swift-potrace

A Swift package implementing the potrace algorithm. Potrace allows you to transform a bitmap into a smooth, scalable vector image.

Background

This is a refactoring of the Potrace class from @pcolton 's potrace iOS application that has been updated to use CGMutablePath rather than the iOS-specific UIBezierPath and to take as its input a CoreGraphics CGImage instance rather than rather bytes.

Documentation

Documentation is incomplete at this time.

Getting Started

swift-potrace is designed for Swift 5. To depend on the logging API package, you need to declare your dependency in your Package.swift:

.package(url: "https://github.com/sfomuseum/swift-potrace", from: "0.0.1"),

and to your application/library target, add "Potrace" to your dependencies, e.g. like this:

.target(name: "PotraceApp", dependencies: [
    .product(name: "Potrace", package: "swift-potrace")
]

Example

import CoreGraphics
import Potrace

// Load your CGImage as necessary here
var cg_image: CGImage

let potrace = try Potrace(image: cg_image)
potrace.process()
        
let svgString = potrace.getSVG()
print(svgString)

Known-knowns

The Potrace.swift file produces an "initialization of 'UnsafeMutableRawPointer' results in a dangling pointer" warning that I am not sure how to deal with. I have chosen to live with it since the original code that this package was derived from produces the same error. That's not really a very good reason but that is today's reason. Any suggestions or fixes would be welcome.

See also

• https://github.com/sfomuseum/swift-potrace-cli
• https://github.com/pcolton/potrace