It is possible to create a sankey diagram in Adobe LiveCycle Designer, it seems to me that it is very complicated.
I don't see a way to create such diagram with Designer, as it too limited in its graphical elements (rectangles, lines, arcs, circles).
For those kinds of diagrams you would need polygones and Bézier curves.
Your only option is to use a image field to import a pixel image of an already rendered sankey diagram.
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