mxConstantsSTYLE_PERIMETER_SPACING Field

Defines the key for the perimeter spacing. This is the distance between the connection point and the perimeter in pixels. When used in a vertex style, this applies to all incoming edges to floating ports (edges that terminate on the perimeter of the vertex). When used in an edge style, this spacing applies to the source and target separately, if they terminate in floating ports (on the perimeter of the vertex).

public static string STYLE_PERIMETER_SPACING