二维码初解

import java.util.Hashtable;

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 com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

import android.graphics.Bitmap;
import android.graphics.Bitmap.Config;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.media.ThumbnailUtils;

public class TwoDCodeUtils {

    /**
     * 黑点颜色
     */
    private static final int BLACK = 0xFF000000;
    /**
     * 白色
     */
    private static final int WHITE = 0xFFFFFFFF;
    /**
     * 正方形二维码宽度
     */
    private static final int CODE_WIDTH = 440;
    /**
     * LOGO宽度值,最大不能大于二维码20%宽度值,大于可能会导致二维码信息失效
     */
    private static final int LOGO_WIDTH_MAX = CODE_WIDTH / 5;
    /**
     * LOGO宽度值,最小不能小于二维码10%宽度值,小于影响Logo与二维码的整体搭配
     */
    private static final int LOGO_WIDTH_MIN = CODE_WIDTH / 10;

    public static Bitmap Create2DCode(String str) {

        try {
            // 生成二维矩阵,编码时指定大小,不要生成了图片以后再进行缩放,这样会模糊导致识别失败
            BitMatrix matrix = new MultiFormatWriter().encode(str,
                    BarcodeFormat.QR_CODE, CODE_WIDTH, CODE_WIDTH);
            int width = matrix.getWidth();
            int height = matrix.getHeight();
            // 二维矩阵转为一维像素数组,也就是一直横着排了
            int[] pixels = new int[width * height];
            for (int y = 0; y < height; y++) {
                for (int x = 0; x < width; x++) {
                    if (matrix.get(x, y)) {
                        pixels[y * width + x] = BLACK;

                    }

                }
            }

            Bitmap bitmap = Bitmap.createBitmap(width, height,
                    Bitmap.Config.ARGB_8888);
            // 通过像素数组生成bitmap,具体参考api
            bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
            return bitmap;
        } catch (WriterException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }

        return null;
    }

    /**
     * @return 返回带有白色背景框logo
     */
    public Bitmap modifyLogo(Bitmap bgBitmap, Bitmap logoBitmap) {

        int bgWidth = bgBitmap.getWidth();
        int bgHeigh = bgBitmap.getHeight();
        // 通过ThumbnailUtils压缩原图片，并指定宽高为背景图的3/4
        logoBitmap = ThumbnailUtils.extractThumbnail(logoBitmap,
                bgWidth * 3 / 4, bgHeigh * 3 / 4,
                ThumbnailUtils.OPTIONS_RECYCLE_INPUT);
        Bitmap cvBitmap = Bitmap.createBitmap(bgWidth, bgHeigh,
                Config.ARGB_8888);
        Canvas canvas = new Canvas(cvBitmap);
        // 开始合成图片
        canvas.drawBitmap(bgBitmap, 0, 0, null);
        canvas.drawBitmap(logoBitmap, (bgWidth - logoBitmap.getWidth()) / 2,
                (bgHeigh - logoBitmap.getHeight()) / 2, null);
        canvas.save(Canvas.ALL_SAVE_FLAG);// 保存
        canvas.restore();
        if (cvBitmap.isRecycled()) {
            cvBitmap.recycle();
        }
        return cvBitmap;
    }

    /**
     * 生成带LOGO的二维码
     */

    public Bitmap createCode(String content, Bitmap logoBitmap)
            throws WriterException {
        int logoWidth = logoBitmap.getWidth();
        int logoHeight = logoBitmap.getHeight();
        int logoHaleWidth = logoWidth >= CODE_WIDTH ? LOGO_WIDTH_MIN
                : LOGO_WIDTH_MAX;
        int logoHaleHeight = logoHeight >= CODE_WIDTH ? LOGO_WIDTH_MIN
                : LOGO_WIDTH_MAX;
        // 将logo图片按martix设置的信息缩放
        Matrix m = new Matrix();
        /*
         * 给的源码是,由于优快云上传的资源不能改动，这里注意改一下 float sx = (float) 2*logoHaleWidth /
         * logoWidth; float sy = (float) 2*logoHaleHeight / logoHeight;
         */
        float sx = (float) logoHaleWidth / logoWidth;
        float sy = (float) logoHaleHeight / logoHeight;
        m.setScale(sx, sy);// 设置缩放信息
        Bitmap newLogoBitmap = Bitmap.createBitmap(logoBitmap, 0, 0, logoWidth,
                logoHeight, m, false);
        int newLogoWidth = newLogoBitmap.getWidth();
        int newLogoHeight = newLogoBitmap.getHeight();
        Hashtable<EncodeHintType, Object> hints = new Hashtable<EncodeHintType, Object>();
        hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);// 设置容错级别,H为最高
        hints.put(EncodeHintType.MAX_SIZE, LOGO_WIDTH_MAX);// 设置图片的最大值
        hints.put(EncodeHintType.MIN_SIZE, LOGO_WIDTH_MIN);// 设置图片的最小值
        hints.put(EncodeHintType.MARGIN, 2);// 设置白色边距值
        // 生成二维矩阵,编码时指定大小,不要生成了图片以后再进行缩放,这样会模糊导致识别失败
        BitMatrix matrix = new MultiFormatWriter().encode(content,
                BarcodeFormat.QR_CODE, CODE_WIDTH, CODE_WIDTH, hints);
        int width = matrix.getWidth();
        int height = matrix.getHeight();
        int halfW = width / 2;
        int halfH = height / 2;
        // 二维矩阵转为一维像素数组,也就是一直横着排了
        int[] pixels = new int[width * height];
        for (int y = 0; y < height; y++) {
            for (int x = 0; x < width; x++) {
                /*
                 * 取值范围,可以画图理解下 halfW + newLogoWidth / 2 - (halfW - newLogoWidth
                 * / 2) = newLogoWidth halfH + newLogoHeight / 2 - (halfH -
                 * newLogoHeight) = newLogoHeight
                 */
                if (x > halfW - newLogoWidth / 2
                        && x < halfW + newLogoWidth / 2
                        && y > halfH - newLogoHeight / 2
                        && y < halfH + newLogoHeight / 2) {// 该位置用于存放图片信息
                    /*
                     * 记录图片每个像素信息 halfW - newLogoWidth / 2 < x < halfW +
                     * newLogoWidth / 2 --> 0 < x - halfW + newLogoWidth / 2 <
                     * newLogoWidth halfH - newLogoHeight / 2 < y < halfH +
                     * newLogoHeight / 2 -->0 < y - halfH + newLogoHeight / 2 <
                     * newLogoHeight
                     * 刚好取值newLogoBitmap。getPixel(0-newLogoWidth,0-
                     * newLogoHeight);
                     */
                    pixels[y * width + x] = newLogoBitmap.getPixel(x - halfW
                            + newLogoWidth / 2, y - halfH + newLogoHeight / 2);
                } else {
                    pixels[y * width + x] = matrix.get(x, y) ? BLACK : WHITE;// 设置信息
                }
            }
        }
        Bitmap bitmap = Bitmap.createBitmap(width, height,
                Bitmap.Config.ARGB_8888);
        // 通过像素数组生成bitmap,具体参考api
        bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
        return bitmap;
    }

}