Davide, sure no problems.
Basically, whole calculation is made in the last line. Between square brackets, there are two values, which sets anchorpoint: [X,Y]
X – its horizontal placement, where L stands for left point of layer’s source, while W – width of the layer.
Y – is a vertical placement, where T stands for top point of layer’s source, while H – the height of the layer.
With that said, first array item for X (L+ W) is value calculated from left part of the source, added with full width (W). Meaning, it will set anchor point to right, horizontally.
Now if you want it to stay on the left, just keep L alone in the last line of expression ([L ,T+H/2])
T + H/2 in this case stands for middle of the layer (meaning, we take TOP + half of the layer height)
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