DefineShape4 extends the capabilities of DefineShape3 by using a new line style record in the
shape. LINESTYLE2 allows new types of joins and caps as well as scaling options and the
ability to fill a stroke.
DefineShape4 specifies not only the shape bounds but also the edge bounds of the shape.
While the shape bounds are calculated along the outside of the strokes, the edge bounds are
taken from the outside of the edges, as shown in the following diagram. The EdgeBounds
field assists Flash Player in accurately determining certain layouts.
In addition, DefineShape4 includes new hinting flags UsesNonScalingStrokes and
UsesScalingStrokes. These flags assist Flash Player in creating the best possible area for
invalidation.