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qr-scan-difficulty-check / server /zxing /ZxingServer.java

QR Scan Difficulty Check

b43c3a8 verified 3 days ago

5.36 kB

import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.DecodeHintType;
import com.google.zxing.LuminanceSource;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.ReaderException;
import com.google.zxing.Result;
import com.google.zxing.ResultMetadataType;
import com.google.zxing.common.HybridBinarizer;

import javax.imageio.ImageIO;
import java.awt.image.BufferedImage;
import java.io.BufferedReader;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileDescriptor;
import java.io.FileOutputStream;
import java.io.InputStreamReader;
import java.io.PrintStream;
import java.nio.charset.StandardCharsets;
import java.util.Base64;
import java.util.EnumMap;
import java.util.LinkedHashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

/**
 * ZXing core 3.5.2 as Android's Settings app calls it (SettingsLib QrCamera): QR only, HybridBinarizer,
 * decodeWithState on the frame, then on the inverted frame; no TRY_HARDER.
 * stdin: "id<TAB>path" lines, each an 8-bit gray PNG. stdout: one JSON line per input, flushed, with every byte
 * form of the content ZXing returns (its text as UTF-8 and, where it fits, ISO-8859-1, and its raw byte
 * segments), base64-encoded: a read counts when one of them is the picture's content.
 */
public class ZxingServer {

    /** A plain gray plane, as SettingsLib's QrYuvLuminanceSource hands ZXing the camera's Y plane. */
    static final class GraySource extends LuminanceSource {
        private final byte[] data;

        GraySource(byte[] data, int width, int height) {
            super(width, height);
            this.data = data;
        }

        @Override
        public byte[] getRow(int y, byte[] row) {
            int w = getWidth();
            if (row == null || row.length < w) row = new byte[w];
            System.arraycopy(data, y * w, row, 0, w);
            return row;
        }

        @Override
        public byte[] getMatrix() {
            return data;
        }
    }

    static Result decode(MultiFormatReader reader, LuminanceSource source) {
        try {
            return reader.decodeWithState(new BinaryBitmap(new HybridBinarizer(source)));
        } catch (ReaderException e) {
            return null;
        } finally {
            reader.reset();
        }
    }

    @SuppressWarnings("unchecked")
    static Set<String> contents(Result r) throws Exception {
        Base64.Encoder b64 = Base64.getEncoder();
        Set<String> out = new LinkedHashSet<>();
        String text = r.getText() == null ? "" : r.getText();
        out.add(b64.encodeToString(text.getBytes(StandardCharsets.UTF_8)));
        if (StandardCharsets.ISO_8859_1.newEncoder().canEncode(text)) {
            out.add(b64.encodeToString(text.getBytes(StandardCharsets.ISO_8859_1)));
        }
        Map<ResultMetadataType, Object> md = r.getResultMetadata();
        if (md != null && md.get(ResultMetadataType.BYTE_SEGMENTS) instanceof List) {
            ByteArrayOutputStream bos = new ByteArrayOutputStream();
            for (byte[] seg : (List<byte[]>) md.get(ResultMetadataType.BYTE_SEGMENTS)) bos.write(seg);
            if (bos.size() > 0) out.add(b64.encodeToString(bos.toByteArray()));
        }
        return out;
    }

    public static void main(String[] args) throws Exception {
        Map<DecodeHintType, Object> hints = new EnumMap<>(DecodeHintType.class);
        hints.put(DecodeHintType.POSSIBLE_FORMATS, List.of(BarcodeFormat.QR_CODE));
        MultiFormatReader reader = new MultiFormatReader();
        reader.setHints(hints);

        PrintStream out = new PrintStream(new FileOutputStream(FileDescriptor.out), true, StandardCharsets.UTF_8);
        BufferedReader in = new BufferedReader(new InputStreamReader(System.in, StandardCharsets.UTF_8));
        String line;
        while ((line = in.readLine()) != null) {
            String[] parts = line.split("\t", 2);
            if (parts.length < 2 || !parts[0].matches("[0-9]+")) continue;
            String id = parts[0];
            BufferedImage img;
            try {
                img = ImageIO.read(new File(parts[1]));
            } catch (Exception e) {
                img = null;
            }
            if (img == null || img.getType() != BufferedImage.TYPE_BYTE_GRAY) {
                out.println("{\"id\":" + id + ",\"error\":\"not an 8-bit gray PNG\"}");
                continue;
            }
            int w = img.getWidth();
            int h = img.getHeight();
            byte[] y = (byte[]) img.getRaster().getDataElements(0, 0, w, h, null);
            LuminanceSource src = new GraySource(y, w, h);
            Result r = decode(reader, src);
            boolean inverted = false;
            if (r == null) {  // QrCamera: "Check color inversion QR code"
                r = decode(reader, src.invert());
                inverted = r != null;
            }
            StringBuilder sb = new StringBuilder();
            sb.append("{\"id\":").append(id).append(",\"inverted\":").append(inverted).append(",\"contents\":[");
            if (r != null) {
                int i = 0;
                for (String c : contents(r)) sb.append(i++ > 0 ? "," : "").append('"').append(c).append('"');
            }
            sb.append("]}");
            out.println(sb);
        }
    }
}

	import com.google.zxing.BarcodeFormat;
	import com.google.zxing.BinaryBitmap;
	import com.google.zxing.DecodeHintType;
	import com.google.zxing.LuminanceSource;
	import com.google.zxing.MultiFormatReader;
	import com.google.zxing.ReaderException;
	import com.google.zxing.Result;
	import com.google.zxing.ResultMetadataType;
	import com.google.zxing.common.HybridBinarizer;

	import javax.imageio.ImageIO;
	import java.awt.image.BufferedImage;
	import java.io.BufferedReader;
	import java.io.ByteArrayOutputStream;
	import java.io.File;
	import java.io.FileDescriptor;
	import java.io.FileOutputStream;
	import java.io.InputStreamReader;
	import java.io.PrintStream;
	import java.nio.charset.StandardCharsets;
	import java.util.Base64;
	import java.util.EnumMap;
	import java.util.LinkedHashSet;
	import java.util.List;
	import java.util.Map;
	import java.util.Set;

	/**
	* ZXing core 3.5.2 as Android's Settings app calls it (SettingsLib QrCamera): QR only, HybridBinarizer,
	* decodeWithState on the frame, then on the inverted frame; no TRY_HARDER.
	* stdin: "id<TAB>path" lines, each an 8-bit gray PNG. stdout: one JSON line per input, flushed, with every byte
	* form of the content ZXing returns (its text as UTF-8 and, where it fits, ISO-8859-1, and its raw byte
	* segments), base64-encoded: a read counts when one of them is the picture's content.
	*/
	public class ZxingServer {

	/** A plain gray plane, as SettingsLib's QrYuvLuminanceSource hands ZXing the camera's Y plane. */
	static final class GraySource extends LuminanceSource {
	private final byte[] data;

	GraySource(byte[] data, int width, int height) {
	super(width, height);
	this.data = data;
	}

	@Override
	public byte[] getRow(int y, byte[] row) {
	int w = getWidth();
	if (row == null \|\| row.length < w) row = new byte[w];
	System.arraycopy(data, y * w, row, 0, w);
	return row;
	}

	@Override
	public byte[] getMatrix() {
	return data;
	}
	}

	static Result decode(MultiFormatReader reader, LuminanceSource source) {
	try {
	return reader.decodeWithState(new BinaryBitmap(new HybridBinarizer(source)));
	} catch (ReaderException e) {
	return null;
	} finally {
	reader.reset();
	}
	}

	@SuppressWarnings("unchecked")
	static Set<String> contents(Result r) throws Exception {
	Base64.Encoder b64 = Base64.getEncoder();
	Set<String> out = new LinkedHashSet<>();
	String text = r.getText() == null ? "" : r.getText();
	out.add(b64.encodeToString(text.getBytes(StandardCharsets.UTF_8)));
	if (StandardCharsets.ISO_8859_1.newEncoder().canEncode(text)) {
	out.add(b64.encodeToString(text.getBytes(StandardCharsets.ISO_8859_1)));
	}
	Map<ResultMetadataType, Object> md = r.getResultMetadata();
	if (md != null && md.get(ResultMetadataType.BYTE_SEGMENTS) instanceof List) {
	ByteArrayOutputStream bos = new ByteArrayOutputStream();
	for (byte[] seg : (List<byte[]>) md.get(ResultMetadataType.BYTE_SEGMENTS)) bos.write(seg);
	if (bos.size() > 0) out.add(b64.encodeToString(bos.toByteArray()));
	}
	return out;
	}

	public static void main(String[] args) throws Exception {
	Map<DecodeHintType, Object> hints = new EnumMap<>(DecodeHintType.class);
	hints.put(DecodeHintType.POSSIBLE_FORMATS, List.of(BarcodeFormat.QR_CODE));
	MultiFormatReader reader = new MultiFormatReader();
	reader.setHints(hints);

	PrintStream out = new PrintStream(new FileOutputStream(FileDescriptor.out), true, StandardCharsets.UTF_8);
	BufferedReader in = new BufferedReader(new InputStreamReader(System.in, StandardCharsets.UTF_8));
	String line;
	while ((line = in.readLine()) != null) {
	String[] parts = line.split("\t", 2);
	if (parts.length < 2 \|\| !parts[0].matches("[0-9]+")) continue;
	String id = parts[0];
	BufferedImage img;
	try {
	img = ImageIO.read(new File(parts[1]));
	} catch (Exception e) {
	img = null;
	}
	if (img == null \|\| img.getType() != BufferedImage.TYPE_BYTE_GRAY) {
	out.println("{\"id\":" + id + ",\"error\":\"not an 8-bit gray PNG\"}");
	continue;
	}
	int w = img.getWidth();
	int h = img.getHeight();
	byte[] y = (byte[]) img.getRaster().getDataElements(0, 0, w, h, null);
	LuminanceSource src = new GraySource(y, w, h);
	Result r = decode(reader, src);
	boolean inverted = false;
	if (r == null) { // QrCamera: "Check color inversion QR code"
	r = decode(reader, src.invert());
	inverted = r != null;
	}
	StringBuilder sb = new StringBuilder();
	sb.append("{\"id\":").append(id).append(",\"inverted\":").append(inverted).append(",\"contents\":[");
	if (r != null) {
	int i = 0;
	for (String c : contents(r)) sb.append(i++ > 0 ? "," : "").append('"').append(c).append('"');
	}
	sb.append("]}");
	out.println(sb);
	}
	}
	}