Compute how large should be the graph at each depth
Arguments
- graph
The graph from which nodes positions (x axis) will be calculated.
- df_y
Y coordinates which are useful to simplify the graph.
- root_node
root_node
is the reference to calculate the X coordinates of its children. It is a dataframe with a name and a relative_position columns. If NULL, it appplies the function recursively on each root of the graph.