ImageUtil.java

/**
 * This file is part of alf.io.
 *
 * alf.io is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 *
 * alf.io is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with alf.io.  If not, see <http://www.gnu.org/licenses/>.
 */
package alfio.util;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.client.j2se.MatrixToImageWriter;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.util.EnumMap;
import java.util.Map;

public final class ImageUtil {
    private ImageUtil() {
    }

    public static byte[] createQRCode(String text) {
        try {
            ByteArrayOutputStream baos = new ByteArrayOutputStream();
            Map<EncodeHintType, Object> hintMap = new EnumMap<>(EncodeHintType.class);
            hintMap.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
            BitMatrix matrix = new MultiFormatWriter().encode(text, BarcodeFormat.QR_CODE, 200, 200, hintMap);
            MatrixToImageWriter.writeToStream(matrix, "png", baos);
            return baos.toByteArray();
        } catch (WriterException | IOException e) {
            throw new IllegalStateException(e);
        }
    }

}