http://imagej.273.s1.nabble.com/How-to-Apply-Global-Scale-Value-tp3699164p3699165.html
use ImagePlus.getGlobalCalibration() to get the Calibration object. Use
the methods of Calibration to get the information you want. See
> I sent the message below about a week ago, but because it appeared on a
> weekend, it might not have caught the attention of the folks who might
> be able to answer it. I'm hoping that someone who knows will be able to
> answer this (I fear "painfully basic") question:
>
> I'm modifying (with my very rudimentary java skills) a plugin to report
> the x,y coordinates of points on which one clicks... (the rest of the
> plugin handles numbering and marking points and was kindly provided to
> me by a generous imageJ user in Spain [thank you!]). I've figured out
> how to report the location of a click in pixels and write that to the
> results window, but since the image has been scaled (Analyze > Set Scale
> - global) outside the plugin, I'd also like to report the scaled values,
> since the image information header reports scaled values. However, I've
> not located the function / variable into which the global scale factor
> is stored by the Set Scale dialog... Can someone let me know what this
> variable is and briefly how to apply it? [or point me to the appropriate
> documentation of this variable, which I'm sure is there, but I cannot
> seem to find].
>
> Thanks,
> John
> - - - - -
> John Livesey,
[hidden email] / 01-209-946-2485