｢‍｣ Lingenic Pen-Path

A 2D stroke graphics library using the pen-and-path model.

Overview

Pen-Path provides primitives for creating stroke-based vector graphics, inspired by calligraphic and technical drawing traditions. A pen (circular, elliptical, or rectangular) traces along a path to produce filled outlines.

Core Concepts

• Point: 2D coordinate in centipoints (7200 per inch)
• Path: Sequence of points connected by line, curve, or corner segments
• Pen: Shape that sweeps along a path
• Stroke: Filled envelope from sweeping a pen along a path

Units

All coordinates use centipoints (Cp):

• 7200 centipoints = 1 inch
• 100 centipoints = 1 point (1/72 inch)

Integer coordinates avoid floating-point precision issues while providing sub-point accuracy.

Path Connectors

Symbol	Name	Description
⏤	Line	Straight segment
⌒	Curve	Smooth curve (Hobby's algorithm)
∠	Corner	Sharp angle break
↻	Cycle	Close path to start

Pen Types

• Circular: Fixed-width strokes
• Elliptical: Calligraphic variation
• Rectangular: Technical/architectural lines

Color Models

• RGB/RGBA: Screen display (0-255 per channel)
• CMYK: Print output (0-100% per channel)
• Grayscale: Single-channel with alpha
• HSL: Hue/Saturation/Lightness
• Spot: Named single-ink colors (Pantone-style) with tint
• Sepia: Warm monochrome for aged document aesthetics

Usage

use pen_path::{Point, Path, Pen, Color, Stroke, StrokeOptions};
use pen_path::render::SvgOps;

// Create a path (coordinates in centipoints)
let path = Path::builder()
    .move_to(10000, 10000)
    .line_to(50000, 10000)
    .line_to(30000, 40000)
    .close();

// Create a 10pt circular pen
let pen = Pen::circular(1000);

// Stroke and render
let stroke = Stroke::new(path, pen, Color::BLACK);
let envelope = stroke.to_envelope(&StrokeOptions::default());

Output Formats

• PDF: Direct PDF path operators
• SVG: Standard SVG path data

License

Apache-2.0

Part of ｢‍｣ Lingenic Compose

Pen-Path is a component of the ｢‍｣ Lingenic Compose typesetting system.

http://compose.lingenic.com/