How can I get the value of anypoint from a graph

[Gladbach]

Hi, All

How can I get the value of anypoint of a waveform from a graph, in other words,  how to get the coordinate from a graph.

There is also another problem. How to save the values of a waveform in a graph to a txt file, is there any functions can convert the waveform to data directly.

Thanks.

[RobertoBozzolo]

To interactively obtain the coordinates of a point on a graph plot you must enable cursors on your graph and setup a callback on the control. In the callback you can use GetGraphCursor (panel, control, 1, &x, &y); to obtain X and Y values of the selected point. Take a look at samples\userint\graphcursors.prj example.

To produce a text file from your data, I suggest you use ArrayToFile function: it produces a text file already separated in columns out of a data file. The only hint is that it can manage only one input file: in case you have separate files for your data (time, measure1, measure2...) you must create a dynamic array (NumberOfPoints * NumberOfArrays) long and store your measures in this temporary array one blok after the other: ArrayToFile can be arranged so that it creates an output file of the correct format.

That is: you can produce an array this way:
meas1[0], meas1[1] .... meas1[n], meas2[0], meas2[1] ... meas2[n], meas3[0] .....

and obtain such an output:
meas1[0], meas2[0], meas3[0]
meas1[1], meas2[1], meas3[1]
...
meas1[n], meas2[n], meas3[n]

Message Edited by Roberto Bozzolo on 03-29-2006 08:23 AM

[Gladbach]

Excuse for my English, and thank you very much!

[bilalD]

With CVI 8.0 and higher, you can also use GetGraphCoordsFromPoint() to convert graph pixel coordinates to graph data points. See the help for that function for more information.