void drawRectangles (Rectangle [] rects) {
    int /*long*/ window = OS.gdk_get_default_root_window();
    if (parent != null) {
        window = OS.GTK_WIDGET_WINDOW (parent.paintHandle());
    }
    if (window == 0) return;

    if (OS.USE_CAIRO) {

        if(parent != null){
            int /*long*/ cairo = OS.gdk_cairo_create(window);
            if (cairo == 0) error (SWT.ERROR_NO_HANDLES);
            Cairo.cairo_set_source_rgb(cairo, 1, 1, 1);
            Cairo.cairo_set_line_width(cairo, 1);
            Cairo.cairo_set_operator(cairo,Cairo.CAIRO_OPERATOR_DIFFERENCE);
            Cairo.cairo_set_antialias(cairo, Cairo.CAIRO_ANTIALIAS_NONE);
            for (int i=0; i<rects.length; i++) {
                Rectangle rect = rects [i];
                Cairo.cairo_rectangle (cairo, rect.x, rect.y, rect.width, rect.height);
                Cairo.cairo_stroke(cairo);
            }
            Cairo.cairo_destroy(cairo);
            return;
        }else{
                int /*long*/ width = OS.gdk_window_get_width(window);
                int /*long*/ height = OS.gdk_window_get_height(window);
                int /*long*/ xDisplay = OS.gdk_x11_display_get_xdisplay(OS.gdk_display_get_default());
                int /*long*/ xDrawable = OS.gdk_x11_drawable_get_xid(window);
                int /*long*/ xVisual = OS.gdk_x11_visual_get_xvisual(OS.gdk_visual_get_system());
                int /*long*/ srcSurface = Cairo.cairo_xlib_surface_create(xDisplay, xDrawable, xVisual, width, height);
                int /*long*/ cairo = Cairo.cairo_create(srcSurface);
                if (cairo == 0) error (SWT.ERROR_NO_HANDLES);
            Cairo.cairo_set_source_rgb(cairo, 1, 1, 1);
            Cairo.cairo_set_line_width(cairo, 1);
            Cairo.cairo_set_operator(cairo,Cairo.CAIRO_OPERATOR_DIFFERENCE);
            Cairo.cairo_set_antialias(cairo, Cairo.CAIRO_ANTIALIAS_NONE);
            for (int i=0; i<rects.length; i++) {
                Rectangle rect = rects [i];
                Cairo.cairo_rectangle (cairo, rect.x, rect.y, rect.width, rect.height);
                Cairo.cairo_stroke(cairo);
            }
            Cairo.cairo_destroy(cairo);
            return;
        }

    }

    int /*long*/ gc = OS.gdk_gc_new (window);
    if (gc == 0) return;
    int /*long*/ colormap = OS.gdk_colormap_get_system ();
    GdkColor color = new GdkColor ();
    OS.gdk_color_white (colormap, color);
    OS.gdk_gc_set_foreground (gc, color);
    OS.gdk_gc_set_subwindow (gc, OS.GDK_INCLUDE_INFERIORS);
    OS.gdk_gc_set_function (gc, OS.GDK_XOR);
    for (int i=0; i<rects.length; i++) {
        Rectangle rect = rects [i];
        int x = rect.x;
        if (parent != null && (parent.style & SWT.MIRRORED) != 0) x = parent.getClientWidth () - rect.width - x;
        OS.gdk_draw_rectangle (window, gc, 0, x, rect.y, rect.width, rect.height);
    }
    OS.g_object_unref (gc);
}