@Override
    public int getOpacity() {
        Bitmap bm = state.bitmap;
        return bm == null || bm.hasAlpha() || state.paint.getAlpha() < 255
                ? PixelFormat.TRANSLUCENT : PixelFormat.OPAQUE;
    }
A static {@link GlideDrawable} for displaying a single image.
core/src/main/java/com/bumptech/glide/load/resource/bitmap/GlideBitmapDrawable.java