使用zxing生成带logo的二维码图片

        很多时候需要我们在生成的二维码中间加logo图片，二维码加logo图片，思想很简单就是：就是将logo图片叠加到生成的二维码图片中间，两个图片叠加一起就是了。但是会遇到一个问题，如果logo加得太大的话，会导致二维码扫描不出来；加的太小则不怎么明显。这是我们需要调整生成二维码的容错率，容错率的设置从7%-30%，容错率设置的越高，二维码的有效像素点就越多。由于我们使用的是zxing,所以我们需要看看怎么设置zxing的二维码容错率。

如：hint.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
ErrorCorrectionLevel就是容错率。另外，发现默认生成出来的图片，除了二维码以外，还有一圈白色边框比较宽，如果背景不是白色的话比较难看。查看zxing源码QRCodeWriter.java中，有个变量QUIET_ZONE_SIZE；是控制的边框的宽度,默认是4，最小值是1，这里我们修改成0或者1都可以，再生成图片，效果就很好了。下面给出生成带logo的二维码图片的代码：

package zmx.zxing.test;

import java.awt.AlphaComposite;
import java.awt.Graphics2D;
import java.awt.image.BufferedImage;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.util.Hashtable;

import javax.imageio.ImageIO;

import org.apache.commons.codec.binary.Base64;
import org.apache.commons.codec.binary.Base64OutputStream;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.NotFoundException;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;
/**
*
* @author zhangwenchao
*
*/
public class QRCodeKit {

public static final String QRCODE_DEFAULT_CHARSET = "UTF-8"; //默认编码

public static final int QRCODE_DEFAULT_HEIGHT = 300;

public static final int QRCODE_DEFAULT_WIDTH = 300;

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

public static void main(String[] args) throws IOException, NotFoundException{
String data = "http://www.baidu.com";
File logoFile = new File("D:/projects/testWeb/src/zmx/zxing/test/logo.png");
BufferedImage image = QRCodeKit.createQRCodeWithLogo(data, logoFile);
ImageIO.write(image, "png", new File("D:/projects/testWeb/src/zmx/zxing/test/michael_zxing_logo.png"));
System.out.println("done");
}

/**
* Create qrcode with default settings
* @author zhangwenchao
* @param data
* @return
*/
public static BufferedImage createQRCode(String data) {
return createQRCode(data, QRCODE_DEFAULT_WIDTH, QRCODE_DEFAULT_HEIGHT);
}

/**
* Create qrcode with default charset
* @author zhangwenchao
* @param data
* @param width
* @param height
* @return
*/
public static BufferedImage createQRCode(String data, int width, int height) {
return createQRCode(data, QRCODE_DEFAULT_CHARSET, width, height);
}

/**
* Create qrcode with specified charset
* @author zhangwenchao
* @param data
* @param charset
* @param width
* @param height
* @return
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
public static BufferedImage createQRCode(String data, String charset, int width, int height) {
Hashtable hint = new Hashtable();
hint.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
hint.put(EncodeHintType.CHARACTER_SET, charset);

return createQRCode(data, charset, hint, width, height);
}

/**
* Create qrcode with specified hint
* @author zhangwenchao
* @param data
* @param charset
* @param hint
* @param width
* @param height
* @return
*/
public static BufferedImage createQRCode(String data, String charset, Hashtable<EncodeHintType, ?> hint, int width,
int height) {
BitMatrix matrix;
try {
matrix = new MultiFormatWriter().encode(new String(data.getBytes(charset), charset), BarcodeFormat.QR_CODE,
width, height, hint);
return toBufferedImage(matrix);
} catch (WriterException e) {
throw new RuntimeException(e.getMessage(), e);
} catch (Exception e) {
throw new RuntimeException(e.getMessage(), e);
}
}
public static BufferedImage toBufferedImage(BitMatrix matrix) {
int width = matrix.getWidth();
int height = matrix.getHeight();
BufferedImage image = new BufferedImage(width, height,
BufferedImage.TYPE_INT_RGB);
for (int x = 0; x < width; x++) {
for (int y = 0; y < height; y++) {
image.setRGB(x, y, matrix.get(x, y) ? BLACK : WHITE);
}
}
return image;
}
/**
* Create qrcode with default settings and logo
* @author zhangwenchao
* @param data
* @param logoFile
* @return
*/
public static BufferedImage createQRCodeWithLogo(String data, File logoFile) {
return createQRCodeWithLogo(data, QRCODE_DEFAULT_WIDTH, QRCODE_DEFAULT_HEIGHT, logoFile);
}

/**
* Create qrcode with default charset and logo
* @author zhangwenchao
* @param data
* @param width
* @param height
* @param logoFile
* @return
*/
public static BufferedImage createQRCodeWithLogo(String data, int width, int height, File logoFile) {
return createQRCodeWithLogo(data, QRCODE_DEFAULT_CHARSET, width, height, logoFile);
}

/**
* Create qrcode with specified charset and logo
* @author zhangwenchao
* @param data
* @param charset
* @param width
* @param height
* @param logoFile
* @return
*/
@SuppressWarnings({ "unchecked", "rawtypes" })
public static BufferedImage createQRCodeWithLogo(String data, String charset, int width, int height, File logoFile) {
Hashtable hint = new Hashtable();
hint.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);
hint.put(EncodeHintType.CHARACTER_SET, charset);
return createQRCodeWithLogo(data, charset, hint, width, height, logoFile);
}

/**
* Create qrcode with specified hint and logo
* @author zhangwenchao
* @param data
* @param charset
* @param hint
* @param width
* @param height
* @param logoFile
* @return
*/
public static BufferedImage createQRCodeWithLogo(String data, String charset, Hashtable<EncodeHintType, ?> hint,
int width, int height, File logoFile) {
try {
BufferedImage qrcode = createQRCode(data, charset, hint, width, height);
BufferedImage logo = ImageIO.read(logoFile);
int deltaHeight = height - logo.getHeight();
int deltaWidth = width - logo.getWidth();

BufferedImage combined = new BufferedImage(height, width, BufferedImage.TYPE_INT_ARGB);
Graphics2D g = (Graphics2D) combined.getGraphics();
g.drawImage(qrcode, 0, 0, null);
g.setComposite(AlphaComposite.getInstance(AlphaComposite.SRC_OVER, 1f));
g.drawImage(logo, (int) Math.round(deltaWidth / 2), (int) Math.round(deltaHeight / 2), null);

return combined;
} catch (IOException e) {
throw new RuntimeException(e.getMessage(), e);
} catch (Exception e) {
throw new RuntimeException(e.getMessage(), e);
}
}

/**
* Return base64 for image
* @author zhangwenchao
* @param image
* @return
*/
public static String getImageBase64String(BufferedImage image) {
String result = null;
try {
ByteArrayOutputStream os = new ByteArrayOutputStream();
OutputStream b64 = new Base64OutputStream(os);
ImageIO.write(image, "png", b64);
result = os.toString("UTF-8");
} catch (UnsupportedEncodingException e) {
throw new RuntimeException(e.getMessage(), e);
} catch (IOException e) {
throw new RuntimeException(e.getMessage(), e);
}
return result;
}

/**
* Decode the base64Image data to image
* @author zhangwenchao
* @param base64ImageString
* @param file
*/
public static void convertBase64StringToImage(String base64ImageString, File file) {
FileOutputStream os;
try {
Base64 d = new Base64();
byte[] bs = d.decode(base64ImageString);
os = new FileOutputStream(file.getAbsolutePath());
os.write(bs);
os.close();
} catch (FileNotFoundException e) {
throw new RuntimeException(e.getMessage(), e);
} catch (IOException e) {
throw new RuntimeException(e.getMessage(), e);
} catch (Exception e) {
throw new RuntimeException(e.getMessage(), e);
}
}

}