junlincao

    public static boolean isDark(Bitmap bitmap) {
        final float darkThreshold = bitmap.getWidth() * bitmap.getHeight() * 0.45f;
        final int w = bitmap.getWidth();
        final int h = bitmap.getHeight();

        int darkPixels = 0;
        int[] lineColor = new int[w];
        for (int i = 0; i < h - 1; i++) {
            bitmap.getPixels(lineColor, 0, w, 0, i, w, 1);
            for (int color : lineColor) {