adj

from gi.repository import Gtk
from gi.repository import Gdk

class app:
    def __init__(self):
        self.value = 50

        win = Gtk.Window()
        win.connect("delete_event", Gtk.main_quit)
        win.set_default_size(300,100)

        box = Gtk.Box()

        self.button_p = Gtk.Button(">")
        self.button_p.connect("clicked",self.plus)
        self.button_m = Gtk.Button("<")
        self.button_m.connect("clicked",self.minus)

        self.scroll = Gtk.ScrolledWindow(None, None)
        view = Gtk.Viewport(None, None)
        label = Gtk.Label('''
        \rsome text



        \rsome shit


        \rshit''')

        view.add(label)
        self.scroll.add(view)

        box.pack_start(self.button_p,True,True,0)
        box.pack_start(self.button_m,True,True,0)
        box.pack_start(self.scroll,True,True,0)

        win.add(box)
        win.show_all()

        self.position = self.scroll.get_vadjustment()
        self.position.set_value(self.value)
        # self.scroll.set_vadjustment(self.position)

        Gtk.main()

    def plus(self,e):
        self.value += 10
        self.scroll.set_vadjustment(self.position)

    def minus(self,e):
        self.value -= 10
        self.scroll.set_vadjustment(self.position)

app()