The easiest would seem to be to place a transparent picture control above
the graph. You can catch mouse events in the picture control, draw your
rectangle and once it's drawn convert the coordinates you got from the
drawing routine into X-Y graph coordinates.
Overlapping transparent controls slow down the panel updates though so if
you're wanting to select an ROI on a continually updating graph it may be
better to put your graph in a picture control as well, rather than using one
of the graph primitives.
Alfred A. Manuel
wrote in message
news:3C14BD48.7A12E65B@physics.unige.ch...
> Is there a way for the user to select a region of interest (ROI) on a
> LabVIEW intensity chart or graph ?
>
> How to select a line or a rectangle us
ing one "click and drag", instead
> having to position two cursors. Such options are avalalible for
> IMAQ-vision displays. What about LabVIEW ?
