Enum which describes the diagram image horizontal alignment.
| Enumerator | 
|---|
| HA_Left | The image is horizontally aligned on left.  | 
| HA_Center | The image is horizontally centered.  | 
| HA_Right | The image is horizontally aligned on right.  | 
| HA_Stretch | The image is horizontally stretched to whole bounding rectangle width.  |