gistfile1.txt

I'm trying to layout a widget like this:
----------------------------
|          [IMAGE]         |
|[.....a label here.......]|
----------------------------
Where the image is centered at the top, and the label is centered at the bottom. 

Here's some code:
-----------------------------
from kivy.app import App
from kivy.uix.widget import Widget
from kivy.factory import Factory

class KivyCenterBug(App):
    def build(self):
        m = Factory.Marker(pos=(400, 100))
        self.root.add_widget(m)

if __name__ == '__main__':
    KivyCenterBug().run()
--------------------------------
# KV file
Widget:
    
    Marker:
        pos: 400, 500
    Label:
        pos: 10, 10
        width: root.width - 20
        text_size: self.size
        text: 'Top marker is positioned in KV file. Bottom marker is positioned by python. Center widget in bottom row has the image misalligned.'


<Marker@Widget>:
    puzzle_name: ''

    size: 300, 200
    DebugArea
    Image:
        size: self.texture_size     # !!! Image's size is set to texture_size
        id: the_image
        center_x: root.center_x
        top: root.top
        source: 'puzzle_dot.png'
        DebugArea
    Label:
        size: root.width, 100
        text_size: self.size
        center_x: root.center_x
        y: root.y
        text: 'This marker tries to resize Image to its texture_size. It becomes misalligned when positioned by Python, but not when positioned by KV'
        DebugArea


<DebugArea@Widget>:
    # Draw an X to show where the parent widget is.
    size: self.parent.size
    pos: self.parent.pos
    canvas:
        Color:
            rgba: 1, 0, 1, .3
        Line:
            points: root.x, root.y, root.x + root.width, root.y + root.height
        Line:
            points: root.x, root.y + root.height, root.x + root.width, root.y
        Line:
            rectangle: root.x + 2, root.y + 2, root.width - 4, root.height - 4
    Label:
        color: 1, 0, 1, 0.7
        font_size: 12
        center: root.center
        text: '{root.parent.__class__.__name__}'.format(root=root, pos=root.pos, size=root.size, pos_hint=root.parent.pos_hint, size_hint=root.parent.size_hint)

Screenshot: