SetDrawYGrid — Whether or not to draw the Y grid lines
$plot->SetDrawYGrid($dyg
)
SetDrawYGrid
enables or disables the drawing of the Y
grid lines. (The Y grid lines are the horizontal lines which intersect the
Y axis and are parallel to the X axis.)
The default is to draw the Y grid for vertical plots,
and not draw the Y grid for horizontal plots.
Grid lines are drawn at tick mark positions.
SetLightGridColor sets the color of the grid lines.