Chapter 2 Graphics Tutorial
2-12
Defining Fill Patterns
With a little work, you can construct your own fill patterns. You can generate 8 × 8 dot
patterns using the FPAT (generate Fill PATtern) command, or 16 × 16 dot patterns using
the XPAT (generate eXpanded fill PATtern) command. This section gives examples of
both.
!R! RES;
MZP 1, 1;
FPAT 16, 40, 68, 130, 65, 34, 20, 8;
BLK 1, 1;
PAGE;
EXIT;
Line 4 of this command sequence prints a filled block using a fill pattern defined by the
FPAT command on line 3.
Each of the eight numbers in the FPAT defines one row of an 8
× 8 dot pattern. The pat-
tern follows:
Figure 2. 10. Dot Pattern and a Filled Block
For this pattern, the numbers across the top indicate the value of each column. The num-
bers down the right side are the sums of the values of columns that contain black dots in
that row.
Once this pattern has been defined by the FPAT command, it is used as the fill pattern
until printing system parameters are reset with RES, another pattern is selected with PAT,
a different pattern is defined with FPAT, or a shade of gray is defined and selected by
GPAT.
Now let’s look at an example using the XPAT command.
The XPAT command uses the format
XPAT pattern-number; bit map;
Note that the pattern-number parameter must be a value from 100 to 105 and followed
by a semicolon, not a comma.
The following example demonstrates the XPAT command in a PRESCRIBE command
sequence.
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