A native Swift library to read and write FITS files

Description

FITSKit is a pure Swift library to process the image data of FITS 4.0 file files, commonly used to store astronomical data.

The aim is to implement a modern, native Swift library to utilize the full computing power of modern apple hardware. In particuary, I was seeking for a simple solution to read, render & review FITS files on an iPad.

FITSKit is a highly plattform depenedend library. It compiles and runs exclusively on iOS / iPadOS / macCatalyst. It utilizes apples standard libraries Core Image and Accelerate to process, render & manipulate image data stored in FITS files. It is meant as an addition to the general FITS file format library FitsCore.

FITSCore	FITSKit	FITSTool
Fits file format read & write	Image rendering & manipulation	Command line tool
macOS, iOS & Linux	iOS / macCatalyst	Linux

Features

• Read & Write FITS 4.0 files
  • Image format conversion using Accelerate
  • [x| BITPIX 8 support
  • BITPIX 16 support
  • BITPIX 32 support
  • BITPIX 64 support
  • BITPIX -32 support
  • BITPIX -64 support
• Native code
  • Swift 5.4
  • Compiles for macCatalyst
  • Compiles for iPadOS / iOS

Getting started

Package Manager

With the swift package manager, add the library to your dependencies

dependencies: [
.package(url: "https://github.com/brampf/fitskit.git", from: "0.1.0")
]

then simply add the FITSKit import to your target

.target(name: "YourApp", dependencies: ["FITSKit"])

Documentation

There are several decoders to decode the raw image data of an FITS DataUnit into either an CGImage or into an vImage_Buffer

• GrayscaleDecoder : Renders grayscale images from two-dimensional data
• RGBDecoder : Renders RGB images from tree-dimensional data
• BayerDecoder : Renders RGB images from two-dimensional data

Please note: Decoders only translate the raw byte patterns into processable images and does not apply color correction of any kind.

Don't care, just give me a picture, alright?

import FITSKit

let image = try file.prime.decode()

Grayscale Decoder

Applicable on two-dimensional (NAXIS == 2) data units

import FITSKit

let image = try file.prime.decode(GrayscaleDecoder.self, ())

RGB Decoder

Applicable on three-dimensional (NAXIS == 3) data units

import FITSKit

let image = try file.prime.decode(RGB_Decoder<RGB>.self, ())
}

The RGB Decoder allows parametrization of the output and can also decode grayscale images

import FITSKit

let image = try file.prime.decode(RGB_Decoder<Mono>.self, ())
}

Bayer Decoder (De-Bayering / Demosaic)

Applicable on two-dimensional (NAXIS == 2) data units

import FITSKit

let image = try file.prime.decode(BayerDecoder.self, .RGGB)
}

License

MIT license; see LICENSE. (c) 2021