Game, set up a convention for managing half-pixels for centering elements

[LeHerosInconnu]

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Describe the problem requiring a solution

I suggest to set up a convention for managing half-pixels for centering elements.

Also for the "half pixel" that can't be separated when an uneven number is used, e.g. 25 pixels divided by two gives 12.5, i.e. 12 pixels on one side and 13 pixels on the other, we should set up a convention so that the non-separable pixel is always added on the right side for a horizontal dimension, i.e. in the example 12 pixels on the left and 13 pixels on the right, and is always added at the bottom for a vertical dimension, i.e. in the example, 12 pixels at the top and 13 pixels at the bottom.

Originally posted by @LeHerosInconnu in #9180 (comment)

Describe the possible solution

For horizontal and vertical centering of elements, text or graphics in a button, button in a window, window in a screen, in short any element in another element, make sure that pixels that cannot be split are added to the right for the horizontal dimension and to the bottom for the vertical dimension.

Additional info

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