用户端生成二维码 添加到另一张图中去

1、二维码生成
二维码生成用到了Zxing 包,gradle 中引用

    compile 'com.google.zxing:core:3.2.1'

生成带有logo的二维码

public class QrCodeUtil{
       /**
     * 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 = 180;
    /**
     * 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 / 4;
    /**
     *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;
    /**
     * 生成的二维码图片存储的URI
     */
    private Uri imageFileUri;


    /**
     * 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();
       
        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;
    }
}

2、图片合成，利用canvas合成图片

public class ImageUtil{
     public  static  Bitmap compoundBitmap(Bitmap BitmapOne,Bitmap BitmapTwo){
        Bitmap newBitmap = null;
        newBitmap = Bitmap.createBitmap(BitmapOne);
        Canvas canvas = new Canvas(newBitmap);
        Paint paint = new Paint();
        int w = BitmapOne.getWidth();
        int h = BitmapOne.getHeight();
        int w_2 = BitmapTwo.getWidth();
        int h_2 = BitmapTwo.getHeight();BitmapOne.getHeight(), paint);
        paint = new Paint();
        //设置第二张图片的 左、上的位置坐标
        canvas.drawBitmap(BitmapTwo, 16,
                h-16-h_2, paint);
        canvas.save(Canvas.ALL_SAVE_FLAG);
        // 存储新合成的图片
        canvas.restore();
        return newBitmap;
    }
}

3、调用,这里第一张图我是从网络取的，所以需要下载图片

//生成二维码
 final QrCodeUtil qrCodeUtil = new QrCodeUtil();

  try {
       bitmapQrCode = qrCodeUtil.createCode("https://www.baidu.com/", BitmapFactory.decodeResource(getResources(), R.drawable.finish_icon_highligh));
      } catch (WriterException e) {
       e.printStackTrace();
     }

//下载网络背景图
Glide.with(CtxHelper.getApp())
                    .load("//upload-images.jianshu.io/upload_images/2048265-44f59db66cecd375.jpg?imageMogr2/auto-orient/strip%7CimageView2/2/w/1240")
                    .asBitmap().into(new SimpleTarget<Bitmap>() {
                @Override
                public void onLoadFailed(Exception e, Drawable errorDrawable) {
                    super.onLoadFailed(e, errorDrawable);
                    //下载失败
                }

                @Override
                public void onResourceReady(Bitmap resource, GlideAnimation<? super Bitmap> glideAnimation) {
                    //下载成功
                    if (bitmapQrCode != null) {
                         //合成图片
                        Bitmap bitmap = ImageUtils.compoundImage(resource, bitmapQrCode);
                        if (bitmap != null) {
                            //将重新生成的图片显示到界面上
                            mIvBanner.setImageBitmap(bitmap);
                        }
                    }
                }
            });

总结：到这功能就实现了，补充一下图片合成的几种方法：
1、上面例子中的利用canvas画出来

public void compoundImage(View v) {
    // 防止出现Immutable bitmap passed to Canvas constructor错误
    Bitmap bitmap1 = BitmapFactory.decodeResource(getResources(),
        R.drawable.apple).copy(Bitmap.Config.ARGB_8888, true);
    Bitmap bitmap2 = ((BitmapDrawable) getResources().getDrawable(
        R.drawable.go)).getBitmap();
    Bitmap newBitmap = null;
    newBitmap = Bitmap.createBitmap(bitmap1);
    Canvas canvas = new Canvas(newBitmap);
    Paint paint = new Paint();
    int w = bitmap1.getWidth();
    int h = bitmap1.getHeight();
    int w_2 = bitmap2.getWidth();
    int h_2 = bitmap2.getHeight();
    paint = new Paint();
    // 设置第二张图片的位置
    canvas.drawBitmap(bitmap2, Math.abs(w - w_2) / 2,
        Math.abs(h - h_2) / 2, paint);
    canvas.save(Canvas.ALL_SAVE_FLAG);
    // 存储新合成的图片
    canvas.restore();
    image.setImageBitmap(newBitmap);
}

2、使用系统的LayerDrawable类

public void compoundImage(View v) {
    Bitmap bitmap1 = ((BitmapDrawable) getResources().getDrawable(
        R.drawable.apple)).getBitmap();
    Bitmap bitmap2 = ((BitmapDrawable) getResources().getDrawable(
        R.drawable.go)).getBitmap();
    Drawable[] array = new Drawable[2];
    array[0] = new BitmapDrawable(bitmap1);
    array[1] = new BitmapDrawable(bitmap2);
    LayerDrawable la = new LayerDrawable(array);
    // 其中第一个参数为层的索引号，后面的四个参数分别为left、top、right和bottom
    la.setLayerInset(0, 0, 0, 0, 0);
    la.setLayerInset(1, 20, 20, 20, 20);
    image.setImageDrawable(la);
}