taler-android

Android apps for GNU Taler (wallet, PoS, cashier)
Log | Files | Refs | README | LICENSE

QrLuminance.kt (2309B)

      1 /*
      2  * This file is part of GNU Taler
      3  * (C) 2026 Taler Systems S.A.
      4  *
      5  * GNU Taler is free software; you can redistribute it and/or modify it under the
      6  * terms of the GNU General Public License as published by the Free Software
      7  * Foundation; either version 3, or (at your option) any later version.
      8  *
      9  * GNU Taler is distributed in the hope that it will be useful, but WITHOUT ANY
     10  * WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR
     11  * A PARTICULAR PURPOSE.  See the GNU General Public License for more details.
     12  *
     13  * You should have received a copy of the GNU General Public License along with
     14  * GNU Taler; see the file COPYING.  If not, see <http://www.gnu.org/licenses/>
     15  */
     16 
     17 package net.taler.merchantpos.config
     18 
     19 import com.google.zxing.PlanarYUVLuminanceSource
     20 
     21 import java.nio.ByteBuffer
     22 
     23 /** Camera planes may contain padding between rows and between individual pixels. */
     24 internal fun qrLuminance(
     25     buffer: ByteBuffer,
     26     width: Int,
     27     height: Int,
     28     rowStride: Int,
     29     pixelStride: Int,
     30     rotation: Int,
     31 ): PlanarYUVLuminanceSource
     32 {
     33     require(width > 0 && height > 0 && pixelStride > 0)
     34     require(rowStride.toLong() >= (width - 1L) * pixelStride + 1)
     35     require(rotation in setOf(0, 90, 180, 270))
     36     require((height - 1L) * rowStride + (width - 1L) * pixelStride < buffer.remaining())
     37     val swapped = rotation == 90 || rotation == 270
     38     val outputWidth = if (swapped) height else width
     39     val outputHeight = if (swapped) width else height
     40     val pixels = ByteArray(Math.multiplyExact(width, height))
     41     val offset = buffer.position()
     42     for (y in 0 until height)
     43     {
     44         for (x in 0 until width)
     45         {
     46             val destination =
     47                 when (rotation)
     48                 {
     49                     90 -> x * outputWidth + height - 1 - y
     50                     180 -> (height - 1 - y) * outputWidth + width - 1 - x
     51                     270 -> (width - 1 - x) * outputWidth + y
     52                     else -> y * outputWidth + x
     53                 }
     54             pixels[destination] = buffer.get(offset + y * rowStride + x * pixelStride)
     55         }
     56     }
     57     return PlanarYUVLuminanceSource(
     58         pixels,
     59         outputWidth,
     60         outputHeight,
     61         0,
     62         0,
     63         outputWidth,
     64         outputHeight,
     65         false,
     66     )
     67 }