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ZXing-C++ Kotlin/Native Library

Install

The easiest way to use the library is to fetch if from mavenCentral. Simply add

implementation("io.github.zxing-cpp:kotlin-native:2.2.1")

to your build.gradle.kts file in the dependencies section of nativeMain source set.

Use

Reading

A trivial use case looks like this:

import zxingcpp.BarcodeFormat
import zxingcpp.BarcodeReader
import zxingcpp.ImageFormat
import zxingcpp.ImageView

val data: ByteArray = ...    // the image data
val width: Int = ...         // the image width
val height: Int = ...        // the image height
val format: ImageFormat = ImageFormat.Lum // ImageFormat.Lum assumes grey scale image data

val image: ImageView = ImageView(data, width, height, format)
val barcodeReader = BarcodeReader().apply {
   formats = setOf(BarcodeFormat.EAN13, BarcodeFormat.QRCode)
   tryHarder = true
   maxNumberOfSymbols = 3
   // more options, see documentation
}

barcodeReader.read(image).joinToString("\n") { barcode: Barcode ->
   "${barcode.format} (${barcode.contentType}): ${barcode.text}"
}

Here you have to load your image into memory by yourself and pass the decoded data to the constructor of ImageView.

Writing

A trivial use case looks like this:

import zxingcpp.*

val text: String = "Hello, World!"
val format = BarcodeFormat.QRCode

@OptIn(ExperimentalWriterApi::class)
val cOpts = CreatorOptions(format) // more options, see documentation

@OptIn(ExperimentalWriterApi::class)
val barcode = Barcode(text, cOpts)
// or
@OptIn(ExperimentalWriterApi::class)
val barcode2 = Barcode(text.encodeToByteArray(), format)

@OptIn(ExperimentalWriterApi::class)
val wOpts = WriterOptions().apply {
   sizeHint = 400
   // more options, see documentation
}

@OptIn(ExperimentalWriterApi::class)
val svg: String = barcode.toSVG(wOpts)
@OptIn(ExperimentalWriterApi::class)
val image: Image = barcode.toImage(wOpts)

Note: The Writer api is still experimental and may change in future versions. You will have to opt-in zxingcpp.ExperimentalWriterApi to use it.

Build locally

  1. Install JDK, CMake and Android NDK(With $ANDROID_NDK correctly configured) and ensure their executable binaries appear in $PATH.
  2. Prepare kotlin/native toolchain (You can easily do this by cloning K/N Toolchain Initializer and executing gradle build so that kotlin will download toolchains needed into user's home dir.).
  3. Ensure there's run_konan available in $PATH or specify path of kotlin-native toolchain in local.properties like konan.dir=/home/user/.konan/kotlin-native-prebuilt-linux-x86_64-1.9.22.
  4. Ensure there's llvm-ar available in $PATH for mingwX64 target building.

And then you can build the project from the command line:

$ ./gradlew :assemble