cmusv.mr.carbon.utils.QRCodeGenerator.java Source code

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Here is the source code for cmusv.mr.carbon.utils.QRCodeGenerator.java

Source

package cmusv.mr.carbon.utils;

/*
 * Copyright (C) 2008 ZXing authors
 *
 * 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.
 */

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import android.graphics.Bitmap;
import java.util.EnumMap;
import java.util.Map;

import org.apache.commons.codec.binary.Base64;

class QRCodeGenerator {

    private static final String TAG = QRCodeGenerator.class.getSimpleName();

    private static final int WHITE = 0xFFFFFFFF;
    private static final int BLACK = 0xFF000000;

    private static BarcodeFormat format = BarcodeFormat.QR_CODE;

    public static Bitmap encodeAsBitmap(String contentsToEncode, int dimension, boolean isEncoded)
            throws WriterException {
        if (contentsToEncode == null) {
            return null;
        }
        if (isEncoded) {
            Base64 base64 = new Base64();
            contentsToEncode = new String(base64.encode(contentsToEncode.getBytes()));
        }

        Map<EncodeHintType, Object> hints = null;
        String encoding = guessAppropriateEncoding(contentsToEncode);
        if (encoding != null) {
            hints = new EnumMap<EncodeHintType, Object>(EncodeHintType.class);
            hints.put(EncodeHintType.CHARACTER_SET, encoding);
        }
        MultiFormatWriter writer = new MultiFormatWriter();
        BitMatrix result = writer.encode(contentsToEncode, format, dimension, dimension, hints);
        int width = result.getWidth();
        int height = result.getHeight();
        int[] pixels = new int[width * height];
        for (int y = 0; y < height; y++) {
            int offset = y * width;
            for (int x = 0; x < width; x++) {
                pixels[offset + x] = result.get(x, y) ? BLACK : WHITE;
            }
        }

        Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
        bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
        return bitmap;
    }

    private static String guessAppropriateEncoding(CharSequence contents) {
        // Very crude at the moment
        for (int i = 0; i < contents.length(); i++) {
            if (contents.charAt(i) > 0xFF) {
                return "UTF-8";
            }
        }
        return null;
    }

}