Aegis/app/src/main/java/com/beemdevelopment/aegis/helpers/QrCodeAnalyzer.java

package com.beemdevelopment.aegis.helpers;

import android.os.Handler;
import android.os.Looper;
import android.util.Log;
import android.util.Size;

import androidx.annotation.NonNull;
import androidx.camera.core.ImageAnalysis;
import androidx.camera.core.ImageProxy;

import com.google.zxing.BinaryBitmap;
import com.google.zxing.ChecksumException;
import com.google.zxing.FormatException;
import com.google.zxing.NotFoundException;
import com.google.zxing.PlanarYUVLuminanceSource;
import com.google.zxing.Result;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.QRCodeReader;

import java.nio.ByteBuffer;

import static android.graphics.ImageFormat.YUV_420_888;
import static android.graphics.ImageFormat.YUV_422_888;
import static android.graphics.ImageFormat.YUV_444_888;

public class QrCodeAnalyzer implements ImageAnalysis.Analyzer {
    private static final String TAG = QrCodeAnalyzer.class.getSimpleName();
    public static final Size RESOLUTION = new Size(1200, 1600);

    private final QrCodeAnalyzer.Listener _listener;

    public QrCodeAnalyzer(QrCodeAnalyzer.Listener listener) {
        _listener = listener;
    }

    @Override
    public void analyze(@NonNull ImageProxy image) {
        int format = image.getFormat();
        if (format != YUV_420_888 && format != YUV_422_888 && format != YUV_444_888) {
            Log.e(TAG, String.format("Expected YUV format, got %d instead", format));
            image.close();
            return;
        }

        byte[] data = getLuminancePlaneData(image);
        PlanarYUVLuminanceSource source = new PlanarYUVLuminanceSource(
                data, image.getWidth(), image.getHeight(), 0, 0, image.getWidth(), image.getHeight(), false
        );

        QRCodeReader reader = new QRCodeReader();
        BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
        try {
            Result result = reader.decode(bitmap);
            if (_listener != null) {
                new Handler(Looper.getMainLooper()).post(() -> _listener.onQrCodeDetected(result));
            }
        } catch (ChecksumException | FormatException | NotFoundException ignored) {

        } finally {
            image.close();
        }
    }

    private static byte[] getLuminancePlaneData(ImageProxy image) {
        ImageProxy.PlaneProxy plane = image.getPlanes()[0];
        ByteBuffer buf = plane.getBuffer();
        byte[] data = new byte[buf.remaining()];
        buf.get(data);
        buf.rewind();

        int width = image.getWidth();
        int height = image.getHeight();
        int rowStride = plane.getRowStride();
        int pixelStride = plane.getPixelStride();

        if (width != rowStride || pixelStride != 1) {
            // remove padding from the Y plane data
            byte[] cleanData = new byte[width * height];
            for (int y = 0; y < height; y++) {
                for (int x = 0; x < width; x++) {
                    cleanData[y * width + x] = data[y * rowStride + x * pixelStride];
                }
            }

            return cleanData;
        }

        return data;
    }

    public interface Listener {
        void onQrCodeDetected(Result result);
    }
}