A java class that reads text from stdin and outputs a pbm (Portable Bit Map) encoded QR Code on stdout.

InToPbm.java

/*
 * Copyright 2010 Scott Douglas-Watson
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

/*
 * Description: A java class that reads text from stdin and outputs a pbm (Portable 
 * Bit Map) encoded QR Code on stdout. 
 *
 * URL: http://gist.github.com/420377
 * 
 * Requires:
 *   core.jar from http://code.google.com/p/zxing/
 * 
 * See also:
 *   Emacs region to QR code function http://gist.github.com/420386
 */

import com.google.zxing.BarcodeFormat;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;

public class InToQrPbm {

    private static String readInput() throws IOException {
        BufferedReader in = new BufferedReader(
                new InputStreamReader(System.in));
        StringBuilder sb = new StringBuilder();
        for (String s = in.readLine(); s != null; s = in.readLine()) {
            sb.append(s).append('\n');
        }
        return sb.toString().trim();
    }

    private static String toPBM(BitMatrix bytes, boolean invert) {
        String black = "1 ";
        String white = "0 ";

        if (invert)  {
            black = "0 ";
            white = "1 ";
        }

        StringBuilder sb = new StringBuilder("P1\n");
        sb.append(bytes.getWidth()).append(" ").append(bytes.getHeight());
        sb.append("\n");
        for (int y = 0; y < bytes.getHeight(); y++) {
            for (int x = 0; x < bytes.getWidth(); x++) {
                sb.append(bytes.get(x, y) ? black : white);
            }
            sb.deleteCharAt(sb.length() - 1);
            sb.append("\n");
        }
        return sb.toString();
    }

    private static BitMatrix generateQRCode(String s) throws WriterException {
        return new MultiFormatWriter().encode(s, BarcodeFormat.QR_CODE,
                300, 300);
    }

    public static void main(String[] args) throws IOException, WriterException {
        boolean invert =  false;
        for (String a : args)  {
            if ("-i".equals(a))  {
                invert = true;
                break;
            }
        }

        String input = readInput();
        if (!"".equals(input)) {
            System.out.println(toPBM(generateQRCode(input), invert));
        }
    }
}