16.40.8 <draw:marker> attributes appear incomplete

Change description of 16.40.8 <draw:marker> to: The element <draw:marker> represents a marker, which is used to paint polygons at the start or end point of a stroke depending on whether it is referenced by a draw:marker-start or draw:marker-end attribute. The marker geometry is defined by a svg:d attribute. Note: The marker geometry could be imagined as an arrow whose vertex points upwards. When the marker is painted, its geometry is first mapped to the stroke start or end point as follows: If the marker is referenced by a draw:marker-start attribute, the marker geometry is scaled so that its width equals the width specified by draw:marker-start-width attribute. If the marker is referenced by a draw:marker-end attribute, the marker geometry is scaled so that its width equals the width specified by draw:marker-end-width attribute. The aspect ratio of the geometry is in both cases kept. The geometry then gets horizontally centered. It gets vertically positioned relative to an offset value which is specified by the draw:marker-start-center attribute for markers referenced by a draw:marker-start attribute, and by the draw:marker-end-center attribute for markers referenced by a draw:marker-end attribute. The attribute value true defines an offset of 0.5 and the attribute value false defines an offset of 0.3, which is also the default value. The offset specifies the marker's vertical position in a range from 0.0 to 1.0, where the value 0.0 means the geometry's bottom bound is aligned to the X axis of the local coordinate system of the marker geometry, and where the value 1.0 means the top bound to be aligned to the X axis of the local coordinate system of the marker geometry. If the marker referenced by a draw:marker-start attribute, the marker geometry is then rotated so that the Y axis is aligned to the direction of the stroke in the start/end point direction. It then gets painted to the stroke so that the origin of the coordinate system of the mapped marker geometry is positioned at the start point's position. If the marker is referenced by a draw:marker-end attribute, the marker geometry is then rotated so that the X axis is aligned to the direction of the stroke in the end/start point direction. It then gets painted to the stroke so that the origin of the coordinate system of the mapped marker geometry is positioned at the end point's position. Markers are not available as automatic styles.