err.kv

<MyLayout>:
    orientation: 'vertical'
    padding: 0
    spacing: 0
    size: root.width, root.height

    Label:
        size_hint: 1, None
        pos_hint: 0, 0
        text_size: self.width, None
        font_size: self.height * 0.5
        text: {err}
    
    AndroidCamera:
        index: 0
        id: a_cam
        size_hint: 0, 0
        resolution: self.camera_resolution
        allow_stretch: True
        play: True
        disabled: True
        opacity: 0
        canvas.before:
            PushMatrix
            Rotate:
                angle: -90
                origin: self.center
            Scale:
                x: self.cam_ratio
                y: self.cam_ratio
                origin: self.center
        canvas.after:
            PopMatrix
       
    Label:
        size_hint: 0, 0
        id: text_out
        font_size: self.height * 0.1
        disabled: True
        opacity: 0
        text: ''
    Label:
        size_hint: 0, 0
        id: fps_text
        font_size: self.height * 0.1
        disabled: True
        opacity: 0
        text: ''