advertisement
Printable Area
The printable area is the area on the paper where the printer can physically print. The origin may be changed using the DECOPM command. If DECOPM is reset, then the origin is at the corner of the printable area. If DECOPM is set, then the origin is near the corner of the physical page.
Unit Conversions and the Origin
Because the origin is at (1,1) and not (0,0), calculations need to take this translation into account. The formula to convert from centipoints to decipoints (and vice versa) is as follows: target = ((source-1)*ratio)+1 where target is the coordinate in the new system, source is the coordinate in the old system, and ratio is the size ratio between the two measurement units.
For example, the coordinate system origin is at (1,1) in pixels, decipoints, or centipoints. For a 300 dpi printer, the next diagonal pixel is at (2,2) in pixel units, but at (25,25) in centipoints. Similarly, a decipoint coordinate of (2,2) is at (11,11) in centipoints.
Positioning and Movement
Active Horizontal Position: This is the horizontal position where printing will occur next. It is updated after each print operation.
Active Vertical Position: This is the vertical position where printing will occur next. It is updated after each print operation.
Horizontal Advance Increment (HAI): This is added to the previous
Active Horizontal Position to determine the next Active Horizontal position at the conclusion of a print operation. The classes of HAI are:
▪ Fixed
▪ Font-dependent
▪ Proportional
Vertical Advance Increment (VAI): This is added to the previous
Active Vertical Position to determine the next Active Vertical position at the conclusion of a print operation. The two classes of VAI are:
▪ Fixed
▪ Font-dependent
GEK-00029B
253
5000 Series Programmer’s Manual
advertisement