- Draw a text string relative to the viewport
Draw a text string on the plot at a position specified relative
to the viewport. The command uses the PGPLOT routine PGMTEXT.
This command is a an ICL hidden procedure which uses the
mtext side xpos ypos justification text
SIDE = _CHAR (Read and Write)
The side of the viewport where the text is to plotted. This
may be one of the following:
"T" - The top edge.
"B" - The bottom edge.
"L" - The left-hand edge.
"R" - The right-hand edge.
"LV" - The left-hand edge, but with the string written
"RV" - The right-hand edge, but with the string written
XPOS = _REAL (Read and Write)
The number of character heights from the viewport where the
text is to be plotted (negative values are allowed). 
YPOS = _REAL (Read and Write)
The fraction along the edge where the text is to be plotted. 
JUSTIFICATION = _REAL (Read and Write)
The justification about the specified point (in the range 0.0
to 1.0). Here, 0.0 means left justify the text relative to
the data point, 1.0 means right justify the text relative to
the data point, 0.5 means centre the string on the data point,
other values will give intermediate justifications. 
TEXT = _CHAR (Read and Write)
The text string to be plotted. This may include any of the
PGPLOT control sequences for producing special characters.