function centerWindow(center_window)
    local screenW,screenH=guiGetScreenSize()
    local windowW,windowH=guiGetSize(center_window,false)
    local x,y = (screenW-windowW)/2,(screenH-windowH)/2
    guiSetPosition(center_window,x,y,false)
end

Panel_adı = guiCreateWindow(202, 147, 430, 305, "Panel ismi", false)
centerWindow(Panel_adı)