HP LaserJet 4100 HP PCL/PJL reference (PCL 5 Printer Language) - Technical Ref - Page 180

Note commands (PA0,1750;PM0), the absolute coordinates (0,1750) specify the first point of your polygon. Each subsequent pair of coordinates defines a point, or vertex, of the polygon. You can define points with the pen up or down. However, the EP command only draws between points that are defined when the pen is down. On the other hand, the FP command fills the area(s) between all vertices, regardless of whether the pen is up or down when defined. It is good programming practice to 'close' the polygon before exiting polygon mode. Closing a polygon means adding the final vertex that defines a continuous shape; the last coordinates or increments represent the same location as the first. If you have not closed the polygon, executing (PM1) or (PM2) forces closure by adding a point to close the polygon. You can also use the Initialize (IN) or Default Values (DF) commands while in polygon mode. Both commands exit polygon mode, clear the polygon buffer, and begin executing subsequent commands immediately. You must exit polygon mode to execute other HP-GL/2 graphics commands. Sending an ?E while in polygon mode causes the printer to exit polygon mode, clear the polygon buffer, exit HP-GL/2 mode, and eject a page. Sending an ?E while in polygon mode is not recommended, but it performs an important function (allowing you to recover from a previous job that left the printer in polygon mode). (PM1) Use (PM1) to close the current polygon (or subpolygon) and remain in polygon mode; the printer adds a closure point if necessary. When you use (PM1), the point after (PM1) becomes the first point of the next subpolygon. This move is not used as a boundary when filling a polygon with FP. When drawing the polygon, the pen always moves to this point in the up position, regardless of the current pen status. Each subsequent coordinate pair after (PM1) defines a point of the subpolygon. 21-36 The Polygon Group EN