GPX_HEIGHT
GPX_HEIGHT - row * font->fontheight;
sy = GPX_HEIGHT - (1 + uc / ss->ss_gpr) * font->fontheight;
ss->ss_adder->y_clip_max = GPX_HEIGHT;
ss->ss_adder->scroll_y_max = GPX_HEIGHT;
ss->ss_adder->y_limit = GPX_HEIGHT;