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/*
* Copyright © 2017-2022 WireGuard LLC. All Rights Reserved.
* SPDX-License-Identifier: Apache-2.0
*/
package com.wireguard.android.util
import android.content.ContentResolver
import android.graphics.Bitmap
import android.graphics.BitmapFactory
import android.net.Uri
import android.util.Log
import com.google.zxing.BinaryBitmap
import com.google.zxing.DecodeHintType
import com.google.zxing.NotFoundException
import com.google.zxing.RGBLuminanceSource
import com.google.zxing.Reader
import com.google.zxing.Result
import com.google.zxing.common.HybridBinarizer
import kotlinx.coroutines.Dispatchers
import kotlinx.coroutines.withContext
/**
* Encapsulates the logic of scanning a barcode from a file,
* @property contentResolver - Resolver to read the incoming data
* @property reader - An instance of zxing's [Reader] class to parse the image
*/
class QrCodeFromFileScanner(
private val contentResolver: ContentResolver,
private val reader: Reader,
) {
private fun scanBitmapForResult(source: Bitmap): Result {
val width = source.width
val height = source.height
val pixels = IntArray(width * height)
source.getPixels(pixels, 0, width, 0, 0, width, height)
val bBitmap = BinaryBitmap(HybridBinarizer(RGBLuminanceSource(width, height, pixels)))
return reader.decode(bBitmap, mapOf(DecodeHintType.TRY_HARDER to true))
}
private fun downscaleBitmap(source: Bitmap, scaledSize: Int): Bitmap {
val originalWidth = source.width
val originalHeight = source.height
var newWidth = -1
var newHeight = -1
val multFactor: Float
when {
originalHeight > originalWidth -> {
newHeight = scaledSize
multFactor = originalWidth.toFloat() / originalHeight.toFloat()
newWidth = (newHeight * multFactor).toInt()
}
originalWidth > originalHeight -> {
newWidth = scaledSize
multFactor = originalHeight.toFloat() / originalWidth.toFloat()
newHeight = (newWidth * multFactor).toInt()
}
originalHeight == originalWidth -> {
newHeight = scaledSize
newWidth = scaledSize
}
}
return Bitmap.createScaledBitmap(source, newWidth, newHeight, false)
}
private fun doScan(data: Uri): Result {
Log.d(TAG, "Starting to scan an image: $data")
contentResolver.openInputStream(data).use { inputStream ->
val originalBitmap = BitmapFactory.decodeStream(inputStream)
?: throw IllegalArgumentException("Can't decode stream to Bitmap")
return try {
scanBitmapForResult(originalBitmap).also {
Log.d(TAG, "Found result in original image")
}
} catch (e: Exception) {
Log.e(TAG, "Original image scan finished with error: $e, will try downscaled image")
val scaleBitmap = downscaleBitmap(originalBitmap, 500)
scanBitmapForResult(originalBitmap).also { scaleBitmap.recycle() }
} finally {
originalBitmap.recycle()
}
}
}
/**
* Attempts to parse incoming data
* @return result of the decoding operation
* @throws NotFoundException when parser didn't find QR code in the image
*/
suspend fun scan(data: Uri) = withContext(Dispatchers.Default) { doScan(data) }
companion object {
private const val TAG = "QrCodeFromFileScanner"
/**
* Given a reference to a file, check if this file could be parsed by this class
* @return true if the file can be parsed, false if not
*/
fun validContentType(contentResolver: ContentResolver, data: Uri): Boolean {
return contentResolver.getType(data)?.startsWith("image/") == true
}
}
}
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