i_shape

v0.7.0

Published

8 months ago

Boolean Operations for 2D Polygons. Supported operations: intersection, union, difference, XOR, and self-intersections for all polygon varieties.

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nailxsharipov

iShape-js

Demo

Try out iShape with an interactive demo. The demo covers operations like union, intersection, difference and exclusion

Features

Operations: union, intersection, difference, and exclusion.
Polygons: with holes, self-intersections, and multiple paths.
Simplification: removes degenerate vertices and merges collinear edges.
Fill Rules: even-odd and non-zero.

Getting Started

Direct include

Download Library Files:

i_shape.js
i_shape_bg.wasm

You can find it at: pkg

Place Files:

Place these files in a directory that your HTML file can access; in this example, the directory is named ./ishape

NPM

Installation

You can install the iShape library from NPM:

npm install i_shape

The NPM package is available here

Import and Usage

After installing the NPM package, you can import it in your JavaScript or TypeScript file as follows:

import init, { Overlay, OverlayGraph, OverlayRule, ShapeType, FillRule } from './ishape/i_shape.js';

// Your code here

Example

Here is a simple HTML example that demonstrates how to use the iShape library for union operation.

<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>iShape</title>
    <style>
        #result {
            background-color: #f5f5f5;
            border: 1px solid #ccc;
            padding: 10px;
            white-space: pre-wrap;
            font-family: monospace;
        }
        textarea {
            width: 100%;
            height: 150px;
            padding: 10px;
            font-family: monospace;
            margin-bottom: 10px;
        }
    </style>
    <script type="module">
        import init, { Overlay, OverlayGraph, OverlayRule, ShapeType, FillRule} from './ishape/i_shape.js';

        init();

        document.getElementById('union').addEventListener('click', () => {
            
            const subjInput = document.getElementById('subjInput').value;
            const clipInput = document.getElementById('clipInput').value;

            const subj = JSON.parse(subjInput);
            const clip = JSON.parse(clipInput);

            const overlay = new Overlay();
            overlay.add_shape(subj, ShapeType.Subject);
            overlay.add_shape(clip, ShapeType.Clip);

            // build segments geometry
            const graph = overlay.build_graph(FillRule.EvenOdd);

            // apply union operation
            const union = graph.extract_shapes(OverlayRule.Union);

            // add more operations if required

            const resultText = JSON.stringify(union, null, 2);
            document.getElementById('result').innerText = `Result:\n${resultText}`;
        });
    </script>
</head>
<body>
    <textarea id="subjInput" placeholder='Enter "subj" polygon here...'>{"paths": [{"points": [[200, 300], [200, 100], [400, 100], [400, 300]]}]}</textarea>
    <textarea id="clipInput" placeholder='Enter "clip" polygon here...'>{"paths": [{"points": [[300, 400], [300, 200], [500, 200], [500, 400]]}]}</textarea>
    <button id="union">Union</button>
    <pre id="result"></pre>
</body>
</html>

Explanation:

Import classes and initialize the WebAssembly module using init(). Use the imported classes to perform geometric operations.

Overlay Rules

Union, A or B

Union

Intersection, A and B

Intersection

Difference, B - A

Difference

Exclusion, A xor B

Exclusion