FFmpeg video resize calculator GTK3

#!/usr/bin/env python

from gi.repository import Gtk


class reuse_init(object):


    def make_label(self, text):
        label = Gtk.Label(text)
        label.set_use_underline(True)
        label.set_alignment(1.0, 0.5)
        label.show()
        return label

    def make_slider_and_spinner(self, init, min, max, step, page, digits):
        controls = {'adj':Gtk.Adjustment(init, min, max, step, page), 'slider':Gtk.HScale(), 'spinner':Gtk.SpinButton()}
        controls['slider'].set_adjustment(controls['adj'])
        controls['slider'].set_draw_value(False)
        controls['spinner'].set_adjustment(controls['adj'])
        controls['spinner'].set_digits(digits)
        controls['slider'].show()
        controls['spinner'].show()
        return controls


class ProgrammaGTK(reuse_init):


    def __init__(self):

        self.window =  Gtk.Window(type=Gtk.WindowType.TOPLEVEL)
        self.window.connect("destroy", self.on_window_destroy)
        self.window.set_title("FFmpeg video resize calculator")
        self.window.set_position(1) # 1 center, 0 none,
        self.window.set_border_width(30)
        self.window.set_default_size(500,-1)
        #----------------------------------
        # -------- table ---------------
        self.table = Gtk.Table(3, 3, True)
        self.table.set_homogeneous(False)
        self.table.set_row_spacings(8)
        self.table.set_col_spacings(8)
        #self.window.add(self.table)
        #------------------------------------
        # ------------------------------------
        self.box1 = Gtk.ComboBox()
        self.liststore = Gtk.ListStore(int,str)
        self.liststore.append([0,"W"])
        self.liststore.append([1, "H"])
        self.box1.set_model(self.liststore)
        self.cell = Gtk.CellRendererText()
        self.box1.pack_start(self.cell, True)
        self.box1.add_attribute(self.cell, 'text', 1)
        self.box1.set_active(0)
        self.table.attach(self.box1, 0, 1, 0, 1)
        self.box1.connect("changed", self.on_button1_clicked)
        #------------------------------------
        self.box2 = Gtk.ComboBox()
        self.liststore2 = Gtk.ListStore(int,str)
        self.liststore2.append([0,"16/9"])
        self.liststore2.append([1, "4/3"])
        self.box2.set_model(self.liststore2)
        self.cell = Gtk.CellRendererText()
        self.box2.pack_start(self.cell, True)
        self.box2.add_attribute(self.cell, 'text', 1)
        self.box2.set_active(0)
        self.table.attach(self.box2, 0, 1, 1, 2)
        self.box2.connect("changed", self.on_button1_clicked)
        #--------------------------------
        self.labelout = Gtk.Label("")
        self.labelout.set_selectable(1)
        #self.table.attach(self.labelout, 0, 3, 2, 3)
        #-----------------------------------------
        self.size_spinner = self.make_slider_and_spinner(702, 200, 2000, 1, 10, 0)
        self.table.attach(self.size_spinner['slider'], 1, 2, 0, 1)
        self.table.attach(self.size_spinner['spinner'], 2, 3, 0, 1)
        self.size_spinner['slider'].set_size_request(150,-1)
        self.size_spinner['adj'].set_value(702.001) #mettere decimali se no non si vede
        self.size_spinner['adj'].connect("value-changed", self.on_button1_clicked)
        #-------------------------------------------------------
        self.check = Gtk.CheckButton("lanczos")
        self.check.connect("toggled", self.on_button1_clicked)
        self.table.attach(self.check, 2, 3, 1, 2)
        #------------------------
        #self.button1 = Gtk.Button(label="Calcola")
        #self.button1.connect("clicked", self.on_button1_clicked)
        #self.table.attach(self.button1, 2, 3, 1, 2)

        #-- VBox -------------------------
        self.vbox1 = Gtk.VBox()
        self.vbox1.set_spacing(12)
        self.vbox1.pack_start(self.table, 1, 0, 0)

        self.frame = Gtk.Frame()
        self.frame.set_shadow_type(3) # 3 GTK_SHADOW_ETCHED_IN , 1 GTK_SHADOW_IN
        self.frame.set_label("  FFmpeg filter string (select and copy):  ")
        self.ali1 = Gtk.Alignment()
        self.ali1.set_padding(12 ,12, 12, 12)
        self.frame.add(self.ali1)
        self.ali1.add(self.labelout)



        self.vbox1.pack_start(self.frame, 1, 0, 0)

        self.window.add (self.vbox1)
        #---------------------------------
        self.window.show_all()
        self.calcola()

    def on_window_destroy(self, *args):
            Gtk.main_quit(*args)

    def on_button1_clicked(self, button):
            self.calcola()

    def calcola(self):
        numero = self.size_spinner['adj'].get_value()

        if ( (int(numero) % 2) != 0):
          numero = int(numero) + 1
        else:
          numero = int(numero)

        dar = self.box2.get_active()
        lato = self.box1.get_active()

        if (dar == 1):
          if (lato == 0):
            n2 = numero/4*3
          else:
            n2 = numero/3*4
          setdar = ",setdar=4/3,setsar=1/1"
        else:
          if (lato == 0):
            n2 = numero/16*9
          else:
            n2 = numero/9*16
          setdar = ",setdar=16/9,setsar=1/1"

        if ( (int(n2) % 2) != 0):
          n2 = int(n2) + 1
        else:
          n2 = int(n2)

        stringa = "-vf scale="
        if (lato == 0):
          stringa = stringa + str(numero) + ":" + str(n2)
        else:
          stringa = stringa + str(n2) + ":" + str(numero)

        lanc = self.check.get_active()
        if lanc:
          stringa = stringa + ":flags=lanczos" + setdar
        else:
          stringa = stringa + setdar
        self.labelout.set_text(stringa)

    def main(self):
        Gtk.main()




if __name__ == "__main__":
    hwg = ProgrammaGTK()
    Gtk.main()