Specifies sources of entity attributes.
Values:
| IG_VECT_ATTR_SOURCE_ACTUAL | Use an actual value of attribute. Color is defined by its red, green, blue and alpha components, line type and fill type use they default values. |
| IG_VECT_ATTR_SOURCE_NONE | Same as IG_VECT_ATTR_SOURCE_ACTUAL. |
| IG_VECT_ATTR_SOURCE_BLOCK | Use an attribute attached to the current block. |
| IG_VECT_ATTR_SOURCE_LAYER | Use the layer attribute. |
Remarks:
Attribute sources are applicable to draw color, fill color, line type, fill type and thickness.