The PLOT statement, like the MOVE and DRAW statements, moves the pen to the specified location and optionally specifies when the pen is to be raised or lowered. For example:
PLOT 45,80,-1
first lowers the pen and then moves it to location 45,80. If the optional pen-control value is not specified, the pen is lowered after a move. The pen-control value is interpreted as follows.
Pen Control
Action
positive even #, & zero
pen is raised after a move
positive odd #
pen is lowered after a move
negative even #
pen is raised before a move
negative odd #
pen is lowered before a move
Negative values cause the pen action to occur before the move and positive values cause the pen action to occur after the move. Even numbers cause the pen to be raised, and odd numbers cause the pen to be lowered.
A two or three column numeric array can be used to supply the coordinate and optional pen-control values. If a three-column array is specified, the third-column specifies the pen-control value to use for each row. It can also specify many other operations as covered later in this section. The earlier MOVE/DRAW example could have used the PLOT statement as follows:
10 GINIT
20 DATA 100,100,-1, 100,0,-2, 0,100,-1
30 INTEGER A(2,2)
40 READ A(*)
50 PLOT A(*)
60 END
This example draws the same large X on the screen using the PLOT statement and a three-column data array to specify the coordinates and the pen-control values.
