Android Bitmap binarization and grayscale

1. Bitmap grayscale

   //获取灰度图片
    public static Bitmap getHuiDu(Bitmap bitMap, Context context) {

        int width = bitMap.getWidth();//Width 图片宽度
        int height = bitMap.getHeight();// Height 图片高度

        Bitmap bmpGrayscale = Bitmap.createBitmap(width, height, Config.RGB_565);
        // bmpGrayscale 设置灰度之后的bitmap对象

        //设置灰度
        Canvas c = new Canvas(bmpGrayscale);
        Paint paint = new Paint();
        ColorMatrix cm = new ColorMatrix();
        cm.setSaturation(0);
        ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);
        paint.setColorFilter(f);
        c.drawBitmap(bitMap, 0, 0, paint);
        c.save();
        c.restore();
);

        return bmpGrayscale;
    }

2. Bitmap binarization, ARGB_8888 is used here

  public static Bitmap convertToBMW(Bitmap bmp) {
        int width = bmp.getWidth(); // 获取位图的宽
        int height = bmp.getHeight(); // 获取位图的高
        int[] pixels = new int[width * height]; // 通过位图的大小创建像素点数组
        // 设定二值化的域值，默认值为100
        int tmp = 150;
        bmp.getPixels(pixels, 0, width, 0, 0, width, height);
        int alpha = 0xFF << 24;
        for (int i = 0; i < height; i++) {
            for (int j = 0; j < width; j++) {
                int grey = pixels[width * i + j];
                // 分离三原色
                alpha = ((grey & 0xFF000000) >> 24);
                int red = ((grey & 0x00FF0000) >> 16);
                int green = ((grey & 0x0000FF00) >> 8);
                int blue = (grey & 0x000000FF);
                int i1 = 0xFFFF;


                if (red > tmp) {
                    red = 255;
                } else {
                    red = 0;
                }
                if (blue > tmp) {
                    blue = 255;
                } else {
                    blue = 0;
                }
                if (green > tmp) {
                    green = 255;
                } else {
                    green = 0;
                }
                pixels[width * i + j] = alpha << 24 | red << 16 | green << 8
                        | blue;
                if (pixels[width * i + j] == -1) {
                    pixels[width * i + j] = -1;

                } else {
                    pixels[width * i + j] = -16777216;
                }
            }
        }
        // 新建图片
        Bitmap newBmp = Bitmap.createBitmap(width, height, Config.ARGB_8888);
        // 设置图片数据
        newBmp.setPixels(pixels, 0, width, 0, 0, width, height);
        Bitmap resizeBmp = ThumbnailUtils.extractThumbnail(newBmp, width, height);

//        return getHuiDu(resizeBmp, AppApplication.getIntance());
        return resizeBmp;
    }