getting drawable area an awt support mac os x?

i have subclassed have overridden slight i wish pull whole essence window manually.

however, graphics object, (0,0) corresponds top left palm dilemma window inside due bar decoration, initial drawable pixel.

can i establish prepare initial drawable pixel (ie, tallness decoration) cross-platform manner, avoiding controlling mac os x-specific ? i forced nest member method tangible drawable area window?

here, formula fails centre blue retard inside paintable area window:

@override
public vacant paint (graphics g) {
    g.setcolor(color.blue);
    g.setpaintmode();
    g.fillrect(30, 30, getwidth()-60, getheight()-60);
}