What are the rules for non-positive widget positions within an image?

If widget row = 0, Appx will center the widget (vertically) within the image

If widget row < 0 the widget will appear abs(row) rows above the bottom of the image

If widget column = 0, the widget will be centered (horizontally) within the image

If widget column < 0, the widget will appear abs(column) columns to the left of the right edge of the image