Center an Icon inside a Python kivy button?

Question

Kivy

<Messenger>
    BoxLayout:
        orientation: 'vertical'
        BoxLayout:
            pos_hint: {'top': 1}
            size_hint: 1, 0.075
            orientation: 'horizontal'
            Button:
                Image:
                    source: 'params.png'
                    size_hint_y: None
                    size_hint_x: None
                    y: self.parent.y + self.parent.height/2
                    x: self.parent.x + self.parent.width/2
                    #heigth: self.parent.width/self.image_ratio
                    #heigth: self.parent.height
                    width: 30
                    keep_ratio: True
                    allow_stretch: True
            Button:
                text: 'button'
            Button:
                text: 'button'
        BoxLayout:
            orientation: 'vertical'
            Button:
                text: 'button'

Hello everyone, I'm learning kivy, now I want to write a small program, but I just can't figure out how to place the icon inside the button so that the icon is strictly in the middle. I would like to see at the top a line of three buttons, such as a header, and below the rest of the working field. If anything, then Messenger is inherited from Screen, suddenly this is important.

Answer 1

ButtonBehavior doesn't work? https://kivy.org/doc/stable/api-kivy.uix.behaviors...