AMT Datasouth 4000 - Manual (Page 54)

User's Guide 54
Example of a Procedure defined in PAL TM
The following procedure is defined in Pal_Procs_and_Formats.txt and illustrates how PAL commands
may be combined in a procedure to create a completely new function or capability. The file
Pal_Procs_and_Formats.txt must be copied to the printer prior to using any of these utilities. The
following utility shows how PAL operators are used to create a simple Box draw procedure. This Box
procedure makes use of another procedure defined called inchtopts. This procedures takes measurements
in inches and converts to points which is the native unit used by PAL. The advantage of using a
procedure like this to draw boxes is to simplify the use of the PAL language. Instead of issuing 7 PAL
commands to draw a box, this single procedure may be called with 5 parameters (lower left corner x,y,
upper right corner x,y, and line width).
%========================================================================
% Box draw procedure
% Usage: botX(in.) botY(in.) topX(in.) topY(in.) lwidth(in.) Box
% Example: 0.1 0.1 3.9 1.9 0.01 Box
%
% (topX, topY)
% +--------*
% | |
% | |
% *--------+
% (botX, botY)
%
%========================================================================
/Box
{
/lwidth exch def
/topY exch def
/topX exch def
/botY exch def
/botX exch def
botX inchtopts botY inchtopts moveto
botX inchtopts topY inchtopts lineto
topX inchtopts topY inchtopts lineto
topX inchtopts botY inchtopts lineto
closepath
lwidth inchtopts setlinewidth
stroke
} bind def
Example of calling a Procedure from a host application
The two lines preceded by % are comment lines ignored by the PAL interpreter and don't actually need to
be transmitted to the printer. The last line shows the actual call to the procedure named Box defined in
Pal_Procs_and_Formats.txt. Note that floating point numbers must have a leading 0 for example 0.1
instead of .1. Also note while the example below uses many spaces between parameters, this is only for
clarity and only a single whitespace character is actually needed i.e. 0.1 0.1 3.9 1.9 0.01 Box would also
work.
% Box draw
% botX(in.) botY(in.) topX(in.) topY(in.) lwidth(in.) Box
0.1 0.1 3.9 1.9 0.01 Box