# Units of Measurement

Numbers that are used to specify dimensions in form definitions and page definitions can be in any of five units of measurement. They are specified in a command stream as follows:
IN
Inches
MM
Millimeters
CM
Centimeters
POINTS
Points are a common measurement in printing that are used to measure character height, as in 20-point type. A point is approximately 1/72 inch.
PELS
Equates to L-units. The number of pels per inch is a user-specified parameter. The default is 240 pels per inch.
These measurement units can be used in the SETUNITS command:
LPI
Lines per inch
CPI
Characters per inch
The parameters in PPFA that define a measurement can include any of the first five units of measurement that are shown in the previous list. For example:
``````POSITION  1 IN  1 IN ;
or
POSITION  1 MM  1 MM ;``````
However, PPFA converts all measurements to logical units (L-units) as the common measurement. (Normally, 1 inch equals 240 L-units, but this number can be changed by the user.) If a fraction exists, the first decimal point is truncated. A SETUNITS command defines a unit of measurement that is to be used as the default for any parameter that does not specify a dimension. This default is in effect until another SETUNITS command is encountered. The following example shows part of a PPFA command stream in which a SETUNITS command sets the units of measurement to one inch for a subsequent POSITION (or OFFSET or LINEONE) subcommand.
``````SETUNITS  1 IN 1 IN ;
⋮
POSITION (or OFFSET or LINEONE) 1 1 ;``````
In the following example, SETUNITS can be used as a multiplier. The SETUNITS command sets two-inch x and y default values. The POSITION subcommand values are multiplied by the default values creating a position four inches horizontally and four inches vertically from a given reference point. See SETUNITS Command for a more detailed explanation.
``````SETUNITS 2 IN 2 IN ;
⋮POSITION 2 2 ;``````