PLOT moves the pen to the specified X and Y position. You may specify when the pen is to be raised or lowered with the optional pen-control value. A two or three column array may be used to supply the coordinate and pen-control values.
If you specify a destination which is outside the clipping area, the logical position is set to that point but the pen is not moved. Only the portion of the vector which lies inside the clipping area is plotted.
The optional pen-control value controls whether the pen is moved up or down and whether the change occurs before or after the move:
Pen-control Value
Affect
zero and positive even
raise after move
positive odd
lowered after move
negative odd
lowered before move
negative even
raised before move
The default pen-control value, one, specifies the pen is lowered after a move.
Array
PLOT uses a two-dimensional two- or three-column array to plot polygons. The array specifies the polygon shape using column one for X coordinates and column two for Y coordinates. The optional third-column specifies the operation (pen-control, AREA PEN, AREA INTENSITY, LINE TYPE, PEN, FILL and EDGE) for each row of the array. If a two-column array is specified, the default operation on each row is one, pen down after move.
The table below shows the meaning of columns 1 and 2 for each of the operations specified in column 3. These operations apply to PLOT, IPLOT, RPLOT and SYMBOL.
Column 1
Column 2
Column 3
Column 3 Meaning
X value
Y value
< -2
use even/odd pen control
X
Y
-2
Pen up before moving
X
Y
-1
Pen down before moving
X
Y
0
Pen up after moving
X
Y
1
Pen down after moving
X
Y
2
Pen up after moving
pen number
---
3
PEN
line type
repeat value
4
LINE TYPE
color
---
5
AREA INTENSITY
---
---
6
Start polygon mode w/FILL
---
---
7
End polygon mode
---
---
8
End of data for array
---
---
9
No operation, values ignored
---
---
10
Start polygon w/EDGE
---
---
11
Start polygon w/FILL & EDGE
---
---
12
Draw a FRAME
pen number
---
13
AREA PEN
red value
green value
14
AREA INTENSITY
blue value
---
15
AREA INTENSITY
---
---
>15
No operation, values ignored
Select AREA R/G/B color
Operation 5 in column 3 selects the AREA INTENSITY color (see COLOR for an explanation of AREA INTENSITY colors). The column one value is divided into red, green and blue numbers, each five bits in length (the sixteenth bit of column one is ignored). Each five-bit number specifies a value in the range zero to sixteen. This number is subtracted from sixteen to calculate the intensity value for each of the colors: red, green, blue. Intensities range in value from zero (darkest) to sixteen (most intense).
For example, if column 1 is set to zero, then each of the three groups in column 1 is set to zero. Sixteen minus zero yields sixteen for all three groups. Sixteen is full intensity, therefore, the area fill color will be white.
The following equation calculates the value for column one given R, G, B values in the range zero to one.
Operations 14 and 15 can also be used to select the AREA INTENSITY red, green and blue values. The range of intensity is zero (no color) to 32,767 (full intensity). Operation 14 should be done before 15 and the operation takes effect when operation 15 is done.
FILL and EDGE
A polygon is formed from a line sequence of 2 or more points with the optional FILL or EDGE specifiers. A polygon is drawn by plotting the first point, each successive point and closed by drawing the final point back to the first point.
If FILL is specified, the polygon is filled with the current AREA fill color and if EDGE is specified, the polygon is edged with the current PEN color. The array pen-control instructions supersede any other instructions on pen movement, LINE TYPE , FILL, and EDGE specifiers.
