zxing生成二维码 - 无内边距

1. 导入zxing

  compile 'com.google.zxing:core:3.3.0'

2. 生成bitmap

   /**
     * 生成二维码
     */
 private Bitmap encodeAsBitmap(String contents, BarcodeFormat format, int img_width, int img_height) {
        String contentsToEncode = contents;
        if (contentsToEncode == null) {
            return null;
        }
        Map hints = new EnumMap<>(EncodeHintType.class);
        //hints.put(EncodeHintType.CHARACTER_SET, encoding);
        hints.put(EncodeHintType.MARGIN, 0); /* default = 4 */
        MultiFormatWriter writer = new MultiFormatWriter();
        BitMatrix result;
        try {
            result = writer.encode(contentsToEncode, format, img_width, img_height, hints);
        } catch (Exception e) {
            // Unsupported format
            e.printStackTrace();
            return null;
        }

        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 : Color.WHITE;
            }
        }

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