title: d3 Sankey assign fixed x,y position
body: <p>I have a sankey diagram in which the user can move and position the nodes freely. I want to save the exact pixel-position selected by the user and use it in the next regeneration of the diagram.</p>
  
  <p>The only way I have managed to approach this until now was to use the "x layer" of the node instead of the exact x-position (not the x-coordinate in pixels but the x-coordinate in layers/levels - 1,2,3 etc...). </p>
  
  <p>Is there a way to use the pixel coordinate instead?</p>