polygon-offsetting

Small crate, no dependencies, to offset a polygon (only margin).

Features

• very fast
• from a simple Vec of 2D coordinates (f64 tuples), compute its offset contour, its perimeter and area
• the initial polygon must be closed
• you must ensure that your polygon does not intersect itself

Examples

cargo run --example example_offsetting --release

fn example_offsetting() -> Result <(), Box<dyn std::error::Error>> {
	// the initial polygon must be closed
	let points: Vec<(f64, f64)> = vec![
		(0., 0.),
		(100., 0.),
		(40., 20.),
		(100., 20.),
		(100., 60.),
		(95., 78.),
		(55., 40.),
		(0., 60.),
		(0.0, 0.0)
	];

	// the size of our margin, if egal to 0 no offsetting will be computed
	let offset_size: f64 = 12.25;
	// tolerance is the arc segments precision in polygon offsetting (rounded corner)
	let tolerance: f64 = 0.1;

	let mut polygon = Polygon::new(&points, offset_size).map_err(|e| { e })?;
	let offset: Offset = polygon.offsetting(tolerance).map_err(|e| { e })?;

	println!("Initial contour length: {:?}", points.len());
	println!("Offset contour length: {:?}", offset.contour.len());
	println!("offset area: {:?}", offset.area);
	println!("offset perimeter: {:?}", offset.perimeter);
    
    draw_svg_offset(
	    &points,
	    &offset,
	    "/examples/svg/",
        "example_offsetting",
	).map_err(|e| { 
	    print!("Error on creating offset svg: {:?}", e);
	    e 
	})?;

    Ok(())
}

Licence

MIT License

Copyright (c) 2024 Akirami

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
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The above copyright notice and this permission notice shall be included in all
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FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
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