long overrideDefaultAnnoSize(float size, bool isFixed)
This methods sets the annotation font size for the layer to size. If isFixed is FALSE, size is taken to be millimeters on the map projection. If isFixed is TRUE, size is taken to be pixels on the view. Thus, in the former case, the associated text object will appear larger and larger as the view is zoomed in, whereas in the former case the text object will remain the same size (i.e. a fixed number of pixels) as the view is zoomed.
The size defined via this method will be used during all subsequent calls to doAnnotation for this layer.
This method returns 0 upon success, and returns an error code if size is less than 1.