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CSDN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;    }}