These are all the possible values for the IG_ISIS_TAG_EMPHASIS tag.
Values:
| IG_ISIS_EMPHASIS_OFF | No emphasis. |
| IG_ISIS_EMPHASIS_LOW | Low emphasis setting. |
| IG_ISIS_EMPHASIS_MEDIUM | Medium emphasis setting. |
| IG_ISIS_EMPHASIS_HIGH | High emphasis setting. |
| IG_ISIS_EMPHASIS_SMOOTH | Smooth emphasis setting. |