gboolean
main_win_open( MainWin* mw, const char* file_path)
{
    GError *error;
    GInputStream* input_stream;
    GFile *file = g_file_new_for_path(file_path);

    gssize n_read;
    gboolean res;
    guchar buffer[LOAD_BUFFER_SIZE];

    input_stream = g_file_read(file,generator_cancellable ,NULL);

    res = TRUE;
    while (1){
        n_read = g_input_stream_read(input_stream, buffer, sizeof (buffer),generator_cancellable,error);

        if (n_read < 0) {
                        res = FALSE;
                        error = NULL;
                        break;
                }

    if (n_read == 0)
        break;

    if (!gdk_pixbuf_loader_write(mw->loader, buffer, sizeof(buffer), error)){
       res = FALSE;
       error = NULL;
       break;
       }
    }

    if (res){
        mw->animation = gdk_pixbuf_loader_get_animation((mw->loader));
        gtk_anim_view_set_anim (mw->aview,mw->animation);
        return TRUE;
    }

    // close gdkpixbufloader
    if (!gdk_pixbuf_loader_close (mw->loader, error)) {
        res = FALSE;
        error = NULL;
        return FALSE;
    }

    gtk_widget_show_all(mw->box);
}