The head factor for shapes like arrows and keyholes. The line factor for these shapes can be modified through the ShapeLineFactor property.
The head factor range is between 1 and 100: if the value exceeds this range, 50 will be assumed; by default the factor 50 is selected.
Applies only when the Shape property is set to SHAPE_ARROW or SHAPE_KEYHOLE
Here the ShapeHeadFactor property is set to 50 (default):
here the ShapeHeadFactor property is set to 90:
here the ShapeHeadFactor property is set to 5:
all of the pictures above have the ShapeLineFactor property set to 50.