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PLOTCOORD

 

The PlotCoord function returns the relative position of a plotted point.  The format is

 

PlotCoord(PlotName$,Axis$,V)

 

PlotName$ is the name of the plot that is displayed on the tab at the top of the plot window. This parameter can be a string constant within single quotes or a predefined string variable.

 

Axis$ indicates which axis the value refers to.  Axis$ can be 'X', 'X1', 'X2', 'Y', 'Y1', or 'Y2'.  The 2 refers to the 2nd axis if present.  For example, Y2 refers to the axis on the right of the plot.   This parameter can be a string constant within single quotes or a predefined string variable.

 

V is the value on the specified axis of the specified plot for which the position is returned.

 

The relative position returned by the function is a number which will be between 0 and 1 if the point is within the plot rectangle.  A result of 0 for the X axis indicates that the point is at the left of the plot and 1 indicates it is at the top.  For the Y axis, a value of 0 indicates that the point is at the bottom of the plot and 1 is at the top.  Values less than 0 or greater than 1 indicate that the point is not within the plot rectangle.

 

This function is most useful when used with the AddPlotText macro command so that text may be placed at a specific position on the plot.

 

 

Example:  

{This example will use a macro to display a P-h plot and place a blue 'C' to mark the critical point}

 

$UnitSystem SI K

$RunMacroAfter)

DeletePlot 1

F$='Acetone'

PropPlot F$ PH 6 310 340 380 420 460 510 0 DoQLines

P=P_crit(F$)

h=enthalpy(F$,P=P,x=1)

P$=PlotTabName$(0)

XPos=PlotCoord(P$, 'X', h)

YPos=PlotCoord(P$, 'Y', P)

AddPlotText P$ X=XPos  Y=YPos Text='C' Color=Blue Style=Bold Size=18

$endMacro