class Chart {
  constructor(elementId: string, width: number, height: number, settings?: Partial<Settings>)
  radix(data: AstroData): Radix      // Draw a natal/radix chart
  transit(data: AstroData): Transit  // Draw a transit overlay
  scale(factor: number): void        // Scale the chart
  calibrate(): Chart                 // Debug overlay
}

// project/src/index.ts — re-exports Chart as default

Drawing Pipeline (inside `Radix`)

Order of operations in Radix constructor + draw methods:

Step	Method	File	What it does
1	`drawBg()`	`project/src/radix.ts`	Background hemisphere via `paper.segment()`
2	`drawUniverse()`	`project/src/radix.ts`	12 zodiac sign color segments + 12 zodiac symbol glyphs
3	`drawRuler()`	`project/src/radix.ts`	Degree tick marks around the wheel
4	`drawPoints()`	`project/src/radix.ts`	Planet symbols, pointer lines, degree/retro/dignity labels
5	`drawCusps()`	`project/src/radix.ts`	12 cusp lines (dashed around planets), house numbers
6	`drawAxis()`	`project/src/radix.ts`	Asc/Ds/Ic/Mc axis lines with symbols
7	`drawCircles()`	`project/src/radix.ts`	Outer, inner, indoor circle strokes

Aspects are drawn via Radix.aspects() which uses project/src/aspect.ts.

Key Source Files (download URLs)

Core rendering

File	Description
svg.ts	SVG primitives: `segment()`, `circle()`, `line()`, `text()`, and 50+ glyph methods (`sun()`, `moon()`, `aries()`, `taurus()`, ... `pluto()`, `chiron()`, `nnode()`, `fortune()`). The `<path d="...">` arc math lives at lines ~1468-1478.
radix.ts	Chart composition — orchestrates all SVG calls. `LocatedPoint` interface, `AstroData` type, collision avoidance via `assemble()`.
chart.ts	Public entry point. Creates `SVG`, delegates to `Radix` or `Transit`.

Data + logic

File	Description
settings.ts	Default constants: `COLORS_SIGNS`, `SYMBOL_SIGNS`, `INNER_CIRCLE_RADIUS_RATIO`, `INDOOR_CIRCLE_RADIUS_RATIO`, `RULER_RADIUS`, `SYMBOL_SCALE`, `PADDING`, etc.
utils.ts	`getPointPosition()`, `getRulerPositions()`, `getDashedLinesPositions()`, `getDescriptionPosition()`, `assemble()`, `validate()`, `radiansToDegree()`.
zodiac.ts	Zodiac sign boundaries, essential dignities (domicile, exaltation, detriment, fall), retrograde detection.
aspect.ts	`AspectCalculator` class — computes aspects between planet points (conjunction, opposition, trine, square, sextile, etc.).
transit.ts	Transit chart — draws on top of an existing radix.
animation/animator.ts	Animated chart transitions.
animation/timer.ts	Animation timing helper.
index.ts	Public API barrel file.

Built artifact

File	Description
dist/astrochart.js	Webpack bundle — the file loaded by the doc site and distributed to end-users.

SVG Primitives API (svg.ts)

Method	Signature	Purpose
`segment()`	`(x, y, radius, a1, a2, thickness, lFlag?, sFlag?)`	Arc slice (used for sign segments, background)
`circle()`	`(cx, cy, radius)`	Circle stroke (chart rings)
`line()`	`(x1, y1, x2, y2)`	Straight line (cusps, pointers, ruler ticks)
`text()`	`(txt, x, y, size, color)`	Symbol/text glyph
`getSymbol()`	`(name, x, y)`	Dispatches to the correct glyph method
`radialLine()`	—	Radial spoke from center to edge

Key constants (defined in settings.ts, used in svg.ts line ~1468):

LARGE_ARC_FLAG = 1
SWEET_FLAG = 0

Doc Site (what renders the GitHub Pages UI)

The documentation site that appears at https://astrodraw.github.io/ is built with Docusaurus v2.3.1 (seen in <meta name="generator">).

File	Description
website/	Docusaurus source (docusaurus.config, sidebar, pages)
docs/	Doc content markdown

The homepage hero banner contains an inline SVG showing a React-like logo (unrelated to this library — it's Docusaurus template branding). The actual AstroChart demo rendering on the page uses the Chart class targeting <div id="paper">.

Key Data Structures

// From radix.ts
export type Points = Record<string, number[]>
export interface LocatedPoint {
  name: string   // planet name, e.g. "Sun", "Moon"
  x: number      // computed screen x
  y: number      // computed screen y
  r: number      // collision radius
  angle: number  // shifted position in degrees
  pointer?: number
  index?: number
}
export interface AstroData {
  planets: Points   // {"Sun":[120], "Moon":[45], ...}
  cusps: number[]   // [300, 340, 30, 60, 75, 90, 116, 172, 210, 236, 250, 274]
}

Notes

The library is TypeScript (compiled via webpack, not tsc).
No runtime dependencies — pure DOM SVG manipulation.
Tests use Jest (jest.config.js).
The project/ subdirectory is the actual library source; the repo root contains build/config/docs.

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