Shape representation is similar to most vector formats in that shapes are defined by a list of edges called a path. A path may be closed (where the start and end of the path meet to close the figure), or open (where the path forms an open-ended stroke). A path may contain a mixture of straight edges, curved edges, and “pen up and move” commands. The latter allows multiple disconnected figures to be described by a single shape structure.
A fill style defines the appearance of an area enclosed by a path. Fill styles supported by SWF include a solid color or two gradient fills.
A line style defines the appearance of the outline of a path. The line style may be a stroke of any thickness and color.
Most vector formats only allow one fill and line style per path. SWF extends this concept by allowing each edge to have its own line and fill style. This can have unpredictable results when fill styles change in the middle of a path. Flash also supports two fill styles per edge, one for each side of the edge.
Note: This capability is not utilized by the Flash writer and all edges of a polygon or line will have the same line and fill styles.