ZEROLINES command

Syntax: ZEROLINES
Qualifiers: \HORIZONTAL, \VERTICAL
Defaults: both horizontal and vertical lines drawn
Examples: ZEROLINES
ZEROLINES\HORIZONTAL
ZEROLINES\VERTICAL

The ZEROLINES command draws horizontal and/or vertical lines on a graph through (0,0) depending on the qualifier that is used.

qualifierresult
\HORIZONTAL    a line is drawn through (0,0) parallel to the x-axis,
from the left edge to the right edge
\VERTICAL a line is drawn through (0,0) parallel to the y-axis,
from the bottom edge to the top edge

Examples

The following script produces the figure below.

 WINDOW 5
 SCALES -5 5 -5 5
 GRAPH\AXESONLY
 SET CURVECOLOR RED
 ZEROLINES
 WINDOW 7
 SCALES -5 5 -5 5
 GRAPH\AXESONLY
 SET CURVECOLOR RED
 ZEROLINES/HORIZONTAL
 WINDOW 12 25 0 75 50
 SCALES -5 5 -5 5
 GRAPH\AXESONLY
 SET CURVECOLOR RED
 ZEROLINES/VERTICAL