| Constant | Value | Description |
| APS_TEXT | 0 | Unit is text coordinates (Row, Col) |
| APS_MILL | 1 | Unit is millimeters (25.4 mm per inch) |
| APS_CENT | 2 | Unit is centimeters (2.54 cent per inch) |
| APS_INCH | 3 | Unit is inchs (1 : 1) |
| APS_PIXEL | 4 | Unit is pixels (device dependant) |
| APS_PICA | 5 | Unit is picas (6 picas per inch) |
| APS_POINT | 6 | Unit is points (72 points per inch) |
| APS_TWIPS | 7 | Unit is twips (1440 twips per inch) |
| APS_CLIP | 8 | Unit is text coordinates (Row, Col) or (Col / Row) but compatible with PageScript for Clipper APS_TEXT unit |